Farr High School

HIGHER CHEMISTRY

Unit 2Naturersquos Chemistry

1

Exam Questions

UPDATED APRIL 201821 Esters Fats and Oils

1 What is the structural formula for glycerol

2 An ester has the following structural formula CH3CH2CH2COOCH2CH3The name of this ester isA propyl propanoateB ethyl butanoateC butyl ethanoateD ethyl propanoate

3 Esters are formed by the reaction between which two functional groupsA A hydroxyl group and a carboxyl groupB A hydroxyl group and a carbonyl groupC A hydroxide group and a carboxyl groupD A hydroxide group and a carbonyl group

4 Rum flavouring is based on the compound with the formula shown

It can be made fromA ethanol and butanoic acidB propanol and ethanoic acidC butanol and methanoic acidD propanol and propanoic acid

5 Hydrolysis of an ester gave an alcohol and a carboxylic acid both of which had the samemolecular mass of 60 The structure of the ester was

2

6 Fats have higher melting points than oils because comparing fats and oilsA fats have more hydrogen bondsB fat molecules are more saturatedC fat molecules are more loosely packedD fats have more cross-links between molecules

7 Which of the following reactions takes place during the lsquohardeningrsquo of vegetable oilA AdditionB HydrolysisC DehydrationD Oxidation

8 Fats are formed by the condensation reaction between glycerol molecules and fatty acidmolecules In this reaction the mole ratio of glycerol molecules to fatty acid molecules isA 1 1B 1 2C 1 3D 3 1

9 Oils are generallyA solid at room temperature and contain a high proportion of unsaturated

moleculesB solid at room temperature and contain a high proportion of saturated

moleculesC liquid at room temperature and contain a high proportion of unsaturated

moleculesD liquid at room temperature and contain a high proportion of saturated

molecules

10 Which of the following fatty acids is unsaturatedA C19H39COOHB C21H43COOHC C17H31COOHD C13H27COOH

11 Which of the following alcohols is likely to be obtained on hydrolysis of butter

3

12 Oil molecules are more likely to react with oxygen in the air than fat molecules During the reaction the oil molecules

A are reducedB become rancidC are hydrolysedD become unsaturated

13 Which of the following mixtures will form when NaOH(aq) is added to a mixture of propanol and ethanoic acid

A Propanol and sodium ethanoateB Ethanoic acid and sodium propanoateC Sodium hydroxide and propyl ethanoateD Sodium hydroxide and ethyl propanoate

14 Oils contain carbon to carbon double bonds which can undergo addition reactions with iodine The iodine number of an oil is the mass of iodine in grams that will react with 100 g of oilWhich line in the table shows the oil that is likely to have the lowest melting point

15 When an oil is hydrolysed which of the following molecules is always produced

4

16 The antibiotic erythromycin has the following structure

To remove its bitter taste the erythromycin is reacted to give the compound with the structure shown below

Which of the following types of compound has been reacted with erythromycin to produce this compound

A AlcoholB AldehydeC Carboxylic acidD Ketone

17 vegetable oil rarr vegetable fat

Which of the following reactions brings about the above change

A HydrolysisB CondensationC HydrogenationD Dehydrogenation

18 Which of the following fatty acids is the most unsaturated

A C15H29COOHB C15H31COOHC C17H31COOHD C17H35COOH

19 Which of the following is an isomer of ethyl propanoate (CH3CH2COOCH2CH3)

A Methyl propanoateB Pentan-2-oneC Pentanoic acidD Pentane-12-diol

5

20 Which of the following is a structural formula for glycerol

6

21 One of the chemicals released in a bee sting is an ester that has the structure shown

This ester can be produced by the reaction of an alcohol with an alkanoic acid

(a) Name this acid (1)

(b) The ester can be prepared in the lab by heating a mixture of the reactants with a catalyst

(i) Name the catalyst used in the reaction (1)

(ii) What improvement could be made to the experimental set-up shown in the diagram

(1)

22 Propan-1-ol and propanoic acid react to form an esterThe mixture of excess reactants and ester product is poured onto sodium hydrogencarbonate solution

(a) What evidence would show that an ester is formed (1)

(b) Draw a structural formula for this ester (1)

23 The ester methyl stearate is also a useful vehicle fuel A student prepared this ester from methanol and stearic acid during the Prescribed Practical Activity ldquoMaking EstersrdquoDescribe how this ester was prepared (2)

24 Foodstuffs have labels that list ingredients and provide nutritional information The label on a tub of margarine lists hydrogenated vegetable oils as one of the ingredients Why have some of the vegetable oils in this product been hydrogenated (1)

7

25 A typical triglyceride found in olive oil is shown below

(a) To which family of organic compounds do triglycerides belong (1)

(b) Olive oil can be hardened for use in margarinesWhat happens to the triglyceride molecules during the hardening of olive oil (1)

(c) Give one reason why oils can be a useful part of a balanced diet (1)

26 When vegetable oils are hydrolysed mixtures of fatty acids are obtained The fatty acids can be classified by their degree of unsaturation The table below shows the composition of each of the mixtures of fatty acids obtained when palm oil and olive oil were hydrolysed

(a) Why does palm oil have a higher melting point than olive oil (1)

(b) One of the fatty acids produced by the hydrolysis of palm oil is linoleic acid C17H31COOH To which class (saturated monounsaturated or polyunsaturated) does this fatty acid belong (1)

(c) When a mixture of palm oil and olive oil is hydrolysed using a solution of sodium hydroxide a mixture of the sodium salts of the fatty acids is obtained State a use for these fatty acid salts (1)

8

27

4-hydroxybenzoic acid can react with alcohols to form compounds known asparabens

(a) Name the functional group circled in the structure of 4minushydroxybenzoic acid (1)

(b) Name the type of reaction taking place when parabens are formed (1)

(c) Draw the paraben formed when 4minushydroxybenzoic acid reacts with ethanol (1)

(d) Parabens can be used as preservatives in cosmetics and toiletries Parabens are absorbed into the body through the skin The following table indicates the absorption of some parabens

State a conclusion that can be drawn from the information in the table (1)

9

28 When fats and oils are hydrolysed mixtures of fatty acids are obtained

(a) Name the other product obtained in this reaction (1)

(b)The table below shows the percentage composition of the fatty acid mixtures obtained by hydrolysis of coconut oil and olive oil

(i) One of the fatty acids produced by the hydrolysis of olive oil is linoleic acid C17H31COOHState the class of fatty acid to which linoleic acid belongs (1)

(ii) Hydrolysed coconut oil contains the fatty acid caprylic acid with the formula CH3(CH2)6COOHState the systematic name for caprylic acid (1)

(c) The degree of unsaturation of oil can be tested by adding drops of bromine solution to the oil Bromine adds across carbon to carbon double bonds in the fatty acid chains

The following apparatus can be used to compare the degree ofunsaturation of different oils

10

(i) Describe how this apparatus could be used to show that olive oil has a greater degree of unsaturation than coconut oil (2)

(ii) Suggest why hexane is used as the solvent rather than water (1)

(iii) Coconut oil has a melting point of 25 degC Olive oil has a melting point of minus6C

Give two reasons why coconut oil has a higher melting point than olive oil (2)

29 Traditional nail varnishes use ethyl ethanoate and butyl ethanoate as solvents

(a)Draw a structural formula for butyl ethanoate (1)(b)Ethyl ethanoate can be made in the laboratory using the following apparatus

Suggest why a wet paper towel is wrapped around the test tube (1)

(c) Name the type of reaction that takes place during the formation of ethyl ethanoate (1)

30 Pentyl butanoate is responsible for some of the flavour in apricots and strawberries

(a)Hydrolysis of pentyl butanoate using sodium hydroxide produces an alcohol and the salt of the carboxylic acid

(i) Name the alcohol that would be formed when pentyl butanoate is hydrolysed(1)

(ii) Draw a structural formula for the sodium salt of the carboxylic acid that would be formed (1)

(b)Fats and oils belong to the same class of compounds as pentyl butanoate(i) Name this class of compounds (1)

11

(ii) When a fat is hydrolysed using sodium hydroxide sodium salts of fatty acids are producedState a use for sodium salts of fatty acids (1)

22 Proteins

1 When a protein is denaturedA its overall shape is distortedB its amide links are hydrolysedC it is broken into separate peptide fragmentsD it decomposes into amino acids

2 Which of the following compounds can be classified as proteinsA FatsB OilsC EnzymesD Amino acids

3 The monomer units used to construct enzyme molecules areA alcoholsB estersC amino acidsD fatty acids

4 Amino acids are converted into proteins byA hydrationB hydrolysisC hydrogenationD condensation

5 The arrangement of amino acids in a peptide isZ-X-W-V-Y

where the letters V W X Y and Z represent amino acidsOn partial hydrolysis of the peptide which of the following sets of dipeptides is possibleA V-Y Z-X W-Y X-WB Z-X V-Y W-V X-WC Z-X X-V W-V V-YD X-W X-Z Z-W Y-V

6 Which of the following is an amine

12

7 Which of the following arrangements of atoms shows a peptide link

8 The following molecules are found in herbicides Which of the following contains an amide link

9 In α-amino acids the amino group is on the carbon atom adjacent to the acid group

Which of the following is an α-amino acid

10 A tripeptide X has the structure

Partial hydrolysis of X yields a mixture of dipeptidesWhich of the following dipeptides could be produced on hydrolysing X

13

11 The rate of hydrolysis of protein using an enzyme was studied at different temperatures Which of the following graphs would be obtained

12 The rate of hydrolysis of protein using an enzyme was studied at different temperaturesWhich of the following graphs would be obtained

14

13 Polymers can be classified as natural or synthetic(a) Keratin a natural polymer is a protein found in hair

The hydrolysis of keratin produces different monomers of the type shown

(i) What name is given to monomers like glycine alanine and cysteine (1)(ii) What is meant by a hydrolysis reaction (1)

(b) Dacron a synthetic polymer is used in heart surgery A section of the polymer is shown

What name is given to the link made by the shaded group of atoms in this section of the polymer (1)

14 Chemists have developed cheeses specifically for use in cheeseburgers(a) When ordinary cheddar cheese is grilled the shapes of the protein molecules

change and the proteins and fats separate leaving a chewy solid and an oily liquidWhat name is given to the change in protein structure which occurs when ordinary cheddar is grilled (1)

(b) To make cheese for burgers grated cheddar cheese soluble milk proteins and some water are mixed and heated to no more than 82 degC As the cheese begins to melt an emulsifying agent is added and the mixture is stirred

15

(i) Why would a water bath be used to heat the mixture (1)(ii) A section of the structure of a soluble milk protein is shown below

Draw a structural formula for any one of the amino acids formed when this section of

protein is hydrolysed (1)

(iii) The emulsifier used is trisodium citrate a salt formed when citric acid is neutralised using sodium hydroxide Complete the equation below showing a structural formula for the trisodium citrate formed (1) sp 8

15 Phenylalanine and alanine are both amino acids

(a) Phenylalanine is an essential amino acid

(i) What is meant by an essential amino acid (1)

16

(ii) How many hydrogen atoms are present in a molecule of phenylalanine (1)

(b) Phenylalanine and alanine can react to form the dipeptide shown

Circle the peptide link in this molecule (1)

(c) Draw a structural formula for the other dipeptide that can be formed from phenylalanine and alanine (1)

16 Uncooked egg white is mainly composed of dissolved proteins During cooking processes the proteins become denatured as the protein chains unwind and the egg white solidifies

(a) Explain why the protein chains unwind (1)

(b)The temperature at which the protein becomes denatured is called the melting temperature The melting temperature of a protein can be determined using fluorescence In this technique the protein is mixed with a dye that gives out visible light when it attaches to hydrophobic parts of the protein molecule The hydrophobic parts of the structure are on the inside of the protein and the dye has no access to them unless the protein unwinds

(i) Ovalbumin is a protein found in egg white Part of the structure of unwound ovalbumin is shown below

Circle the part of the structure to which the hydrophobic dye is most likely to attach (1)

17

(ii) Another protein in egg white is conalbumin The temperature of a conalbumindye mixture is gradually increased The fluorescence is measured and a graph is produced

The melting temperature is the temperature at which the fluorescence is halfway between the highest and lowest fluorescence valuesDetermine the melting temperature in ordmC for this protein (1)

(c) Once cooked and eaten the digestive system breaks the protein chains into amino acids with the help of enzymes

(i) State the name of the digestion process where enzymes break down proteins into amino acids (1)

(ii)

(A) State how many amino acid molecules joined to form this section of protein (1)

(B) Draw the structure of one amino acid that would be produced when this section of the protein chain is broken down (1)

17 Peptide molecules can be classified according to the number of amino acid units joined by peptide bonds in the molecule

18

(a) Complete the table to identify the type of peptide with the following amino acid sequence

alanine-glycine-valine-proline-tyrosine-serine (1)

(b) Partial hydrolysis of another pentapeptide molecule gave a mixture of three smaller peptide molecules with the following amino acid sequences

leucine-glycine-valineisoleucine-leucineglycine-valine-serine

Write the amino acid sequence for the original pentapeptide molecule (1)

helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip(c) Some amino acids needed to form polypeptides cannot be produced in the human body

State the term used to describe amino acids that the body cannot make (1)

(d)Paper chromatography is often used to analyse the mixtures of amino acids produced when peptides are broken downOn a chromatogram the retention factor Rf for a substance can be a useful method of identifying the substance

The structure of the pentapeptide methionine enkephalin was investigatedA sample of the pentapeptide was completely hydrolysed into its constituent amino acids and this amino acid mixture was applied to a piece of chromatography paper and placed in a solventThe chromatogram obtained is shown below

19

(i) Suggest why only four spots were obtained on the chromatogram of the hydrolysed pentapeptide (1)

(ii) It is known that this amino acid mixture contains the amino acid methionine The Rf value for methionine in this solvent is 040Draw a circle around the spot on the chromatogram that corresponds to methionine (1)

(e) Over the last decade several families of extremely stable peptide molecules have been discovered where the peptide chain forms a ring

(i) A simple cyclic dipeptide is shown

Draw a structural formula for one of the amino acids that would be formed on complete hydrolysis of the above cyclic dipeptide (1)

(ii) Alpha-amanitin is a highly toxic cyclic peptide found in death cap mushrooms The lethal dose for humans is 100 mg per kg of body mass1middot0 g of death cap mushrooms contains 250 mg of alpha-amanitinCalculate the minimum mass of death cap mushrooms that would contain the lethal dose for a 75 kg adult (2)

18 Dishwasher tablets produce the bleach hydrogen peroxide H2O2 One action of this oxidising agent is to oxidise food

(a)(i) Suggest another action of the bleach produced by the dishwasher tablets (1)

20

(ii) Hydrogen peroxide decomposes to form water and oxygen

2H2O2(ℓ) rarr 2H2O(ℓ) + O2(g)

A dishwasher tablet produces 0middot051 g of hydrogen peroxide (mass of one mole = 34 g)

Calculate the volume of oxygen that would be produced when0middot051 g of hydrogen peroxide decomposesTake the volume of 1 mole of oxygen gas to be 24 litres(3)

(b)Enzymes are commonly added to dishwasher tablets These are used to break down proteins(i) The proteins are broken down into small water-soluble molecules

Name the small water-soluble molecules made when proteins are broken down completely (1)

(ii) The structure of a section of protein chain found in egg white is shown

(A)Name the functional group circled (1)(B)Draw a structural formula for one of the molecules that would be made

when this section of egg white protein chain is completely broken down (1)

(iii) As part of the program in the dishwasher the conditions in the dishwasher change so that the enzyme molecules no longer work because they change shape

21

(A) State the term used to describe the change in shape of enzyme molecules(1)

(B) Suggest a change in conditions which would cause the enzyme molecules to change shape (1)

(d) A bleach activator is frequently added to dishwasher tablets to speed up the bleaching reaction One common bleach activator is TAED TAED could be produced in a process which involves a number of stages

(i) The first stage in producing TAED is shown below

Suggest a name for this type of reaction (1)

(ii) The final stage in the process producing TAED is shown below

Draw a structural formula for TAED (1)

22

23 The Chemistry of Cooking

1 Vanillin and zingerone are flavour molecules

Which line in the table correctly compares the properties of vanillin and zingerone

23

2 Erythrose can be used in the production of a chewing gum that helps prevent tooth decay

Which of the following compounds will be the best solvent for erythrose

3 The following molecules give flavour to food Which of the following flavour molecules would be most likely to be retained in the food when the food is cooked in water

24

4 Cooking involves many chemical reactions Proteins fats oils and esters are some examples of compounds found in food A chemist suggested that cooking food could change compounds from being fat-soluble to water-soluble Use your knowledge of chemistry to comment on the accuracy of this statement(3)

25

24 The Oxidation of Food

1 Apples and bananas turn brown when cut or bruised The first step of the reaction causing

the browning is shown below

Which of the following terms correctly describes this reactionA ReductionB OxidationC DehydrationD Condensation

2 Which of the following reactions can be classified as reductionA CH3CH2OH rarr CH3COOHB CH3 CH(OH)CH3 rarr CH3COCH3C CH3CH2COCH3 rarr CH3CH2CH(OH)CH3D CH3CH2CHO rarr CH3CH2COOH

3 The dehydration of butan-2-ol can produce two isomeric alkenes but-1-ene andbut-2-ene Which of the following alkanols can similarly produce on dehydration a pair of isomeric alkenesA Propan-2-olB Pentan-3-olC Hexan-3-olD Heptan-4-ol

4 Which of the following compounds is an alkanone

26

5 Which of the following is an aldehyde

6 Which of the following compounds would react with sodium hydroxide solution to forma saltA CH3CHOB CH3COOHC CH3COCH3D CH3CH2OH

7 Which line in the table shows the correct functional group for each homologous series

8 Which of the following organic compounds is an isomer of hexanalA 2-MethylbutanalB 3-Methylpentan-2-oneC 22-Dimethylbutan-1-olD 3-Ethylpentanal

27

9 The name of this compound is

A methanolB methanalC methanoic acidD methanone

10 Which alcohol could be oxidised to a carboxylic acid

11 Which of the following structural formulae represents a tertiary alcohol

12 Compound X reacted with hot copper(II) oxide and the organic product did not give acolour change when heated with Fehlingrsquos solution Compound X could beA butan-1-olB butan-2-olC butanoneD butanoic acid

28

13 Which two isomers would each produce an acid when warmed with acidified potassiumdichromate solution

A 1 and 2B 2 and 3C 1 and 4D 3 and 4

14 After heating for several minutes as shown in the diagram the pH indicator solution turned red

Liquid Q could beA propanoneB paraffinC propan-1-olD propan-2-ol

29

15 Enzymes are involved in the browning of cut fruitOne reaction taking place is

Which of the following correctly describes the above reaction

A OxidationB ReductionC HydrolysisD Condensation

16 Which of the following statements is correct for ketones

A They are formed by oxidation of tertiary alcohols

B They contain the group

C They contain a carboxyl groupD They will not react with Fehlingrsquos solution

17 Carvone is a natural product that can be extracted from orange peel

Which line in the table correctly describes the reaction of carvone with bromine solution and with acidified potassium dichromate solution

30

18 Which of the following is an isomer of 22-dimethylpentan-1-ol

A CH3CH2CH2CH(CH3)CH2OHB (CH3)3CCH(CH3)CH2OHC CH3CH2CH2CH2CH2CH2CH2CH2OHD (CH3)2CHC(CH3)2CH2CH2OH

19 The equation for the reduction reaction taking place when ethanal reacts with Tollensrsquo reagent is

A Cu2+(aq) + eminus rarr Cu+(aq)

B Ag+(aq) + eminus rarr Ag(s)

C Cr2O72minus(aq) + 14H+(aq) + 6eminus rarr 2Cr3+(aq) + 7H2O(ℓ)

D MnO4minus(aq) + 8H+(aq) + 5eminus rarr Mn2+(aq) + 4H2O(ℓ)

20 The name of the compound with structure

isA 23-dimethylpentan-4-oneB 23-dimethylpentan-2-alC 34-dimethylpentan-2-oneD 34-dimethylpentan-2-al

21 What is the systematic name for the compound below

A 222-trimethylethanolB 22-dimethylpropan-1-olC 22-dimethylpropan-3-olD 22-dimethylpentan-1-ol

31

22 The structure of a molecule found in olive oil can be represented as shown

(a) Olive oil can be hydrolysed using sodium hydroxide solution to produce sodium salts of fatty acids Name the other product of this reaction (1)

(b) In what way does the structure of a fat molecule differ from that of an oil molecule (1)

(c) Over time open containers of olive oil develop a rancid flavour What substance is reacting with the oil to cause these unwanted changes to take place (1)

23 A student writes the following statement It is incorrect Explain the mistake in the studentrsquos reasoning (1)

Alcohols are alkaline because of their OH groups

24 Carbon compounds take part in a wide variety of chemical reactions (a)

Name this type of chemical reaction (1)

(b)

Draw a structural formula for C3H6O (1)

25 Alkanols can be oxidised to alkanoic acids

32

(a) Why can Step 1 be described as an oxidation reaction (1)

(b) Acidified potassium dichromate solution can be used to oxidise propanal in Step 2 What colour change would be observed in this reaction (1)

26 Amines can be produced by reacting ammonia with an aldehyde or a ketone This reaction an example of reductive amination occurs in two stages

Stage 1 Amination

Stage 2 Reduction

(a) Give another name for the type of reaction taking place in Stage 2

(b) Draw the structural formula for the amine produced when butanal undergoes reductive amination with ammonia

27 Using a cobalt catalyst alkenes react with a mixture of hydrogen and carbon monoxideThe products are two isomeric aldehydes Propene reacts with the mixture as shown

(a) What name is given to a mixture of hydrogen and carbon monoxide (1)

(b) Draw a structural formula for compound B (1)

(c) (i) What would be observed if compound A was gently heated with Tollensrsquo reagent

(1)(ii) How would the reaction mixture be heated (1)

33

(d) Aldehydes can also be formed by the reaction of some alcohols with copper(II) oxideName the type of alcohol that would react with copper(II) oxide to form an aldehyde (1)

28 Aldehydes and ketones can take part in a reaction sometimes known as an aldol condensation The simplest aldol reaction involves two molecules of ethanal

In the reaction the carbon atom next to the carbonyl functional group of one molecule forms a bond with the carbonyl carbon atom of the second molecule

(a) Draw a structural formula for the product formed when propanone is used instead of ethanal in this type of reaction (1)

(b) Name an aldehyde that would not take part in an aldol condensation (1)

(c) Apart from the structure of the reactants suggest what is unusual about applying the term ldquocondensationrdquo to this particular type of reaction (1)

29 Primary secondary and tertiary alkanols can be prepared by the reaction of carbonyl compounds with Grignard reagents

Step 1The Grignard reagent reacts with the carbonyl compound

Step 2The reaction of the product of Step 1 with dilute acid produces the alkanol

(a) Describe the difference between a primary a secondary and a tertiary alkanol

You may wish to include labelled structures in your answer (1)34

(b) Suggest a name for the type of reaction that takes place in Step 1 (1)

(c) The same Grignard reagent can be used to produce the alkanol below

Name the carbonyl compound used in this reaction (1)

30 Hairspray is a mixture of chemicals(a) A primary alcohol 2-methylpropan-1-ol is added to hairspray to help it dry quickly on the hair

Draw a structural formula for a secondary alcohol that is an isomer of2-methylpropan-1-ol (1)

(b) Triethanol amine and triisopropyl amine are bases used to neutralise acidic compounds in the hairspray to prevent damage to the hair

In terms of the intermolecular bonding present explain clearly why triethanol amine has a much higher boiling point than triisopropyl amine (2)

35

36

31 Chocolate contains various compounds(a) Many of the flavour and aroma molecules found in chocolate are aldehydes and

ketones Two examples are shown below

Phenylethanal can be easily oxidised but 13-diphenylpropan-2-one cannot(i) Name a chemical that could be used to distinguish between these two

compounds (1)

(ii) Name the type of organic compound formed when phenylethanal is oxidised (1)

(b) Glycerol monostearate is an emulsifier used in chocolate

(i) Why is glycerol monostearate added to chocolate (1)

(ii) Draw a structural formula for glycerol (1)

(c) Theobromine a compound present in chocolate can cause illness in dogs and cats To decide if treatment is necessary vets must calculate the mass of theobromine consumed 1middot0 g of chocolate contains 1middot4 mg of theobromine Calculate the mass in mg of theobromine in a 17 g biscuit of which 28 is chocolate Show your working clearly (2)

(d) The flavour and texture of chocolate comes from a blend of compoundsUsing your knowledge of chemistry describe how you could show that there are ionic compounds and covalent compounds present in chocolate (3)

37

32 Ethanol has many uses

(a) Ethanol is found at relatively low concentrations in wine

(i) Name the chemical reaction that produces ethanol in wine (1)

(ii) Standard ethanol solutions were used to produce a graph of density against

concentration of ethanol given as a percentage of alcohol by volume ( abv)

What is the concentration of ethanol in units of abv in a solution of density 0middot9818 g cmminus3 (1)

(b) Whisky contains a higher concentration of ethanol

(i) Before 1980 the concentration of alcohol in drinks was measured in terms of degrees proof The concentration of alcohol in two drinks is shown in the table below both as abv and degrees proof

38

A cask strength whisky has an alcohol concentration of 65 abv Calculate the alcohol concentration of this whisky in degrees proof (1)

(ii) A barrel containing 195 litres of cask strength whisky costs pound1300 The cask strength whisky is diluted with water to reduce the concentration of alcohol from 65 abv to 46 abv before it is bottled Calculate the cost of the cask strength whisky needed to produce a 0middot70 litre bottle Show your working clearly (2)

(iii) 5-Butyl-4-methyltetrahydrofuran-2-ol is a flavour compound found in whisky

stored in oak barrels

Write the systematic name for the compound shown below (1) 13 11

33 (a) One test for glucose involves Fehlingrsquos solutionCircle the part of the glucose molecule that reacts with Fehlingrsquos solution (1)

(b) In solution sugar molecules exist in an equilibrium in straight-chain and ring forms

To change from the straight-chain form to the ring form the oxygen of the hydroxyl on carbon number 5 joins to the carbonyl carbon This is shown below for glucose

39

Draw the structure of a ring form for fructose (1)

34 (a) During the free radical chain reaction small molecules join to form large chain molecules

One example of a small molecule used is

Name the functional group circled above (1)

(b)Alcohol wipes are used to finish the varnishing treatment Alcohol wipes contain the alcohol propan-2-olState why propan-2-ol can be described as a secondary alcohol (1)

35 A student was carrying out an investigation into alcohols aldehydes and ketones

(a)The student was given three alcohols labelled as A B and C These alcohols were all isomers with the formula C4H9OH

(i) Draw a structural formula for the secondary alcohol with the formula C4H9OH(1)

(ii) The student set up the following experiment

A Suggest why a water bath is an appropriate method of heating the reaction mixture (1)

B Describe the colour change that would have been observed with alcohols A and C (1)

40

C Alcohol B is not oxidised State the type of alcohol which cannot be oxidised by acidified dichromate solution (1)

(iii) The student set up a second experiment with alcohol A

Hot copper(II) oxide is an oxidising agentA When alcohol A (C4H9OH) is oxidised the product turns the pH paper

redSuggest a name for the product (1)

B Complete the ion-electron equation for the oxidation reaction

C4H9OH rarr C4H8O2 (1)

(b)The student found the following information about the boiling points of some aldehydes

41

(i) Name the aldehyde that has a boiling point of 119 degC (1)(ii) Predict the boiling point in degC of the following molecule (1)

(iii) Using information from the table describe one way in which differences in structure affect the boiling point of isomeric aldehydes (1)

(iv) State what would be observed when an aldehyde is gently heated with Tollensrsquo reagent (1)

(c) Ketones contain a carbonyl groupName the type of intermolecular interaction between ketone molecules (1)

42

25 Soaps Detergents and Emulsions

1 Soaps are produced by the following reaction

This reaction is an example ofA condensationB esterificationC hydrolysisD oxidation

2 Which of the following is the salt of a long-chain fatty acid

A FatB OilC SoapD Glycerol

3 Emulsifiers for use in food are commonly made by reacting edible oils with

A estersB glycerolC fatty acidsD amino acids

4 A fatty acid is a long chain carboxylic acid Examples of fatty acids are shown in the table below

43

(a) What is the systematic name for linolenic acid (1)(b) Stearic acid reacts with sodium hydroxide solution to form sodium stearate

(i) Name the type of reaction taking place when stearic acid reacts with sodium hydroxide (1)

(ii) Explain fully how sodium stearate acts to keep grease and non-polar substances suspended in water during cleaning (3)

5 Small children can find it difficult to swallow tablets or pills so ibuprofen is supplied as an ldquoinfant formulardquo emulsion(a) The emulsifier used is polysorbate 80 Its structure is shown below

Explain why this molecule acts as an emulsifier (2)

(b) The emulsion contains 2 g of ibuprofen in every 100 cm3 of emulsion The recommended dose for treating a 6 month old baby is 0middot050 g Calculate the volume in cm3 of ldquoinfant formulardquo needed to treat a 6 month old baby (1)

6 Occasionally seabirds can become contaminated with hydrocarbons from oil spills This causes problems for birds because their feathers lose their waterproofing making the birds susceptible to temperature changes and

44

affecting their buoyancy If the birds attempt to clean themselves to remove the oil they may swallow the hydrocarbons causing damage to their internal organsContaminated seabirds can be cleaned by rubbing vegetable oil into their feathers and feet before the birds are rinsed with diluted washing-up liquidUsing your knowledge of chemistry comment on the problems created for seabirds by oil spills and the actions taken to treat affected birds (3)

7 Dishwasher tablets contain chemicals which remove dirt from dishesDishwasher tablets include detergents These molecules act like soaps to allow mixing of fat-soluble dirt and water(a)During the cleaning process the detergent molecules combine with fat-

soluble dirtA simplified diagram of a detergent molecule is shown

Complete the diagram below to show how detergent molecules combine with fat-soluble dirt (1)

(b)State the term used to describe the non-polar hydrocarbon tail of a detergent molecule (1)

45

26 Fragrances1 Myrcene is a simple terpene

Terpenes contain at least one isoprene unit Which of the following shows a correctly highlighted isoprene unit

2 Limonene is one of the terpene molecules responsible for the flavour of lemons

How many isoprene units are used in the production of one limonene moleculeA 1B 2C 3D 4

46

3 The structure of caryophyllene which can be extracted from clove oil is

Which of the following would be the best solvent for extracting caryophylleneA HexaneB HexanalC HexanolD Hexanone

4 The structure of isoprene is

Limonene is a terpene molecule present in lemons

How many isoprene units are joined together in a limonene molecule

A 1B 2

47

C 3D 4

5 Essential oils are

A non-water soluble non-volatile compoundsB non-water soluble volatile compoundsC water soluble non-volatile compoundsD water soluble volatile compounds

6 Two typical compounds that are present in many perfumes are shown

(a) Why does geraniol evaporate more slowly than limonene (1)

(b) The structure of one of the first synthetic scents used in perfume is shown below

(i) Name the family of carbonyl compounds to which this synthetic scent belongs (1)

(ii) Complete the structure below to show the product formed when this scent is

oxidised (1)

(c) Traces of a liquid were discovered in a bottle believed to contain perfume belonging to Queen Hatshepsut ruler of Egypt over 3500 years ago

Perfumes were made by dissolving plant extracts containing pleasant smelling terpenes and esters in an edible oil A little ethanol and water may also have been addedUsing your knowledge of chemistry comment on the possible smell(s) when such a bottle is opened after being stored for thousands of years (3)

48

49

7 A team of chemists are developing a fragrance for use in a shower gel for men(a) To give the gel a fruity smell the chemists are considering adding an ester

They synthesise six isomeric esters Volunteers smell each ester and give it a rating out of one hundred depending on how fruity the smell is

(i) Name the ester with the fruit-smell rating of 92 (1)

(ii) Shown below are the structures of three more isomers

Arrange these esters in order of decreasing fruit-smell rating (1)

50

(b) To create a fragrance for men the compound civetone is added

Draw a structural formula for the alcohol that can be oxidised to form civetone (1)

(c) To make the shower gel produce a cold tingling sensation when applied to the skin menthol is added

Like terpenes menthol is formed from isoprene (2-methylbuta-13-diene)Circle an isoprene unit on the menthol structure above (1)

8 Many of the compounds in perfumes are molecules consisting of joined isoprene units

(a) State the name that is given to molecules consisting of joined isoprene units (1)

(b)Geraniol is one of the compounds found in perfume It has the following structural formula and systematic name

Linalool can also be present Its structural formula is shown

51

(i) State the systematic name for linalool (1)(ii) Explain why linalool can be classified as a tertiary alcohol (1)

9 The component molecules found in lavender oils are terpenes or terpenoids(a)A chiral carbon is a carbon atom attached to four different atoms or groups of

atomsAn example is shown below

A molecule of the terpenoid linalool has a chiral carbon Linalool has the following structure

Circle the chiral carbon atom in the linalool structure (1)

(b)Farnesene is a terpene consisting of three isoprene units (2-methylbuta-13-diene) joined togetherWrite the molecular formula of farnesene (1)

52

27 Skin Care

1 Which of the following is not a step in a free radical chain reaction

A ActivationB InitiationC PropagationD Termination

2 Fluorine reacts with methane via a free radical chain reaction Some steps in the chain reaction are shown in the table below

Complete the table by(a) inserting the missing name for the first step (1)

(b) showing another possible termination reaction in the final row of the table (1)

3 Suncreams contain antioxidantsThe antioxidant compound A can prevent damage to skin by reacting with free

radicalssuch as NO2bull

53

Why can compound A be described as a free radical scavenger in the reaction shown above

4 Hydrogen and chlorine gases are used in an experiment to demonstrate a free radical reaction A plastic bottle is wrapped with black tape leaving a ldquowindowrdquo on one sideThe bottle is filled with a mixture of hydrogen and chlorine When bright light shines on the bottle there is an explosion

A free radical chain reaction is initiated when light energy causes chlorine radicals to form as shown below

(a) Complete the equations below showing possible propagation and termination steps

(2)

54

(b) Why is the plastic bottle used in the experiment wrapped in black tape (1)

5 Chloramines can be removed from water using ultraviolet light treatment

One step in the process is the formation of free radicals

(a)State what is meant by the term free radical (1)

(b)Another step in the process is shown below

State the name for this type of step in a free radical reaction (1)

6 Modern shellac nail varnishes are more durable and so last longer than traditional nail polish

The shellac nail varnish is applied in thin layers to the nails and then the fingers are placed under a UV lamp

(a) The Skin Care Foundation has recommended that a sun-block is applied to the fingers and hand before using the lampSuggest why the Skin Care Foundation makes this recommendation (1)

(b) A free radical chain reaction takes place and the varnish hardens (i) State what is meant by the term free radical (1)

(ii) The shellac nail varnish contains a mixture of ingredients that take part in the free radical chain reactionOne of the steps in the free radical chain reaction is

55

State the term used to describe this type of step in a free radical chain reaction(1)

7 Skin care products contain a mixture of polar covalent non-polar covalent and ionic compounds The compounds need to stay mixed within the product Skin care products also need to spread easily and remain on the skin for a period of time as well as provide physical and chemical protection from the sun In order to do this skin care products contain a range of chemicals including water fats and oils antioxidants minerals and sun blockUsing your knowledge of chemistry explain the role of different chemicals in skin care products (3)

General Questions

1 A mixture of carbon monoxide and hydrogen can be converted into water and a mixture of hydrocarbons

nCO + (2n + 1)H2 rarr nH2O + hydrocarbons

What is the general formula for the hydrocarbons producedA CnH2nndash2B CnH2nC CnH2n+1D CnH2n+2

2 Butadiene is the first member of a homologous series of hydrocarbons called dienesWhat is the general formula for this seriesA CnHn+2B CnHn+3C CnH2nD CnH2nndash2

3 Which of the following statements about methanol is falseA It can be made from synthesis gasB It can be dehydrated to form an alkeneC It can be oxidised to give a carboxylic acidD It reacts with acidified potassium dichromate solution

56

4

Which line in the table correctly describes reactions X and Y

5

Which line in the table correctly describes reactions X and Y

6 Which of the following fuels when burned would make no contribution to globalwarming

57

A HydrogenB Natural gasC PetrolD Coal

7 Which of the following hydrocarbons always gives the same product when one of itshydrogen atoms is replaced by a chlorine atomA HexaneB Hex-1-eneC CyclohexaneD Cyclohexene

8 Which of the following compounds does not have isomeric structuresA C2HCl3B C2H4Cl2C PropeneD Propan-1-ol

9 What organic compound is produced by the dehydration of ethanol A EthaneB EtheneC EthanalD Ethanoic acid

10

The above equation representsA hydrationB hydrogenationC condensationD hydrolysis

11

Which of the following compounds is an isomer of the structure shown aboveA ButanalB ButanoneC Butan-1-olD Butanoic acid

58

12 A compound with molecular formula C6H12O2 could beA hexanalB hexan-2-olC hexan-2-oneD hexanoic acid

13 Propan-2-ol can be prepared from propane as follows

Which line in the table correctly describes the types of reaction taking place at Steps 1 and 2

14 Which of the following compounds would be the most water soluble

15 Cyanohydrin compounds can be made from carbonyl compounds by reacting the carbonyl compound with hydrogen cyanide (HCN)

59

Which carbonyl compound would react with hydrogen cyanide (HCN) to form the following compound

16 Ethyne is the first member of the homologous series called the alkynes

Ethyne can undergo addition reactions as shown in the flow diagram

(a) Compound 2 is an isomer of 12-dichloroethaneDraw a structural formula for compound 2 (1)

(b) Reagents A B and C are three different diatomic gasesUsing information in the flow diagram identify reagents A B and C (1)

60

Reagent Gas

A

B

C

17 In 1865 the German chemist Kekuleacute proposed a ring structure for benzene This structure was based on alternating single and double bonds

(a) (i) Describe a chemical test that would indicate that the above chemical structure for benzene is incorrect (1)

(ii) Briefly describe the correct structure for benzene (1)

(b) Benzene can be formed from cyclohexaneC6H12 rarr C6H6 + 3H2

What name is given to this type of reaction (1)18 Infra-red spectroscopy is a technique that can be used to identify the bonds that

arepresent in a molecule Different bonds absorb infra-red radiation of different wavenumbers This is due to differences in the bond lsquostretchrsquo These absorptions are recorded in a spectrumA spectrum for propan-1-ol is shown

61

The correlation table on page 13 of the data booklet shows the wavenumber ranges for the absorptions due to different bonds

(a) Use the correlation table to identify the bonds responsible for the two absorptions x and y that are circled in the propan-1-ol spectrum (1)

(b) Propan-1-ol reacts with ethanoic acid(i) What name is given to this type of reaction (1)(ii) Draw a spectrum that could be obtained for the organic product of this

reaction (1)

19 Paracetamol is a widely used painkiller

(a) Write the molecular formula for paracetamol (1)

(b) One antidote for paracetamol overdose is methionine

62

To what family of organic compounds does methionine belong (1)

(c) The concentration of paracetamol in a solution can be determined by measuring how much UV radiation it absorbs

The graph shows how the absorbance of a sample containing 0middot040 g l ndash1 paracetamol varies with wavelength

The quantity of UV radiation of wavelength 245 nm absorbed is directly proportional to the concentration of paracetamolThe absorbance of a second sample of paracetamol solution measured at 245 nm was 0middot90 What is the concentration in g l ndash1 of this second paracetamol solution (1)

20 Many carbon compounds containing oxygen are very flammableThe table shows information about two families of isomersThe lowest temperature at which a compound will ignite is called its flash point

(a) A compound with the molecular formula C6H14O has a boiling point of 158 degC63

Draw a structural formula for this compound (1)

(b) For a family of isomers in the table write a general statement linking the flash points of the compounds to their structures (1)

21 Hydrogels are used in disposable nappies They are fine powders that can absorb up to 500 times their own weight in waterA hydrogel is a very long molecule with carboxyl groups at regular intervals along its length A short section of a hydrogel molecule is shown below

Hydrogels are extremely good at soaking up water because the water molecules are strongly attracted to them

Using your knowledge of chemistry comment on how suitable hydrogels would be for absorbing liquids or solutions spilled in a chemistry lab (1)

64

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

Exam Questions

UPDATED APRIL 201821 Esters Fats and Oils

1 What is the structural formula for glycerol

2 An ester has the following structural formula CH3CH2CH2COOCH2CH3The name of this ester isA propyl propanoateB ethyl butanoateC butyl ethanoateD ethyl propanoate

3 Esters are formed by the reaction between which two functional groupsA A hydroxyl group and a carboxyl groupB A hydroxyl group and a carbonyl groupC A hydroxide group and a carboxyl groupD A hydroxide group and a carbonyl group

4 Rum flavouring is based on the compound with the formula shown

It can be made fromA ethanol and butanoic acidB propanol and ethanoic acidC butanol and methanoic acidD propanol and propanoic acid

5 Hydrolysis of an ester gave an alcohol and a carboxylic acid both of which had the samemolecular mass of 60 The structure of the ester was

2

6 Fats have higher melting points than oils because comparing fats and oilsA fats have more hydrogen bondsB fat molecules are more saturatedC fat molecules are more loosely packedD fats have more cross-links between molecules

7 Which of the following reactions takes place during the lsquohardeningrsquo of vegetable oilA AdditionB HydrolysisC DehydrationD Oxidation

8 Fats are formed by the condensation reaction between glycerol molecules and fatty acidmolecules In this reaction the mole ratio of glycerol molecules to fatty acid molecules isA 1 1B 1 2C 1 3D 3 1

9 Oils are generallyA solid at room temperature and contain a high proportion of unsaturated

moleculesB solid at room temperature and contain a high proportion of saturated

moleculesC liquid at room temperature and contain a high proportion of unsaturated

moleculesD liquid at room temperature and contain a high proportion of saturated

molecules

10 Which of the following fatty acids is unsaturatedA C19H39COOHB C21H43COOHC C17H31COOHD C13H27COOH

11 Which of the following alcohols is likely to be obtained on hydrolysis of butter

3

12 Oil molecules are more likely to react with oxygen in the air than fat molecules During the reaction the oil molecules

A are reducedB become rancidC are hydrolysedD become unsaturated

13 Which of the following mixtures will form when NaOH(aq) is added to a mixture of propanol and ethanoic acid

A Propanol and sodium ethanoateB Ethanoic acid and sodium propanoateC Sodium hydroxide and propyl ethanoateD Sodium hydroxide and ethyl propanoate

14 Oils contain carbon to carbon double bonds which can undergo addition reactions with iodine The iodine number of an oil is the mass of iodine in grams that will react with 100 g of oilWhich line in the table shows the oil that is likely to have the lowest melting point

15 When an oil is hydrolysed which of the following molecules is always produced

4

16 The antibiotic erythromycin has the following structure

To remove its bitter taste the erythromycin is reacted to give the compound with the structure shown below

Which of the following types of compound has been reacted with erythromycin to produce this compound

A AlcoholB AldehydeC Carboxylic acidD Ketone

17 vegetable oil rarr vegetable fat

Which of the following reactions brings about the above change

A HydrolysisB CondensationC HydrogenationD Dehydrogenation

18 Which of the following fatty acids is the most unsaturated

A C15H29COOHB C15H31COOHC C17H31COOHD C17H35COOH

19 Which of the following is an isomer of ethyl propanoate (CH3CH2COOCH2CH3)

A Methyl propanoateB Pentan-2-oneC Pentanoic acidD Pentane-12-diol

5

20 Which of the following is a structural formula for glycerol

6

21 One of the chemicals released in a bee sting is an ester that has the structure shown

This ester can be produced by the reaction of an alcohol with an alkanoic acid

(a) Name this acid (1)

(b) The ester can be prepared in the lab by heating a mixture of the reactants with a catalyst

(i) Name the catalyst used in the reaction (1)

(ii) What improvement could be made to the experimental set-up shown in the diagram

(1)

22 Propan-1-ol and propanoic acid react to form an esterThe mixture of excess reactants and ester product is poured onto sodium hydrogencarbonate solution

(a) What evidence would show that an ester is formed (1)

(b) Draw a structural formula for this ester (1)

23 The ester methyl stearate is also a useful vehicle fuel A student prepared this ester from methanol and stearic acid during the Prescribed Practical Activity ldquoMaking EstersrdquoDescribe how this ester was prepared (2)

24 Foodstuffs have labels that list ingredients and provide nutritional information The label on a tub of margarine lists hydrogenated vegetable oils as one of the ingredients Why have some of the vegetable oils in this product been hydrogenated (1)

7

25 A typical triglyceride found in olive oil is shown below

(a) To which family of organic compounds do triglycerides belong (1)

(b) Olive oil can be hardened for use in margarinesWhat happens to the triglyceride molecules during the hardening of olive oil (1)

(c) Give one reason why oils can be a useful part of a balanced diet (1)

26 When vegetable oils are hydrolysed mixtures of fatty acids are obtained The fatty acids can be classified by their degree of unsaturation The table below shows the composition of each of the mixtures of fatty acids obtained when palm oil and olive oil were hydrolysed

(a) Why does palm oil have a higher melting point than olive oil (1)

(b) One of the fatty acids produced by the hydrolysis of palm oil is linoleic acid C17H31COOH To which class (saturated monounsaturated or polyunsaturated) does this fatty acid belong (1)

(c) When a mixture of palm oil and olive oil is hydrolysed using a solution of sodium hydroxide a mixture of the sodium salts of the fatty acids is obtained State a use for these fatty acid salts (1)

8

27

4-hydroxybenzoic acid can react with alcohols to form compounds known asparabens

(a) Name the functional group circled in the structure of 4minushydroxybenzoic acid (1)

(b) Name the type of reaction taking place when parabens are formed (1)

(c) Draw the paraben formed when 4minushydroxybenzoic acid reacts with ethanol (1)

(d) Parabens can be used as preservatives in cosmetics and toiletries Parabens are absorbed into the body through the skin The following table indicates the absorption of some parabens

State a conclusion that can be drawn from the information in the table (1)

9

28 When fats and oils are hydrolysed mixtures of fatty acids are obtained

(a) Name the other product obtained in this reaction (1)

(b)The table below shows the percentage composition of the fatty acid mixtures obtained by hydrolysis of coconut oil and olive oil

(i) One of the fatty acids produced by the hydrolysis of olive oil is linoleic acid C17H31COOHState the class of fatty acid to which linoleic acid belongs (1)

(ii) Hydrolysed coconut oil contains the fatty acid caprylic acid with the formula CH3(CH2)6COOHState the systematic name for caprylic acid (1)

(c) The degree of unsaturation of oil can be tested by adding drops of bromine solution to the oil Bromine adds across carbon to carbon double bonds in the fatty acid chains

The following apparatus can be used to compare the degree ofunsaturation of different oils

10

(i) Describe how this apparatus could be used to show that olive oil has a greater degree of unsaturation than coconut oil (2)

(ii) Suggest why hexane is used as the solvent rather than water (1)

(iii) Coconut oil has a melting point of 25 degC Olive oil has a melting point of minus6C

Give two reasons why coconut oil has a higher melting point than olive oil (2)

29 Traditional nail varnishes use ethyl ethanoate and butyl ethanoate as solvents

(a)Draw a structural formula for butyl ethanoate (1)(b)Ethyl ethanoate can be made in the laboratory using the following apparatus

Suggest why a wet paper towel is wrapped around the test tube (1)

(c) Name the type of reaction that takes place during the formation of ethyl ethanoate (1)

30 Pentyl butanoate is responsible for some of the flavour in apricots and strawberries

(a)Hydrolysis of pentyl butanoate using sodium hydroxide produces an alcohol and the salt of the carboxylic acid

(i) Name the alcohol that would be formed when pentyl butanoate is hydrolysed(1)

(ii) Draw a structural formula for the sodium salt of the carboxylic acid that would be formed (1)

(b)Fats and oils belong to the same class of compounds as pentyl butanoate(i) Name this class of compounds (1)

11

(ii) When a fat is hydrolysed using sodium hydroxide sodium salts of fatty acids are producedState a use for sodium salts of fatty acids (1)

22 Proteins

1 When a protein is denaturedA its overall shape is distortedB its amide links are hydrolysedC it is broken into separate peptide fragmentsD it decomposes into amino acids

2 Which of the following compounds can be classified as proteinsA FatsB OilsC EnzymesD Amino acids

3 The monomer units used to construct enzyme molecules areA alcoholsB estersC amino acidsD fatty acids

4 Amino acids are converted into proteins byA hydrationB hydrolysisC hydrogenationD condensation

5 The arrangement of amino acids in a peptide isZ-X-W-V-Y

where the letters V W X Y and Z represent amino acidsOn partial hydrolysis of the peptide which of the following sets of dipeptides is possibleA V-Y Z-X W-Y X-WB Z-X V-Y W-V X-WC Z-X X-V W-V V-YD X-W X-Z Z-W Y-V

6 Which of the following is an amine

12

7 Which of the following arrangements of atoms shows a peptide link

8 The following molecules are found in herbicides Which of the following contains an amide link

9 In α-amino acids the amino group is on the carbon atom adjacent to the acid group

Which of the following is an α-amino acid

10 A tripeptide X has the structure

Partial hydrolysis of X yields a mixture of dipeptidesWhich of the following dipeptides could be produced on hydrolysing X

13

11 The rate of hydrolysis of protein using an enzyme was studied at different temperatures Which of the following graphs would be obtained

12 The rate of hydrolysis of protein using an enzyme was studied at different temperaturesWhich of the following graphs would be obtained

14

13 Polymers can be classified as natural or synthetic(a) Keratin a natural polymer is a protein found in hair

The hydrolysis of keratin produces different monomers of the type shown

(i) What name is given to monomers like glycine alanine and cysteine (1)(ii) What is meant by a hydrolysis reaction (1)

(b) Dacron a synthetic polymer is used in heart surgery A section of the polymer is shown

What name is given to the link made by the shaded group of atoms in this section of the polymer (1)

14 Chemists have developed cheeses specifically for use in cheeseburgers(a) When ordinary cheddar cheese is grilled the shapes of the protein molecules

change and the proteins and fats separate leaving a chewy solid and an oily liquidWhat name is given to the change in protein structure which occurs when ordinary cheddar is grilled (1)

(b) To make cheese for burgers grated cheddar cheese soluble milk proteins and some water are mixed and heated to no more than 82 degC As the cheese begins to melt an emulsifying agent is added and the mixture is stirred

15

(i) Why would a water bath be used to heat the mixture (1)(ii) A section of the structure of a soluble milk protein is shown below

Draw a structural formula for any one of the amino acids formed when this section of

protein is hydrolysed (1)

(iii) The emulsifier used is trisodium citrate a salt formed when citric acid is neutralised using sodium hydroxide Complete the equation below showing a structural formula for the trisodium citrate formed (1) sp 8

15 Phenylalanine and alanine are both amino acids

(a) Phenylalanine is an essential amino acid

(i) What is meant by an essential amino acid (1)

16

(ii) How many hydrogen atoms are present in a molecule of phenylalanine (1)

(b) Phenylalanine and alanine can react to form the dipeptide shown

Circle the peptide link in this molecule (1)

(c) Draw a structural formula for the other dipeptide that can be formed from phenylalanine and alanine (1)

16 Uncooked egg white is mainly composed of dissolved proteins During cooking processes the proteins become denatured as the protein chains unwind and the egg white solidifies

(a) Explain why the protein chains unwind (1)

(b)The temperature at which the protein becomes denatured is called the melting temperature The melting temperature of a protein can be determined using fluorescence In this technique the protein is mixed with a dye that gives out visible light when it attaches to hydrophobic parts of the protein molecule The hydrophobic parts of the structure are on the inside of the protein and the dye has no access to them unless the protein unwinds

(i) Ovalbumin is a protein found in egg white Part of the structure of unwound ovalbumin is shown below

Circle the part of the structure to which the hydrophobic dye is most likely to attach (1)

17

(ii) Another protein in egg white is conalbumin The temperature of a conalbumindye mixture is gradually increased The fluorescence is measured and a graph is produced

The melting temperature is the temperature at which the fluorescence is halfway between the highest and lowest fluorescence valuesDetermine the melting temperature in ordmC for this protein (1)

(c) Once cooked and eaten the digestive system breaks the protein chains into amino acids with the help of enzymes

(i) State the name of the digestion process where enzymes break down proteins into amino acids (1)

(ii)

(A) State how many amino acid molecules joined to form this section of protein (1)

(B) Draw the structure of one amino acid that would be produced when this section of the protein chain is broken down (1)

17 Peptide molecules can be classified according to the number of amino acid units joined by peptide bonds in the molecule

18

(a) Complete the table to identify the type of peptide with the following amino acid sequence

alanine-glycine-valine-proline-tyrosine-serine (1)

(b) Partial hydrolysis of another pentapeptide molecule gave a mixture of three smaller peptide molecules with the following amino acid sequences

leucine-glycine-valineisoleucine-leucineglycine-valine-serine

Write the amino acid sequence for the original pentapeptide molecule (1)

helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip(c) Some amino acids needed to form polypeptides cannot be produced in the human body

State the term used to describe amino acids that the body cannot make (1)

(d)Paper chromatography is often used to analyse the mixtures of amino acids produced when peptides are broken downOn a chromatogram the retention factor Rf for a substance can be a useful method of identifying the substance

The structure of the pentapeptide methionine enkephalin was investigatedA sample of the pentapeptide was completely hydrolysed into its constituent amino acids and this amino acid mixture was applied to a piece of chromatography paper and placed in a solventThe chromatogram obtained is shown below

19

(i) Suggest why only four spots were obtained on the chromatogram of the hydrolysed pentapeptide (1)

(ii) It is known that this amino acid mixture contains the amino acid methionine The Rf value for methionine in this solvent is 040Draw a circle around the spot on the chromatogram that corresponds to methionine (1)

(e) Over the last decade several families of extremely stable peptide molecules have been discovered where the peptide chain forms a ring

(i) A simple cyclic dipeptide is shown

Draw a structural formula for one of the amino acids that would be formed on complete hydrolysis of the above cyclic dipeptide (1)

(ii) Alpha-amanitin is a highly toxic cyclic peptide found in death cap mushrooms The lethal dose for humans is 100 mg per kg of body mass1middot0 g of death cap mushrooms contains 250 mg of alpha-amanitinCalculate the minimum mass of death cap mushrooms that would contain the lethal dose for a 75 kg adult (2)

18 Dishwasher tablets produce the bleach hydrogen peroxide H2O2 One action of this oxidising agent is to oxidise food

(a)(i) Suggest another action of the bleach produced by the dishwasher tablets (1)

20

(ii) Hydrogen peroxide decomposes to form water and oxygen

2H2O2(ℓ) rarr 2H2O(ℓ) + O2(g)

A dishwasher tablet produces 0middot051 g of hydrogen peroxide (mass of one mole = 34 g)

Calculate the volume of oxygen that would be produced when0middot051 g of hydrogen peroxide decomposesTake the volume of 1 mole of oxygen gas to be 24 litres(3)

(b)Enzymes are commonly added to dishwasher tablets These are used to break down proteins(i) The proteins are broken down into small water-soluble molecules

Name the small water-soluble molecules made when proteins are broken down completely (1)

(ii) The structure of a section of protein chain found in egg white is shown

(A)Name the functional group circled (1)(B)Draw a structural formula for one of the molecules that would be made

when this section of egg white protein chain is completely broken down (1)

(iii) As part of the program in the dishwasher the conditions in the dishwasher change so that the enzyme molecules no longer work because they change shape

21

(A) State the term used to describe the change in shape of enzyme molecules(1)

(B) Suggest a change in conditions which would cause the enzyme molecules to change shape (1)

(d) A bleach activator is frequently added to dishwasher tablets to speed up the bleaching reaction One common bleach activator is TAED TAED could be produced in a process which involves a number of stages

(i) The first stage in producing TAED is shown below

Suggest a name for this type of reaction (1)

(ii) The final stage in the process producing TAED is shown below

Draw a structural formula for TAED (1)

22

23 The Chemistry of Cooking

1 Vanillin and zingerone are flavour molecules

Which line in the table correctly compares the properties of vanillin and zingerone

23

2 Erythrose can be used in the production of a chewing gum that helps prevent tooth decay

Which of the following compounds will be the best solvent for erythrose

3 The following molecules give flavour to food Which of the following flavour molecules would be most likely to be retained in the food when the food is cooked in water

24

4 Cooking involves many chemical reactions Proteins fats oils and esters are some examples of compounds found in food A chemist suggested that cooking food could change compounds from being fat-soluble to water-soluble Use your knowledge of chemistry to comment on the accuracy of this statement(3)

25

24 The Oxidation of Food

1 Apples and bananas turn brown when cut or bruised The first step of the reaction causing

the browning is shown below

Which of the following terms correctly describes this reactionA ReductionB OxidationC DehydrationD Condensation

2 Which of the following reactions can be classified as reductionA CH3CH2OH rarr CH3COOHB CH3 CH(OH)CH3 rarr CH3COCH3C CH3CH2COCH3 rarr CH3CH2CH(OH)CH3D CH3CH2CHO rarr CH3CH2COOH

3 The dehydration of butan-2-ol can produce two isomeric alkenes but-1-ene andbut-2-ene Which of the following alkanols can similarly produce on dehydration a pair of isomeric alkenesA Propan-2-olB Pentan-3-olC Hexan-3-olD Heptan-4-ol

4 Which of the following compounds is an alkanone

26

5 Which of the following is an aldehyde

6 Which of the following compounds would react with sodium hydroxide solution to forma saltA CH3CHOB CH3COOHC CH3COCH3D CH3CH2OH

7 Which line in the table shows the correct functional group for each homologous series

8 Which of the following organic compounds is an isomer of hexanalA 2-MethylbutanalB 3-Methylpentan-2-oneC 22-Dimethylbutan-1-olD 3-Ethylpentanal

27

9 The name of this compound is

A methanolB methanalC methanoic acidD methanone

10 Which alcohol could be oxidised to a carboxylic acid

11 Which of the following structural formulae represents a tertiary alcohol

12 Compound X reacted with hot copper(II) oxide and the organic product did not give acolour change when heated with Fehlingrsquos solution Compound X could beA butan-1-olB butan-2-olC butanoneD butanoic acid

28

13 Which two isomers would each produce an acid when warmed with acidified potassiumdichromate solution

A 1 and 2B 2 and 3C 1 and 4D 3 and 4

14 After heating for several minutes as shown in the diagram the pH indicator solution turned red

Liquid Q could beA propanoneB paraffinC propan-1-olD propan-2-ol

29

15 Enzymes are involved in the browning of cut fruitOne reaction taking place is

Which of the following correctly describes the above reaction

A OxidationB ReductionC HydrolysisD Condensation

16 Which of the following statements is correct for ketones

A They are formed by oxidation of tertiary alcohols

B They contain the group

C They contain a carboxyl groupD They will not react with Fehlingrsquos solution

17 Carvone is a natural product that can be extracted from orange peel

Which line in the table correctly describes the reaction of carvone with bromine solution and with acidified potassium dichromate solution

30

18 Which of the following is an isomer of 22-dimethylpentan-1-ol

A CH3CH2CH2CH(CH3)CH2OHB (CH3)3CCH(CH3)CH2OHC CH3CH2CH2CH2CH2CH2CH2CH2OHD (CH3)2CHC(CH3)2CH2CH2OH

19 The equation for the reduction reaction taking place when ethanal reacts with Tollensrsquo reagent is

A Cu2+(aq) + eminus rarr Cu+(aq)

B Ag+(aq) + eminus rarr Ag(s)

C Cr2O72minus(aq) + 14H+(aq) + 6eminus rarr 2Cr3+(aq) + 7H2O(ℓ)

D MnO4minus(aq) + 8H+(aq) + 5eminus rarr Mn2+(aq) + 4H2O(ℓ)

20 The name of the compound with structure

isA 23-dimethylpentan-4-oneB 23-dimethylpentan-2-alC 34-dimethylpentan-2-oneD 34-dimethylpentan-2-al

21 What is the systematic name for the compound below

A 222-trimethylethanolB 22-dimethylpropan-1-olC 22-dimethylpropan-3-olD 22-dimethylpentan-1-ol

31

22 The structure of a molecule found in olive oil can be represented as shown

(a) Olive oil can be hydrolysed using sodium hydroxide solution to produce sodium salts of fatty acids Name the other product of this reaction (1)

(b) In what way does the structure of a fat molecule differ from that of an oil molecule (1)

(c) Over time open containers of olive oil develop a rancid flavour What substance is reacting with the oil to cause these unwanted changes to take place (1)

23 A student writes the following statement It is incorrect Explain the mistake in the studentrsquos reasoning (1)

Alcohols are alkaline because of their OH groups

24 Carbon compounds take part in a wide variety of chemical reactions (a)

Name this type of chemical reaction (1)

(b)

Draw a structural formula for C3H6O (1)

25 Alkanols can be oxidised to alkanoic acids

32

(a) Why can Step 1 be described as an oxidation reaction (1)

(b) Acidified potassium dichromate solution can be used to oxidise propanal in Step 2 What colour change would be observed in this reaction (1)

26 Amines can be produced by reacting ammonia with an aldehyde or a ketone This reaction an example of reductive amination occurs in two stages

Stage 1 Amination

Stage 2 Reduction

(a) Give another name for the type of reaction taking place in Stage 2

(b) Draw the structural formula for the amine produced when butanal undergoes reductive amination with ammonia

27 Using a cobalt catalyst alkenes react with a mixture of hydrogen and carbon monoxideThe products are two isomeric aldehydes Propene reacts with the mixture as shown

(a) What name is given to a mixture of hydrogen and carbon monoxide (1)

(b) Draw a structural formula for compound B (1)

(c) (i) What would be observed if compound A was gently heated with Tollensrsquo reagent

(1)(ii) How would the reaction mixture be heated (1)

33

(d) Aldehydes can also be formed by the reaction of some alcohols with copper(II) oxideName the type of alcohol that would react with copper(II) oxide to form an aldehyde (1)

28 Aldehydes and ketones can take part in a reaction sometimes known as an aldol condensation The simplest aldol reaction involves two molecules of ethanal

In the reaction the carbon atom next to the carbonyl functional group of one molecule forms a bond with the carbonyl carbon atom of the second molecule

(a) Draw a structural formula for the product formed when propanone is used instead of ethanal in this type of reaction (1)

(b) Name an aldehyde that would not take part in an aldol condensation (1)

(c) Apart from the structure of the reactants suggest what is unusual about applying the term ldquocondensationrdquo to this particular type of reaction (1)

29 Primary secondary and tertiary alkanols can be prepared by the reaction of carbonyl compounds with Grignard reagents

Step 1The Grignard reagent reacts with the carbonyl compound

Step 2The reaction of the product of Step 1 with dilute acid produces the alkanol

(a) Describe the difference between a primary a secondary and a tertiary alkanol

You may wish to include labelled structures in your answer (1)34

(b) Suggest a name for the type of reaction that takes place in Step 1 (1)

(c) The same Grignard reagent can be used to produce the alkanol below

Name the carbonyl compound used in this reaction (1)

30 Hairspray is a mixture of chemicals(a) A primary alcohol 2-methylpropan-1-ol is added to hairspray to help it dry quickly on the hair

Draw a structural formula for a secondary alcohol that is an isomer of2-methylpropan-1-ol (1)

(b) Triethanol amine and triisopropyl amine are bases used to neutralise acidic compounds in the hairspray to prevent damage to the hair

In terms of the intermolecular bonding present explain clearly why triethanol amine has a much higher boiling point than triisopropyl amine (2)

35

36

31 Chocolate contains various compounds(a) Many of the flavour and aroma molecules found in chocolate are aldehydes and

ketones Two examples are shown below

Phenylethanal can be easily oxidised but 13-diphenylpropan-2-one cannot(i) Name a chemical that could be used to distinguish between these two

compounds (1)

(ii) Name the type of organic compound formed when phenylethanal is oxidised (1)

(b) Glycerol monostearate is an emulsifier used in chocolate

(i) Why is glycerol monostearate added to chocolate (1)

(ii) Draw a structural formula for glycerol (1)

(c) Theobromine a compound present in chocolate can cause illness in dogs and cats To decide if treatment is necessary vets must calculate the mass of theobromine consumed 1middot0 g of chocolate contains 1middot4 mg of theobromine Calculate the mass in mg of theobromine in a 17 g biscuit of which 28 is chocolate Show your working clearly (2)

(d) The flavour and texture of chocolate comes from a blend of compoundsUsing your knowledge of chemistry describe how you could show that there are ionic compounds and covalent compounds present in chocolate (3)

37

32 Ethanol has many uses

(a) Ethanol is found at relatively low concentrations in wine

(i) Name the chemical reaction that produces ethanol in wine (1)

(ii) Standard ethanol solutions were used to produce a graph of density against

concentration of ethanol given as a percentage of alcohol by volume ( abv)

What is the concentration of ethanol in units of abv in a solution of density 0middot9818 g cmminus3 (1)

(b) Whisky contains a higher concentration of ethanol

(i) Before 1980 the concentration of alcohol in drinks was measured in terms of degrees proof The concentration of alcohol in two drinks is shown in the table below both as abv and degrees proof

38

A cask strength whisky has an alcohol concentration of 65 abv Calculate the alcohol concentration of this whisky in degrees proof (1)

(ii) A barrel containing 195 litres of cask strength whisky costs pound1300 The cask strength whisky is diluted with water to reduce the concentration of alcohol from 65 abv to 46 abv before it is bottled Calculate the cost of the cask strength whisky needed to produce a 0middot70 litre bottle Show your working clearly (2)

(iii) 5-Butyl-4-methyltetrahydrofuran-2-ol is a flavour compound found in whisky

stored in oak barrels

Write the systematic name for the compound shown below (1) 13 11

33 (a) One test for glucose involves Fehlingrsquos solutionCircle the part of the glucose molecule that reacts with Fehlingrsquos solution (1)

(b) In solution sugar molecules exist in an equilibrium in straight-chain and ring forms

To change from the straight-chain form to the ring form the oxygen of the hydroxyl on carbon number 5 joins to the carbonyl carbon This is shown below for glucose

39

Draw the structure of a ring form for fructose (1)

34 (a) During the free radical chain reaction small molecules join to form large chain molecules

One example of a small molecule used is

Name the functional group circled above (1)

(b)Alcohol wipes are used to finish the varnishing treatment Alcohol wipes contain the alcohol propan-2-olState why propan-2-ol can be described as a secondary alcohol (1)

35 A student was carrying out an investigation into alcohols aldehydes and ketones

(a)The student was given three alcohols labelled as A B and C These alcohols were all isomers with the formula C4H9OH

(i) Draw a structural formula for the secondary alcohol with the formula C4H9OH(1)

(ii) The student set up the following experiment

A Suggest why a water bath is an appropriate method of heating the reaction mixture (1)

B Describe the colour change that would have been observed with alcohols A and C (1)

40

C Alcohol B is not oxidised State the type of alcohol which cannot be oxidised by acidified dichromate solution (1)

(iii) The student set up a second experiment with alcohol A

Hot copper(II) oxide is an oxidising agentA When alcohol A (C4H9OH) is oxidised the product turns the pH paper

redSuggest a name for the product (1)

B Complete the ion-electron equation for the oxidation reaction

C4H9OH rarr C4H8O2 (1)

(b)The student found the following information about the boiling points of some aldehydes

41

(i) Name the aldehyde that has a boiling point of 119 degC (1)(ii) Predict the boiling point in degC of the following molecule (1)

(iii) Using information from the table describe one way in which differences in structure affect the boiling point of isomeric aldehydes (1)

(iv) State what would be observed when an aldehyde is gently heated with Tollensrsquo reagent (1)

(c) Ketones contain a carbonyl groupName the type of intermolecular interaction between ketone molecules (1)

42

25 Soaps Detergents and Emulsions

1 Soaps are produced by the following reaction

This reaction is an example ofA condensationB esterificationC hydrolysisD oxidation

2 Which of the following is the salt of a long-chain fatty acid

A FatB OilC SoapD Glycerol

3 Emulsifiers for use in food are commonly made by reacting edible oils with

A estersB glycerolC fatty acidsD amino acids

4 A fatty acid is a long chain carboxylic acid Examples of fatty acids are shown in the table below

43

(a) What is the systematic name for linolenic acid (1)(b) Stearic acid reacts with sodium hydroxide solution to form sodium stearate

(i) Name the type of reaction taking place when stearic acid reacts with sodium hydroxide (1)

(ii) Explain fully how sodium stearate acts to keep grease and non-polar substances suspended in water during cleaning (3)

5 Small children can find it difficult to swallow tablets or pills so ibuprofen is supplied as an ldquoinfant formulardquo emulsion(a) The emulsifier used is polysorbate 80 Its structure is shown below

Explain why this molecule acts as an emulsifier (2)

(b) The emulsion contains 2 g of ibuprofen in every 100 cm3 of emulsion The recommended dose for treating a 6 month old baby is 0middot050 g Calculate the volume in cm3 of ldquoinfant formulardquo needed to treat a 6 month old baby (1)

6 Occasionally seabirds can become contaminated with hydrocarbons from oil spills This causes problems for birds because their feathers lose their waterproofing making the birds susceptible to temperature changes and

44

affecting their buoyancy If the birds attempt to clean themselves to remove the oil they may swallow the hydrocarbons causing damage to their internal organsContaminated seabirds can be cleaned by rubbing vegetable oil into their feathers and feet before the birds are rinsed with diluted washing-up liquidUsing your knowledge of chemistry comment on the problems created for seabirds by oil spills and the actions taken to treat affected birds (3)

7 Dishwasher tablets contain chemicals which remove dirt from dishesDishwasher tablets include detergents These molecules act like soaps to allow mixing of fat-soluble dirt and water(a)During the cleaning process the detergent molecules combine with fat-

soluble dirtA simplified diagram of a detergent molecule is shown

Complete the diagram below to show how detergent molecules combine with fat-soluble dirt (1)

(b)State the term used to describe the non-polar hydrocarbon tail of a detergent molecule (1)

45

26 Fragrances1 Myrcene is a simple terpene

Terpenes contain at least one isoprene unit Which of the following shows a correctly highlighted isoprene unit

2 Limonene is one of the terpene molecules responsible for the flavour of lemons

How many isoprene units are used in the production of one limonene moleculeA 1B 2C 3D 4

46

3 The structure of caryophyllene which can be extracted from clove oil is

Which of the following would be the best solvent for extracting caryophylleneA HexaneB HexanalC HexanolD Hexanone

4 The structure of isoprene is

Limonene is a terpene molecule present in lemons

How many isoprene units are joined together in a limonene molecule

A 1B 2

47

C 3D 4

5 Essential oils are

A non-water soluble non-volatile compoundsB non-water soluble volatile compoundsC water soluble non-volatile compoundsD water soluble volatile compounds

6 Two typical compounds that are present in many perfumes are shown

(a) Why does geraniol evaporate more slowly than limonene (1)

(b) The structure of one of the first synthetic scents used in perfume is shown below

(i) Name the family of carbonyl compounds to which this synthetic scent belongs (1)

(ii) Complete the structure below to show the product formed when this scent is

oxidised (1)

(c) Traces of a liquid were discovered in a bottle believed to contain perfume belonging to Queen Hatshepsut ruler of Egypt over 3500 years ago

Perfumes were made by dissolving plant extracts containing pleasant smelling terpenes and esters in an edible oil A little ethanol and water may also have been addedUsing your knowledge of chemistry comment on the possible smell(s) when such a bottle is opened after being stored for thousands of years (3)

48

49

7 A team of chemists are developing a fragrance for use in a shower gel for men(a) To give the gel a fruity smell the chemists are considering adding an ester

They synthesise six isomeric esters Volunteers smell each ester and give it a rating out of one hundred depending on how fruity the smell is

(i) Name the ester with the fruit-smell rating of 92 (1)

(ii) Shown below are the structures of three more isomers

Arrange these esters in order of decreasing fruit-smell rating (1)

50

(b) To create a fragrance for men the compound civetone is added

Draw a structural formula for the alcohol that can be oxidised to form civetone (1)

(c) To make the shower gel produce a cold tingling sensation when applied to the skin menthol is added

Like terpenes menthol is formed from isoprene (2-methylbuta-13-diene)Circle an isoprene unit on the menthol structure above (1)

8 Many of the compounds in perfumes are molecules consisting of joined isoprene units

(a) State the name that is given to molecules consisting of joined isoprene units (1)

(b)Geraniol is one of the compounds found in perfume It has the following structural formula and systematic name

Linalool can also be present Its structural formula is shown

51

(i) State the systematic name for linalool (1)(ii) Explain why linalool can be classified as a tertiary alcohol (1)

9 The component molecules found in lavender oils are terpenes or terpenoids(a)A chiral carbon is a carbon atom attached to four different atoms or groups of

atomsAn example is shown below

A molecule of the terpenoid linalool has a chiral carbon Linalool has the following structure

Circle the chiral carbon atom in the linalool structure (1)

(b)Farnesene is a terpene consisting of three isoprene units (2-methylbuta-13-diene) joined togetherWrite the molecular formula of farnesene (1)

52

27 Skin Care

1 Which of the following is not a step in a free radical chain reaction

A ActivationB InitiationC PropagationD Termination

2 Fluorine reacts with methane via a free radical chain reaction Some steps in the chain reaction are shown in the table below

Complete the table by(a) inserting the missing name for the first step (1)

(b) showing another possible termination reaction in the final row of the table (1)

3 Suncreams contain antioxidantsThe antioxidant compound A can prevent damage to skin by reacting with free

radicalssuch as NO2bull

53

Why can compound A be described as a free radical scavenger in the reaction shown above

4 Hydrogen and chlorine gases are used in an experiment to demonstrate a free radical reaction A plastic bottle is wrapped with black tape leaving a ldquowindowrdquo on one sideThe bottle is filled with a mixture of hydrogen and chlorine When bright light shines on the bottle there is an explosion

A free radical chain reaction is initiated when light energy causes chlorine radicals to form as shown below

(a) Complete the equations below showing possible propagation and termination steps

(2)

54

(b) Why is the plastic bottle used in the experiment wrapped in black tape (1)

5 Chloramines can be removed from water using ultraviolet light treatment

One step in the process is the formation of free radicals

(a)State what is meant by the term free radical (1)

(b)Another step in the process is shown below

State the name for this type of step in a free radical reaction (1)

6 Modern shellac nail varnishes are more durable and so last longer than traditional nail polish

The shellac nail varnish is applied in thin layers to the nails and then the fingers are placed under a UV lamp

(a) The Skin Care Foundation has recommended that a sun-block is applied to the fingers and hand before using the lampSuggest why the Skin Care Foundation makes this recommendation (1)

(b) A free radical chain reaction takes place and the varnish hardens (i) State what is meant by the term free radical (1)

(ii) The shellac nail varnish contains a mixture of ingredients that take part in the free radical chain reactionOne of the steps in the free radical chain reaction is

55

State the term used to describe this type of step in a free radical chain reaction(1)

7 Skin care products contain a mixture of polar covalent non-polar covalent and ionic compounds The compounds need to stay mixed within the product Skin care products also need to spread easily and remain on the skin for a period of time as well as provide physical and chemical protection from the sun In order to do this skin care products contain a range of chemicals including water fats and oils antioxidants minerals and sun blockUsing your knowledge of chemistry explain the role of different chemicals in skin care products (3)

General Questions

1 A mixture of carbon monoxide and hydrogen can be converted into water and a mixture of hydrocarbons

nCO + (2n + 1)H2 rarr nH2O + hydrocarbons

What is the general formula for the hydrocarbons producedA CnH2nndash2B CnH2nC CnH2n+1D CnH2n+2

2 Butadiene is the first member of a homologous series of hydrocarbons called dienesWhat is the general formula for this seriesA CnHn+2B CnHn+3C CnH2nD CnH2nndash2

3 Which of the following statements about methanol is falseA It can be made from synthesis gasB It can be dehydrated to form an alkeneC It can be oxidised to give a carboxylic acidD It reacts with acidified potassium dichromate solution

56

4

Which line in the table correctly describes reactions X and Y

5

Which line in the table correctly describes reactions X and Y

6 Which of the following fuels when burned would make no contribution to globalwarming

57

A HydrogenB Natural gasC PetrolD Coal

7 Which of the following hydrocarbons always gives the same product when one of itshydrogen atoms is replaced by a chlorine atomA HexaneB Hex-1-eneC CyclohexaneD Cyclohexene

8 Which of the following compounds does not have isomeric structuresA C2HCl3B C2H4Cl2C PropeneD Propan-1-ol

9 What organic compound is produced by the dehydration of ethanol A EthaneB EtheneC EthanalD Ethanoic acid

10

The above equation representsA hydrationB hydrogenationC condensationD hydrolysis

11

Which of the following compounds is an isomer of the structure shown aboveA ButanalB ButanoneC Butan-1-olD Butanoic acid

58

12 A compound with molecular formula C6H12O2 could beA hexanalB hexan-2-olC hexan-2-oneD hexanoic acid

13 Propan-2-ol can be prepared from propane as follows

Which line in the table correctly describes the types of reaction taking place at Steps 1 and 2

14 Which of the following compounds would be the most water soluble

15 Cyanohydrin compounds can be made from carbonyl compounds by reacting the carbonyl compound with hydrogen cyanide (HCN)

59

Which carbonyl compound would react with hydrogen cyanide (HCN) to form the following compound

16 Ethyne is the first member of the homologous series called the alkynes

Ethyne can undergo addition reactions as shown in the flow diagram

(a) Compound 2 is an isomer of 12-dichloroethaneDraw a structural formula for compound 2 (1)

(b) Reagents A B and C are three different diatomic gasesUsing information in the flow diagram identify reagents A B and C (1)

60

Reagent Gas

A

B

C

17 In 1865 the German chemist Kekuleacute proposed a ring structure for benzene This structure was based on alternating single and double bonds

(a) (i) Describe a chemical test that would indicate that the above chemical structure for benzene is incorrect (1)

(ii) Briefly describe the correct structure for benzene (1)

(b) Benzene can be formed from cyclohexaneC6H12 rarr C6H6 + 3H2

What name is given to this type of reaction (1)18 Infra-red spectroscopy is a technique that can be used to identify the bonds that

arepresent in a molecule Different bonds absorb infra-red radiation of different wavenumbers This is due to differences in the bond lsquostretchrsquo These absorptions are recorded in a spectrumA spectrum for propan-1-ol is shown

61

The correlation table on page 13 of the data booklet shows the wavenumber ranges for the absorptions due to different bonds

(a) Use the correlation table to identify the bonds responsible for the two absorptions x and y that are circled in the propan-1-ol spectrum (1)

(b) Propan-1-ol reacts with ethanoic acid(i) What name is given to this type of reaction (1)(ii) Draw a spectrum that could be obtained for the organic product of this

reaction (1)

19 Paracetamol is a widely used painkiller

(a) Write the molecular formula for paracetamol (1)

(b) One antidote for paracetamol overdose is methionine

62

To what family of organic compounds does methionine belong (1)

(c) The concentration of paracetamol in a solution can be determined by measuring how much UV radiation it absorbs

The graph shows how the absorbance of a sample containing 0middot040 g l ndash1 paracetamol varies with wavelength

The quantity of UV radiation of wavelength 245 nm absorbed is directly proportional to the concentration of paracetamolThe absorbance of a second sample of paracetamol solution measured at 245 nm was 0middot90 What is the concentration in g l ndash1 of this second paracetamol solution (1)

20 Many carbon compounds containing oxygen are very flammableThe table shows information about two families of isomersThe lowest temperature at which a compound will ignite is called its flash point

(a) A compound with the molecular formula C6H14O has a boiling point of 158 degC63

Draw a structural formula for this compound (1)

(b) For a family of isomers in the table write a general statement linking the flash points of the compounds to their structures (1)

21 Hydrogels are used in disposable nappies They are fine powders that can absorb up to 500 times their own weight in waterA hydrogel is a very long molecule with carboxyl groups at regular intervals along its length A short section of a hydrogel molecule is shown below

Hydrogels are extremely good at soaking up water because the water molecules are strongly attracted to them

Using your knowledge of chemistry comment on how suitable hydrogels would be for absorbing liquids or solutions spilled in a chemistry lab (1)

64

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

6 Fats have higher melting points than oils because comparing fats and oilsA fats have more hydrogen bondsB fat molecules are more saturatedC fat molecules are more loosely packedD fats have more cross-links between molecules

7 Which of the following reactions takes place during the lsquohardeningrsquo of vegetable oilA AdditionB HydrolysisC DehydrationD Oxidation

8 Fats are formed by the condensation reaction between glycerol molecules and fatty acidmolecules In this reaction the mole ratio of glycerol molecules to fatty acid molecules isA 1 1B 1 2C 1 3D 3 1

9 Oils are generallyA solid at room temperature and contain a high proportion of unsaturated

moleculesB solid at room temperature and contain a high proportion of saturated

moleculesC liquid at room temperature and contain a high proportion of unsaturated

moleculesD liquid at room temperature and contain a high proportion of saturated

molecules

10 Which of the following fatty acids is unsaturatedA C19H39COOHB C21H43COOHC C17H31COOHD C13H27COOH

11 Which of the following alcohols is likely to be obtained on hydrolysis of butter

3

12 Oil molecules are more likely to react with oxygen in the air than fat molecules During the reaction the oil molecules

A are reducedB become rancidC are hydrolysedD become unsaturated

13 Which of the following mixtures will form when NaOH(aq) is added to a mixture of propanol and ethanoic acid

A Propanol and sodium ethanoateB Ethanoic acid and sodium propanoateC Sodium hydroxide and propyl ethanoateD Sodium hydroxide and ethyl propanoate

14 Oils contain carbon to carbon double bonds which can undergo addition reactions with iodine The iodine number of an oil is the mass of iodine in grams that will react with 100 g of oilWhich line in the table shows the oil that is likely to have the lowest melting point

15 When an oil is hydrolysed which of the following molecules is always produced

4

16 The antibiotic erythromycin has the following structure

To remove its bitter taste the erythromycin is reacted to give the compound with the structure shown below

Which of the following types of compound has been reacted with erythromycin to produce this compound

A AlcoholB AldehydeC Carboxylic acidD Ketone

17 vegetable oil rarr vegetable fat

Which of the following reactions brings about the above change

A HydrolysisB CondensationC HydrogenationD Dehydrogenation

18 Which of the following fatty acids is the most unsaturated

A C15H29COOHB C15H31COOHC C17H31COOHD C17H35COOH

19 Which of the following is an isomer of ethyl propanoate (CH3CH2COOCH2CH3)

A Methyl propanoateB Pentan-2-oneC Pentanoic acidD Pentane-12-diol

5

20 Which of the following is a structural formula for glycerol

6

21 One of the chemicals released in a bee sting is an ester that has the structure shown

This ester can be produced by the reaction of an alcohol with an alkanoic acid

(a) Name this acid (1)

(b) The ester can be prepared in the lab by heating a mixture of the reactants with a catalyst

(i) Name the catalyst used in the reaction (1)

(ii) What improvement could be made to the experimental set-up shown in the diagram

(1)

22 Propan-1-ol and propanoic acid react to form an esterThe mixture of excess reactants and ester product is poured onto sodium hydrogencarbonate solution

(a) What evidence would show that an ester is formed (1)

(b) Draw a structural formula for this ester (1)

23 The ester methyl stearate is also a useful vehicle fuel A student prepared this ester from methanol and stearic acid during the Prescribed Practical Activity ldquoMaking EstersrdquoDescribe how this ester was prepared (2)

24 Foodstuffs have labels that list ingredients and provide nutritional information The label on a tub of margarine lists hydrogenated vegetable oils as one of the ingredients Why have some of the vegetable oils in this product been hydrogenated (1)

7

25 A typical triglyceride found in olive oil is shown below

(a) To which family of organic compounds do triglycerides belong (1)

(b) Olive oil can be hardened for use in margarinesWhat happens to the triglyceride molecules during the hardening of olive oil (1)

(c) Give one reason why oils can be a useful part of a balanced diet (1)

26 When vegetable oils are hydrolysed mixtures of fatty acids are obtained The fatty acids can be classified by their degree of unsaturation The table below shows the composition of each of the mixtures of fatty acids obtained when palm oil and olive oil were hydrolysed

(a) Why does palm oil have a higher melting point than olive oil (1)

(b) One of the fatty acids produced by the hydrolysis of palm oil is linoleic acid C17H31COOH To which class (saturated monounsaturated or polyunsaturated) does this fatty acid belong (1)

(c) When a mixture of palm oil and olive oil is hydrolysed using a solution of sodium hydroxide a mixture of the sodium salts of the fatty acids is obtained State a use for these fatty acid salts (1)

8

27

4-hydroxybenzoic acid can react with alcohols to form compounds known asparabens

(a) Name the functional group circled in the structure of 4minushydroxybenzoic acid (1)

(b) Name the type of reaction taking place when parabens are formed (1)

(c) Draw the paraben formed when 4minushydroxybenzoic acid reacts with ethanol (1)

(d) Parabens can be used as preservatives in cosmetics and toiletries Parabens are absorbed into the body through the skin The following table indicates the absorption of some parabens

State a conclusion that can be drawn from the information in the table (1)

9

28 When fats and oils are hydrolysed mixtures of fatty acids are obtained

(a) Name the other product obtained in this reaction (1)

(b)The table below shows the percentage composition of the fatty acid mixtures obtained by hydrolysis of coconut oil and olive oil

(i) One of the fatty acids produced by the hydrolysis of olive oil is linoleic acid C17H31COOHState the class of fatty acid to which linoleic acid belongs (1)

(ii) Hydrolysed coconut oil contains the fatty acid caprylic acid with the formula CH3(CH2)6COOHState the systematic name for caprylic acid (1)

(c) The degree of unsaturation of oil can be tested by adding drops of bromine solution to the oil Bromine adds across carbon to carbon double bonds in the fatty acid chains

The following apparatus can be used to compare the degree ofunsaturation of different oils

10

(i) Describe how this apparatus could be used to show that olive oil has a greater degree of unsaturation than coconut oil (2)

(ii) Suggest why hexane is used as the solvent rather than water (1)

(iii) Coconut oil has a melting point of 25 degC Olive oil has a melting point of minus6C

Give two reasons why coconut oil has a higher melting point than olive oil (2)

29 Traditional nail varnishes use ethyl ethanoate and butyl ethanoate as solvents

(a)Draw a structural formula for butyl ethanoate (1)(b)Ethyl ethanoate can be made in the laboratory using the following apparatus

Suggest why a wet paper towel is wrapped around the test tube (1)

(c) Name the type of reaction that takes place during the formation of ethyl ethanoate (1)

30 Pentyl butanoate is responsible for some of the flavour in apricots and strawberries

(a)Hydrolysis of pentyl butanoate using sodium hydroxide produces an alcohol and the salt of the carboxylic acid

(i) Name the alcohol that would be formed when pentyl butanoate is hydrolysed(1)

(ii) Draw a structural formula for the sodium salt of the carboxylic acid that would be formed (1)

(b)Fats and oils belong to the same class of compounds as pentyl butanoate(i) Name this class of compounds (1)

11

(ii) When a fat is hydrolysed using sodium hydroxide sodium salts of fatty acids are producedState a use for sodium salts of fatty acids (1)

22 Proteins

1 When a protein is denaturedA its overall shape is distortedB its amide links are hydrolysedC it is broken into separate peptide fragmentsD it decomposes into amino acids

2 Which of the following compounds can be classified as proteinsA FatsB OilsC EnzymesD Amino acids

3 The monomer units used to construct enzyme molecules areA alcoholsB estersC amino acidsD fatty acids

4 Amino acids are converted into proteins byA hydrationB hydrolysisC hydrogenationD condensation

5 The arrangement of amino acids in a peptide isZ-X-W-V-Y

where the letters V W X Y and Z represent amino acidsOn partial hydrolysis of the peptide which of the following sets of dipeptides is possibleA V-Y Z-X W-Y X-WB Z-X V-Y W-V X-WC Z-X X-V W-V V-YD X-W X-Z Z-W Y-V

6 Which of the following is an amine

12

7 Which of the following arrangements of atoms shows a peptide link

8 The following molecules are found in herbicides Which of the following contains an amide link

9 In α-amino acids the amino group is on the carbon atom adjacent to the acid group

Which of the following is an α-amino acid

10 A tripeptide X has the structure

Partial hydrolysis of X yields a mixture of dipeptidesWhich of the following dipeptides could be produced on hydrolysing X

13

11 The rate of hydrolysis of protein using an enzyme was studied at different temperatures Which of the following graphs would be obtained

12 The rate of hydrolysis of protein using an enzyme was studied at different temperaturesWhich of the following graphs would be obtained

14

13 Polymers can be classified as natural or synthetic(a) Keratin a natural polymer is a protein found in hair

The hydrolysis of keratin produces different monomers of the type shown

(i) What name is given to monomers like glycine alanine and cysteine (1)(ii) What is meant by a hydrolysis reaction (1)

(b) Dacron a synthetic polymer is used in heart surgery A section of the polymer is shown

What name is given to the link made by the shaded group of atoms in this section of the polymer (1)

14 Chemists have developed cheeses specifically for use in cheeseburgers(a) When ordinary cheddar cheese is grilled the shapes of the protein molecules

change and the proteins and fats separate leaving a chewy solid and an oily liquidWhat name is given to the change in protein structure which occurs when ordinary cheddar is grilled (1)

(b) To make cheese for burgers grated cheddar cheese soluble milk proteins and some water are mixed and heated to no more than 82 degC As the cheese begins to melt an emulsifying agent is added and the mixture is stirred

15

(i) Why would a water bath be used to heat the mixture (1)(ii) A section of the structure of a soluble milk protein is shown below

Draw a structural formula for any one of the amino acids formed when this section of

protein is hydrolysed (1)

(iii) The emulsifier used is trisodium citrate a salt formed when citric acid is neutralised using sodium hydroxide Complete the equation below showing a structural formula for the trisodium citrate formed (1) sp 8

15 Phenylalanine and alanine are both amino acids

(a) Phenylalanine is an essential amino acid

(i) What is meant by an essential amino acid (1)

16

(ii) How many hydrogen atoms are present in a molecule of phenylalanine (1)

(b) Phenylalanine and alanine can react to form the dipeptide shown

Circle the peptide link in this molecule (1)

(c) Draw a structural formula for the other dipeptide that can be formed from phenylalanine and alanine (1)

16 Uncooked egg white is mainly composed of dissolved proteins During cooking processes the proteins become denatured as the protein chains unwind and the egg white solidifies

(a) Explain why the protein chains unwind (1)

(b)The temperature at which the protein becomes denatured is called the melting temperature The melting temperature of a protein can be determined using fluorescence In this technique the protein is mixed with a dye that gives out visible light when it attaches to hydrophobic parts of the protein molecule The hydrophobic parts of the structure are on the inside of the protein and the dye has no access to them unless the protein unwinds

(i) Ovalbumin is a protein found in egg white Part of the structure of unwound ovalbumin is shown below

Circle the part of the structure to which the hydrophobic dye is most likely to attach (1)

17

(ii) Another protein in egg white is conalbumin The temperature of a conalbumindye mixture is gradually increased The fluorescence is measured and a graph is produced

The melting temperature is the temperature at which the fluorescence is halfway between the highest and lowest fluorescence valuesDetermine the melting temperature in ordmC for this protein (1)

(c) Once cooked and eaten the digestive system breaks the protein chains into amino acids with the help of enzymes

(i) State the name of the digestion process where enzymes break down proteins into amino acids (1)

(ii)

(A) State how many amino acid molecules joined to form this section of protein (1)

(B) Draw the structure of one amino acid that would be produced when this section of the protein chain is broken down (1)

17 Peptide molecules can be classified according to the number of amino acid units joined by peptide bonds in the molecule

18

(a) Complete the table to identify the type of peptide with the following amino acid sequence

alanine-glycine-valine-proline-tyrosine-serine (1)

(b) Partial hydrolysis of another pentapeptide molecule gave a mixture of three smaller peptide molecules with the following amino acid sequences

leucine-glycine-valineisoleucine-leucineglycine-valine-serine

Write the amino acid sequence for the original pentapeptide molecule (1)

helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip(c) Some amino acids needed to form polypeptides cannot be produced in the human body

State the term used to describe amino acids that the body cannot make (1)

(d)Paper chromatography is often used to analyse the mixtures of amino acids produced when peptides are broken downOn a chromatogram the retention factor Rf for a substance can be a useful method of identifying the substance

The structure of the pentapeptide methionine enkephalin was investigatedA sample of the pentapeptide was completely hydrolysed into its constituent amino acids and this amino acid mixture was applied to a piece of chromatography paper and placed in a solventThe chromatogram obtained is shown below

19

(i) Suggest why only four spots were obtained on the chromatogram of the hydrolysed pentapeptide (1)

(ii) It is known that this amino acid mixture contains the amino acid methionine The Rf value for methionine in this solvent is 040Draw a circle around the spot on the chromatogram that corresponds to methionine (1)

(e) Over the last decade several families of extremely stable peptide molecules have been discovered where the peptide chain forms a ring

(i) A simple cyclic dipeptide is shown

Draw a structural formula for one of the amino acids that would be formed on complete hydrolysis of the above cyclic dipeptide (1)

(ii) Alpha-amanitin is a highly toxic cyclic peptide found in death cap mushrooms The lethal dose for humans is 100 mg per kg of body mass1middot0 g of death cap mushrooms contains 250 mg of alpha-amanitinCalculate the minimum mass of death cap mushrooms that would contain the lethal dose for a 75 kg adult (2)

18 Dishwasher tablets produce the bleach hydrogen peroxide H2O2 One action of this oxidising agent is to oxidise food

(a)(i) Suggest another action of the bleach produced by the dishwasher tablets (1)

20

(ii) Hydrogen peroxide decomposes to form water and oxygen

2H2O2(ℓ) rarr 2H2O(ℓ) + O2(g)

A dishwasher tablet produces 0middot051 g of hydrogen peroxide (mass of one mole = 34 g)

Calculate the volume of oxygen that would be produced when0middot051 g of hydrogen peroxide decomposesTake the volume of 1 mole of oxygen gas to be 24 litres(3)

(b)Enzymes are commonly added to dishwasher tablets These are used to break down proteins(i) The proteins are broken down into small water-soluble molecules

Name the small water-soluble molecules made when proteins are broken down completely (1)

(ii) The structure of a section of protein chain found in egg white is shown

(A)Name the functional group circled (1)(B)Draw a structural formula for one of the molecules that would be made

when this section of egg white protein chain is completely broken down (1)

(iii) As part of the program in the dishwasher the conditions in the dishwasher change so that the enzyme molecules no longer work because they change shape

21

(A) State the term used to describe the change in shape of enzyme molecules(1)

(B) Suggest a change in conditions which would cause the enzyme molecules to change shape (1)

(d) A bleach activator is frequently added to dishwasher tablets to speed up the bleaching reaction One common bleach activator is TAED TAED could be produced in a process which involves a number of stages

(i) The first stage in producing TAED is shown below

Suggest a name for this type of reaction (1)

(ii) The final stage in the process producing TAED is shown below

Draw a structural formula for TAED (1)

22

23 The Chemistry of Cooking

1 Vanillin and zingerone are flavour molecules

Which line in the table correctly compares the properties of vanillin and zingerone

23

2 Erythrose can be used in the production of a chewing gum that helps prevent tooth decay

Which of the following compounds will be the best solvent for erythrose

3 The following molecules give flavour to food Which of the following flavour molecules would be most likely to be retained in the food when the food is cooked in water

24

4 Cooking involves many chemical reactions Proteins fats oils and esters are some examples of compounds found in food A chemist suggested that cooking food could change compounds from being fat-soluble to water-soluble Use your knowledge of chemistry to comment on the accuracy of this statement(3)

25

24 The Oxidation of Food

1 Apples and bananas turn brown when cut or bruised The first step of the reaction causing

the browning is shown below

Which of the following terms correctly describes this reactionA ReductionB OxidationC DehydrationD Condensation

2 Which of the following reactions can be classified as reductionA CH3CH2OH rarr CH3COOHB CH3 CH(OH)CH3 rarr CH3COCH3C CH3CH2COCH3 rarr CH3CH2CH(OH)CH3D CH3CH2CHO rarr CH3CH2COOH

3 The dehydration of butan-2-ol can produce two isomeric alkenes but-1-ene andbut-2-ene Which of the following alkanols can similarly produce on dehydration a pair of isomeric alkenesA Propan-2-olB Pentan-3-olC Hexan-3-olD Heptan-4-ol

4 Which of the following compounds is an alkanone

26

5 Which of the following is an aldehyde

6 Which of the following compounds would react with sodium hydroxide solution to forma saltA CH3CHOB CH3COOHC CH3COCH3D CH3CH2OH

7 Which line in the table shows the correct functional group for each homologous series

8 Which of the following organic compounds is an isomer of hexanalA 2-MethylbutanalB 3-Methylpentan-2-oneC 22-Dimethylbutan-1-olD 3-Ethylpentanal

27

9 The name of this compound is

A methanolB methanalC methanoic acidD methanone

10 Which alcohol could be oxidised to a carboxylic acid

11 Which of the following structural formulae represents a tertiary alcohol

12 Compound X reacted with hot copper(II) oxide and the organic product did not give acolour change when heated with Fehlingrsquos solution Compound X could beA butan-1-olB butan-2-olC butanoneD butanoic acid

28

13 Which two isomers would each produce an acid when warmed with acidified potassiumdichromate solution

A 1 and 2B 2 and 3C 1 and 4D 3 and 4

14 After heating for several minutes as shown in the diagram the pH indicator solution turned red

Liquid Q could beA propanoneB paraffinC propan-1-olD propan-2-ol

29

15 Enzymes are involved in the browning of cut fruitOne reaction taking place is

Which of the following correctly describes the above reaction

A OxidationB ReductionC HydrolysisD Condensation

16 Which of the following statements is correct for ketones

A They are formed by oxidation of tertiary alcohols

B They contain the group

C They contain a carboxyl groupD They will not react with Fehlingrsquos solution

17 Carvone is a natural product that can be extracted from orange peel

Which line in the table correctly describes the reaction of carvone with bromine solution and with acidified potassium dichromate solution

30

18 Which of the following is an isomer of 22-dimethylpentan-1-ol

A CH3CH2CH2CH(CH3)CH2OHB (CH3)3CCH(CH3)CH2OHC CH3CH2CH2CH2CH2CH2CH2CH2OHD (CH3)2CHC(CH3)2CH2CH2OH

19 The equation for the reduction reaction taking place when ethanal reacts with Tollensrsquo reagent is

A Cu2+(aq) + eminus rarr Cu+(aq)

B Ag+(aq) + eminus rarr Ag(s)

C Cr2O72minus(aq) + 14H+(aq) + 6eminus rarr 2Cr3+(aq) + 7H2O(ℓ)

D MnO4minus(aq) + 8H+(aq) + 5eminus rarr Mn2+(aq) + 4H2O(ℓ)

20 The name of the compound with structure

isA 23-dimethylpentan-4-oneB 23-dimethylpentan-2-alC 34-dimethylpentan-2-oneD 34-dimethylpentan-2-al

21 What is the systematic name for the compound below

A 222-trimethylethanolB 22-dimethylpropan-1-olC 22-dimethylpropan-3-olD 22-dimethylpentan-1-ol

31

22 The structure of a molecule found in olive oil can be represented as shown

(a) Olive oil can be hydrolysed using sodium hydroxide solution to produce sodium salts of fatty acids Name the other product of this reaction (1)

(b) In what way does the structure of a fat molecule differ from that of an oil molecule (1)

(c) Over time open containers of olive oil develop a rancid flavour What substance is reacting with the oil to cause these unwanted changes to take place (1)

23 A student writes the following statement It is incorrect Explain the mistake in the studentrsquos reasoning (1)

Alcohols are alkaline because of their OH groups

24 Carbon compounds take part in a wide variety of chemical reactions (a)

Name this type of chemical reaction (1)

(b)

Draw a structural formula for C3H6O (1)

25 Alkanols can be oxidised to alkanoic acids

32

(a) Why can Step 1 be described as an oxidation reaction (1)

(b) Acidified potassium dichromate solution can be used to oxidise propanal in Step 2 What colour change would be observed in this reaction (1)

26 Amines can be produced by reacting ammonia with an aldehyde or a ketone This reaction an example of reductive amination occurs in two stages

Stage 1 Amination

Stage 2 Reduction

(a) Give another name for the type of reaction taking place in Stage 2

(b) Draw the structural formula for the amine produced when butanal undergoes reductive amination with ammonia

27 Using a cobalt catalyst alkenes react with a mixture of hydrogen and carbon monoxideThe products are two isomeric aldehydes Propene reacts with the mixture as shown

(a) What name is given to a mixture of hydrogen and carbon monoxide (1)

(b) Draw a structural formula for compound B (1)

(c) (i) What would be observed if compound A was gently heated with Tollensrsquo reagent

(1)(ii) How would the reaction mixture be heated (1)

33

(d) Aldehydes can also be formed by the reaction of some alcohols with copper(II) oxideName the type of alcohol that would react with copper(II) oxide to form an aldehyde (1)

28 Aldehydes and ketones can take part in a reaction sometimes known as an aldol condensation The simplest aldol reaction involves two molecules of ethanal

In the reaction the carbon atom next to the carbonyl functional group of one molecule forms a bond with the carbonyl carbon atom of the second molecule

(a) Draw a structural formula for the product formed when propanone is used instead of ethanal in this type of reaction (1)

(b) Name an aldehyde that would not take part in an aldol condensation (1)

(c) Apart from the structure of the reactants suggest what is unusual about applying the term ldquocondensationrdquo to this particular type of reaction (1)

29 Primary secondary and tertiary alkanols can be prepared by the reaction of carbonyl compounds with Grignard reagents

Step 1The Grignard reagent reacts with the carbonyl compound

Step 2The reaction of the product of Step 1 with dilute acid produces the alkanol

(a) Describe the difference between a primary a secondary and a tertiary alkanol

You may wish to include labelled structures in your answer (1)34

(b) Suggest a name for the type of reaction that takes place in Step 1 (1)

(c) The same Grignard reagent can be used to produce the alkanol below

Name the carbonyl compound used in this reaction (1)

30 Hairspray is a mixture of chemicals(a) A primary alcohol 2-methylpropan-1-ol is added to hairspray to help it dry quickly on the hair

Draw a structural formula for a secondary alcohol that is an isomer of2-methylpropan-1-ol (1)

(b) Triethanol amine and triisopropyl amine are bases used to neutralise acidic compounds in the hairspray to prevent damage to the hair

In terms of the intermolecular bonding present explain clearly why triethanol amine has a much higher boiling point than triisopropyl amine (2)

35

36

31 Chocolate contains various compounds(a) Many of the flavour and aroma molecules found in chocolate are aldehydes and

ketones Two examples are shown below

Phenylethanal can be easily oxidised but 13-diphenylpropan-2-one cannot(i) Name a chemical that could be used to distinguish between these two

compounds (1)

(ii) Name the type of organic compound formed when phenylethanal is oxidised (1)

(b) Glycerol monostearate is an emulsifier used in chocolate

(i) Why is glycerol monostearate added to chocolate (1)

(ii) Draw a structural formula for glycerol (1)

(c) Theobromine a compound present in chocolate can cause illness in dogs and cats To decide if treatment is necessary vets must calculate the mass of theobromine consumed 1middot0 g of chocolate contains 1middot4 mg of theobromine Calculate the mass in mg of theobromine in a 17 g biscuit of which 28 is chocolate Show your working clearly (2)

(d) The flavour and texture of chocolate comes from a blend of compoundsUsing your knowledge of chemistry describe how you could show that there are ionic compounds and covalent compounds present in chocolate (3)

37

32 Ethanol has many uses

(a) Ethanol is found at relatively low concentrations in wine

(i) Name the chemical reaction that produces ethanol in wine (1)

(ii) Standard ethanol solutions were used to produce a graph of density against

concentration of ethanol given as a percentage of alcohol by volume ( abv)

What is the concentration of ethanol in units of abv in a solution of density 0middot9818 g cmminus3 (1)

(b) Whisky contains a higher concentration of ethanol

(i) Before 1980 the concentration of alcohol in drinks was measured in terms of degrees proof The concentration of alcohol in two drinks is shown in the table below both as abv and degrees proof

38

A cask strength whisky has an alcohol concentration of 65 abv Calculate the alcohol concentration of this whisky in degrees proof (1)

(ii) A barrel containing 195 litres of cask strength whisky costs pound1300 The cask strength whisky is diluted with water to reduce the concentration of alcohol from 65 abv to 46 abv before it is bottled Calculate the cost of the cask strength whisky needed to produce a 0middot70 litre bottle Show your working clearly (2)

(iii) 5-Butyl-4-methyltetrahydrofuran-2-ol is a flavour compound found in whisky

stored in oak barrels

Write the systematic name for the compound shown below (1) 13 11

33 (a) One test for glucose involves Fehlingrsquos solutionCircle the part of the glucose molecule that reacts with Fehlingrsquos solution (1)

(b) In solution sugar molecules exist in an equilibrium in straight-chain and ring forms

To change from the straight-chain form to the ring form the oxygen of the hydroxyl on carbon number 5 joins to the carbonyl carbon This is shown below for glucose

39

Draw the structure of a ring form for fructose (1)

34 (a) During the free radical chain reaction small molecules join to form large chain molecules

One example of a small molecule used is

Name the functional group circled above (1)

(b)Alcohol wipes are used to finish the varnishing treatment Alcohol wipes contain the alcohol propan-2-olState why propan-2-ol can be described as a secondary alcohol (1)

35 A student was carrying out an investigation into alcohols aldehydes and ketones

(a)The student was given three alcohols labelled as A B and C These alcohols were all isomers with the formula C4H9OH

(i) Draw a structural formula for the secondary alcohol with the formula C4H9OH(1)

(ii) The student set up the following experiment

A Suggest why a water bath is an appropriate method of heating the reaction mixture (1)

B Describe the colour change that would have been observed with alcohols A and C (1)

40

C Alcohol B is not oxidised State the type of alcohol which cannot be oxidised by acidified dichromate solution (1)

(iii) The student set up a second experiment with alcohol A

Hot copper(II) oxide is an oxidising agentA When alcohol A (C4H9OH) is oxidised the product turns the pH paper

redSuggest a name for the product (1)

B Complete the ion-electron equation for the oxidation reaction

C4H9OH rarr C4H8O2 (1)

(b)The student found the following information about the boiling points of some aldehydes

41

(i) Name the aldehyde that has a boiling point of 119 degC (1)(ii) Predict the boiling point in degC of the following molecule (1)

(iii) Using information from the table describe one way in which differences in structure affect the boiling point of isomeric aldehydes (1)

(iv) State what would be observed when an aldehyde is gently heated with Tollensrsquo reagent (1)

(c) Ketones contain a carbonyl groupName the type of intermolecular interaction between ketone molecules (1)

42

25 Soaps Detergents and Emulsions

1 Soaps are produced by the following reaction

This reaction is an example ofA condensationB esterificationC hydrolysisD oxidation

2 Which of the following is the salt of a long-chain fatty acid

A FatB OilC SoapD Glycerol

3 Emulsifiers for use in food are commonly made by reacting edible oils with

A estersB glycerolC fatty acidsD amino acids

4 A fatty acid is a long chain carboxylic acid Examples of fatty acids are shown in the table below

43

(a) What is the systematic name for linolenic acid (1)(b) Stearic acid reacts with sodium hydroxide solution to form sodium stearate

(i) Name the type of reaction taking place when stearic acid reacts with sodium hydroxide (1)

(ii) Explain fully how sodium stearate acts to keep grease and non-polar substances suspended in water during cleaning (3)

5 Small children can find it difficult to swallow tablets or pills so ibuprofen is supplied as an ldquoinfant formulardquo emulsion(a) The emulsifier used is polysorbate 80 Its structure is shown below

Explain why this molecule acts as an emulsifier (2)

(b) The emulsion contains 2 g of ibuprofen in every 100 cm3 of emulsion The recommended dose for treating a 6 month old baby is 0middot050 g Calculate the volume in cm3 of ldquoinfant formulardquo needed to treat a 6 month old baby (1)

6 Occasionally seabirds can become contaminated with hydrocarbons from oil spills This causes problems for birds because their feathers lose their waterproofing making the birds susceptible to temperature changes and

44

affecting their buoyancy If the birds attempt to clean themselves to remove the oil they may swallow the hydrocarbons causing damage to their internal organsContaminated seabirds can be cleaned by rubbing vegetable oil into their feathers and feet before the birds are rinsed with diluted washing-up liquidUsing your knowledge of chemistry comment on the problems created for seabirds by oil spills and the actions taken to treat affected birds (3)

7 Dishwasher tablets contain chemicals which remove dirt from dishesDishwasher tablets include detergents These molecules act like soaps to allow mixing of fat-soluble dirt and water(a)During the cleaning process the detergent molecules combine with fat-

soluble dirtA simplified diagram of a detergent molecule is shown

Complete the diagram below to show how detergent molecules combine with fat-soluble dirt (1)

(b)State the term used to describe the non-polar hydrocarbon tail of a detergent molecule (1)

45

26 Fragrances1 Myrcene is a simple terpene

Terpenes contain at least one isoprene unit Which of the following shows a correctly highlighted isoprene unit

2 Limonene is one of the terpene molecules responsible for the flavour of lemons

How many isoprene units are used in the production of one limonene moleculeA 1B 2C 3D 4

46

3 The structure of caryophyllene which can be extracted from clove oil is

Which of the following would be the best solvent for extracting caryophylleneA HexaneB HexanalC HexanolD Hexanone

4 The structure of isoprene is

Limonene is a terpene molecule present in lemons

How many isoprene units are joined together in a limonene molecule

A 1B 2

47

C 3D 4

5 Essential oils are

A non-water soluble non-volatile compoundsB non-water soluble volatile compoundsC water soluble non-volatile compoundsD water soluble volatile compounds

6 Two typical compounds that are present in many perfumes are shown

(a) Why does geraniol evaporate more slowly than limonene (1)

(b) The structure of one of the first synthetic scents used in perfume is shown below

(i) Name the family of carbonyl compounds to which this synthetic scent belongs (1)

(ii) Complete the structure below to show the product formed when this scent is

oxidised (1)

(c) Traces of a liquid were discovered in a bottle believed to contain perfume belonging to Queen Hatshepsut ruler of Egypt over 3500 years ago

Perfumes were made by dissolving plant extracts containing pleasant smelling terpenes and esters in an edible oil A little ethanol and water may also have been addedUsing your knowledge of chemistry comment on the possible smell(s) when such a bottle is opened after being stored for thousands of years (3)

48

49

7 A team of chemists are developing a fragrance for use in a shower gel for men(a) To give the gel a fruity smell the chemists are considering adding an ester

They synthesise six isomeric esters Volunteers smell each ester and give it a rating out of one hundred depending on how fruity the smell is

(i) Name the ester with the fruit-smell rating of 92 (1)

(ii) Shown below are the structures of three more isomers

Arrange these esters in order of decreasing fruit-smell rating (1)

50

(b) To create a fragrance for men the compound civetone is added

Draw a structural formula for the alcohol that can be oxidised to form civetone (1)

(c) To make the shower gel produce a cold tingling sensation when applied to the skin menthol is added

Like terpenes menthol is formed from isoprene (2-methylbuta-13-diene)Circle an isoprene unit on the menthol structure above (1)

8 Many of the compounds in perfumes are molecules consisting of joined isoprene units

(a) State the name that is given to molecules consisting of joined isoprene units (1)

(b)Geraniol is one of the compounds found in perfume It has the following structural formula and systematic name

Linalool can also be present Its structural formula is shown

51

(i) State the systematic name for linalool (1)(ii) Explain why linalool can be classified as a tertiary alcohol (1)

9 The component molecules found in lavender oils are terpenes or terpenoids(a)A chiral carbon is a carbon atom attached to four different atoms or groups of

atomsAn example is shown below

A molecule of the terpenoid linalool has a chiral carbon Linalool has the following structure

Circle the chiral carbon atom in the linalool structure (1)

(b)Farnesene is a terpene consisting of three isoprene units (2-methylbuta-13-diene) joined togetherWrite the molecular formula of farnesene (1)

52

27 Skin Care

1 Which of the following is not a step in a free radical chain reaction

A ActivationB InitiationC PropagationD Termination

2 Fluorine reacts with methane via a free radical chain reaction Some steps in the chain reaction are shown in the table below

Complete the table by(a) inserting the missing name for the first step (1)

(b) showing another possible termination reaction in the final row of the table (1)

3 Suncreams contain antioxidantsThe antioxidant compound A can prevent damage to skin by reacting with free

radicalssuch as NO2bull

53

Why can compound A be described as a free radical scavenger in the reaction shown above

4 Hydrogen and chlorine gases are used in an experiment to demonstrate a free radical reaction A plastic bottle is wrapped with black tape leaving a ldquowindowrdquo on one sideThe bottle is filled with a mixture of hydrogen and chlorine When bright light shines on the bottle there is an explosion

A free radical chain reaction is initiated when light energy causes chlorine radicals to form as shown below

(a) Complete the equations below showing possible propagation and termination steps

(2)

54

(b) Why is the plastic bottle used in the experiment wrapped in black tape (1)

5 Chloramines can be removed from water using ultraviolet light treatment

One step in the process is the formation of free radicals

(a)State what is meant by the term free radical (1)

(b)Another step in the process is shown below

State the name for this type of step in a free radical reaction (1)

6 Modern shellac nail varnishes are more durable and so last longer than traditional nail polish

The shellac nail varnish is applied in thin layers to the nails and then the fingers are placed under a UV lamp

(a) The Skin Care Foundation has recommended that a sun-block is applied to the fingers and hand before using the lampSuggest why the Skin Care Foundation makes this recommendation (1)

(b) A free radical chain reaction takes place and the varnish hardens (i) State what is meant by the term free radical (1)

(ii) The shellac nail varnish contains a mixture of ingredients that take part in the free radical chain reactionOne of the steps in the free radical chain reaction is

55

State the term used to describe this type of step in a free radical chain reaction(1)

7 Skin care products contain a mixture of polar covalent non-polar covalent and ionic compounds The compounds need to stay mixed within the product Skin care products also need to spread easily and remain on the skin for a period of time as well as provide physical and chemical protection from the sun In order to do this skin care products contain a range of chemicals including water fats and oils antioxidants minerals and sun blockUsing your knowledge of chemistry explain the role of different chemicals in skin care products (3)

General Questions

1 A mixture of carbon monoxide and hydrogen can be converted into water and a mixture of hydrocarbons

nCO + (2n + 1)H2 rarr nH2O + hydrocarbons

What is the general formula for the hydrocarbons producedA CnH2nndash2B CnH2nC CnH2n+1D CnH2n+2

2 Butadiene is the first member of a homologous series of hydrocarbons called dienesWhat is the general formula for this seriesA CnHn+2B CnHn+3C CnH2nD CnH2nndash2

3 Which of the following statements about methanol is falseA It can be made from synthesis gasB It can be dehydrated to form an alkeneC It can be oxidised to give a carboxylic acidD It reacts with acidified potassium dichromate solution

56

4

Which line in the table correctly describes reactions X and Y

5

Which line in the table correctly describes reactions X and Y

6 Which of the following fuels when burned would make no contribution to globalwarming

57

A HydrogenB Natural gasC PetrolD Coal

7 Which of the following hydrocarbons always gives the same product when one of itshydrogen atoms is replaced by a chlorine atomA HexaneB Hex-1-eneC CyclohexaneD Cyclohexene

8 Which of the following compounds does not have isomeric structuresA C2HCl3B C2H4Cl2C PropeneD Propan-1-ol

9 What organic compound is produced by the dehydration of ethanol A EthaneB EtheneC EthanalD Ethanoic acid

10

The above equation representsA hydrationB hydrogenationC condensationD hydrolysis

11

Which of the following compounds is an isomer of the structure shown aboveA ButanalB ButanoneC Butan-1-olD Butanoic acid

58

12 A compound with molecular formula C6H12O2 could beA hexanalB hexan-2-olC hexan-2-oneD hexanoic acid

13 Propan-2-ol can be prepared from propane as follows

Which line in the table correctly describes the types of reaction taking place at Steps 1 and 2

14 Which of the following compounds would be the most water soluble

15 Cyanohydrin compounds can be made from carbonyl compounds by reacting the carbonyl compound with hydrogen cyanide (HCN)

59

Which carbonyl compound would react with hydrogen cyanide (HCN) to form the following compound

16 Ethyne is the first member of the homologous series called the alkynes

Ethyne can undergo addition reactions as shown in the flow diagram

(a) Compound 2 is an isomer of 12-dichloroethaneDraw a structural formula for compound 2 (1)

(b) Reagents A B and C are three different diatomic gasesUsing information in the flow diagram identify reagents A B and C (1)

60

Reagent Gas

A

B

C

17 In 1865 the German chemist Kekuleacute proposed a ring structure for benzene This structure was based on alternating single and double bonds

(a) (i) Describe a chemical test that would indicate that the above chemical structure for benzene is incorrect (1)

(ii) Briefly describe the correct structure for benzene (1)

(b) Benzene can be formed from cyclohexaneC6H12 rarr C6H6 + 3H2

What name is given to this type of reaction (1)18 Infra-red spectroscopy is a technique that can be used to identify the bonds that

arepresent in a molecule Different bonds absorb infra-red radiation of different wavenumbers This is due to differences in the bond lsquostretchrsquo These absorptions are recorded in a spectrumA spectrum for propan-1-ol is shown

61

The correlation table on page 13 of the data booklet shows the wavenumber ranges for the absorptions due to different bonds

(a) Use the correlation table to identify the bonds responsible for the two absorptions x and y that are circled in the propan-1-ol spectrum (1)

(b) Propan-1-ol reacts with ethanoic acid(i) What name is given to this type of reaction (1)(ii) Draw a spectrum that could be obtained for the organic product of this

reaction (1)

19 Paracetamol is a widely used painkiller

(a) Write the molecular formula for paracetamol (1)

(b) One antidote for paracetamol overdose is methionine

62

To what family of organic compounds does methionine belong (1)

(c) The concentration of paracetamol in a solution can be determined by measuring how much UV radiation it absorbs

The graph shows how the absorbance of a sample containing 0middot040 g l ndash1 paracetamol varies with wavelength

The quantity of UV radiation of wavelength 245 nm absorbed is directly proportional to the concentration of paracetamolThe absorbance of a second sample of paracetamol solution measured at 245 nm was 0middot90 What is the concentration in g l ndash1 of this second paracetamol solution (1)

20 Many carbon compounds containing oxygen are very flammableThe table shows information about two families of isomersThe lowest temperature at which a compound will ignite is called its flash point

(a) A compound with the molecular formula C6H14O has a boiling point of 158 degC63

Draw a structural formula for this compound (1)

(b) For a family of isomers in the table write a general statement linking the flash points of the compounds to their structures (1)

21 Hydrogels are used in disposable nappies They are fine powders that can absorb up to 500 times their own weight in waterA hydrogel is a very long molecule with carboxyl groups at regular intervals along its length A short section of a hydrogel molecule is shown below

Hydrogels are extremely good at soaking up water because the water molecules are strongly attracted to them

Using your knowledge of chemistry comment on how suitable hydrogels would be for absorbing liquids or solutions spilled in a chemistry lab (1)

64

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

12 Oil molecules are more likely to react with oxygen in the air than fat molecules During the reaction the oil molecules

A are reducedB become rancidC are hydrolysedD become unsaturated

13 Which of the following mixtures will form when NaOH(aq) is added to a mixture of propanol and ethanoic acid

A Propanol and sodium ethanoateB Ethanoic acid and sodium propanoateC Sodium hydroxide and propyl ethanoateD Sodium hydroxide and ethyl propanoate

14 Oils contain carbon to carbon double bonds which can undergo addition reactions with iodine The iodine number of an oil is the mass of iodine in grams that will react with 100 g of oilWhich line in the table shows the oil that is likely to have the lowest melting point

15 When an oil is hydrolysed which of the following molecules is always produced

4

16 The antibiotic erythromycin has the following structure

To remove its bitter taste the erythromycin is reacted to give the compound with the structure shown below

Which of the following types of compound has been reacted with erythromycin to produce this compound

A AlcoholB AldehydeC Carboxylic acidD Ketone

17 vegetable oil rarr vegetable fat

Which of the following reactions brings about the above change

A HydrolysisB CondensationC HydrogenationD Dehydrogenation

18 Which of the following fatty acids is the most unsaturated

A C15H29COOHB C15H31COOHC C17H31COOHD C17H35COOH

19 Which of the following is an isomer of ethyl propanoate (CH3CH2COOCH2CH3)

A Methyl propanoateB Pentan-2-oneC Pentanoic acidD Pentane-12-diol

5

20 Which of the following is a structural formula for glycerol

6

21 One of the chemicals released in a bee sting is an ester that has the structure shown

This ester can be produced by the reaction of an alcohol with an alkanoic acid

(a) Name this acid (1)

(b) The ester can be prepared in the lab by heating a mixture of the reactants with a catalyst

(i) Name the catalyst used in the reaction (1)

(ii) What improvement could be made to the experimental set-up shown in the diagram

(1)

22 Propan-1-ol and propanoic acid react to form an esterThe mixture of excess reactants and ester product is poured onto sodium hydrogencarbonate solution

(a) What evidence would show that an ester is formed (1)

(b) Draw a structural formula for this ester (1)

23 The ester methyl stearate is also a useful vehicle fuel A student prepared this ester from methanol and stearic acid during the Prescribed Practical Activity ldquoMaking EstersrdquoDescribe how this ester was prepared (2)

24 Foodstuffs have labels that list ingredients and provide nutritional information The label on a tub of margarine lists hydrogenated vegetable oils as one of the ingredients Why have some of the vegetable oils in this product been hydrogenated (1)

7

25 A typical triglyceride found in olive oil is shown below

(a) To which family of organic compounds do triglycerides belong (1)

(b) Olive oil can be hardened for use in margarinesWhat happens to the triglyceride molecules during the hardening of olive oil (1)

(c) Give one reason why oils can be a useful part of a balanced diet (1)

26 When vegetable oils are hydrolysed mixtures of fatty acids are obtained The fatty acids can be classified by their degree of unsaturation The table below shows the composition of each of the mixtures of fatty acids obtained when palm oil and olive oil were hydrolysed

(a) Why does palm oil have a higher melting point than olive oil (1)

(b) One of the fatty acids produced by the hydrolysis of palm oil is linoleic acid C17H31COOH To which class (saturated monounsaturated or polyunsaturated) does this fatty acid belong (1)

(c) When a mixture of palm oil and olive oil is hydrolysed using a solution of sodium hydroxide a mixture of the sodium salts of the fatty acids is obtained State a use for these fatty acid salts (1)

8

27

4-hydroxybenzoic acid can react with alcohols to form compounds known asparabens

(a) Name the functional group circled in the structure of 4minushydroxybenzoic acid (1)

(b) Name the type of reaction taking place when parabens are formed (1)

(c) Draw the paraben formed when 4minushydroxybenzoic acid reacts with ethanol (1)

(d) Parabens can be used as preservatives in cosmetics and toiletries Parabens are absorbed into the body through the skin The following table indicates the absorption of some parabens

State a conclusion that can be drawn from the information in the table (1)

9

28 When fats and oils are hydrolysed mixtures of fatty acids are obtained

(a) Name the other product obtained in this reaction (1)

(b)The table below shows the percentage composition of the fatty acid mixtures obtained by hydrolysis of coconut oil and olive oil

(i) One of the fatty acids produced by the hydrolysis of olive oil is linoleic acid C17H31COOHState the class of fatty acid to which linoleic acid belongs (1)

(ii) Hydrolysed coconut oil contains the fatty acid caprylic acid with the formula CH3(CH2)6COOHState the systematic name for caprylic acid (1)

(c) The degree of unsaturation of oil can be tested by adding drops of bromine solution to the oil Bromine adds across carbon to carbon double bonds in the fatty acid chains

The following apparatus can be used to compare the degree ofunsaturation of different oils

10

(i) Describe how this apparatus could be used to show that olive oil has a greater degree of unsaturation than coconut oil (2)

(ii) Suggest why hexane is used as the solvent rather than water (1)

(iii) Coconut oil has a melting point of 25 degC Olive oil has a melting point of minus6C

Give two reasons why coconut oil has a higher melting point than olive oil (2)

29 Traditional nail varnishes use ethyl ethanoate and butyl ethanoate as solvents

(a)Draw a structural formula for butyl ethanoate (1)(b)Ethyl ethanoate can be made in the laboratory using the following apparatus

Suggest why a wet paper towel is wrapped around the test tube (1)

(c) Name the type of reaction that takes place during the formation of ethyl ethanoate (1)

30 Pentyl butanoate is responsible for some of the flavour in apricots and strawberries

(a)Hydrolysis of pentyl butanoate using sodium hydroxide produces an alcohol and the salt of the carboxylic acid

(i) Name the alcohol that would be formed when pentyl butanoate is hydrolysed(1)

(ii) Draw a structural formula for the sodium salt of the carboxylic acid that would be formed (1)

(b)Fats and oils belong to the same class of compounds as pentyl butanoate(i) Name this class of compounds (1)

11

(ii) When a fat is hydrolysed using sodium hydroxide sodium salts of fatty acids are producedState a use for sodium salts of fatty acids (1)

22 Proteins

1 When a protein is denaturedA its overall shape is distortedB its amide links are hydrolysedC it is broken into separate peptide fragmentsD it decomposes into amino acids

2 Which of the following compounds can be classified as proteinsA FatsB OilsC EnzymesD Amino acids

3 The monomer units used to construct enzyme molecules areA alcoholsB estersC amino acidsD fatty acids

4 Amino acids are converted into proteins byA hydrationB hydrolysisC hydrogenationD condensation

5 The arrangement of amino acids in a peptide isZ-X-W-V-Y

where the letters V W X Y and Z represent amino acidsOn partial hydrolysis of the peptide which of the following sets of dipeptides is possibleA V-Y Z-X W-Y X-WB Z-X V-Y W-V X-WC Z-X X-V W-V V-YD X-W X-Z Z-W Y-V

6 Which of the following is an amine

12

7 Which of the following arrangements of atoms shows a peptide link

8 The following molecules are found in herbicides Which of the following contains an amide link

9 In α-amino acids the amino group is on the carbon atom adjacent to the acid group

Which of the following is an α-amino acid

10 A tripeptide X has the structure

Partial hydrolysis of X yields a mixture of dipeptidesWhich of the following dipeptides could be produced on hydrolysing X

13

11 The rate of hydrolysis of protein using an enzyme was studied at different temperatures Which of the following graphs would be obtained

12 The rate of hydrolysis of protein using an enzyme was studied at different temperaturesWhich of the following graphs would be obtained

14

13 Polymers can be classified as natural or synthetic(a) Keratin a natural polymer is a protein found in hair

The hydrolysis of keratin produces different monomers of the type shown

(i) What name is given to monomers like glycine alanine and cysteine (1)(ii) What is meant by a hydrolysis reaction (1)

(b) Dacron a synthetic polymer is used in heart surgery A section of the polymer is shown

What name is given to the link made by the shaded group of atoms in this section of the polymer (1)

14 Chemists have developed cheeses specifically for use in cheeseburgers(a) When ordinary cheddar cheese is grilled the shapes of the protein molecules

change and the proteins and fats separate leaving a chewy solid and an oily liquidWhat name is given to the change in protein structure which occurs when ordinary cheddar is grilled (1)

(b) To make cheese for burgers grated cheddar cheese soluble milk proteins and some water are mixed and heated to no more than 82 degC As the cheese begins to melt an emulsifying agent is added and the mixture is stirred

15

(i) Why would a water bath be used to heat the mixture (1)(ii) A section of the structure of a soluble milk protein is shown below

Draw a structural formula for any one of the amino acids formed when this section of

protein is hydrolysed (1)

(iii) The emulsifier used is trisodium citrate a salt formed when citric acid is neutralised using sodium hydroxide Complete the equation below showing a structural formula for the trisodium citrate formed (1) sp 8

15 Phenylalanine and alanine are both amino acids

(a) Phenylalanine is an essential amino acid

(i) What is meant by an essential amino acid (1)

16

(ii) How many hydrogen atoms are present in a molecule of phenylalanine (1)

(b) Phenylalanine and alanine can react to form the dipeptide shown

Circle the peptide link in this molecule (1)

(c) Draw a structural formula for the other dipeptide that can be formed from phenylalanine and alanine (1)

16 Uncooked egg white is mainly composed of dissolved proteins During cooking processes the proteins become denatured as the protein chains unwind and the egg white solidifies

(a) Explain why the protein chains unwind (1)

(b)The temperature at which the protein becomes denatured is called the melting temperature The melting temperature of a protein can be determined using fluorescence In this technique the protein is mixed with a dye that gives out visible light when it attaches to hydrophobic parts of the protein molecule The hydrophobic parts of the structure are on the inside of the protein and the dye has no access to them unless the protein unwinds

(i) Ovalbumin is a protein found in egg white Part of the structure of unwound ovalbumin is shown below

Circle the part of the structure to which the hydrophobic dye is most likely to attach (1)

17

(ii) Another protein in egg white is conalbumin The temperature of a conalbumindye mixture is gradually increased The fluorescence is measured and a graph is produced

The melting temperature is the temperature at which the fluorescence is halfway between the highest and lowest fluorescence valuesDetermine the melting temperature in ordmC for this protein (1)

(c) Once cooked and eaten the digestive system breaks the protein chains into amino acids with the help of enzymes

(i) State the name of the digestion process where enzymes break down proteins into amino acids (1)

(ii)

(A) State how many amino acid molecules joined to form this section of protein (1)

(B) Draw the structure of one amino acid that would be produced when this section of the protein chain is broken down (1)

17 Peptide molecules can be classified according to the number of amino acid units joined by peptide bonds in the molecule

18

(a) Complete the table to identify the type of peptide with the following amino acid sequence

alanine-glycine-valine-proline-tyrosine-serine (1)

(b) Partial hydrolysis of another pentapeptide molecule gave a mixture of three smaller peptide molecules with the following amino acid sequences

leucine-glycine-valineisoleucine-leucineglycine-valine-serine

Write the amino acid sequence for the original pentapeptide molecule (1)

helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip(c) Some amino acids needed to form polypeptides cannot be produced in the human body

State the term used to describe amino acids that the body cannot make (1)

(d)Paper chromatography is often used to analyse the mixtures of amino acids produced when peptides are broken downOn a chromatogram the retention factor Rf for a substance can be a useful method of identifying the substance

The structure of the pentapeptide methionine enkephalin was investigatedA sample of the pentapeptide was completely hydrolysed into its constituent amino acids and this amino acid mixture was applied to a piece of chromatography paper and placed in a solventThe chromatogram obtained is shown below

19

(i) Suggest why only four spots were obtained on the chromatogram of the hydrolysed pentapeptide (1)

(ii) It is known that this amino acid mixture contains the amino acid methionine The Rf value for methionine in this solvent is 040Draw a circle around the spot on the chromatogram that corresponds to methionine (1)

(e) Over the last decade several families of extremely stable peptide molecules have been discovered where the peptide chain forms a ring

(i) A simple cyclic dipeptide is shown

Draw a structural formula for one of the amino acids that would be formed on complete hydrolysis of the above cyclic dipeptide (1)

(ii) Alpha-amanitin is a highly toxic cyclic peptide found in death cap mushrooms The lethal dose for humans is 100 mg per kg of body mass1middot0 g of death cap mushrooms contains 250 mg of alpha-amanitinCalculate the minimum mass of death cap mushrooms that would contain the lethal dose for a 75 kg adult (2)

18 Dishwasher tablets produce the bleach hydrogen peroxide H2O2 One action of this oxidising agent is to oxidise food

(a)(i) Suggest another action of the bleach produced by the dishwasher tablets (1)

20

(ii) Hydrogen peroxide decomposes to form water and oxygen

2H2O2(ℓ) rarr 2H2O(ℓ) + O2(g)

A dishwasher tablet produces 0middot051 g of hydrogen peroxide (mass of one mole = 34 g)

Calculate the volume of oxygen that would be produced when0middot051 g of hydrogen peroxide decomposesTake the volume of 1 mole of oxygen gas to be 24 litres(3)

(b)Enzymes are commonly added to dishwasher tablets These are used to break down proteins(i) The proteins are broken down into small water-soluble molecules

Name the small water-soluble molecules made when proteins are broken down completely (1)

(ii) The structure of a section of protein chain found in egg white is shown

(A)Name the functional group circled (1)(B)Draw a structural formula for one of the molecules that would be made

when this section of egg white protein chain is completely broken down (1)

(iii) As part of the program in the dishwasher the conditions in the dishwasher change so that the enzyme molecules no longer work because they change shape

21

(A) State the term used to describe the change in shape of enzyme molecules(1)

(B) Suggest a change in conditions which would cause the enzyme molecules to change shape (1)

(d) A bleach activator is frequently added to dishwasher tablets to speed up the bleaching reaction One common bleach activator is TAED TAED could be produced in a process which involves a number of stages

(i) The first stage in producing TAED is shown below

Suggest a name for this type of reaction (1)

(ii) The final stage in the process producing TAED is shown below

Draw a structural formula for TAED (1)

22

23 The Chemistry of Cooking

1 Vanillin and zingerone are flavour molecules

Which line in the table correctly compares the properties of vanillin and zingerone

23

2 Erythrose can be used in the production of a chewing gum that helps prevent tooth decay

Which of the following compounds will be the best solvent for erythrose

3 The following molecules give flavour to food Which of the following flavour molecules would be most likely to be retained in the food when the food is cooked in water

24

4 Cooking involves many chemical reactions Proteins fats oils and esters are some examples of compounds found in food A chemist suggested that cooking food could change compounds from being fat-soluble to water-soluble Use your knowledge of chemistry to comment on the accuracy of this statement(3)

25

24 The Oxidation of Food

1 Apples and bananas turn brown when cut or bruised The first step of the reaction causing

the browning is shown below

Which of the following terms correctly describes this reactionA ReductionB OxidationC DehydrationD Condensation

2 Which of the following reactions can be classified as reductionA CH3CH2OH rarr CH3COOHB CH3 CH(OH)CH3 rarr CH3COCH3C CH3CH2COCH3 rarr CH3CH2CH(OH)CH3D CH3CH2CHO rarr CH3CH2COOH

3 The dehydration of butan-2-ol can produce two isomeric alkenes but-1-ene andbut-2-ene Which of the following alkanols can similarly produce on dehydration a pair of isomeric alkenesA Propan-2-olB Pentan-3-olC Hexan-3-olD Heptan-4-ol

4 Which of the following compounds is an alkanone

26

5 Which of the following is an aldehyde

6 Which of the following compounds would react with sodium hydroxide solution to forma saltA CH3CHOB CH3COOHC CH3COCH3D CH3CH2OH

7 Which line in the table shows the correct functional group for each homologous series

8 Which of the following organic compounds is an isomer of hexanalA 2-MethylbutanalB 3-Methylpentan-2-oneC 22-Dimethylbutan-1-olD 3-Ethylpentanal

27

9 The name of this compound is

A methanolB methanalC methanoic acidD methanone

10 Which alcohol could be oxidised to a carboxylic acid

11 Which of the following structural formulae represents a tertiary alcohol

12 Compound X reacted with hot copper(II) oxide and the organic product did not give acolour change when heated with Fehlingrsquos solution Compound X could beA butan-1-olB butan-2-olC butanoneD butanoic acid

28

13 Which two isomers would each produce an acid when warmed with acidified potassiumdichromate solution

A 1 and 2B 2 and 3C 1 and 4D 3 and 4

14 After heating for several minutes as shown in the diagram the pH indicator solution turned red

Liquid Q could beA propanoneB paraffinC propan-1-olD propan-2-ol

29

15 Enzymes are involved in the browning of cut fruitOne reaction taking place is

Which of the following correctly describes the above reaction

A OxidationB ReductionC HydrolysisD Condensation

16 Which of the following statements is correct for ketones

A They are formed by oxidation of tertiary alcohols

B They contain the group

C They contain a carboxyl groupD They will not react with Fehlingrsquos solution

17 Carvone is a natural product that can be extracted from orange peel

Which line in the table correctly describes the reaction of carvone with bromine solution and with acidified potassium dichromate solution

30

18 Which of the following is an isomer of 22-dimethylpentan-1-ol

A CH3CH2CH2CH(CH3)CH2OHB (CH3)3CCH(CH3)CH2OHC CH3CH2CH2CH2CH2CH2CH2CH2OHD (CH3)2CHC(CH3)2CH2CH2OH

19 The equation for the reduction reaction taking place when ethanal reacts with Tollensrsquo reagent is

A Cu2+(aq) + eminus rarr Cu+(aq)

B Ag+(aq) + eminus rarr Ag(s)

C Cr2O72minus(aq) + 14H+(aq) + 6eminus rarr 2Cr3+(aq) + 7H2O(ℓ)

D MnO4minus(aq) + 8H+(aq) + 5eminus rarr Mn2+(aq) + 4H2O(ℓ)

20 The name of the compound with structure

isA 23-dimethylpentan-4-oneB 23-dimethylpentan-2-alC 34-dimethylpentan-2-oneD 34-dimethylpentan-2-al

21 What is the systematic name for the compound below

A 222-trimethylethanolB 22-dimethylpropan-1-olC 22-dimethylpropan-3-olD 22-dimethylpentan-1-ol

31

22 The structure of a molecule found in olive oil can be represented as shown

(a) Olive oil can be hydrolysed using sodium hydroxide solution to produce sodium salts of fatty acids Name the other product of this reaction (1)

(b) In what way does the structure of a fat molecule differ from that of an oil molecule (1)

(c) Over time open containers of olive oil develop a rancid flavour What substance is reacting with the oil to cause these unwanted changes to take place (1)

23 A student writes the following statement It is incorrect Explain the mistake in the studentrsquos reasoning (1)

Alcohols are alkaline because of their OH groups

24 Carbon compounds take part in a wide variety of chemical reactions (a)

Name this type of chemical reaction (1)

(b)

Draw a structural formula for C3H6O (1)

25 Alkanols can be oxidised to alkanoic acids

32

(a) Why can Step 1 be described as an oxidation reaction (1)

(b) Acidified potassium dichromate solution can be used to oxidise propanal in Step 2 What colour change would be observed in this reaction (1)

26 Amines can be produced by reacting ammonia with an aldehyde or a ketone This reaction an example of reductive amination occurs in two stages

Stage 1 Amination

Stage 2 Reduction

(a) Give another name for the type of reaction taking place in Stage 2

(b) Draw the structural formula for the amine produced when butanal undergoes reductive amination with ammonia

27 Using a cobalt catalyst alkenes react with a mixture of hydrogen and carbon monoxideThe products are two isomeric aldehydes Propene reacts with the mixture as shown

(a) What name is given to a mixture of hydrogen and carbon monoxide (1)

(b) Draw a structural formula for compound B (1)

(c) (i) What would be observed if compound A was gently heated with Tollensrsquo reagent

(1)(ii) How would the reaction mixture be heated (1)

33

(d) Aldehydes can also be formed by the reaction of some alcohols with copper(II) oxideName the type of alcohol that would react with copper(II) oxide to form an aldehyde (1)

28 Aldehydes and ketones can take part in a reaction sometimes known as an aldol condensation The simplest aldol reaction involves two molecules of ethanal

In the reaction the carbon atom next to the carbonyl functional group of one molecule forms a bond with the carbonyl carbon atom of the second molecule

(a) Draw a structural formula for the product formed when propanone is used instead of ethanal in this type of reaction (1)

(b) Name an aldehyde that would not take part in an aldol condensation (1)

(c) Apart from the structure of the reactants suggest what is unusual about applying the term ldquocondensationrdquo to this particular type of reaction (1)

29 Primary secondary and tertiary alkanols can be prepared by the reaction of carbonyl compounds with Grignard reagents

Step 1The Grignard reagent reacts with the carbonyl compound

Step 2The reaction of the product of Step 1 with dilute acid produces the alkanol

(a) Describe the difference between a primary a secondary and a tertiary alkanol

You may wish to include labelled structures in your answer (1)34

(b) Suggest a name for the type of reaction that takes place in Step 1 (1)

(c) The same Grignard reagent can be used to produce the alkanol below

Name the carbonyl compound used in this reaction (1)

30 Hairspray is a mixture of chemicals(a) A primary alcohol 2-methylpropan-1-ol is added to hairspray to help it dry quickly on the hair

Draw a structural formula for a secondary alcohol that is an isomer of2-methylpropan-1-ol (1)

(b) Triethanol amine and triisopropyl amine are bases used to neutralise acidic compounds in the hairspray to prevent damage to the hair

In terms of the intermolecular bonding present explain clearly why triethanol amine has a much higher boiling point than triisopropyl amine (2)

35

36

31 Chocolate contains various compounds(a) Many of the flavour and aroma molecules found in chocolate are aldehydes and

ketones Two examples are shown below

Phenylethanal can be easily oxidised but 13-diphenylpropan-2-one cannot(i) Name a chemical that could be used to distinguish between these two

compounds (1)

(ii) Name the type of organic compound formed when phenylethanal is oxidised (1)

(b) Glycerol monostearate is an emulsifier used in chocolate

(i) Why is glycerol monostearate added to chocolate (1)

(ii) Draw a structural formula for glycerol (1)

(c) Theobromine a compound present in chocolate can cause illness in dogs and cats To decide if treatment is necessary vets must calculate the mass of theobromine consumed 1middot0 g of chocolate contains 1middot4 mg of theobromine Calculate the mass in mg of theobromine in a 17 g biscuit of which 28 is chocolate Show your working clearly (2)

(d) The flavour and texture of chocolate comes from a blend of compoundsUsing your knowledge of chemistry describe how you could show that there are ionic compounds and covalent compounds present in chocolate (3)

37

32 Ethanol has many uses

(a) Ethanol is found at relatively low concentrations in wine

(i) Name the chemical reaction that produces ethanol in wine (1)

(ii) Standard ethanol solutions were used to produce a graph of density against

concentration of ethanol given as a percentage of alcohol by volume ( abv)

What is the concentration of ethanol in units of abv in a solution of density 0middot9818 g cmminus3 (1)

(b) Whisky contains a higher concentration of ethanol

(i) Before 1980 the concentration of alcohol in drinks was measured in terms of degrees proof The concentration of alcohol in two drinks is shown in the table below both as abv and degrees proof

38

A cask strength whisky has an alcohol concentration of 65 abv Calculate the alcohol concentration of this whisky in degrees proof (1)

(ii) A barrel containing 195 litres of cask strength whisky costs pound1300 The cask strength whisky is diluted with water to reduce the concentration of alcohol from 65 abv to 46 abv before it is bottled Calculate the cost of the cask strength whisky needed to produce a 0middot70 litre bottle Show your working clearly (2)

(iii) 5-Butyl-4-methyltetrahydrofuran-2-ol is a flavour compound found in whisky

stored in oak barrels

Write the systematic name for the compound shown below (1) 13 11

33 (a) One test for glucose involves Fehlingrsquos solutionCircle the part of the glucose molecule that reacts with Fehlingrsquos solution (1)

(b) In solution sugar molecules exist in an equilibrium in straight-chain and ring forms

To change from the straight-chain form to the ring form the oxygen of the hydroxyl on carbon number 5 joins to the carbonyl carbon This is shown below for glucose

39

Draw the structure of a ring form for fructose (1)

34 (a) During the free radical chain reaction small molecules join to form large chain molecules

One example of a small molecule used is

Name the functional group circled above (1)

(b)Alcohol wipes are used to finish the varnishing treatment Alcohol wipes contain the alcohol propan-2-olState why propan-2-ol can be described as a secondary alcohol (1)

35 A student was carrying out an investigation into alcohols aldehydes and ketones

(a)The student was given three alcohols labelled as A B and C These alcohols were all isomers with the formula C4H9OH

(i) Draw a structural formula for the secondary alcohol with the formula C4H9OH(1)

(ii) The student set up the following experiment

A Suggest why a water bath is an appropriate method of heating the reaction mixture (1)

B Describe the colour change that would have been observed with alcohols A and C (1)

40

C Alcohol B is not oxidised State the type of alcohol which cannot be oxidised by acidified dichromate solution (1)

(iii) The student set up a second experiment with alcohol A

Hot copper(II) oxide is an oxidising agentA When alcohol A (C4H9OH) is oxidised the product turns the pH paper

redSuggest a name for the product (1)

B Complete the ion-electron equation for the oxidation reaction

C4H9OH rarr C4H8O2 (1)

(b)The student found the following information about the boiling points of some aldehydes

41

(i) Name the aldehyde that has a boiling point of 119 degC (1)(ii) Predict the boiling point in degC of the following molecule (1)

(iii) Using information from the table describe one way in which differences in structure affect the boiling point of isomeric aldehydes (1)

(iv) State what would be observed when an aldehyde is gently heated with Tollensrsquo reagent (1)

(c) Ketones contain a carbonyl groupName the type of intermolecular interaction between ketone molecules (1)

42

25 Soaps Detergents and Emulsions

1 Soaps are produced by the following reaction

This reaction is an example ofA condensationB esterificationC hydrolysisD oxidation

2 Which of the following is the salt of a long-chain fatty acid

A FatB OilC SoapD Glycerol

3 Emulsifiers for use in food are commonly made by reacting edible oils with

A estersB glycerolC fatty acidsD amino acids

4 A fatty acid is a long chain carboxylic acid Examples of fatty acids are shown in the table below

43

(a) What is the systematic name for linolenic acid (1)(b) Stearic acid reacts with sodium hydroxide solution to form sodium stearate

(i) Name the type of reaction taking place when stearic acid reacts with sodium hydroxide (1)

(ii) Explain fully how sodium stearate acts to keep grease and non-polar substances suspended in water during cleaning (3)

5 Small children can find it difficult to swallow tablets or pills so ibuprofen is supplied as an ldquoinfant formulardquo emulsion(a) The emulsifier used is polysorbate 80 Its structure is shown below

Explain why this molecule acts as an emulsifier (2)

(b) The emulsion contains 2 g of ibuprofen in every 100 cm3 of emulsion The recommended dose for treating a 6 month old baby is 0middot050 g Calculate the volume in cm3 of ldquoinfant formulardquo needed to treat a 6 month old baby (1)

6 Occasionally seabirds can become contaminated with hydrocarbons from oil spills This causes problems for birds because their feathers lose their waterproofing making the birds susceptible to temperature changes and

44

affecting their buoyancy If the birds attempt to clean themselves to remove the oil they may swallow the hydrocarbons causing damage to their internal organsContaminated seabirds can be cleaned by rubbing vegetable oil into their feathers and feet before the birds are rinsed with diluted washing-up liquidUsing your knowledge of chemistry comment on the problems created for seabirds by oil spills and the actions taken to treat affected birds (3)

7 Dishwasher tablets contain chemicals which remove dirt from dishesDishwasher tablets include detergents These molecules act like soaps to allow mixing of fat-soluble dirt and water(a)During the cleaning process the detergent molecules combine with fat-

soluble dirtA simplified diagram of a detergent molecule is shown

Complete the diagram below to show how detergent molecules combine with fat-soluble dirt (1)

(b)State the term used to describe the non-polar hydrocarbon tail of a detergent molecule (1)

45

26 Fragrances1 Myrcene is a simple terpene

Terpenes contain at least one isoprene unit Which of the following shows a correctly highlighted isoprene unit

2 Limonene is one of the terpene molecules responsible for the flavour of lemons

How many isoprene units are used in the production of one limonene moleculeA 1B 2C 3D 4

46

3 The structure of caryophyllene which can be extracted from clove oil is

Which of the following would be the best solvent for extracting caryophylleneA HexaneB HexanalC HexanolD Hexanone

4 The structure of isoprene is

Limonene is a terpene molecule present in lemons

How many isoprene units are joined together in a limonene molecule

A 1B 2

47

C 3D 4

5 Essential oils are

A non-water soluble non-volatile compoundsB non-water soluble volatile compoundsC water soluble non-volatile compoundsD water soluble volatile compounds

6 Two typical compounds that are present in many perfumes are shown

(a) Why does geraniol evaporate more slowly than limonene (1)

(b) The structure of one of the first synthetic scents used in perfume is shown below

(i) Name the family of carbonyl compounds to which this synthetic scent belongs (1)

(ii) Complete the structure below to show the product formed when this scent is

oxidised (1)

(c) Traces of a liquid were discovered in a bottle believed to contain perfume belonging to Queen Hatshepsut ruler of Egypt over 3500 years ago

Perfumes were made by dissolving plant extracts containing pleasant smelling terpenes and esters in an edible oil A little ethanol and water may also have been addedUsing your knowledge of chemistry comment on the possible smell(s) when such a bottle is opened after being stored for thousands of years (3)

48

49

7 A team of chemists are developing a fragrance for use in a shower gel for men(a) To give the gel a fruity smell the chemists are considering adding an ester

They synthesise six isomeric esters Volunteers smell each ester and give it a rating out of one hundred depending on how fruity the smell is

(i) Name the ester with the fruit-smell rating of 92 (1)

(ii) Shown below are the structures of three more isomers

Arrange these esters in order of decreasing fruit-smell rating (1)

50

(b) To create a fragrance for men the compound civetone is added

Draw a structural formula for the alcohol that can be oxidised to form civetone (1)

(c) To make the shower gel produce a cold tingling sensation when applied to the skin menthol is added

Like terpenes menthol is formed from isoprene (2-methylbuta-13-diene)Circle an isoprene unit on the menthol structure above (1)

8 Many of the compounds in perfumes are molecules consisting of joined isoprene units

(a) State the name that is given to molecules consisting of joined isoprene units (1)

(b)Geraniol is one of the compounds found in perfume It has the following structural formula and systematic name

Linalool can also be present Its structural formula is shown

51

(i) State the systematic name for linalool (1)(ii) Explain why linalool can be classified as a tertiary alcohol (1)

9 The component molecules found in lavender oils are terpenes or terpenoids(a)A chiral carbon is a carbon atom attached to four different atoms or groups of

atomsAn example is shown below

A molecule of the terpenoid linalool has a chiral carbon Linalool has the following structure

Circle the chiral carbon atom in the linalool structure (1)

(b)Farnesene is a terpene consisting of three isoprene units (2-methylbuta-13-diene) joined togetherWrite the molecular formula of farnesene (1)

52

27 Skin Care

1 Which of the following is not a step in a free radical chain reaction

A ActivationB InitiationC PropagationD Termination

2 Fluorine reacts with methane via a free radical chain reaction Some steps in the chain reaction are shown in the table below

Complete the table by(a) inserting the missing name for the first step (1)

(b) showing another possible termination reaction in the final row of the table (1)

3 Suncreams contain antioxidantsThe antioxidant compound A can prevent damage to skin by reacting with free

radicalssuch as NO2bull

53

Why can compound A be described as a free radical scavenger in the reaction shown above

4 Hydrogen and chlorine gases are used in an experiment to demonstrate a free radical reaction A plastic bottle is wrapped with black tape leaving a ldquowindowrdquo on one sideThe bottle is filled with a mixture of hydrogen and chlorine When bright light shines on the bottle there is an explosion

A free radical chain reaction is initiated when light energy causes chlorine radicals to form as shown below

(a) Complete the equations below showing possible propagation and termination steps

(2)

54

(b) Why is the plastic bottle used in the experiment wrapped in black tape (1)

5 Chloramines can be removed from water using ultraviolet light treatment

One step in the process is the formation of free radicals

(a)State what is meant by the term free radical (1)

(b)Another step in the process is shown below

State the name for this type of step in a free radical reaction (1)

6 Modern shellac nail varnishes are more durable and so last longer than traditional nail polish

The shellac nail varnish is applied in thin layers to the nails and then the fingers are placed under a UV lamp

(a) The Skin Care Foundation has recommended that a sun-block is applied to the fingers and hand before using the lampSuggest why the Skin Care Foundation makes this recommendation (1)

(b) A free radical chain reaction takes place and the varnish hardens (i) State what is meant by the term free radical (1)

(ii) The shellac nail varnish contains a mixture of ingredients that take part in the free radical chain reactionOne of the steps in the free radical chain reaction is

55

State the term used to describe this type of step in a free radical chain reaction(1)

7 Skin care products contain a mixture of polar covalent non-polar covalent and ionic compounds The compounds need to stay mixed within the product Skin care products also need to spread easily and remain on the skin for a period of time as well as provide physical and chemical protection from the sun In order to do this skin care products contain a range of chemicals including water fats and oils antioxidants minerals and sun blockUsing your knowledge of chemistry explain the role of different chemicals in skin care products (3)

General Questions

1 A mixture of carbon monoxide and hydrogen can be converted into water and a mixture of hydrocarbons

nCO + (2n + 1)H2 rarr nH2O + hydrocarbons

What is the general formula for the hydrocarbons producedA CnH2nndash2B CnH2nC CnH2n+1D CnH2n+2

2 Butadiene is the first member of a homologous series of hydrocarbons called dienesWhat is the general formula for this seriesA CnHn+2B CnHn+3C CnH2nD CnH2nndash2

3 Which of the following statements about methanol is falseA It can be made from synthesis gasB It can be dehydrated to form an alkeneC It can be oxidised to give a carboxylic acidD It reacts with acidified potassium dichromate solution

56

4

Which line in the table correctly describes reactions X and Y

5

Which line in the table correctly describes reactions X and Y

6 Which of the following fuels when burned would make no contribution to globalwarming

57

A HydrogenB Natural gasC PetrolD Coal

7 Which of the following hydrocarbons always gives the same product when one of itshydrogen atoms is replaced by a chlorine atomA HexaneB Hex-1-eneC CyclohexaneD Cyclohexene

8 Which of the following compounds does not have isomeric structuresA C2HCl3B C2H4Cl2C PropeneD Propan-1-ol

9 What organic compound is produced by the dehydration of ethanol A EthaneB EtheneC EthanalD Ethanoic acid

10

The above equation representsA hydrationB hydrogenationC condensationD hydrolysis

11

Which of the following compounds is an isomer of the structure shown aboveA ButanalB ButanoneC Butan-1-olD Butanoic acid

58

12 A compound with molecular formula C6H12O2 could beA hexanalB hexan-2-olC hexan-2-oneD hexanoic acid

13 Propan-2-ol can be prepared from propane as follows

Which line in the table correctly describes the types of reaction taking place at Steps 1 and 2

14 Which of the following compounds would be the most water soluble

15 Cyanohydrin compounds can be made from carbonyl compounds by reacting the carbonyl compound with hydrogen cyanide (HCN)

59

Which carbonyl compound would react with hydrogen cyanide (HCN) to form the following compound

16 Ethyne is the first member of the homologous series called the alkynes

Ethyne can undergo addition reactions as shown in the flow diagram

(a) Compound 2 is an isomer of 12-dichloroethaneDraw a structural formula for compound 2 (1)

(b) Reagents A B and C are three different diatomic gasesUsing information in the flow diagram identify reagents A B and C (1)

60

Reagent Gas

A

B

C

17 In 1865 the German chemist Kekuleacute proposed a ring structure for benzene This structure was based on alternating single and double bonds

(a) (i) Describe a chemical test that would indicate that the above chemical structure for benzene is incorrect (1)

(ii) Briefly describe the correct structure for benzene (1)

(b) Benzene can be formed from cyclohexaneC6H12 rarr C6H6 + 3H2

What name is given to this type of reaction (1)18 Infra-red spectroscopy is a technique that can be used to identify the bonds that

arepresent in a molecule Different bonds absorb infra-red radiation of different wavenumbers This is due to differences in the bond lsquostretchrsquo These absorptions are recorded in a spectrumA spectrum for propan-1-ol is shown

61

The correlation table on page 13 of the data booklet shows the wavenumber ranges for the absorptions due to different bonds

(a) Use the correlation table to identify the bonds responsible for the two absorptions x and y that are circled in the propan-1-ol spectrum (1)

(b) Propan-1-ol reacts with ethanoic acid(i) What name is given to this type of reaction (1)(ii) Draw a spectrum that could be obtained for the organic product of this

reaction (1)

19 Paracetamol is a widely used painkiller

(a) Write the molecular formula for paracetamol (1)

(b) One antidote for paracetamol overdose is methionine

62

To what family of organic compounds does methionine belong (1)

(c) The concentration of paracetamol in a solution can be determined by measuring how much UV radiation it absorbs

The graph shows how the absorbance of a sample containing 0middot040 g l ndash1 paracetamol varies with wavelength

The quantity of UV radiation of wavelength 245 nm absorbed is directly proportional to the concentration of paracetamolThe absorbance of a second sample of paracetamol solution measured at 245 nm was 0middot90 What is the concentration in g l ndash1 of this second paracetamol solution (1)

20 Many carbon compounds containing oxygen are very flammableThe table shows information about two families of isomersThe lowest temperature at which a compound will ignite is called its flash point

(a) A compound with the molecular formula C6H14O has a boiling point of 158 degC63

Draw a structural formula for this compound (1)

(b) For a family of isomers in the table write a general statement linking the flash points of the compounds to their structures (1)

21 Hydrogels are used in disposable nappies They are fine powders that can absorb up to 500 times their own weight in waterA hydrogel is a very long molecule with carboxyl groups at regular intervals along its length A short section of a hydrogel molecule is shown below

Hydrogels are extremely good at soaking up water because the water molecules are strongly attracted to them

Using your knowledge of chemistry comment on how suitable hydrogels would be for absorbing liquids or solutions spilled in a chemistry lab (1)

64

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

16 The antibiotic erythromycin has the following structure

To remove its bitter taste the erythromycin is reacted to give the compound with the structure shown below

Which of the following types of compound has been reacted with erythromycin to produce this compound

A AlcoholB AldehydeC Carboxylic acidD Ketone

17 vegetable oil rarr vegetable fat

Which of the following reactions brings about the above change

A HydrolysisB CondensationC HydrogenationD Dehydrogenation

18 Which of the following fatty acids is the most unsaturated

A C15H29COOHB C15H31COOHC C17H31COOHD C17H35COOH

19 Which of the following is an isomer of ethyl propanoate (CH3CH2COOCH2CH3)

A Methyl propanoateB Pentan-2-oneC Pentanoic acidD Pentane-12-diol

5

20 Which of the following is a structural formula for glycerol

6

21 One of the chemicals released in a bee sting is an ester that has the structure shown

This ester can be produced by the reaction of an alcohol with an alkanoic acid

(a) Name this acid (1)

(b) The ester can be prepared in the lab by heating a mixture of the reactants with a catalyst

(i) Name the catalyst used in the reaction (1)

(ii) What improvement could be made to the experimental set-up shown in the diagram

(1)

22 Propan-1-ol and propanoic acid react to form an esterThe mixture of excess reactants and ester product is poured onto sodium hydrogencarbonate solution

(a) What evidence would show that an ester is formed (1)

(b) Draw a structural formula for this ester (1)

23 The ester methyl stearate is also a useful vehicle fuel A student prepared this ester from methanol and stearic acid during the Prescribed Practical Activity ldquoMaking EstersrdquoDescribe how this ester was prepared (2)

24 Foodstuffs have labels that list ingredients and provide nutritional information The label on a tub of margarine lists hydrogenated vegetable oils as one of the ingredients Why have some of the vegetable oils in this product been hydrogenated (1)

7

25 A typical triglyceride found in olive oil is shown below

(a) To which family of organic compounds do triglycerides belong (1)

(b) Olive oil can be hardened for use in margarinesWhat happens to the triglyceride molecules during the hardening of olive oil (1)

(c) Give one reason why oils can be a useful part of a balanced diet (1)

26 When vegetable oils are hydrolysed mixtures of fatty acids are obtained The fatty acids can be classified by their degree of unsaturation The table below shows the composition of each of the mixtures of fatty acids obtained when palm oil and olive oil were hydrolysed

(a) Why does palm oil have a higher melting point than olive oil (1)

(b) One of the fatty acids produced by the hydrolysis of palm oil is linoleic acid C17H31COOH To which class (saturated monounsaturated or polyunsaturated) does this fatty acid belong (1)

(c) When a mixture of palm oil and olive oil is hydrolysed using a solution of sodium hydroxide a mixture of the sodium salts of the fatty acids is obtained State a use for these fatty acid salts (1)

8

27

4-hydroxybenzoic acid can react with alcohols to form compounds known asparabens

(a) Name the functional group circled in the structure of 4minushydroxybenzoic acid (1)

(b) Name the type of reaction taking place when parabens are formed (1)

(c) Draw the paraben formed when 4minushydroxybenzoic acid reacts with ethanol (1)

(d) Parabens can be used as preservatives in cosmetics and toiletries Parabens are absorbed into the body through the skin The following table indicates the absorption of some parabens

State a conclusion that can be drawn from the information in the table (1)

9

28 When fats and oils are hydrolysed mixtures of fatty acids are obtained

(a) Name the other product obtained in this reaction (1)

(b)The table below shows the percentage composition of the fatty acid mixtures obtained by hydrolysis of coconut oil and olive oil

(i) One of the fatty acids produced by the hydrolysis of olive oil is linoleic acid C17H31COOHState the class of fatty acid to which linoleic acid belongs (1)

(ii) Hydrolysed coconut oil contains the fatty acid caprylic acid with the formula CH3(CH2)6COOHState the systematic name for caprylic acid (1)

(c) The degree of unsaturation of oil can be tested by adding drops of bromine solution to the oil Bromine adds across carbon to carbon double bonds in the fatty acid chains

The following apparatus can be used to compare the degree ofunsaturation of different oils

10

(i) Describe how this apparatus could be used to show that olive oil has a greater degree of unsaturation than coconut oil (2)

(ii) Suggest why hexane is used as the solvent rather than water (1)

(iii) Coconut oil has a melting point of 25 degC Olive oil has a melting point of minus6C

Give two reasons why coconut oil has a higher melting point than olive oil (2)

29 Traditional nail varnishes use ethyl ethanoate and butyl ethanoate as solvents

(a)Draw a structural formula for butyl ethanoate (1)(b)Ethyl ethanoate can be made in the laboratory using the following apparatus

Suggest why a wet paper towel is wrapped around the test tube (1)

(c) Name the type of reaction that takes place during the formation of ethyl ethanoate (1)

30 Pentyl butanoate is responsible for some of the flavour in apricots and strawberries

(a)Hydrolysis of pentyl butanoate using sodium hydroxide produces an alcohol and the salt of the carboxylic acid

(i) Name the alcohol that would be formed when pentyl butanoate is hydrolysed(1)

(ii) Draw a structural formula for the sodium salt of the carboxylic acid that would be formed (1)

(b)Fats and oils belong to the same class of compounds as pentyl butanoate(i) Name this class of compounds (1)

11

(ii) When a fat is hydrolysed using sodium hydroxide sodium salts of fatty acids are producedState a use for sodium salts of fatty acids (1)

22 Proteins

1 When a protein is denaturedA its overall shape is distortedB its amide links are hydrolysedC it is broken into separate peptide fragmentsD it decomposes into amino acids

2 Which of the following compounds can be classified as proteinsA FatsB OilsC EnzymesD Amino acids

3 The monomer units used to construct enzyme molecules areA alcoholsB estersC amino acidsD fatty acids

4 Amino acids are converted into proteins byA hydrationB hydrolysisC hydrogenationD condensation

5 The arrangement of amino acids in a peptide isZ-X-W-V-Y

where the letters V W X Y and Z represent amino acidsOn partial hydrolysis of the peptide which of the following sets of dipeptides is possibleA V-Y Z-X W-Y X-WB Z-X V-Y W-V X-WC Z-X X-V W-V V-YD X-W X-Z Z-W Y-V

6 Which of the following is an amine

12

7 Which of the following arrangements of atoms shows a peptide link

8 The following molecules are found in herbicides Which of the following contains an amide link

9 In α-amino acids the amino group is on the carbon atom adjacent to the acid group

Which of the following is an α-amino acid

10 A tripeptide X has the structure

Partial hydrolysis of X yields a mixture of dipeptidesWhich of the following dipeptides could be produced on hydrolysing X

13

11 The rate of hydrolysis of protein using an enzyme was studied at different temperatures Which of the following graphs would be obtained

12 The rate of hydrolysis of protein using an enzyme was studied at different temperaturesWhich of the following graphs would be obtained

14

13 Polymers can be classified as natural or synthetic(a) Keratin a natural polymer is a protein found in hair

The hydrolysis of keratin produces different monomers of the type shown

(i) What name is given to monomers like glycine alanine and cysteine (1)(ii) What is meant by a hydrolysis reaction (1)

(b) Dacron a synthetic polymer is used in heart surgery A section of the polymer is shown

What name is given to the link made by the shaded group of atoms in this section of the polymer (1)

14 Chemists have developed cheeses specifically for use in cheeseburgers(a) When ordinary cheddar cheese is grilled the shapes of the protein molecules

change and the proteins and fats separate leaving a chewy solid and an oily liquidWhat name is given to the change in protein structure which occurs when ordinary cheddar is grilled (1)

(b) To make cheese for burgers grated cheddar cheese soluble milk proteins and some water are mixed and heated to no more than 82 degC As the cheese begins to melt an emulsifying agent is added and the mixture is stirred

15

(i) Why would a water bath be used to heat the mixture (1)(ii) A section of the structure of a soluble milk protein is shown below

Draw a structural formula for any one of the amino acids formed when this section of

protein is hydrolysed (1)

(iii) The emulsifier used is trisodium citrate a salt formed when citric acid is neutralised using sodium hydroxide Complete the equation below showing a structural formula for the trisodium citrate formed (1) sp 8

15 Phenylalanine and alanine are both amino acids

(a) Phenylalanine is an essential amino acid

(i) What is meant by an essential amino acid (1)

16

(ii) How many hydrogen atoms are present in a molecule of phenylalanine (1)

(b) Phenylalanine and alanine can react to form the dipeptide shown

Circle the peptide link in this molecule (1)

(c) Draw a structural formula for the other dipeptide that can be formed from phenylalanine and alanine (1)

16 Uncooked egg white is mainly composed of dissolved proteins During cooking processes the proteins become denatured as the protein chains unwind and the egg white solidifies

(a) Explain why the protein chains unwind (1)

(b)The temperature at which the protein becomes denatured is called the melting temperature The melting temperature of a protein can be determined using fluorescence In this technique the protein is mixed with a dye that gives out visible light when it attaches to hydrophobic parts of the protein molecule The hydrophobic parts of the structure are on the inside of the protein and the dye has no access to them unless the protein unwinds

(i) Ovalbumin is a protein found in egg white Part of the structure of unwound ovalbumin is shown below

Circle the part of the structure to which the hydrophobic dye is most likely to attach (1)

17

(ii) Another protein in egg white is conalbumin The temperature of a conalbumindye mixture is gradually increased The fluorescence is measured and a graph is produced

The melting temperature is the temperature at which the fluorescence is halfway between the highest and lowest fluorescence valuesDetermine the melting temperature in ordmC for this protein (1)

(c) Once cooked and eaten the digestive system breaks the protein chains into amino acids with the help of enzymes

(i) State the name of the digestion process where enzymes break down proteins into amino acids (1)

(ii)

(A) State how many amino acid molecules joined to form this section of protein (1)

(B) Draw the structure of one amino acid that would be produced when this section of the protein chain is broken down (1)

17 Peptide molecules can be classified according to the number of amino acid units joined by peptide bonds in the molecule

18

(a) Complete the table to identify the type of peptide with the following amino acid sequence

alanine-glycine-valine-proline-tyrosine-serine (1)

(b) Partial hydrolysis of another pentapeptide molecule gave a mixture of three smaller peptide molecules with the following amino acid sequences

leucine-glycine-valineisoleucine-leucineglycine-valine-serine

Write the amino acid sequence for the original pentapeptide molecule (1)

helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip(c) Some amino acids needed to form polypeptides cannot be produced in the human body

State the term used to describe amino acids that the body cannot make (1)

(d)Paper chromatography is often used to analyse the mixtures of amino acids produced when peptides are broken downOn a chromatogram the retention factor Rf for a substance can be a useful method of identifying the substance

The structure of the pentapeptide methionine enkephalin was investigatedA sample of the pentapeptide was completely hydrolysed into its constituent amino acids and this amino acid mixture was applied to a piece of chromatography paper and placed in a solventThe chromatogram obtained is shown below

19

(i) Suggest why only four spots were obtained on the chromatogram of the hydrolysed pentapeptide (1)

(ii) It is known that this amino acid mixture contains the amino acid methionine The Rf value for methionine in this solvent is 040Draw a circle around the spot on the chromatogram that corresponds to methionine (1)

(e) Over the last decade several families of extremely stable peptide molecules have been discovered where the peptide chain forms a ring

(i) A simple cyclic dipeptide is shown

Draw a structural formula for one of the amino acids that would be formed on complete hydrolysis of the above cyclic dipeptide (1)

(ii) Alpha-amanitin is a highly toxic cyclic peptide found in death cap mushrooms The lethal dose for humans is 100 mg per kg of body mass1middot0 g of death cap mushrooms contains 250 mg of alpha-amanitinCalculate the minimum mass of death cap mushrooms that would contain the lethal dose for a 75 kg adult (2)

18 Dishwasher tablets produce the bleach hydrogen peroxide H2O2 One action of this oxidising agent is to oxidise food

(a)(i) Suggest another action of the bleach produced by the dishwasher tablets (1)

20

(ii) Hydrogen peroxide decomposes to form water and oxygen

2H2O2(ℓ) rarr 2H2O(ℓ) + O2(g)

A dishwasher tablet produces 0middot051 g of hydrogen peroxide (mass of one mole = 34 g)

Calculate the volume of oxygen that would be produced when0middot051 g of hydrogen peroxide decomposesTake the volume of 1 mole of oxygen gas to be 24 litres(3)

(b)Enzymes are commonly added to dishwasher tablets These are used to break down proteins(i) The proteins are broken down into small water-soluble molecules

Name the small water-soluble molecules made when proteins are broken down completely (1)

(ii) The structure of a section of protein chain found in egg white is shown

(A)Name the functional group circled (1)(B)Draw a structural formula for one of the molecules that would be made

when this section of egg white protein chain is completely broken down (1)

(iii) As part of the program in the dishwasher the conditions in the dishwasher change so that the enzyme molecules no longer work because they change shape

21

(A) State the term used to describe the change in shape of enzyme molecules(1)

(B) Suggest a change in conditions which would cause the enzyme molecules to change shape (1)

(d) A bleach activator is frequently added to dishwasher tablets to speed up the bleaching reaction One common bleach activator is TAED TAED could be produced in a process which involves a number of stages

(i) The first stage in producing TAED is shown below

Suggest a name for this type of reaction (1)

(ii) The final stage in the process producing TAED is shown below

Draw a structural formula for TAED (1)

22

23 The Chemistry of Cooking

1 Vanillin and zingerone are flavour molecules

Which line in the table correctly compares the properties of vanillin and zingerone

23

2 Erythrose can be used in the production of a chewing gum that helps prevent tooth decay

Which of the following compounds will be the best solvent for erythrose

3 The following molecules give flavour to food Which of the following flavour molecules would be most likely to be retained in the food when the food is cooked in water

24

4 Cooking involves many chemical reactions Proteins fats oils and esters are some examples of compounds found in food A chemist suggested that cooking food could change compounds from being fat-soluble to water-soluble Use your knowledge of chemistry to comment on the accuracy of this statement(3)

25

24 The Oxidation of Food

1 Apples and bananas turn brown when cut or bruised The first step of the reaction causing

the browning is shown below

Which of the following terms correctly describes this reactionA ReductionB OxidationC DehydrationD Condensation

2 Which of the following reactions can be classified as reductionA CH3CH2OH rarr CH3COOHB CH3 CH(OH)CH3 rarr CH3COCH3C CH3CH2COCH3 rarr CH3CH2CH(OH)CH3D CH3CH2CHO rarr CH3CH2COOH

3 The dehydration of butan-2-ol can produce two isomeric alkenes but-1-ene andbut-2-ene Which of the following alkanols can similarly produce on dehydration a pair of isomeric alkenesA Propan-2-olB Pentan-3-olC Hexan-3-olD Heptan-4-ol

4 Which of the following compounds is an alkanone

26

5 Which of the following is an aldehyde

6 Which of the following compounds would react with sodium hydroxide solution to forma saltA CH3CHOB CH3COOHC CH3COCH3D CH3CH2OH

7 Which line in the table shows the correct functional group for each homologous series

8 Which of the following organic compounds is an isomer of hexanalA 2-MethylbutanalB 3-Methylpentan-2-oneC 22-Dimethylbutan-1-olD 3-Ethylpentanal

27

9 The name of this compound is

A methanolB methanalC methanoic acidD methanone

10 Which alcohol could be oxidised to a carboxylic acid

11 Which of the following structural formulae represents a tertiary alcohol

12 Compound X reacted with hot copper(II) oxide and the organic product did not give acolour change when heated with Fehlingrsquos solution Compound X could beA butan-1-olB butan-2-olC butanoneD butanoic acid

28

13 Which two isomers would each produce an acid when warmed with acidified potassiumdichromate solution

A 1 and 2B 2 and 3C 1 and 4D 3 and 4

14 After heating for several minutes as shown in the diagram the pH indicator solution turned red

Liquid Q could beA propanoneB paraffinC propan-1-olD propan-2-ol

29

15 Enzymes are involved in the browning of cut fruitOne reaction taking place is

Which of the following correctly describes the above reaction

A OxidationB ReductionC HydrolysisD Condensation

16 Which of the following statements is correct for ketones

A They are formed by oxidation of tertiary alcohols

B They contain the group

C They contain a carboxyl groupD They will not react with Fehlingrsquos solution

17 Carvone is a natural product that can be extracted from orange peel

Which line in the table correctly describes the reaction of carvone with bromine solution and with acidified potassium dichromate solution

30

18 Which of the following is an isomer of 22-dimethylpentan-1-ol

A CH3CH2CH2CH(CH3)CH2OHB (CH3)3CCH(CH3)CH2OHC CH3CH2CH2CH2CH2CH2CH2CH2OHD (CH3)2CHC(CH3)2CH2CH2OH

19 The equation for the reduction reaction taking place when ethanal reacts with Tollensrsquo reagent is

A Cu2+(aq) + eminus rarr Cu+(aq)

B Ag+(aq) + eminus rarr Ag(s)

C Cr2O72minus(aq) + 14H+(aq) + 6eminus rarr 2Cr3+(aq) + 7H2O(ℓ)

D MnO4minus(aq) + 8H+(aq) + 5eminus rarr Mn2+(aq) + 4H2O(ℓ)

20 The name of the compound with structure

isA 23-dimethylpentan-4-oneB 23-dimethylpentan-2-alC 34-dimethylpentan-2-oneD 34-dimethylpentan-2-al

21 What is the systematic name for the compound below

A 222-trimethylethanolB 22-dimethylpropan-1-olC 22-dimethylpropan-3-olD 22-dimethylpentan-1-ol

31

22 The structure of a molecule found in olive oil can be represented as shown

(a) Olive oil can be hydrolysed using sodium hydroxide solution to produce sodium salts of fatty acids Name the other product of this reaction (1)

(b) In what way does the structure of a fat molecule differ from that of an oil molecule (1)

(c) Over time open containers of olive oil develop a rancid flavour What substance is reacting with the oil to cause these unwanted changes to take place (1)

23 A student writes the following statement It is incorrect Explain the mistake in the studentrsquos reasoning (1)

Alcohols are alkaline because of their OH groups

24 Carbon compounds take part in a wide variety of chemical reactions (a)

Name this type of chemical reaction (1)

(b)

Draw a structural formula for C3H6O (1)

25 Alkanols can be oxidised to alkanoic acids

32

(a) Why can Step 1 be described as an oxidation reaction (1)

(b) Acidified potassium dichromate solution can be used to oxidise propanal in Step 2 What colour change would be observed in this reaction (1)

26 Amines can be produced by reacting ammonia with an aldehyde or a ketone This reaction an example of reductive amination occurs in two stages

Stage 1 Amination

Stage 2 Reduction

(a) Give another name for the type of reaction taking place in Stage 2

(b) Draw the structural formula for the amine produced when butanal undergoes reductive amination with ammonia

27 Using a cobalt catalyst alkenes react with a mixture of hydrogen and carbon monoxideThe products are two isomeric aldehydes Propene reacts with the mixture as shown

(a) What name is given to a mixture of hydrogen and carbon monoxide (1)

(b) Draw a structural formula for compound B (1)

(c) (i) What would be observed if compound A was gently heated with Tollensrsquo reagent

(1)(ii) How would the reaction mixture be heated (1)

33

(d) Aldehydes can also be formed by the reaction of some alcohols with copper(II) oxideName the type of alcohol that would react with copper(II) oxide to form an aldehyde (1)

28 Aldehydes and ketones can take part in a reaction sometimes known as an aldol condensation The simplest aldol reaction involves two molecules of ethanal

In the reaction the carbon atom next to the carbonyl functional group of one molecule forms a bond with the carbonyl carbon atom of the second molecule

(a) Draw a structural formula for the product formed when propanone is used instead of ethanal in this type of reaction (1)

(b) Name an aldehyde that would not take part in an aldol condensation (1)

(c) Apart from the structure of the reactants suggest what is unusual about applying the term ldquocondensationrdquo to this particular type of reaction (1)

29 Primary secondary and tertiary alkanols can be prepared by the reaction of carbonyl compounds with Grignard reagents

Step 1The Grignard reagent reacts with the carbonyl compound

Step 2The reaction of the product of Step 1 with dilute acid produces the alkanol

(a) Describe the difference between a primary a secondary and a tertiary alkanol

You may wish to include labelled structures in your answer (1)34

(b) Suggest a name for the type of reaction that takes place in Step 1 (1)

(c) The same Grignard reagent can be used to produce the alkanol below

Name the carbonyl compound used in this reaction (1)

30 Hairspray is a mixture of chemicals(a) A primary alcohol 2-methylpropan-1-ol is added to hairspray to help it dry quickly on the hair

Draw a structural formula for a secondary alcohol that is an isomer of2-methylpropan-1-ol (1)

(b) Triethanol amine and triisopropyl amine are bases used to neutralise acidic compounds in the hairspray to prevent damage to the hair

In terms of the intermolecular bonding present explain clearly why triethanol amine has a much higher boiling point than triisopropyl amine (2)

35

36

31 Chocolate contains various compounds(a) Many of the flavour and aroma molecules found in chocolate are aldehydes and

ketones Two examples are shown below

Phenylethanal can be easily oxidised but 13-diphenylpropan-2-one cannot(i) Name a chemical that could be used to distinguish between these two

compounds (1)

(ii) Name the type of organic compound formed when phenylethanal is oxidised (1)

(b) Glycerol monostearate is an emulsifier used in chocolate

(i) Why is glycerol monostearate added to chocolate (1)

(ii) Draw a structural formula for glycerol (1)

(c) Theobromine a compound present in chocolate can cause illness in dogs and cats To decide if treatment is necessary vets must calculate the mass of theobromine consumed 1middot0 g of chocolate contains 1middot4 mg of theobromine Calculate the mass in mg of theobromine in a 17 g biscuit of which 28 is chocolate Show your working clearly (2)

(d) The flavour and texture of chocolate comes from a blend of compoundsUsing your knowledge of chemistry describe how you could show that there are ionic compounds and covalent compounds present in chocolate (3)

37

32 Ethanol has many uses

(a) Ethanol is found at relatively low concentrations in wine

(i) Name the chemical reaction that produces ethanol in wine (1)

(ii) Standard ethanol solutions were used to produce a graph of density against

concentration of ethanol given as a percentage of alcohol by volume ( abv)

What is the concentration of ethanol in units of abv in a solution of density 0middot9818 g cmminus3 (1)

(b) Whisky contains a higher concentration of ethanol

(i) Before 1980 the concentration of alcohol in drinks was measured in terms of degrees proof The concentration of alcohol in two drinks is shown in the table below both as abv and degrees proof

38

A cask strength whisky has an alcohol concentration of 65 abv Calculate the alcohol concentration of this whisky in degrees proof (1)

(ii) A barrel containing 195 litres of cask strength whisky costs pound1300 The cask strength whisky is diluted with water to reduce the concentration of alcohol from 65 abv to 46 abv before it is bottled Calculate the cost of the cask strength whisky needed to produce a 0middot70 litre bottle Show your working clearly (2)

(iii) 5-Butyl-4-methyltetrahydrofuran-2-ol is a flavour compound found in whisky

stored in oak barrels

Write the systematic name for the compound shown below (1) 13 11

33 (a) One test for glucose involves Fehlingrsquos solutionCircle the part of the glucose molecule that reacts with Fehlingrsquos solution (1)

(b) In solution sugar molecules exist in an equilibrium in straight-chain and ring forms

To change from the straight-chain form to the ring form the oxygen of the hydroxyl on carbon number 5 joins to the carbonyl carbon This is shown below for glucose

39

Draw the structure of a ring form for fructose (1)

34 (a) During the free radical chain reaction small molecules join to form large chain molecules

One example of a small molecule used is

Name the functional group circled above (1)

(b)Alcohol wipes are used to finish the varnishing treatment Alcohol wipes contain the alcohol propan-2-olState why propan-2-ol can be described as a secondary alcohol (1)

35 A student was carrying out an investigation into alcohols aldehydes and ketones

(a)The student was given three alcohols labelled as A B and C These alcohols were all isomers with the formula C4H9OH

(i) Draw a structural formula for the secondary alcohol with the formula C4H9OH(1)

(ii) The student set up the following experiment

A Suggest why a water bath is an appropriate method of heating the reaction mixture (1)

B Describe the colour change that would have been observed with alcohols A and C (1)

40

C Alcohol B is not oxidised State the type of alcohol which cannot be oxidised by acidified dichromate solution (1)

(iii) The student set up a second experiment with alcohol A

Hot copper(II) oxide is an oxidising agentA When alcohol A (C4H9OH) is oxidised the product turns the pH paper

redSuggest a name for the product (1)

B Complete the ion-electron equation for the oxidation reaction

C4H9OH rarr C4H8O2 (1)

(b)The student found the following information about the boiling points of some aldehydes

41

(i) Name the aldehyde that has a boiling point of 119 degC (1)(ii) Predict the boiling point in degC of the following molecule (1)

(iii) Using information from the table describe one way in which differences in structure affect the boiling point of isomeric aldehydes (1)

(iv) State what would be observed when an aldehyde is gently heated with Tollensrsquo reagent (1)

(c) Ketones contain a carbonyl groupName the type of intermolecular interaction between ketone molecules (1)

42

25 Soaps Detergents and Emulsions

1 Soaps are produced by the following reaction

This reaction is an example ofA condensationB esterificationC hydrolysisD oxidation

2 Which of the following is the salt of a long-chain fatty acid

A FatB OilC SoapD Glycerol

3 Emulsifiers for use in food are commonly made by reacting edible oils with

A estersB glycerolC fatty acidsD amino acids

4 A fatty acid is a long chain carboxylic acid Examples of fatty acids are shown in the table below

43

(a) What is the systematic name for linolenic acid (1)(b) Stearic acid reacts with sodium hydroxide solution to form sodium stearate

(i) Name the type of reaction taking place when stearic acid reacts with sodium hydroxide (1)

(ii) Explain fully how sodium stearate acts to keep grease and non-polar substances suspended in water during cleaning (3)

5 Small children can find it difficult to swallow tablets or pills so ibuprofen is supplied as an ldquoinfant formulardquo emulsion(a) The emulsifier used is polysorbate 80 Its structure is shown below

Explain why this molecule acts as an emulsifier (2)

(b) The emulsion contains 2 g of ibuprofen in every 100 cm3 of emulsion The recommended dose for treating a 6 month old baby is 0middot050 g Calculate the volume in cm3 of ldquoinfant formulardquo needed to treat a 6 month old baby (1)

6 Occasionally seabirds can become contaminated with hydrocarbons from oil spills This causes problems for birds because their feathers lose their waterproofing making the birds susceptible to temperature changes and

44

affecting their buoyancy If the birds attempt to clean themselves to remove the oil they may swallow the hydrocarbons causing damage to their internal organsContaminated seabirds can be cleaned by rubbing vegetable oil into their feathers and feet before the birds are rinsed with diluted washing-up liquidUsing your knowledge of chemistry comment on the problems created for seabirds by oil spills and the actions taken to treat affected birds (3)

7 Dishwasher tablets contain chemicals which remove dirt from dishesDishwasher tablets include detergents These molecules act like soaps to allow mixing of fat-soluble dirt and water(a)During the cleaning process the detergent molecules combine with fat-

soluble dirtA simplified diagram of a detergent molecule is shown

Complete the diagram below to show how detergent molecules combine with fat-soluble dirt (1)

(b)State the term used to describe the non-polar hydrocarbon tail of a detergent molecule (1)

45

26 Fragrances1 Myrcene is a simple terpene

Terpenes contain at least one isoprene unit Which of the following shows a correctly highlighted isoprene unit

2 Limonene is one of the terpene molecules responsible for the flavour of lemons

How many isoprene units are used in the production of one limonene moleculeA 1B 2C 3D 4

46

3 The structure of caryophyllene which can be extracted from clove oil is

Which of the following would be the best solvent for extracting caryophylleneA HexaneB HexanalC HexanolD Hexanone

4 The structure of isoprene is

Limonene is a terpene molecule present in lemons

How many isoprene units are joined together in a limonene molecule

A 1B 2

47

C 3D 4

5 Essential oils are

A non-water soluble non-volatile compoundsB non-water soluble volatile compoundsC water soluble non-volatile compoundsD water soluble volatile compounds

6 Two typical compounds that are present in many perfumes are shown

(a) Why does geraniol evaporate more slowly than limonene (1)

(b) The structure of one of the first synthetic scents used in perfume is shown below

(i) Name the family of carbonyl compounds to which this synthetic scent belongs (1)

(ii) Complete the structure below to show the product formed when this scent is

oxidised (1)

(c) Traces of a liquid were discovered in a bottle believed to contain perfume belonging to Queen Hatshepsut ruler of Egypt over 3500 years ago

Perfumes were made by dissolving plant extracts containing pleasant smelling terpenes and esters in an edible oil A little ethanol and water may also have been addedUsing your knowledge of chemistry comment on the possible smell(s) when such a bottle is opened after being stored for thousands of years (3)

48

49

7 A team of chemists are developing a fragrance for use in a shower gel for men(a) To give the gel a fruity smell the chemists are considering adding an ester

They synthesise six isomeric esters Volunteers smell each ester and give it a rating out of one hundred depending on how fruity the smell is

(i) Name the ester with the fruit-smell rating of 92 (1)

(ii) Shown below are the structures of three more isomers

Arrange these esters in order of decreasing fruit-smell rating (1)

50

(b) To create a fragrance for men the compound civetone is added

Draw a structural formula for the alcohol that can be oxidised to form civetone (1)

(c) To make the shower gel produce a cold tingling sensation when applied to the skin menthol is added

Like terpenes menthol is formed from isoprene (2-methylbuta-13-diene)Circle an isoprene unit on the menthol structure above (1)

8 Many of the compounds in perfumes are molecules consisting of joined isoprene units

(a) State the name that is given to molecules consisting of joined isoprene units (1)

(b)Geraniol is one of the compounds found in perfume It has the following structural formula and systematic name

Linalool can also be present Its structural formula is shown

51

(i) State the systematic name for linalool (1)(ii) Explain why linalool can be classified as a tertiary alcohol (1)

9 The component molecules found in lavender oils are terpenes or terpenoids(a)A chiral carbon is a carbon atom attached to four different atoms or groups of

atomsAn example is shown below

A molecule of the terpenoid linalool has a chiral carbon Linalool has the following structure

Circle the chiral carbon atom in the linalool structure (1)

(b)Farnesene is a terpene consisting of three isoprene units (2-methylbuta-13-diene) joined togetherWrite the molecular formula of farnesene (1)

52

27 Skin Care

1 Which of the following is not a step in a free radical chain reaction

A ActivationB InitiationC PropagationD Termination

2 Fluorine reacts with methane via a free radical chain reaction Some steps in the chain reaction are shown in the table below

Complete the table by(a) inserting the missing name for the first step (1)

(b) showing another possible termination reaction in the final row of the table (1)

3 Suncreams contain antioxidantsThe antioxidant compound A can prevent damage to skin by reacting with free

radicalssuch as NO2bull

53

Why can compound A be described as a free radical scavenger in the reaction shown above

4 Hydrogen and chlorine gases are used in an experiment to demonstrate a free radical reaction A plastic bottle is wrapped with black tape leaving a ldquowindowrdquo on one sideThe bottle is filled with a mixture of hydrogen and chlorine When bright light shines on the bottle there is an explosion

A free radical chain reaction is initiated when light energy causes chlorine radicals to form as shown below

(a) Complete the equations below showing possible propagation and termination steps

(2)

54

(b) Why is the plastic bottle used in the experiment wrapped in black tape (1)

5 Chloramines can be removed from water using ultraviolet light treatment

One step in the process is the formation of free radicals

(a)State what is meant by the term free radical (1)

(b)Another step in the process is shown below

State the name for this type of step in a free radical reaction (1)

6 Modern shellac nail varnishes are more durable and so last longer than traditional nail polish

The shellac nail varnish is applied in thin layers to the nails and then the fingers are placed under a UV lamp

(a) The Skin Care Foundation has recommended that a sun-block is applied to the fingers and hand before using the lampSuggest why the Skin Care Foundation makes this recommendation (1)

(b) A free radical chain reaction takes place and the varnish hardens (i) State what is meant by the term free radical (1)

(ii) The shellac nail varnish contains a mixture of ingredients that take part in the free radical chain reactionOne of the steps in the free radical chain reaction is

55

State the term used to describe this type of step in a free radical chain reaction(1)

7 Skin care products contain a mixture of polar covalent non-polar covalent and ionic compounds The compounds need to stay mixed within the product Skin care products also need to spread easily and remain on the skin for a period of time as well as provide physical and chemical protection from the sun In order to do this skin care products contain a range of chemicals including water fats and oils antioxidants minerals and sun blockUsing your knowledge of chemistry explain the role of different chemicals in skin care products (3)

General Questions

1 A mixture of carbon monoxide and hydrogen can be converted into water and a mixture of hydrocarbons

nCO + (2n + 1)H2 rarr nH2O + hydrocarbons

What is the general formula for the hydrocarbons producedA CnH2nndash2B CnH2nC CnH2n+1D CnH2n+2

2 Butadiene is the first member of a homologous series of hydrocarbons called dienesWhat is the general formula for this seriesA CnHn+2B CnHn+3C CnH2nD CnH2nndash2

3 Which of the following statements about methanol is falseA It can be made from synthesis gasB It can be dehydrated to form an alkeneC It can be oxidised to give a carboxylic acidD It reacts with acidified potassium dichromate solution

56

4

Which line in the table correctly describes reactions X and Y

5

Which line in the table correctly describes reactions X and Y

6 Which of the following fuels when burned would make no contribution to globalwarming

57

A HydrogenB Natural gasC PetrolD Coal

7 Which of the following hydrocarbons always gives the same product when one of itshydrogen atoms is replaced by a chlorine atomA HexaneB Hex-1-eneC CyclohexaneD Cyclohexene

8 Which of the following compounds does not have isomeric structuresA C2HCl3B C2H4Cl2C PropeneD Propan-1-ol

9 What organic compound is produced by the dehydration of ethanol A EthaneB EtheneC EthanalD Ethanoic acid

10

The above equation representsA hydrationB hydrogenationC condensationD hydrolysis

11

Which of the following compounds is an isomer of the structure shown aboveA ButanalB ButanoneC Butan-1-olD Butanoic acid

58

12 A compound with molecular formula C6H12O2 could beA hexanalB hexan-2-olC hexan-2-oneD hexanoic acid

13 Propan-2-ol can be prepared from propane as follows

Which line in the table correctly describes the types of reaction taking place at Steps 1 and 2

14 Which of the following compounds would be the most water soluble

15 Cyanohydrin compounds can be made from carbonyl compounds by reacting the carbonyl compound with hydrogen cyanide (HCN)

59

Which carbonyl compound would react with hydrogen cyanide (HCN) to form the following compound

16 Ethyne is the first member of the homologous series called the alkynes

Ethyne can undergo addition reactions as shown in the flow diagram

(a) Compound 2 is an isomer of 12-dichloroethaneDraw a structural formula for compound 2 (1)

(b) Reagents A B and C are three different diatomic gasesUsing information in the flow diagram identify reagents A B and C (1)

60

Reagent Gas

A

B

C

17 In 1865 the German chemist Kekuleacute proposed a ring structure for benzene This structure was based on alternating single and double bonds

(a) (i) Describe a chemical test that would indicate that the above chemical structure for benzene is incorrect (1)

(ii) Briefly describe the correct structure for benzene (1)

(b) Benzene can be formed from cyclohexaneC6H12 rarr C6H6 + 3H2

What name is given to this type of reaction (1)18 Infra-red spectroscopy is a technique that can be used to identify the bonds that

arepresent in a molecule Different bonds absorb infra-red radiation of different wavenumbers This is due to differences in the bond lsquostretchrsquo These absorptions are recorded in a spectrumA spectrum for propan-1-ol is shown

61

The correlation table on page 13 of the data booklet shows the wavenumber ranges for the absorptions due to different bonds

(a) Use the correlation table to identify the bonds responsible for the two absorptions x and y that are circled in the propan-1-ol spectrum (1)

(b) Propan-1-ol reacts with ethanoic acid(i) What name is given to this type of reaction (1)(ii) Draw a spectrum that could be obtained for the organic product of this

reaction (1)

19 Paracetamol is a widely used painkiller

(a) Write the molecular formula for paracetamol (1)

(b) One antidote for paracetamol overdose is methionine

62

To what family of organic compounds does methionine belong (1)

(c) The concentration of paracetamol in a solution can be determined by measuring how much UV radiation it absorbs

The graph shows how the absorbance of a sample containing 0middot040 g l ndash1 paracetamol varies with wavelength

The quantity of UV radiation of wavelength 245 nm absorbed is directly proportional to the concentration of paracetamolThe absorbance of a second sample of paracetamol solution measured at 245 nm was 0middot90 What is the concentration in g l ndash1 of this second paracetamol solution (1)

20 Many carbon compounds containing oxygen are very flammableThe table shows information about two families of isomersThe lowest temperature at which a compound will ignite is called its flash point

(a) A compound with the molecular formula C6H14O has a boiling point of 158 degC63

Draw a structural formula for this compound (1)

(b) For a family of isomers in the table write a general statement linking the flash points of the compounds to their structures (1)

21 Hydrogels are used in disposable nappies They are fine powders that can absorb up to 500 times their own weight in waterA hydrogel is a very long molecule with carboxyl groups at regular intervals along its length A short section of a hydrogel molecule is shown below

Hydrogels are extremely good at soaking up water because the water molecules are strongly attracted to them

Using your knowledge of chemistry comment on how suitable hydrogels would be for absorbing liquids or solutions spilled in a chemistry lab (1)

64

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

20 Which of the following is a structural formula for glycerol

6

21 One of the chemicals released in a bee sting is an ester that has the structure shown

This ester can be produced by the reaction of an alcohol with an alkanoic acid

(a) Name this acid (1)

(b) The ester can be prepared in the lab by heating a mixture of the reactants with a catalyst

(i) Name the catalyst used in the reaction (1)

(ii) What improvement could be made to the experimental set-up shown in the diagram

(1)

22 Propan-1-ol and propanoic acid react to form an esterThe mixture of excess reactants and ester product is poured onto sodium hydrogencarbonate solution

(a) What evidence would show that an ester is formed (1)

(b) Draw a structural formula for this ester (1)

23 The ester methyl stearate is also a useful vehicle fuel A student prepared this ester from methanol and stearic acid during the Prescribed Practical Activity ldquoMaking EstersrdquoDescribe how this ester was prepared (2)

24 Foodstuffs have labels that list ingredients and provide nutritional information The label on a tub of margarine lists hydrogenated vegetable oils as one of the ingredients Why have some of the vegetable oils in this product been hydrogenated (1)

7

25 A typical triglyceride found in olive oil is shown below

(a) To which family of organic compounds do triglycerides belong (1)

(b) Olive oil can be hardened for use in margarinesWhat happens to the triglyceride molecules during the hardening of olive oil (1)

(c) Give one reason why oils can be a useful part of a balanced diet (1)

26 When vegetable oils are hydrolysed mixtures of fatty acids are obtained The fatty acids can be classified by their degree of unsaturation The table below shows the composition of each of the mixtures of fatty acids obtained when palm oil and olive oil were hydrolysed

(a) Why does palm oil have a higher melting point than olive oil (1)

(b) One of the fatty acids produced by the hydrolysis of palm oil is linoleic acid C17H31COOH To which class (saturated monounsaturated or polyunsaturated) does this fatty acid belong (1)

(c) When a mixture of palm oil and olive oil is hydrolysed using a solution of sodium hydroxide a mixture of the sodium salts of the fatty acids is obtained State a use for these fatty acid salts (1)

8

27

4-hydroxybenzoic acid can react with alcohols to form compounds known asparabens

(a) Name the functional group circled in the structure of 4minushydroxybenzoic acid (1)

(b) Name the type of reaction taking place when parabens are formed (1)

(c) Draw the paraben formed when 4minushydroxybenzoic acid reacts with ethanol (1)

(d) Parabens can be used as preservatives in cosmetics and toiletries Parabens are absorbed into the body through the skin The following table indicates the absorption of some parabens

State a conclusion that can be drawn from the information in the table (1)

9

28 When fats and oils are hydrolysed mixtures of fatty acids are obtained

(a) Name the other product obtained in this reaction (1)

(b)The table below shows the percentage composition of the fatty acid mixtures obtained by hydrolysis of coconut oil and olive oil

(i) One of the fatty acids produced by the hydrolysis of olive oil is linoleic acid C17H31COOHState the class of fatty acid to which linoleic acid belongs (1)

(ii) Hydrolysed coconut oil contains the fatty acid caprylic acid with the formula CH3(CH2)6COOHState the systematic name for caprylic acid (1)

(c) The degree of unsaturation of oil can be tested by adding drops of bromine solution to the oil Bromine adds across carbon to carbon double bonds in the fatty acid chains

The following apparatus can be used to compare the degree ofunsaturation of different oils

10

(i) Describe how this apparatus could be used to show that olive oil has a greater degree of unsaturation than coconut oil (2)

(ii) Suggest why hexane is used as the solvent rather than water (1)

(iii) Coconut oil has a melting point of 25 degC Olive oil has a melting point of minus6C

Give two reasons why coconut oil has a higher melting point than olive oil (2)

29 Traditional nail varnishes use ethyl ethanoate and butyl ethanoate as solvents

(a)Draw a structural formula for butyl ethanoate (1)(b)Ethyl ethanoate can be made in the laboratory using the following apparatus

Suggest why a wet paper towel is wrapped around the test tube (1)

(c) Name the type of reaction that takes place during the formation of ethyl ethanoate (1)

30 Pentyl butanoate is responsible for some of the flavour in apricots and strawberries

(a)Hydrolysis of pentyl butanoate using sodium hydroxide produces an alcohol and the salt of the carboxylic acid

(i) Name the alcohol that would be formed when pentyl butanoate is hydrolysed(1)

(ii) Draw a structural formula for the sodium salt of the carboxylic acid that would be formed (1)

(b)Fats and oils belong to the same class of compounds as pentyl butanoate(i) Name this class of compounds (1)

11

(ii) When a fat is hydrolysed using sodium hydroxide sodium salts of fatty acids are producedState a use for sodium salts of fatty acids (1)

22 Proteins

1 When a protein is denaturedA its overall shape is distortedB its amide links are hydrolysedC it is broken into separate peptide fragmentsD it decomposes into amino acids

2 Which of the following compounds can be classified as proteinsA FatsB OilsC EnzymesD Amino acids

3 The monomer units used to construct enzyme molecules areA alcoholsB estersC amino acidsD fatty acids

4 Amino acids are converted into proteins byA hydrationB hydrolysisC hydrogenationD condensation

5 The arrangement of amino acids in a peptide isZ-X-W-V-Y

where the letters V W X Y and Z represent amino acidsOn partial hydrolysis of the peptide which of the following sets of dipeptides is possibleA V-Y Z-X W-Y X-WB Z-X V-Y W-V X-WC Z-X X-V W-V V-YD X-W X-Z Z-W Y-V

6 Which of the following is an amine

12

7 Which of the following arrangements of atoms shows a peptide link

8 The following molecules are found in herbicides Which of the following contains an amide link

9 In α-amino acids the amino group is on the carbon atom adjacent to the acid group

Which of the following is an α-amino acid

10 A tripeptide X has the structure

Partial hydrolysis of X yields a mixture of dipeptidesWhich of the following dipeptides could be produced on hydrolysing X

13

11 The rate of hydrolysis of protein using an enzyme was studied at different temperatures Which of the following graphs would be obtained

12 The rate of hydrolysis of protein using an enzyme was studied at different temperaturesWhich of the following graphs would be obtained

14

13 Polymers can be classified as natural or synthetic(a) Keratin a natural polymer is a protein found in hair

The hydrolysis of keratin produces different monomers of the type shown

(i) What name is given to monomers like glycine alanine and cysteine (1)(ii) What is meant by a hydrolysis reaction (1)

(b) Dacron a synthetic polymer is used in heart surgery A section of the polymer is shown

What name is given to the link made by the shaded group of atoms in this section of the polymer (1)

14 Chemists have developed cheeses specifically for use in cheeseburgers(a) When ordinary cheddar cheese is grilled the shapes of the protein molecules

change and the proteins and fats separate leaving a chewy solid and an oily liquidWhat name is given to the change in protein structure which occurs when ordinary cheddar is grilled (1)

(b) To make cheese for burgers grated cheddar cheese soluble milk proteins and some water are mixed and heated to no more than 82 degC As the cheese begins to melt an emulsifying agent is added and the mixture is stirred

15

(i) Why would a water bath be used to heat the mixture (1)(ii) A section of the structure of a soluble milk protein is shown below

Draw a structural formula for any one of the amino acids formed when this section of

protein is hydrolysed (1)

(iii) The emulsifier used is trisodium citrate a salt formed when citric acid is neutralised using sodium hydroxide Complete the equation below showing a structural formula for the trisodium citrate formed (1) sp 8

15 Phenylalanine and alanine are both amino acids

(a) Phenylalanine is an essential amino acid

(i) What is meant by an essential amino acid (1)

16

(ii) How many hydrogen atoms are present in a molecule of phenylalanine (1)

(b) Phenylalanine and alanine can react to form the dipeptide shown

Circle the peptide link in this molecule (1)

(c) Draw a structural formula for the other dipeptide that can be formed from phenylalanine and alanine (1)

16 Uncooked egg white is mainly composed of dissolved proteins During cooking processes the proteins become denatured as the protein chains unwind and the egg white solidifies

(a) Explain why the protein chains unwind (1)

(b)The temperature at which the protein becomes denatured is called the melting temperature The melting temperature of a protein can be determined using fluorescence In this technique the protein is mixed with a dye that gives out visible light when it attaches to hydrophobic parts of the protein molecule The hydrophobic parts of the structure are on the inside of the protein and the dye has no access to them unless the protein unwinds

(i) Ovalbumin is a protein found in egg white Part of the structure of unwound ovalbumin is shown below

Circle the part of the structure to which the hydrophobic dye is most likely to attach (1)

17

(ii) Another protein in egg white is conalbumin The temperature of a conalbumindye mixture is gradually increased The fluorescence is measured and a graph is produced

The melting temperature is the temperature at which the fluorescence is halfway between the highest and lowest fluorescence valuesDetermine the melting temperature in ordmC for this protein (1)

(c) Once cooked and eaten the digestive system breaks the protein chains into amino acids with the help of enzymes

(i) State the name of the digestion process where enzymes break down proteins into amino acids (1)

(ii)

(A) State how many amino acid molecules joined to form this section of protein (1)

(B) Draw the structure of one amino acid that would be produced when this section of the protein chain is broken down (1)

17 Peptide molecules can be classified according to the number of amino acid units joined by peptide bonds in the molecule

18

(a) Complete the table to identify the type of peptide with the following amino acid sequence

alanine-glycine-valine-proline-tyrosine-serine (1)

(b) Partial hydrolysis of another pentapeptide molecule gave a mixture of three smaller peptide molecules with the following amino acid sequences

leucine-glycine-valineisoleucine-leucineglycine-valine-serine

Write the amino acid sequence for the original pentapeptide molecule (1)

helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip(c) Some amino acids needed to form polypeptides cannot be produced in the human body

State the term used to describe amino acids that the body cannot make (1)

(d)Paper chromatography is often used to analyse the mixtures of amino acids produced when peptides are broken downOn a chromatogram the retention factor Rf for a substance can be a useful method of identifying the substance

The structure of the pentapeptide methionine enkephalin was investigatedA sample of the pentapeptide was completely hydrolysed into its constituent amino acids and this amino acid mixture was applied to a piece of chromatography paper and placed in a solventThe chromatogram obtained is shown below

19

(i) Suggest why only four spots were obtained on the chromatogram of the hydrolysed pentapeptide (1)

(ii) It is known that this amino acid mixture contains the amino acid methionine The Rf value for methionine in this solvent is 040Draw a circle around the spot on the chromatogram that corresponds to methionine (1)

(e) Over the last decade several families of extremely stable peptide molecules have been discovered where the peptide chain forms a ring

(i) A simple cyclic dipeptide is shown

Draw a structural formula for one of the amino acids that would be formed on complete hydrolysis of the above cyclic dipeptide (1)

(ii) Alpha-amanitin is a highly toxic cyclic peptide found in death cap mushrooms The lethal dose for humans is 100 mg per kg of body mass1middot0 g of death cap mushrooms contains 250 mg of alpha-amanitinCalculate the minimum mass of death cap mushrooms that would contain the lethal dose for a 75 kg adult (2)

18 Dishwasher tablets produce the bleach hydrogen peroxide H2O2 One action of this oxidising agent is to oxidise food

(a)(i) Suggest another action of the bleach produced by the dishwasher tablets (1)

20

(ii) Hydrogen peroxide decomposes to form water and oxygen

2H2O2(ℓ) rarr 2H2O(ℓ) + O2(g)

A dishwasher tablet produces 0middot051 g of hydrogen peroxide (mass of one mole = 34 g)

Calculate the volume of oxygen that would be produced when0middot051 g of hydrogen peroxide decomposesTake the volume of 1 mole of oxygen gas to be 24 litres(3)

(b)Enzymes are commonly added to dishwasher tablets These are used to break down proteins(i) The proteins are broken down into small water-soluble molecules

Name the small water-soluble molecules made when proteins are broken down completely (1)

(ii) The structure of a section of protein chain found in egg white is shown

(A)Name the functional group circled (1)(B)Draw a structural formula for one of the molecules that would be made

when this section of egg white protein chain is completely broken down (1)

(iii) As part of the program in the dishwasher the conditions in the dishwasher change so that the enzyme molecules no longer work because they change shape

21

(A) State the term used to describe the change in shape of enzyme molecules(1)

(B) Suggest a change in conditions which would cause the enzyme molecules to change shape (1)

(d) A bleach activator is frequently added to dishwasher tablets to speed up the bleaching reaction One common bleach activator is TAED TAED could be produced in a process which involves a number of stages

(i) The first stage in producing TAED is shown below

Suggest a name for this type of reaction (1)

(ii) The final stage in the process producing TAED is shown below

Draw a structural formula for TAED (1)

22

23 The Chemistry of Cooking

1 Vanillin and zingerone are flavour molecules

Which line in the table correctly compares the properties of vanillin and zingerone

23

2 Erythrose can be used in the production of a chewing gum that helps prevent tooth decay

Which of the following compounds will be the best solvent for erythrose

3 The following molecules give flavour to food Which of the following flavour molecules would be most likely to be retained in the food when the food is cooked in water

24

4 Cooking involves many chemical reactions Proteins fats oils and esters are some examples of compounds found in food A chemist suggested that cooking food could change compounds from being fat-soluble to water-soluble Use your knowledge of chemistry to comment on the accuracy of this statement(3)

25

24 The Oxidation of Food

1 Apples and bananas turn brown when cut or bruised The first step of the reaction causing

the browning is shown below

Which of the following terms correctly describes this reactionA ReductionB OxidationC DehydrationD Condensation

2 Which of the following reactions can be classified as reductionA CH3CH2OH rarr CH3COOHB CH3 CH(OH)CH3 rarr CH3COCH3C CH3CH2COCH3 rarr CH3CH2CH(OH)CH3D CH3CH2CHO rarr CH3CH2COOH

3 The dehydration of butan-2-ol can produce two isomeric alkenes but-1-ene andbut-2-ene Which of the following alkanols can similarly produce on dehydration a pair of isomeric alkenesA Propan-2-olB Pentan-3-olC Hexan-3-olD Heptan-4-ol

4 Which of the following compounds is an alkanone

26

5 Which of the following is an aldehyde

6 Which of the following compounds would react with sodium hydroxide solution to forma saltA CH3CHOB CH3COOHC CH3COCH3D CH3CH2OH

7 Which line in the table shows the correct functional group for each homologous series

8 Which of the following organic compounds is an isomer of hexanalA 2-MethylbutanalB 3-Methylpentan-2-oneC 22-Dimethylbutan-1-olD 3-Ethylpentanal

27

9 The name of this compound is

A methanolB methanalC methanoic acidD methanone

10 Which alcohol could be oxidised to a carboxylic acid

11 Which of the following structural formulae represents a tertiary alcohol

12 Compound X reacted with hot copper(II) oxide and the organic product did not give acolour change when heated with Fehlingrsquos solution Compound X could beA butan-1-olB butan-2-olC butanoneD butanoic acid

28

13 Which two isomers would each produce an acid when warmed with acidified potassiumdichromate solution

A 1 and 2B 2 and 3C 1 and 4D 3 and 4

14 After heating for several minutes as shown in the diagram the pH indicator solution turned red

Liquid Q could beA propanoneB paraffinC propan-1-olD propan-2-ol

29

15 Enzymes are involved in the browning of cut fruitOne reaction taking place is

Which of the following correctly describes the above reaction

A OxidationB ReductionC HydrolysisD Condensation

16 Which of the following statements is correct for ketones

A They are formed by oxidation of tertiary alcohols

B They contain the group

C They contain a carboxyl groupD They will not react with Fehlingrsquos solution

17 Carvone is a natural product that can be extracted from orange peel

Which line in the table correctly describes the reaction of carvone with bromine solution and with acidified potassium dichromate solution

30

18 Which of the following is an isomer of 22-dimethylpentan-1-ol

A CH3CH2CH2CH(CH3)CH2OHB (CH3)3CCH(CH3)CH2OHC CH3CH2CH2CH2CH2CH2CH2CH2OHD (CH3)2CHC(CH3)2CH2CH2OH

19 The equation for the reduction reaction taking place when ethanal reacts with Tollensrsquo reagent is

A Cu2+(aq) + eminus rarr Cu+(aq)

B Ag+(aq) + eminus rarr Ag(s)

C Cr2O72minus(aq) + 14H+(aq) + 6eminus rarr 2Cr3+(aq) + 7H2O(ℓ)

D MnO4minus(aq) + 8H+(aq) + 5eminus rarr Mn2+(aq) + 4H2O(ℓ)

20 The name of the compound with structure

isA 23-dimethylpentan-4-oneB 23-dimethylpentan-2-alC 34-dimethylpentan-2-oneD 34-dimethylpentan-2-al

21 What is the systematic name for the compound below

A 222-trimethylethanolB 22-dimethylpropan-1-olC 22-dimethylpropan-3-olD 22-dimethylpentan-1-ol

31

22 The structure of a molecule found in olive oil can be represented as shown

(a) Olive oil can be hydrolysed using sodium hydroxide solution to produce sodium salts of fatty acids Name the other product of this reaction (1)

(b) In what way does the structure of a fat molecule differ from that of an oil molecule (1)

(c) Over time open containers of olive oil develop a rancid flavour What substance is reacting with the oil to cause these unwanted changes to take place (1)

23 A student writes the following statement It is incorrect Explain the mistake in the studentrsquos reasoning (1)

Alcohols are alkaline because of their OH groups

24 Carbon compounds take part in a wide variety of chemical reactions (a)

Name this type of chemical reaction (1)

(b)

Draw a structural formula for C3H6O (1)

25 Alkanols can be oxidised to alkanoic acids

32

(a) Why can Step 1 be described as an oxidation reaction (1)

(b) Acidified potassium dichromate solution can be used to oxidise propanal in Step 2 What colour change would be observed in this reaction (1)

26 Amines can be produced by reacting ammonia with an aldehyde or a ketone This reaction an example of reductive amination occurs in two stages

Stage 1 Amination

Stage 2 Reduction

(a) Give another name for the type of reaction taking place in Stage 2

(b) Draw the structural formula for the amine produced when butanal undergoes reductive amination with ammonia

27 Using a cobalt catalyst alkenes react with a mixture of hydrogen and carbon monoxideThe products are two isomeric aldehydes Propene reacts with the mixture as shown

(a) What name is given to a mixture of hydrogen and carbon monoxide (1)

(b) Draw a structural formula for compound B (1)

(c) (i) What would be observed if compound A was gently heated with Tollensrsquo reagent

(1)(ii) How would the reaction mixture be heated (1)

33

(d) Aldehydes can also be formed by the reaction of some alcohols with copper(II) oxideName the type of alcohol that would react with copper(II) oxide to form an aldehyde (1)

28 Aldehydes and ketones can take part in a reaction sometimes known as an aldol condensation The simplest aldol reaction involves two molecules of ethanal

In the reaction the carbon atom next to the carbonyl functional group of one molecule forms a bond with the carbonyl carbon atom of the second molecule

(a) Draw a structural formula for the product formed when propanone is used instead of ethanal in this type of reaction (1)

(b) Name an aldehyde that would not take part in an aldol condensation (1)

(c) Apart from the structure of the reactants suggest what is unusual about applying the term ldquocondensationrdquo to this particular type of reaction (1)

29 Primary secondary and tertiary alkanols can be prepared by the reaction of carbonyl compounds with Grignard reagents

Step 1The Grignard reagent reacts with the carbonyl compound

Step 2The reaction of the product of Step 1 with dilute acid produces the alkanol

(a) Describe the difference between a primary a secondary and a tertiary alkanol

You may wish to include labelled structures in your answer (1)34

(b) Suggest a name for the type of reaction that takes place in Step 1 (1)

(c) The same Grignard reagent can be used to produce the alkanol below

Name the carbonyl compound used in this reaction (1)

30 Hairspray is a mixture of chemicals(a) A primary alcohol 2-methylpropan-1-ol is added to hairspray to help it dry quickly on the hair

Draw a structural formula for a secondary alcohol that is an isomer of2-methylpropan-1-ol (1)

(b) Triethanol amine and triisopropyl amine are bases used to neutralise acidic compounds in the hairspray to prevent damage to the hair

In terms of the intermolecular bonding present explain clearly why triethanol amine has a much higher boiling point than triisopropyl amine (2)

35

36

31 Chocolate contains various compounds(a) Many of the flavour and aroma molecules found in chocolate are aldehydes and

ketones Two examples are shown below

Phenylethanal can be easily oxidised but 13-diphenylpropan-2-one cannot(i) Name a chemical that could be used to distinguish between these two

compounds (1)

(ii) Name the type of organic compound formed when phenylethanal is oxidised (1)

(b) Glycerol monostearate is an emulsifier used in chocolate

(i) Why is glycerol monostearate added to chocolate (1)

(ii) Draw a structural formula for glycerol (1)

(c) Theobromine a compound present in chocolate can cause illness in dogs and cats To decide if treatment is necessary vets must calculate the mass of theobromine consumed 1middot0 g of chocolate contains 1middot4 mg of theobromine Calculate the mass in mg of theobromine in a 17 g biscuit of which 28 is chocolate Show your working clearly (2)

(d) The flavour and texture of chocolate comes from a blend of compoundsUsing your knowledge of chemistry describe how you could show that there are ionic compounds and covalent compounds present in chocolate (3)

37

32 Ethanol has many uses

(a) Ethanol is found at relatively low concentrations in wine

(i) Name the chemical reaction that produces ethanol in wine (1)

(ii) Standard ethanol solutions were used to produce a graph of density against

concentration of ethanol given as a percentage of alcohol by volume ( abv)

What is the concentration of ethanol in units of abv in a solution of density 0middot9818 g cmminus3 (1)

(b) Whisky contains a higher concentration of ethanol

(i) Before 1980 the concentration of alcohol in drinks was measured in terms of degrees proof The concentration of alcohol in two drinks is shown in the table below both as abv and degrees proof

38

A cask strength whisky has an alcohol concentration of 65 abv Calculate the alcohol concentration of this whisky in degrees proof (1)

(ii) A barrel containing 195 litres of cask strength whisky costs pound1300 The cask strength whisky is diluted with water to reduce the concentration of alcohol from 65 abv to 46 abv before it is bottled Calculate the cost of the cask strength whisky needed to produce a 0middot70 litre bottle Show your working clearly (2)

(iii) 5-Butyl-4-methyltetrahydrofuran-2-ol is a flavour compound found in whisky

stored in oak barrels

Write the systematic name for the compound shown below (1) 13 11

33 (a) One test for glucose involves Fehlingrsquos solutionCircle the part of the glucose molecule that reacts with Fehlingrsquos solution (1)

(b) In solution sugar molecules exist in an equilibrium in straight-chain and ring forms

To change from the straight-chain form to the ring form the oxygen of the hydroxyl on carbon number 5 joins to the carbonyl carbon This is shown below for glucose

39

Draw the structure of a ring form for fructose (1)

34 (a) During the free radical chain reaction small molecules join to form large chain molecules

One example of a small molecule used is

Name the functional group circled above (1)

(b)Alcohol wipes are used to finish the varnishing treatment Alcohol wipes contain the alcohol propan-2-olState why propan-2-ol can be described as a secondary alcohol (1)

35 A student was carrying out an investigation into alcohols aldehydes and ketones

(a)The student was given three alcohols labelled as A B and C These alcohols were all isomers with the formula C4H9OH

(i) Draw a structural formula for the secondary alcohol with the formula C4H9OH(1)

(ii) The student set up the following experiment

A Suggest why a water bath is an appropriate method of heating the reaction mixture (1)

B Describe the colour change that would have been observed with alcohols A and C (1)

40

C Alcohol B is not oxidised State the type of alcohol which cannot be oxidised by acidified dichromate solution (1)

(iii) The student set up a second experiment with alcohol A

Hot copper(II) oxide is an oxidising agentA When alcohol A (C4H9OH) is oxidised the product turns the pH paper

redSuggest a name for the product (1)

B Complete the ion-electron equation for the oxidation reaction

C4H9OH rarr C4H8O2 (1)

(b)The student found the following information about the boiling points of some aldehydes

41

(i) Name the aldehyde that has a boiling point of 119 degC (1)(ii) Predict the boiling point in degC of the following molecule (1)

(iii) Using information from the table describe one way in which differences in structure affect the boiling point of isomeric aldehydes (1)

(iv) State what would be observed when an aldehyde is gently heated with Tollensrsquo reagent (1)

(c) Ketones contain a carbonyl groupName the type of intermolecular interaction between ketone molecules (1)

42

25 Soaps Detergents and Emulsions

1 Soaps are produced by the following reaction

This reaction is an example ofA condensationB esterificationC hydrolysisD oxidation

2 Which of the following is the salt of a long-chain fatty acid

A FatB OilC SoapD Glycerol

3 Emulsifiers for use in food are commonly made by reacting edible oils with

A estersB glycerolC fatty acidsD amino acids

4 A fatty acid is a long chain carboxylic acid Examples of fatty acids are shown in the table below

43

(a) What is the systematic name for linolenic acid (1)(b) Stearic acid reacts with sodium hydroxide solution to form sodium stearate

(i) Name the type of reaction taking place when stearic acid reacts with sodium hydroxide (1)

(ii) Explain fully how sodium stearate acts to keep grease and non-polar substances suspended in water during cleaning (3)

5 Small children can find it difficult to swallow tablets or pills so ibuprofen is supplied as an ldquoinfant formulardquo emulsion(a) The emulsifier used is polysorbate 80 Its structure is shown below

Explain why this molecule acts as an emulsifier (2)

(b) The emulsion contains 2 g of ibuprofen in every 100 cm3 of emulsion The recommended dose for treating a 6 month old baby is 0middot050 g Calculate the volume in cm3 of ldquoinfant formulardquo needed to treat a 6 month old baby (1)

6 Occasionally seabirds can become contaminated with hydrocarbons from oil spills This causes problems for birds because their feathers lose their waterproofing making the birds susceptible to temperature changes and

44

affecting their buoyancy If the birds attempt to clean themselves to remove the oil they may swallow the hydrocarbons causing damage to their internal organsContaminated seabirds can be cleaned by rubbing vegetable oil into their feathers and feet before the birds are rinsed with diluted washing-up liquidUsing your knowledge of chemistry comment on the problems created for seabirds by oil spills and the actions taken to treat affected birds (3)

7 Dishwasher tablets contain chemicals which remove dirt from dishesDishwasher tablets include detergents These molecules act like soaps to allow mixing of fat-soluble dirt and water(a)During the cleaning process the detergent molecules combine with fat-

soluble dirtA simplified diagram of a detergent molecule is shown

Complete the diagram below to show how detergent molecules combine with fat-soluble dirt (1)

(b)State the term used to describe the non-polar hydrocarbon tail of a detergent molecule (1)

45

26 Fragrances1 Myrcene is a simple terpene

Terpenes contain at least one isoprene unit Which of the following shows a correctly highlighted isoprene unit

2 Limonene is one of the terpene molecules responsible for the flavour of lemons

How many isoprene units are used in the production of one limonene moleculeA 1B 2C 3D 4

46

3 The structure of caryophyllene which can be extracted from clove oil is

Which of the following would be the best solvent for extracting caryophylleneA HexaneB HexanalC HexanolD Hexanone

4 The structure of isoprene is

Limonene is a terpene molecule present in lemons

How many isoprene units are joined together in a limonene molecule

A 1B 2

47

C 3D 4

5 Essential oils are

A non-water soluble non-volatile compoundsB non-water soluble volatile compoundsC water soluble non-volatile compoundsD water soluble volatile compounds

6 Two typical compounds that are present in many perfumes are shown

(a) Why does geraniol evaporate more slowly than limonene (1)

(b) The structure of one of the first synthetic scents used in perfume is shown below

(i) Name the family of carbonyl compounds to which this synthetic scent belongs (1)

(ii) Complete the structure below to show the product formed when this scent is

oxidised (1)

(c) Traces of a liquid were discovered in a bottle believed to contain perfume belonging to Queen Hatshepsut ruler of Egypt over 3500 years ago

Perfumes were made by dissolving plant extracts containing pleasant smelling terpenes and esters in an edible oil A little ethanol and water may also have been addedUsing your knowledge of chemistry comment on the possible smell(s) when such a bottle is opened after being stored for thousands of years (3)

48

49

7 A team of chemists are developing a fragrance for use in a shower gel for men(a) To give the gel a fruity smell the chemists are considering adding an ester

They synthesise six isomeric esters Volunteers smell each ester and give it a rating out of one hundred depending on how fruity the smell is

(i) Name the ester with the fruit-smell rating of 92 (1)

(ii) Shown below are the structures of three more isomers

Arrange these esters in order of decreasing fruit-smell rating (1)

50

(b) To create a fragrance for men the compound civetone is added

Draw a structural formula for the alcohol that can be oxidised to form civetone (1)

(c) To make the shower gel produce a cold tingling sensation when applied to the skin menthol is added

Like terpenes menthol is formed from isoprene (2-methylbuta-13-diene)Circle an isoprene unit on the menthol structure above (1)

8 Many of the compounds in perfumes are molecules consisting of joined isoprene units

(a) State the name that is given to molecules consisting of joined isoprene units (1)

(b)Geraniol is one of the compounds found in perfume It has the following structural formula and systematic name

Linalool can also be present Its structural formula is shown

51

(i) State the systematic name for linalool (1)(ii) Explain why linalool can be classified as a tertiary alcohol (1)

9 The component molecules found in lavender oils are terpenes or terpenoids(a)A chiral carbon is a carbon atom attached to four different atoms or groups of

atomsAn example is shown below

A molecule of the terpenoid linalool has a chiral carbon Linalool has the following structure

Circle the chiral carbon atom in the linalool structure (1)

(b)Farnesene is a terpene consisting of three isoprene units (2-methylbuta-13-diene) joined togetherWrite the molecular formula of farnesene (1)

52

27 Skin Care

1 Which of the following is not a step in a free radical chain reaction

A ActivationB InitiationC PropagationD Termination

2 Fluorine reacts with methane via a free radical chain reaction Some steps in the chain reaction are shown in the table below

Complete the table by(a) inserting the missing name for the first step (1)

(b) showing another possible termination reaction in the final row of the table (1)

3 Suncreams contain antioxidantsThe antioxidant compound A can prevent damage to skin by reacting with free

radicalssuch as NO2bull

53

Why can compound A be described as a free radical scavenger in the reaction shown above

4 Hydrogen and chlorine gases are used in an experiment to demonstrate a free radical reaction A plastic bottle is wrapped with black tape leaving a ldquowindowrdquo on one sideThe bottle is filled with a mixture of hydrogen and chlorine When bright light shines on the bottle there is an explosion

A free radical chain reaction is initiated when light energy causes chlorine radicals to form as shown below

(a) Complete the equations below showing possible propagation and termination steps

(2)

54

(b) Why is the plastic bottle used in the experiment wrapped in black tape (1)

5 Chloramines can be removed from water using ultraviolet light treatment

One step in the process is the formation of free radicals

(a)State what is meant by the term free radical (1)

(b)Another step in the process is shown below

State the name for this type of step in a free radical reaction (1)

6 Modern shellac nail varnishes are more durable and so last longer than traditional nail polish

The shellac nail varnish is applied in thin layers to the nails and then the fingers are placed under a UV lamp

(a) The Skin Care Foundation has recommended that a sun-block is applied to the fingers and hand before using the lampSuggest why the Skin Care Foundation makes this recommendation (1)

(b) A free radical chain reaction takes place and the varnish hardens (i) State what is meant by the term free radical (1)

(ii) The shellac nail varnish contains a mixture of ingredients that take part in the free radical chain reactionOne of the steps in the free radical chain reaction is

55

State the term used to describe this type of step in a free radical chain reaction(1)

7 Skin care products contain a mixture of polar covalent non-polar covalent and ionic compounds The compounds need to stay mixed within the product Skin care products also need to spread easily and remain on the skin for a period of time as well as provide physical and chemical protection from the sun In order to do this skin care products contain a range of chemicals including water fats and oils antioxidants minerals and sun blockUsing your knowledge of chemistry explain the role of different chemicals in skin care products (3)

General Questions

1 A mixture of carbon monoxide and hydrogen can be converted into water and a mixture of hydrocarbons

nCO + (2n + 1)H2 rarr nH2O + hydrocarbons

What is the general formula for the hydrocarbons producedA CnH2nndash2B CnH2nC CnH2n+1D CnH2n+2

2 Butadiene is the first member of a homologous series of hydrocarbons called dienesWhat is the general formula for this seriesA CnHn+2B CnHn+3C CnH2nD CnH2nndash2

3 Which of the following statements about methanol is falseA It can be made from synthesis gasB It can be dehydrated to form an alkeneC It can be oxidised to give a carboxylic acidD It reacts with acidified potassium dichromate solution

56

4

Which line in the table correctly describes reactions X and Y

5

Which line in the table correctly describes reactions X and Y

6 Which of the following fuels when burned would make no contribution to globalwarming

57

A HydrogenB Natural gasC PetrolD Coal

7 Which of the following hydrocarbons always gives the same product when one of itshydrogen atoms is replaced by a chlorine atomA HexaneB Hex-1-eneC CyclohexaneD Cyclohexene

8 Which of the following compounds does not have isomeric structuresA C2HCl3B C2H4Cl2C PropeneD Propan-1-ol

9 What organic compound is produced by the dehydration of ethanol A EthaneB EtheneC EthanalD Ethanoic acid

10

The above equation representsA hydrationB hydrogenationC condensationD hydrolysis

11

Which of the following compounds is an isomer of the structure shown aboveA ButanalB ButanoneC Butan-1-olD Butanoic acid

58

12 A compound with molecular formula C6H12O2 could beA hexanalB hexan-2-olC hexan-2-oneD hexanoic acid

13 Propan-2-ol can be prepared from propane as follows

Which line in the table correctly describes the types of reaction taking place at Steps 1 and 2

14 Which of the following compounds would be the most water soluble

15 Cyanohydrin compounds can be made from carbonyl compounds by reacting the carbonyl compound with hydrogen cyanide (HCN)

59

Which carbonyl compound would react with hydrogen cyanide (HCN) to form the following compound

16 Ethyne is the first member of the homologous series called the alkynes

Ethyne can undergo addition reactions as shown in the flow diagram

(a) Compound 2 is an isomer of 12-dichloroethaneDraw a structural formula for compound 2 (1)

(b) Reagents A B and C are three different diatomic gasesUsing information in the flow diagram identify reagents A B and C (1)

60

Reagent Gas

A

B

C

17 In 1865 the German chemist Kekuleacute proposed a ring structure for benzene This structure was based on alternating single and double bonds

(a) (i) Describe a chemical test that would indicate that the above chemical structure for benzene is incorrect (1)

(ii) Briefly describe the correct structure for benzene (1)

(b) Benzene can be formed from cyclohexaneC6H12 rarr C6H6 + 3H2

What name is given to this type of reaction (1)18 Infra-red spectroscopy is a technique that can be used to identify the bonds that

arepresent in a molecule Different bonds absorb infra-red radiation of different wavenumbers This is due to differences in the bond lsquostretchrsquo These absorptions are recorded in a spectrumA spectrum for propan-1-ol is shown

61

The correlation table on page 13 of the data booklet shows the wavenumber ranges for the absorptions due to different bonds

(a) Use the correlation table to identify the bonds responsible for the two absorptions x and y that are circled in the propan-1-ol spectrum (1)

(b) Propan-1-ol reacts with ethanoic acid(i) What name is given to this type of reaction (1)(ii) Draw a spectrum that could be obtained for the organic product of this

reaction (1)

19 Paracetamol is a widely used painkiller

(a) Write the molecular formula for paracetamol (1)

(b) One antidote for paracetamol overdose is methionine

62

To what family of organic compounds does methionine belong (1)

(c) The concentration of paracetamol in a solution can be determined by measuring how much UV radiation it absorbs

The graph shows how the absorbance of a sample containing 0middot040 g l ndash1 paracetamol varies with wavelength

The quantity of UV radiation of wavelength 245 nm absorbed is directly proportional to the concentration of paracetamolThe absorbance of a second sample of paracetamol solution measured at 245 nm was 0middot90 What is the concentration in g l ndash1 of this second paracetamol solution (1)

20 Many carbon compounds containing oxygen are very flammableThe table shows information about two families of isomersThe lowest temperature at which a compound will ignite is called its flash point

(a) A compound with the molecular formula C6H14O has a boiling point of 158 degC63

Draw a structural formula for this compound (1)

(b) For a family of isomers in the table write a general statement linking the flash points of the compounds to their structures (1)

21 Hydrogels are used in disposable nappies They are fine powders that can absorb up to 500 times their own weight in waterA hydrogel is a very long molecule with carboxyl groups at regular intervals along its length A short section of a hydrogel molecule is shown below

Hydrogels are extremely good at soaking up water because the water molecules are strongly attracted to them

Using your knowledge of chemistry comment on how suitable hydrogels would be for absorbing liquids or solutions spilled in a chemistry lab (1)

64

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

21 One of the chemicals released in a bee sting is an ester that has the structure shown

This ester can be produced by the reaction of an alcohol with an alkanoic acid

(a) Name this acid (1)

(b) The ester can be prepared in the lab by heating a mixture of the reactants with a catalyst

(i) Name the catalyst used in the reaction (1)

(ii) What improvement could be made to the experimental set-up shown in the diagram

(1)

22 Propan-1-ol and propanoic acid react to form an esterThe mixture of excess reactants and ester product is poured onto sodium hydrogencarbonate solution

(a) What evidence would show that an ester is formed (1)

(b) Draw a structural formula for this ester (1)

23 The ester methyl stearate is also a useful vehicle fuel A student prepared this ester from methanol and stearic acid during the Prescribed Practical Activity ldquoMaking EstersrdquoDescribe how this ester was prepared (2)

24 Foodstuffs have labels that list ingredients and provide nutritional information The label on a tub of margarine lists hydrogenated vegetable oils as one of the ingredients Why have some of the vegetable oils in this product been hydrogenated (1)

7

25 A typical triglyceride found in olive oil is shown below

(a) To which family of organic compounds do triglycerides belong (1)

(b) Olive oil can be hardened for use in margarinesWhat happens to the triglyceride molecules during the hardening of olive oil (1)

(c) Give one reason why oils can be a useful part of a balanced diet (1)

26 When vegetable oils are hydrolysed mixtures of fatty acids are obtained The fatty acids can be classified by their degree of unsaturation The table below shows the composition of each of the mixtures of fatty acids obtained when palm oil and olive oil were hydrolysed

(a) Why does palm oil have a higher melting point than olive oil (1)

(b) One of the fatty acids produced by the hydrolysis of palm oil is linoleic acid C17H31COOH To which class (saturated monounsaturated or polyunsaturated) does this fatty acid belong (1)

(c) When a mixture of palm oil and olive oil is hydrolysed using a solution of sodium hydroxide a mixture of the sodium salts of the fatty acids is obtained State a use for these fatty acid salts (1)

8

27

4-hydroxybenzoic acid can react with alcohols to form compounds known asparabens

(a) Name the functional group circled in the structure of 4minushydroxybenzoic acid (1)

(b) Name the type of reaction taking place when parabens are formed (1)

(c) Draw the paraben formed when 4minushydroxybenzoic acid reacts with ethanol (1)

(d) Parabens can be used as preservatives in cosmetics and toiletries Parabens are absorbed into the body through the skin The following table indicates the absorption of some parabens

State a conclusion that can be drawn from the information in the table (1)

9

28 When fats and oils are hydrolysed mixtures of fatty acids are obtained

(a) Name the other product obtained in this reaction (1)

(b)The table below shows the percentage composition of the fatty acid mixtures obtained by hydrolysis of coconut oil and olive oil

(i) One of the fatty acids produced by the hydrolysis of olive oil is linoleic acid C17H31COOHState the class of fatty acid to which linoleic acid belongs (1)

(ii) Hydrolysed coconut oil contains the fatty acid caprylic acid with the formula CH3(CH2)6COOHState the systematic name for caprylic acid (1)

(c) The degree of unsaturation of oil can be tested by adding drops of bromine solution to the oil Bromine adds across carbon to carbon double bonds in the fatty acid chains

The following apparatus can be used to compare the degree ofunsaturation of different oils

10

(i) Describe how this apparatus could be used to show that olive oil has a greater degree of unsaturation than coconut oil (2)

(ii) Suggest why hexane is used as the solvent rather than water (1)

(iii) Coconut oil has a melting point of 25 degC Olive oil has a melting point of minus6C

Give two reasons why coconut oil has a higher melting point than olive oil (2)

29 Traditional nail varnishes use ethyl ethanoate and butyl ethanoate as solvents

(a)Draw a structural formula for butyl ethanoate (1)(b)Ethyl ethanoate can be made in the laboratory using the following apparatus

Suggest why a wet paper towel is wrapped around the test tube (1)

(c) Name the type of reaction that takes place during the formation of ethyl ethanoate (1)

30 Pentyl butanoate is responsible for some of the flavour in apricots and strawberries

(a)Hydrolysis of pentyl butanoate using sodium hydroxide produces an alcohol and the salt of the carboxylic acid

(i) Name the alcohol that would be formed when pentyl butanoate is hydrolysed(1)

(ii) Draw a structural formula for the sodium salt of the carboxylic acid that would be formed (1)

(b)Fats and oils belong to the same class of compounds as pentyl butanoate(i) Name this class of compounds (1)

11

(ii) When a fat is hydrolysed using sodium hydroxide sodium salts of fatty acids are producedState a use for sodium salts of fatty acids (1)

22 Proteins

1 When a protein is denaturedA its overall shape is distortedB its amide links are hydrolysedC it is broken into separate peptide fragmentsD it decomposes into amino acids

2 Which of the following compounds can be classified as proteinsA FatsB OilsC EnzymesD Amino acids

3 The monomer units used to construct enzyme molecules areA alcoholsB estersC amino acidsD fatty acids

4 Amino acids are converted into proteins byA hydrationB hydrolysisC hydrogenationD condensation

5 The arrangement of amino acids in a peptide isZ-X-W-V-Y

where the letters V W X Y and Z represent amino acidsOn partial hydrolysis of the peptide which of the following sets of dipeptides is possibleA V-Y Z-X W-Y X-WB Z-X V-Y W-V X-WC Z-X X-V W-V V-YD X-W X-Z Z-W Y-V

6 Which of the following is an amine

12

7 Which of the following arrangements of atoms shows a peptide link

8 The following molecules are found in herbicides Which of the following contains an amide link

9 In α-amino acids the amino group is on the carbon atom adjacent to the acid group

Which of the following is an α-amino acid

10 A tripeptide X has the structure

Partial hydrolysis of X yields a mixture of dipeptidesWhich of the following dipeptides could be produced on hydrolysing X

13

11 The rate of hydrolysis of protein using an enzyme was studied at different temperatures Which of the following graphs would be obtained

12 The rate of hydrolysis of protein using an enzyme was studied at different temperaturesWhich of the following graphs would be obtained

14

13 Polymers can be classified as natural or synthetic(a) Keratin a natural polymer is a protein found in hair

The hydrolysis of keratin produces different monomers of the type shown

(i) What name is given to monomers like glycine alanine and cysteine (1)(ii) What is meant by a hydrolysis reaction (1)

(b) Dacron a synthetic polymer is used in heart surgery A section of the polymer is shown

What name is given to the link made by the shaded group of atoms in this section of the polymer (1)

14 Chemists have developed cheeses specifically for use in cheeseburgers(a) When ordinary cheddar cheese is grilled the shapes of the protein molecules

change and the proteins and fats separate leaving a chewy solid and an oily liquidWhat name is given to the change in protein structure which occurs when ordinary cheddar is grilled (1)

(b) To make cheese for burgers grated cheddar cheese soluble milk proteins and some water are mixed and heated to no more than 82 degC As the cheese begins to melt an emulsifying agent is added and the mixture is stirred

15

(i) Why would a water bath be used to heat the mixture (1)(ii) A section of the structure of a soluble milk protein is shown below

Draw a structural formula for any one of the amino acids formed when this section of

protein is hydrolysed (1)

(iii) The emulsifier used is trisodium citrate a salt formed when citric acid is neutralised using sodium hydroxide Complete the equation below showing a structural formula for the trisodium citrate formed (1) sp 8

15 Phenylalanine and alanine are both amino acids

(a) Phenylalanine is an essential amino acid

(i) What is meant by an essential amino acid (1)

16

(ii) How many hydrogen atoms are present in a molecule of phenylalanine (1)

(b) Phenylalanine and alanine can react to form the dipeptide shown

Circle the peptide link in this molecule (1)

(c) Draw a structural formula for the other dipeptide that can be formed from phenylalanine and alanine (1)

16 Uncooked egg white is mainly composed of dissolved proteins During cooking processes the proteins become denatured as the protein chains unwind and the egg white solidifies

(a) Explain why the protein chains unwind (1)

(b)The temperature at which the protein becomes denatured is called the melting temperature The melting temperature of a protein can be determined using fluorescence In this technique the protein is mixed with a dye that gives out visible light when it attaches to hydrophobic parts of the protein molecule The hydrophobic parts of the structure are on the inside of the protein and the dye has no access to them unless the protein unwinds

(i) Ovalbumin is a protein found in egg white Part of the structure of unwound ovalbumin is shown below

Circle the part of the structure to which the hydrophobic dye is most likely to attach (1)

17

(ii) Another protein in egg white is conalbumin The temperature of a conalbumindye mixture is gradually increased The fluorescence is measured and a graph is produced

The melting temperature is the temperature at which the fluorescence is halfway between the highest and lowest fluorescence valuesDetermine the melting temperature in ordmC for this protein (1)

(c) Once cooked and eaten the digestive system breaks the protein chains into amino acids with the help of enzymes

(i) State the name of the digestion process where enzymes break down proteins into amino acids (1)

(ii)

(A) State how many amino acid molecules joined to form this section of protein (1)

(B) Draw the structure of one amino acid that would be produced when this section of the protein chain is broken down (1)

17 Peptide molecules can be classified according to the number of amino acid units joined by peptide bonds in the molecule

18

(a) Complete the table to identify the type of peptide with the following amino acid sequence

alanine-glycine-valine-proline-tyrosine-serine (1)

(b) Partial hydrolysis of another pentapeptide molecule gave a mixture of three smaller peptide molecules with the following amino acid sequences

leucine-glycine-valineisoleucine-leucineglycine-valine-serine

Write the amino acid sequence for the original pentapeptide molecule (1)

helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip(c) Some amino acids needed to form polypeptides cannot be produced in the human body

State the term used to describe amino acids that the body cannot make (1)

(d)Paper chromatography is often used to analyse the mixtures of amino acids produced when peptides are broken downOn a chromatogram the retention factor Rf for a substance can be a useful method of identifying the substance

The structure of the pentapeptide methionine enkephalin was investigatedA sample of the pentapeptide was completely hydrolysed into its constituent amino acids and this amino acid mixture was applied to a piece of chromatography paper and placed in a solventThe chromatogram obtained is shown below

19

(i) Suggest why only four spots were obtained on the chromatogram of the hydrolysed pentapeptide (1)

(ii) It is known that this amino acid mixture contains the amino acid methionine The Rf value for methionine in this solvent is 040Draw a circle around the spot on the chromatogram that corresponds to methionine (1)

(e) Over the last decade several families of extremely stable peptide molecules have been discovered where the peptide chain forms a ring

(i) A simple cyclic dipeptide is shown

Draw a structural formula for one of the amino acids that would be formed on complete hydrolysis of the above cyclic dipeptide (1)

(ii) Alpha-amanitin is a highly toxic cyclic peptide found in death cap mushrooms The lethal dose for humans is 100 mg per kg of body mass1middot0 g of death cap mushrooms contains 250 mg of alpha-amanitinCalculate the minimum mass of death cap mushrooms that would contain the lethal dose for a 75 kg adult (2)

18 Dishwasher tablets produce the bleach hydrogen peroxide H2O2 One action of this oxidising agent is to oxidise food

(a)(i) Suggest another action of the bleach produced by the dishwasher tablets (1)

20

(ii) Hydrogen peroxide decomposes to form water and oxygen

2H2O2(ℓ) rarr 2H2O(ℓ) + O2(g)

A dishwasher tablet produces 0middot051 g of hydrogen peroxide (mass of one mole = 34 g)

Calculate the volume of oxygen that would be produced when0middot051 g of hydrogen peroxide decomposesTake the volume of 1 mole of oxygen gas to be 24 litres(3)

(b)Enzymes are commonly added to dishwasher tablets These are used to break down proteins(i) The proteins are broken down into small water-soluble molecules

Name the small water-soluble molecules made when proteins are broken down completely (1)

(ii) The structure of a section of protein chain found in egg white is shown

(A)Name the functional group circled (1)(B)Draw a structural formula for one of the molecules that would be made

when this section of egg white protein chain is completely broken down (1)

(iii) As part of the program in the dishwasher the conditions in the dishwasher change so that the enzyme molecules no longer work because they change shape

21

(A) State the term used to describe the change in shape of enzyme molecules(1)

(B) Suggest a change in conditions which would cause the enzyme molecules to change shape (1)

(d) A bleach activator is frequently added to dishwasher tablets to speed up the bleaching reaction One common bleach activator is TAED TAED could be produced in a process which involves a number of stages

(i) The first stage in producing TAED is shown below

Suggest a name for this type of reaction (1)

(ii) The final stage in the process producing TAED is shown below

Draw a structural formula for TAED (1)

22

23 The Chemistry of Cooking

1 Vanillin and zingerone are flavour molecules

Which line in the table correctly compares the properties of vanillin and zingerone

23

2 Erythrose can be used in the production of a chewing gum that helps prevent tooth decay

Which of the following compounds will be the best solvent for erythrose

3 The following molecules give flavour to food Which of the following flavour molecules would be most likely to be retained in the food when the food is cooked in water

24

4 Cooking involves many chemical reactions Proteins fats oils and esters are some examples of compounds found in food A chemist suggested that cooking food could change compounds from being fat-soluble to water-soluble Use your knowledge of chemistry to comment on the accuracy of this statement(3)

25

24 The Oxidation of Food

1 Apples and bananas turn brown when cut or bruised The first step of the reaction causing

the browning is shown below

Which of the following terms correctly describes this reactionA ReductionB OxidationC DehydrationD Condensation

2 Which of the following reactions can be classified as reductionA CH3CH2OH rarr CH3COOHB CH3 CH(OH)CH3 rarr CH3COCH3C CH3CH2COCH3 rarr CH3CH2CH(OH)CH3D CH3CH2CHO rarr CH3CH2COOH

3 The dehydration of butan-2-ol can produce two isomeric alkenes but-1-ene andbut-2-ene Which of the following alkanols can similarly produce on dehydration a pair of isomeric alkenesA Propan-2-olB Pentan-3-olC Hexan-3-olD Heptan-4-ol

4 Which of the following compounds is an alkanone

26

5 Which of the following is an aldehyde

6 Which of the following compounds would react with sodium hydroxide solution to forma saltA CH3CHOB CH3COOHC CH3COCH3D CH3CH2OH

7 Which line in the table shows the correct functional group for each homologous series

8 Which of the following organic compounds is an isomer of hexanalA 2-MethylbutanalB 3-Methylpentan-2-oneC 22-Dimethylbutan-1-olD 3-Ethylpentanal

27

9 The name of this compound is

A methanolB methanalC methanoic acidD methanone

10 Which alcohol could be oxidised to a carboxylic acid

11 Which of the following structural formulae represents a tertiary alcohol

12 Compound X reacted with hot copper(II) oxide and the organic product did not give acolour change when heated with Fehlingrsquos solution Compound X could beA butan-1-olB butan-2-olC butanoneD butanoic acid

28

13 Which two isomers would each produce an acid when warmed with acidified potassiumdichromate solution

A 1 and 2B 2 and 3C 1 and 4D 3 and 4

14 After heating for several minutes as shown in the diagram the pH indicator solution turned red

Liquid Q could beA propanoneB paraffinC propan-1-olD propan-2-ol

29

15 Enzymes are involved in the browning of cut fruitOne reaction taking place is

Which of the following correctly describes the above reaction

A OxidationB ReductionC HydrolysisD Condensation

16 Which of the following statements is correct for ketones

A They are formed by oxidation of tertiary alcohols

B They contain the group

C They contain a carboxyl groupD They will not react with Fehlingrsquos solution

17 Carvone is a natural product that can be extracted from orange peel

Which line in the table correctly describes the reaction of carvone with bromine solution and with acidified potassium dichromate solution

30

18 Which of the following is an isomer of 22-dimethylpentan-1-ol

A CH3CH2CH2CH(CH3)CH2OHB (CH3)3CCH(CH3)CH2OHC CH3CH2CH2CH2CH2CH2CH2CH2OHD (CH3)2CHC(CH3)2CH2CH2OH

19 The equation for the reduction reaction taking place when ethanal reacts with Tollensrsquo reagent is

A Cu2+(aq) + eminus rarr Cu+(aq)

B Ag+(aq) + eminus rarr Ag(s)

C Cr2O72minus(aq) + 14H+(aq) + 6eminus rarr 2Cr3+(aq) + 7H2O(ℓ)

D MnO4minus(aq) + 8H+(aq) + 5eminus rarr Mn2+(aq) + 4H2O(ℓ)

20 The name of the compound with structure

isA 23-dimethylpentan-4-oneB 23-dimethylpentan-2-alC 34-dimethylpentan-2-oneD 34-dimethylpentan-2-al

21 What is the systematic name for the compound below

A 222-trimethylethanolB 22-dimethylpropan-1-olC 22-dimethylpropan-3-olD 22-dimethylpentan-1-ol

31

22 The structure of a molecule found in olive oil can be represented as shown

(a) Olive oil can be hydrolysed using sodium hydroxide solution to produce sodium salts of fatty acids Name the other product of this reaction (1)

(b) In what way does the structure of a fat molecule differ from that of an oil molecule (1)

(c) Over time open containers of olive oil develop a rancid flavour What substance is reacting with the oil to cause these unwanted changes to take place (1)

23 A student writes the following statement It is incorrect Explain the mistake in the studentrsquos reasoning (1)

Alcohols are alkaline because of their OH groups

24 Carbon compounds take part in a wide variety of chemical reactions (a)

Name this type of chemical reaction (1)

(b)

Draw a structural formula for C3H6O (1)

25 Alkanols can be oxidised to alkanoic acids

32

(a) Why can Step 1 be described as an oxidation reaction (1)

(b) Acidified potassium dichromate solution can be used to oxidise propanal in Step 2 What colour change would be observed in this reaction (1)

26 Amines can be produced by reacting ammonia with an aldehyde or a ketone This reaction an example of reductive amination occurs in two stages

Stage 1 Amination

Stage 2 Reduction

(a) Give another name for the type of reaction taking place in Stage 2

(b) Draw the structural formula for the amine produced when butanal undergoes reductive amination with ammonia

27 Using a cobalt catalyst alkenes react with a mixture of hydrogen and carbon monoxideThe products are two isomeric aldehydes Propene reacts with the mixture as shown

(a) What name is given to a mixture of hydrogen and carbon monoxide (1)

(b) Draw a structural formula for compound B (1)

(c) (i) What would be observed if compound A was gently heated with Tollensrsquo reagent

(1)(ii) How would the reaction mixture be heated (1)

33

(d) Aldehydes can also be formed by the reaction of some alcohols with copper(II) oxideName the type of alcohol that would react with copper(II) oxide to form an aldehyde (1)

28 Aldehydes and ketones can take part in a reaction sometimes known as an aldol condensation The simplest aldol reaction involves two molecules of ethanal

In the reaction the carbon atom next to the carbonyl functional group of one molecule forms a bond with the carbonyl carbon atom of the second molecule

(a) Draw a structural formula for the product formed when propanone is used instead of ethanal in this type of reaction (1)

(b) Name an aldehyde that would not take part in an aldol condensation (1)

(c) Apart from the structure of the reactants suggest what is unusual about applying the term ldquocondensationrdquo to this particular type of reaction (1)

29 Primary secondary and tertiary alkanols can be prepared by the reaction of carbonyl compounds with Grignard reagents

Step 1The Grignard reagent reacts with the carbonyl compound

Step 2The reaction of the product of Step 1 with dilute acid produces the alkanol

(a) Describe the difference between a primary a secondary and a tertiary alkanol

You may wish to include labelled structures in your answer (1)34

(b) Suggest a name for the type of reaction that takes place in Step 1 (1)

(c) The same Grignard reagent can be used to produce the alkanol below

Name the carbonyl compound used in this reaction (1)

30 Hairspray is a mixture of chemicals(a) A primary alcohol 2-methylpropan-1-ol is added to hairspray to help it dry quickly on the hair

Draw a structural formula for a secondary alcohol that is an isomer of2-methylpropan-1-ol (1)

(b) Triethanol amine and triisopropyl amine are bases used to neutralise acidic compounds in the hairspray to prevent damage to the hair

In terms of the intermolecular bonding present explain clearly why triethanol amine has a much higher boiling point than triisopropyl amine (2)

35

36

31 Chocolate contains various compounds(a) Many of the flavour and aroma molecules found in chocolate are aldehydes and

ketones Two examples are shown below

Phenylethanal can be easily oxidised but 13-diphenylpropan-2-one cannot(i) Name a chemical that could be used to distinguish between these two

compounds (1)

(ii) Name the type of organic compound formed when phenylethanal is oxidised (1)

(b) Glycerol monostearate is an emulsifier used in chocolate

(i) Why is glycerol monostearate added to chocolate (1)

(ii) Draw a structural formula for glycerol (1)

(c) Theobromine a compound present in chocolate can cause illness in dogs and cats To decide if treatment is necessary vets must calculate the mass of theobromine consumed 1middot0 g of chocolate contains 1middot4 mg of theobromine Calculate the mass in mg of theobromine in a 17 g biscuit of which 28 is chocolate Show your working clearly (2)

(d) The flavour and texture of chocolate comes from a blend of compoundsUsing your knowledge of chemistry describe how you could show that there are ionic compounds and covalent compounds present in chocolate (3)

37

32 Ethanol has many uses

(a) Ethanol is found at relatively low concentrations in wine

(i) Name the chemical reaction that produces ethanol in wine (1)

(ii) Standard ethanol solutions were used to produce a graph of density against

concentration of ethanol given as a percentage of alcohol by volume ( abv)

What is the concentration of ethanol in units of abv in a solution of density 0middot9818 g cmminus3 (1)

(b) Whisky contains a higher concentration of ethanol

(i) Before 1980 the concentration of alcohol in drinks was measured in terms of degrees proof The concentration of alcohol in two drinks is shown in the table below both as abv and degrees proof

38

A cask strength whisky has an alcohol concentration of 65 abv Calculate the alcohol concentration of this whisky in degrees proof (1)

(ii) A barrel containing 195 litres of cask strength whisky costs pound1300 The cask strength whisky is diluted with water to reduce the concentration of alcohol from 65 abv to 46 abv before it is bottled Calculate the cost of the cask strength whisky needed to produce a 0middot70 litre bottle Show your working clearly (2)

(iii) 5-Butyl-4-methyltetrahydrofuran-2-ol is a flavour compound found in whisky

stored in oak barrels

Write the systematic name for the compound shown below (1) 13 11

33 (a) One test for glucose involves Fehlingrsquos solutionCircle the part of the glucose molecule that reacts with Fehlingrsquos solution (1)

(b) In solution sugar molecules exist in an equilibrium in straight-chain and ring forms

To change from the straight-chain form to the ring form the oxygen of the hydroxyl on carbon number 5 joins to the carbonyl carbon This is shown below for glucose

39

Draw the structure of a ring form for fructose (1)

34 (a) During the free radical chain reaction small molecules join to form large chain molecules

One example of a small molecule used is

Name the functional group circled above (1)

(b)Alcohol wipes are used to finish the varnishing treatment Alcohol wipes contain the alcohol propan-2-olState why propan-2-ol can be described as a secondary alcohol (1)

35 A student was carrying out an investigation into alcohols aldehydes and ketones

(a)The student was given three alcohols labelled as A B and C These alcohols were all isomers with the formula C4H9OH

(i) Draw a structural formula for the secondary alcohol with the formula C4H9OH(1)

(ii) The student set up the following experiment

A Suggest why a water bath is an appropriate method of heating the reaction mixture (1)

B Describe the colour change that would have been observed with alcohols A and C (1)

40

C Alcohol B is not oxidised State the type of alcohol which cannot be oxidised by acidified dichromate solution (1)

(iii) The student set up a second experiment with alcohol A

Hot copper(II) oxide is an oxidising agentA When alcohol A (C4H9OH) is oxidised the product turns the pH paper

redSuggest a name for the product (1)

B Complete the ion-electron equation for the oxidation reaction

C4H9OH rarr C4H8O2 (1)

(b)The student found the following information about the boiling points of some aldehydes

41

(i) Name the aldehyde that has a boiling point of 119 degC (1)(ii) Predict the boiling point in degC of the following molecule (1)

(iii) Using information from the table describe one way in which differences in structure affect the boiling point of isomeric aldehydes (1)

(iv) State what would be observed when an aldehyde is gently heated with Tollensrsquo reagent (1)

(c) Ketones contain a carbonyl groupName the type of intermolecular interaction between ketone molecules (1)

42

25 Soaps Detergents and Emulsions

1 Soaps are produced by the following reaction

This reaction is an example ofA condensationB esterificationC hydrolysisD oxidation

2 Which of the following is the salt of a long-chain fatty acid

A FatB OilC SoapD Glycerol

3 Emulsifiers for use in food are commonly made by reacting edible oils with

A estersB glycerolC fatty acidsD amino acids

4 A fatty acid is a long chain carboxylic acid Examples of fatty acids are shown in the table below

43

(a) What is the systematic name for linolenic acid (1)(b) Stearic acid reacts with sodium hydroxide solution to form sodium stearate

(i) Name the type of reaction taking place when stearic acid reacts with sodium hydroxide (1)

(ii) Explain fully how sodium stearate acts to keep grease and non-polar substances suspended in water during cleaning (3)

5 Small children can find it difficult to swallow tablets or pills so ibuprofen is supplied as an ldquoinfant formulardquo emulsion(a) The emulsifier used is polysorbate 80 Its structure is shown below

Explain why this molecule acts as an emulsifier (2)

(b) The emulsion contains 2 g of ibuprofen in every 100 cm3 of emulsion The recommended dose for treating a 6 month old baby is 0middot050 g Calculate the volume in cm3 of ldquoinfant formulardquo needed to treat a 6 month old baby (1)

6 Occasionally seabirds can become contaminated with hydrocarbons from oil spills This causes problems for birds because their feathers lose their waterproofing making the birds susceptible to temperature changes and

44

affecting their buoyancy If the birds attempt to clean themselves to remove the oil they may swallow the hydrocarbons causing damage to their internal organsContaminated seabirds can be cleaned by rubbing vegetable oil into their feathers and feet before the birds are rinsed with diluted washing-up liquidUsing your knowledge of chemistry comment on the problems created for seabirds by oil spills and the actions taken to treat affected birds (3)

7 Dishwasher tablets contain chemicals which remove dirt from dishesDishwasher tablets include detergents These molecules act like soaps to allow mixing of fat-soluble dirt and water(a)During the cleaning process the detergent molecules combine with fat-

soluble dirtA simplified diagram of a detergent molecule is shown

Complete the diagram below to show how detergent molecules combine with fat-soluble dirt (1)

(b)State the term used to describe the non-polar hydrocarbon tail of a detergent molecule (1)

45

26 Fragrances1 Myrcene is a simple terpene

Terpenes contain at least one isoprene unit Which of the following shows a correctly highlighted isoprene unit

2 Limonene is one of the terpene molecules responsible for the flavour of lemons

How many isoprene units are used in the production of one limonene moleculeA 1B 2C 3D 4

46

3 The structure of caryophyllene which can be extracted from clove oil is

Which of the following would be the best solvent for extracting caryophylleneA HexaneB HexanalC HexanolD Hexanone

4 The structure of isoprene is

Limonene is a terpene molecule present in lemons

How many isoprene units are joined together in a limonene molecule

A 1B 2

47

C 3D 4

5 Essential oils are

A non-water soluble non-volatile compoundsB non-water soluble volatile compoundsC water soluble non-volatile compoundsD water soluble volatile compounds

6 Two typical compounds that are present in many perfumes are shown

(a) Why does geraniol evaporate more slowly than limonene (1)

(b) The structure of one of the first synthetic scents used in perfume is shown below

(i) Name the family of carbonyl compounds to which this synthetic scent belongs (1)

(ii) Complete the structure below to show the product formed when this scent is

oxidised (1)

(c) Traces of a liquid were discovered in a bottle believed to contain perfume belonging to Queen Hatshepsut ruler of Egypt over 3500 years ago

Perfumes were made by dissolving plant extracts containing pleasant smelling terpenes and esters in an edible oil A little ethanol and water may also have been addedUsing your knowledge of chemistry comment on the possible smell(s) when such a bottle is opened after being stored for thousands of years (3)

48

49

7 A team of chemists are developing a fragrance for use in a shower gel for men(a) To give the gel a fruity smell the chemists are considering adding an ester

They synthesise six isomeric esters Volunteers smell each ester and give it a rating out of one hundred depending on how fruity the smell is

(i) Name the ester with the fruit-smell rating of 92 (1)

(ii) Shown below are the structures of three more isomers

Arrange these esters in order of decreasing fruit-smell rating (1)

50

(b) To create a fragrance for men the compound civetone is added

Draw a structural formula for the alcohol that can be oxidised to form civetone (1)

(c) To make the shower gel produce a cold tingling sensation when applied to the skin menthol is added

Like terpenes menthol is formed from isoprene (2-methylbuta-13-diene)Circle an isoprene unit on the menthol structure above (1)

8 Many of the compounds in perfumes are molecules consisting of joined isoprene units

(a) State the name that is given to molecules consisting of joined isoprene units (1)

(b)Geraniol is one of the compounds found in perfume It has the following structural formula and systematic name

Linalool can also be present Its structural formula is shown

51

(i) State the systematic name for linalool (1)(ii) Explain why linalool can be classified as a tertiary alcohol (1)

9 The component molecules found in lavender oils are terpenes or terpenoids(a)A chiral carbon is a carbon atom attached to four different atoms or groups of

atomsAn example is shown below

A molecule of the terpenoid linalool has a chiral carbon Linalool has the following structure

Circle the chiral carbon atom in the linalool structure (1)

(b)Farnesene is a terpene consisting of three isoprene units (2-methylbuta-13-diene) joined togetherWrite the molecular formula of farnesene (1)

52

27 Skin Care

1 Which of the following is not a step in a free radical chain reaction

A ActivationB InitiationC PropagationD Termination

2 Fluorine reacts with methane via a free radical chain reaction Some steps in the chain reaction are shown in the table below

Complete the table by(a) inserting the missing name for the first step (1)

(b) showing another possible termination reaction in the final row of the table (1)

3 Suncreams contain antioxidantsThe antioxidant compound A can prevent damage to skin by reacting with free

radicalssuch as NO2bull

53

Why can compound A be described as a free radical scavenger in the reaction shown above

4 Hydrogen and chlorine gases are used in an experiment to demonstrate a free radical reaction A plastic bottle is wrapped with black tape leaving a ldquowindowrdquo on one sideThe bottle is filled with a mixture of hydrogen and chlorine When bright light shines on the bottle there is an explosion

A free radical chain reaction is initiated when light energy causes chlorine radicals to form as shown below

(a) Complete the equations below showing possible propagation and termination steps

(2)

54

(b) Why is the plastic bottle used in the experiment wrapped in black tape (1)

5 Chloramines can be removed from water using ultraviolet light treatment

One step in the process is the formation of free radicals

(a)State what is meant by the term free radical (1)

(b)Another step in the process is shown below

State the name for this type of step in a free radical reaction (1)

6 Modern shellac nail varnishes are more durable and so last longer than traditional nail polish

The shellac nail varnish is applied in thin layers to the nails and then the fingers are placed under a UV lamp

(a) The Skin Care Foundation has recommended that a sun-block is applied to the fingers and hand before using the lampSuggest why the Skin Care Foundation makes this recommendation (1)

(b) A free radical chain reaction takes place and the varnish hardens (i) State what is meant by the term free radical (1)

(ii) The shellac nail varnish contains a mixture of ingredients that take part in the free radical chain reactionOne of the steps in the free radical chain reaction is

55

State the term used to describe this type of step in a free radical chain reaction(1)

7 Skin care products contain a mixture of polar covalent non-polar covalent and ionic compounds The compounds need to stay mixed within the product Skin care products also need to spread easily and remain on the skin for a period of time as well as provide physical and chemical protection from the sun In order to do this skin care products contain a range of chemicals including water fats and oils antioxidants minerals and sun blockUsing your knowledge of chemistry explain the role of different chemicals in skin care products (3)

General Questions

1 A mixture of carbon monoxide and hydrogen can be converted into water and a mixture of hydrocarbons

nCO + (2n + 1)H2 rarr nH2O + hydrocarbons

What is the general formula for the hydrocarbons producedA CnH2nndash2B CnH2nC CnH2n+1D CnH2n+2

2 Butadiene is the first member of a homologous series of hydrocarbons called dienesWhat is the general formula for this seriesA CnHn+2B CnHn+3C CnH2nD CnH2nndash2

3 Which of the following statements about methanol is falseA It can be made from synthesis gasB It can be dehydrated to form an alkeneC It can be oxidised to give a carboxylic acidD It reacts with acidified potassium dichromate solution

56

4

Which line in the table correctly describes reactions X and Y

5

Which line in the table correctly describes reactions X and Y

6 Which of the following fuels when burned would make no contribution to globalwarming

57

A HydrogenB Natural gasC PetrolD Coal

7 Which of the following hydrocarbons always gives the same product when one of itshydrogen atoms is replaced by a chlorine atomA HexaneB Hex-1-eneC CyclohexaneD Cyclohexene

8 Which of the following compounds does not have isomeric structuresA C2HCl3B C2H4Cl2C PropeneD Propan-1-ol

9 What organic compound is produced by the dehydration of ethanol A EthaneB EtheneC EthanalD Ethanoic acid

10

The above equation representsA hydrationB hydrogenationC condensationD hydrolysis

11

Which of the following compounds is an isomer of the structure shown aboveA ButanalB ButanoneC Butan-1-olD Butanoic acid

58

12 A compound with molecular formula C6H12O2 could beA hexanalB hexan-2-olC hexan-2-oneD hexanoic acid

13 Propan-2-ol can be prepared from propane as follows

Which line in the table correctly describes the types of reaction taking place at Steps 1 and 2

14 Which of the following compounds would be the most water soluble

15 Cyanohydrin compounds can be made from carbonyl compounds by reacting the carbonyl compound with hydrogen cyanide (HCN)

59

Which carbonyl compound would react with hydrogen cyanide (HCN) to form the following compound

16 Ethyne is the first member of the homologous series called the alkynes

Ethyne can undergo addition reactions as shown in the flow diagram

(a) Compound 2 is an isomer of 12-dichloroethaneDraw a structural formula for compound 2 (1)

(b) Reagents A B and C are three different diatomic gasesUsing information in the flow diagram identify reagents A B and C (1)

60

Reagent Gas

A

B

C

17 In 1865 the German chemist Kekuleacute proposed a ring structure for benzene This structure was based on alternating single and double bonds

(a) (i) Describe a chemical test that would indicate that the above chemical structure for benzene is incorrect (1)

(ii) Briefly describe the correct structure for benzene (1)

(b) Benzene can be formed from cyclohexaneC6H12 rarr C6H6 + 3H2

What name is given to this type of reaction (1)18 Infra-red spectroscopy is a technique that can be used to identify the bonds that

arepresent in a molecule Different bonds absorb infra-red radiation of different wavenumbers This is due to differences in the bond lsquostretchrsquo These absorptions are recorded in a spectrumA spectrum for propan-1-ol is shown

61

The correlation table on page 13 of the data booklet shows the wavenumber ranges for the absorptions due to different bonds

(a) Use the correlation table to identify the bonds responsible for the two absorptions x and y that are circled in the propan-1-ol spectrum (1)

(b) Propan-1-ol reacts with ethanoic acid(i) What name is given to this type of reaction (1)(ii) Draw a spectrum that could be obtained for the organic product of this

reaction (1)

19 Paracetamol is a widely used painkiller

(a) Write the molecular formula for paracetamol (1)

(b) One antidote for paracetamol overdose is methionine

62

To what family of organic compounds does methionine belong (1)

(c) The concentration of paracetamol in a solution can be determined by measuring how much UV radiation it absorbs

The graph shows how the absorbance of a sample containing 0middot040 g l ndash1 paracetamol varies with wavelength

The quantity of UV radiation of wavelength 245 nm absorbed is directly proportional to the concentration of paracetamolThe absorbance of a second sample of paracetamol solution measured at 245 nm was 0middot90 What is the concentration in g l ndash1 of this second paracetamol solution (1)

20 Many carbon compounds containing oxygen are very flammableThe table shows information about two families of isomersThe lowest temperature at which a compound will ignite is called its flash point

(a) A compound with the molecular formula C6H14O has a boiling point of 158 degC63

Draw a structural formula for this compound (1)

(b) For a family of isomers in the table write a general statement linking the flash points of the compounds to their structures (1)

21 Hydrogels are used in disposable nappies They are fine powders that can absorb up to 500 times their own weight in waterA hydrogel is a very long molecule with carboxyl groups at regular intervals along its length A short section of a hydrogel molecule is shown below

Hydrogels are extremely good at soaking up water because the water molecules are strongly attracted to them

Using your knowledge of chemistry comment on how suitable hydrogels would be for absorbing liquids or solutions spilled in a chemistry lab (1)

64

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

25 A typical triglyceride found in olive oil is shown below

(a) To which family of organic compounds do triglycerides belong (1)

(b) Olive oil can be hardened for use in margarinesWhat happens to the triglyceride molecules during the hardening of olive oil (1)

(c) Give one reason why oils can be a useful part of a balanced diet (1)

26 When vegetable oils are hydrolysed mixtures of fatty acids are obtained The fatty acids can be classified by their degree of unsaturation The table below shows the composition of each of the mixtures of fatty acids obtained when palm oil and olive oil were hydrolysed

(a) Why does palm oil have a higher melting point than olive oil (1)

(b) One of the fatty acids produced by the hydrolysis of palm oil is linoleic acid C17H31COOH To which class (saturated monounsaturated or polyunsaturated) does this fatty acid belong (1)

(c) When a mixture of palm oil and olive oil is hydrolysed using a solution of sodium hydroxide a mixture of the sodium salts of the fatty acids is obtained State a use for these fatty acid salts (1)

8

27

4-hydroxybenzoic acid can react with alcohols to form compounds known asparabens

(a) Name the functional group circled in the structure of 4minushydroxybenzoic acid (1)

(b) Name the type of reaction taking place when parabens are formed (1)

(c) Draw the paraben formed when 4minushydroxybenzoic acid reacts with ethanol (1)

(d) Parabens can be used as preservatives in cosmetics and toiletries Parabens are absorbed into the body through the skin The following table indicates the absorption of some parabens

State a conclusion that can be drawn from the information in the table (1)

9

28 When fats and oils are hydrolysed mixtures of fatty acids are obtained

(a) Name the other product obtained in this reaction (1)

(b)The table below shows the percentage composition of the fatty acid mixtures obtained by hydrolysis of coconut oil and olive oil

(i) One of the fatty acids produced by the hydrolysis of olive oil is linoleic acid C17H31COOHState the class of fatty acid to which linoleic acid belongs (1)

(ii) Hydrolysed coconut oil contains the fatty acid caprylic acid with the formula CH3(CH2)6COOHState the systematic name for caprylic acid (1)

(c) The degree of unsaturation of oil can be tested by adding drops of bromine solution to the oil Bromine adds across carbon to carbon double bonds in the fatty acid chains

The following apparatus can be used to compare the degree ofunsaturation of different oils

10

(i) Describe how this apparatus could be used to show that olive oil has a greater degree of unsaturation than coconut oil (2)

(ii) Suggest why hexane is used as the solvent rather than water (1)

(iii) Coconut oil has a melting point of 25 degC Olive oil has a melting point of minus6C

Give two reasons why coconut oil has a higher melting point than olive oil (2)

29 Traditional nail varnishes use ethyl ethanoate and butyl ethanoate as solvents

(a)Draw a structural formula for butyl ethanoate (1)(b)Ethyl ethanoate can be made in the laboratory using the following apparatus

Suggest why a wet paper towel is wrapped around the test tube (1)

(c) Name the type of reaction that takes place during the formation of ethyl ethanoate (1)

30 Pentyl butanoate is responsible for some of the flavour in apricots and strawberries

(a)Hydrolysis of pentyl butanoate using sodium hydroxide produces an alcohol and the salt of the carboxylic acid

(i) Name the alcohol that would be formed when pentyl butanoate is hydrolysed(1)

(ii) Draw a structural formula for the sodium salt of the carboxylic acid that would be formed (1)

(b)Fats and oils belong to the same class of compounds as pentyl butanoate(i) Name this class of compounds (1)

11

(ii) When a fat is hydrolysed using sodium hydroxide sodium salts of fatty acids are producedState a use for sodium salts of fatty acids (1)

22 Proteins

1 When a protein is denaturedA its overall shape is distortedB its amide links are hydrolysedC it is broken into separate peptide fragmentsD it decomposes into amino acids

2 Which of the following compounds can be classified as proteinsA FatsB OilsC EnzymesD Amino acids

3 The monomer units used to construct enzyme molecules areA alcoholsB estersC amino acidsD fatty acids

4 Amino acids are converted into proteins byA hydrationB hydrolysisC hydrogenationD condensation

5 The arrangement of amino acids in a peptide isZ-X-W-V-Y

where the letters V W X Y and Z represent amino acidsOn partial hydrolysis of the peptide which of the following sets of dipeptides is possibleA V-Y Z-X W-Y X-WB Z-X V-Y W-V X-WC Z-X X-V W-V V-YD X-W X-Z Z-W Y-V

6 Which of the following is an amine

12

7 Which of the following arrangements of atoms shows a peptide link

8 The following molecules are found in herbicides Which of the following contains an amide link

9 In α-amino acids the amino group is on the carbon atom adjacent to the acid group

Which of the following is an α-amino acid

10 A tripeptide X has the structure

Partial hydrolysis of X yields a mixture of dipeptidesWhich of the following dipeptides could be produced on hydrolysing X

13

11 The rate of hydrolysis of protein using an enzyme was studied at different temperatures Which of the following graphs would be obtained

12 The rate of hydrolysis of protein using an enzyme was studied at different temperaturesWhich of the following graphs would be obtained

14

13 Polymers can be classified as natural or synthetic(a) Keratin a natural polymer is a protein found in hair

The hydrolysis of keratin produces different monomers of the type shown

(i) What name is given to monomers like glycine alanine and cysteine (1)(ii) What is meant by a hydrolysis reaction (1)

(b) Dacron a synthetic polymer is used in heart surgery A section of the polymer is shown

What name is given to the link made by the shaded group of atoms in this section of the polymer (1)

14 Chemists have developed cheeses specifically for use in cheeseburgers(a) When ordinary cheddar cheese is grilled the shapes of the protein molecules

change and the proteins and fats separate leaving a chewy solid and an oily liquidWhat name is given to the change in protein structure which occurs when ordinary cheddar is grilled (1)

(b) To make cheese for burgers grated cheddar cheese soluble milk proteins and some water are mixed and heated to no more than 82 degC As the cheese begins to melt an emulsifying agent is added and the mixture is stirred

15

(i) Why would a water bath be used to heat the mixture (1)(ii) A section of the structure of a soluble milk protein is shown below

Draw a structural formula for any one of the amino acids formed when this section of

protein is hydrolysed (1)

(iii) The emulsifier used is trisodium citrate a salt formed when citric acid is neutralised using sodium hydroxide Complete the equation below showing a structural formula for the trisodium citrate formed (1) sp 8

15 Phenylalanine and alanine are both amino acids

(a) Phenylalanine is an essential amino acid

(i) What is meant by an essential amino acid (1)

16

(ii) How many hydrogen atoms are present in a molecule of phenylalanine (1)

(b) Phenylalanine and alanine can react to form the dipeptide shown

Circle the peptide link in this molecule (1)

(c) Draw a structural formula for the other dipeptide that can be formed from phenylalanine and alanine (1)

16 Uncooked egg white is mainly composed of dissolved proteins During cooking processes the proteins become denatured as the protein chains unwind and the egg white solidifies

(a) Explain why the protein chains unwind (1)

(b)The temperature at which the protein becomes denatured is called the melting temperature The melting temperature of a protein can be determined using fluorescence In this technique the protein is mixed with a dye that gives out visible light when it attaches to hydrophobic parts of the protein molecule The hydrophobic parts of the structure are on the inside of the protein and the dye has no access to them unless the protein unwinds

(i) Ovalbumin is a protein found in egg white Part of the structure of unwound ovalbumin is shown below

Circle the part of the structure to which the hydrophobic dye is most likely to attach (1)

17

(ii) Another protein in egg white is conalbumin The temperature of a conalbumindye mixture is gradually increased The fluorescence is measured and a graph is produced

The melting temperature is the temperature at which the fluorescence is halfway between the highest and lowest fluorescence valuesDetermine the melting temperature in ordmC for this protein (1)

(c) Once cooked and eaten the digestive system breaks the protein chains into amino acids with the help of enzymes

(i) State the name of the digestion process where enzymes break down proteins into amino acids (1)

(ii)

(A) State how many amino acid molecules joined to form this section of protein (1)

(B) Draw the structure of one amino acid that would be produced when this section of the protein chain is broken down (1)

17 Peptide molecules can be classified according to the number of amino acid units joined by peptide bonds in the molecule

18

(a) Complete the table to identify the type of peptide with the following amino acid sequence

alanine-glycine-valine-proline-tyrosine-serine (1)

(b) Partial hydrolysis of another pentapeptide molecule gave a mixture of three smaller peptide molecules with the following amino acid sequences

leucine-glycine-valineisoleucine-leucineglycine-valine-serine

Write the amino acid sequence for the original pentapeptide molecule (1)

helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip(c) Some amino acids needed to form polypeptides cannot be produced in the human body

State the term used to describe amino acids that the body cannot make (1)

(d)Paper chromatography is often used to analyse the mixtures of amino acids produced when peptides are broken downOn a chromatogram the retention factor Rf for a substance can be a useful method of identifying the substance

The structure of the pentapeptide methionine enkephalin was investigatedA sample of the pentapeptide was completely hydrolysed into its constituent amino acids and this amino acid mixture was applied to a piece of chromatography paper and placed in a solventThe chromatogram obtained is shown below

19

(i) Suggest why only four spots were obtained on the chromatogram of the hydrolysed pentapeptide (1)

(ii) It is known that this amino acid mixture contains the amino acid methionine The Rf value for methionine in this solvent is 040Draw a circle around the spot on the chromatogram that corresponds to methionine (1)

(e) Over the last decade several families of extremely stable peptide molecules have been discovered where the peptide chain forms a ring

(i) A simple cyclic dipeptide is shown

Draw a structural formula for one of the amino acids that would be formed on complete hydrolysis of the above cyclic dipeptide (1)

(ii) Alpha-amanitin is a highly toxic cyclic peptide found in death cap mushrooms The lethal dose for humans is 100 mg per kg of body mass1middot0 g of death cap mushrooms contains 250 mg of alpha-amanitinCalculate the minimum mass of death cap mushrooms that would contain the lethal dose for a 75 kg adult (2)

18 Dishwasher tablets produce the bleach hydrogen peroxide H2O2 One action of this oxidising agent is to oxidise food

(a)(i) Suggest another action of the bleach produced by the dishwasher tablets (1)

20

(ii) Hydrogen peroxide decomposes to form water and oxygen

2H2O2(ℓ) rarr 2H2O(ℓ) + O2(g)

A dishwasher tablet produces 0middot051 g of hydrogen peroxide (mass of one mole = 34 g)

Calculate the volume of oxygen that would be produced when0middot051 g of hydrogen peroxide decomposesTake the volume of 1 mole of oxygen gas to be 24 litres(3)

(b)Enzymes are commonly added to dishwasher tablets These are used to break down proteins(i) The proteins are broken down into small water-soluble molecules

Name the small water-soluble molecules made when proteins are broken down completely (1)

(ii) The structure of a section of protein chain found in egg white is shown

(A)Name the functional group circled (1)(B)Draw a structural formula for one of the molecules that would be made

when this section of egg white protein chain is completely broken down (1)

(iii) As part of the program in the dishwasher the conditions in the dishwasher change so that the enzyme molecules no longer work because they change shape

21

(A) State the term used to describe the change in shape of enzyme molecules(1)

(B) Suggest a change in conditions which would cause the enzyme molecules to change shape (1)

(d) A bleach activator is frequently added to dishwasher tablets to speed up the bleaching reaction One common bleach activator is TAED TAED could be produced in a process which involves a number of stages

(i) The first stage in producing TAED is shown below

Suggest a name for this type of reaction (1)

(ii) The final stage in the process producing TAED is shown below

Draw a structural formula for TAED (1)

22

23 The Chemistry of Cooking

1 Vanillin and zingerone are flavour molecules

Which line in the table correctly compares the properties of vanillin and zingerone

23

2 Erythrose can be used in the production of a chewing gum that helps prevent tooth decay

Which of the following compounds will be the best solvent for erythrose

3 The following molecules give flavour to food Which of the following flavour molecules would be most likely to be retained in the food when the food is cooked in water

24

4 Cooking involves many chemical reactions Proteins fats oils and esters are some examples of compounds found in food A chemist suggested that cooking food could change compounds from being fat-soluble to water-soluble Use your knowledge of chemistry to comment on the accuracy of this statement(3)

25

24 The Oxidation of Food

1 Apples and bananas turn brown when cut or bruised The first step of the reaction causing

the browning is shown below

Which of the following terms correctly describes this reactionA ReductionB OxidationC DehydrationD Condensation

2 Which of the following reactions can be classified as reductionA CH3CH2OH rarr CH3COOHB CH3 CH(OH)CH3 rarr CH3COCH3C CH3CH2COCH3 rarr CH3CH2CH(OH)CH3D CH3CH2CHO rarr CH3CH2COOH

3 The dehydration of butan-2-ol can produce two isomeric alkenes but-1-ene andbut-2-ene Which of the following alkanols can similarly produce on dehydration a pair of isomeric alkenesA Propan-2-olB Pentan-3-olC Hexan-3-olD Heptan-4-ol

4 Which of the following compounds is an alkanone

26

5 Which of the following is an aldehyde

6 Which of the following compounds would react with sodium hydroxide solution to forma saltA CH3CHOB CH3COOHC CH3COCH3D CH3CH2OH

7 Which line in the table shows the correct functional group for each homologous series

8 Which of the following organic compounds is an isomer of hexanalA 2-MethylbutanalB 3-Methylpentan-2-oneC 22-Dimethylbutan-1-olD 3-Ethylpentanal

27

9 The name of this compound is

A methanolB methanalC methanoic acidD methanone

10 Which alcohol could be oxidised to a carboxylic acid

11 Which of the following structural formulae represents a tertiary alcohol

12 Compound X reacted with hot copper(II) oxide and the organic product did not give acolour change when heated with Fehlingrsquos solution Compound X could beA butan-1-olB butan-2-olC butanoneD butanoic acid

28

13 Which two isomers would each produce an acid when warmed with acidified potassiumdichromate solution

A 1 and 2B 2 and 3C 1 and 4D 3 and 4

14 After heating for several minutes as shown in the diagram the pH indicator solution turned red

Liquid Q could beA propanoneB paraffinC propan-1-olD propan-2-ol

29

15 Enzymes are involved in the browning of cut fruitOne reaction taking place is

Which of the following correctly describes the above reaction

A OxidationB ReductionC HydrolysisD Condensation

16 Which of the following statements is correct for ketones

A They are formed by oxidation of tertiary alcohols

B They contain the group

C They contain a carboxyl groupD They will not react with Fehlingrsquos solution

17 Carvone is a natural product that can be extracted from orange peel

Which line in the table correctly describes the reaction of carvone with bromine solution and with acidified potassium dichromate solution

30

18 Which of the following is an isomer of 22-dimethylpentan-1-ol

A CH3CH2CH2CH(CH3)CH2OHB (CH3)3CCH(CH3)CH2OHC CH3CH2CH2CH2CH2CH2CH2CH2OHD (CH3)2CHC(CH3)2CH2CH2OH

19 The equation for the reduction reaction taking place when ethanal reacts with Tollensrsquo reagent is

A Cu2+(aq) + eminus rarr Cu+(aq)

B Ag+(aq) + eminus rarr Ag(s)

C Cr2O72minus(aq) + 14H+(aq) + 6eminus rarr 2Cr3+(aq) + 7H2O(ℓ)

D MnO4minus(aq) + 8H+(aq) + 5eminus rarr Mn2+(aq) + 4H2O(ℓ)

20 The name of the compound with structure

isA 23-dimethylpentan-4-oneB 23-dimethylpentan-2-alC 34-dimethylpentan-2-oneD 34-dimethylpentan-2-al

21 What is the systematic name for the compound below

A 222-trimethylethanolB 22-dimethylpropan-1-olC 22-dimethylpropan-3-olD 22-dimethylpentan-1-ol

31

22 The structure of a molecule found in olive oil can be represented as shown

(a) Olive oil can be hydrolysed using sodium hydroxide solution to produce sodium salts of fatty acids Name the other product of this reaction (1)

(b) In what way does the structure of a fat molecule differ from that of an oil molecule (1)

(c) Over time open containers of olive oil develop a rancid flavour What substance is reacting with the oil to cause these unwanted changes to take place (1)

23 A student writes the following statement It is incorrect Explain the mistake in the studentrsquos reasoning (1)

Alcohols are alkaline because of their OH groups

24 Carbon compounds take part in a wide variety of chemical reactions (a)

Name this type of chemical reaction (1)

(b)

Draw a structural formula for C3H6O (1)

25 Alkanols can be oxidised to alkanoic acids

32

(a) Why can Step 1 be described as an oxidation reaction (1)

(b) Acidified potassium dichromate solution can be used to oxidise propanal in Step 2 What colour change would be observed in this reaction (1)

26 Amines can be produced by reacting ammonia with an aldehyde or a ketone This reaction an example of reductive amination occurs in two stages

Stage 1 Amination

Stage 2 Reduction

(a) Give another name for the type of reaction taking place in Stage 2

(b) Draw the structural formula for the amine produced when butanal undergoes reductive amination with ammonia

27 Using a cobalt catalyst alkenes react with a mixture of hydrogen and carbon monoxideThe products are two isomeric aldehydes Propene reacts with the mixture as shown

(a) What name is given to a mixture of hydrogen and carbon monoxide (1)

(b) Draw a structural formula for compound B (1)

(c) (i) What would be observed if compound A was gently heated with Tollensrsquo reagent

(1)(ii) How would the reaction mixture be heated (1)

33

(d) Aldehydes can also be formed by the reaction of some alcohols with copper(II) oxideName the type of alcohol that would react with copper(II) oxide to form an aldehyde (1)

28 Aldehydes and ketones can take part in a reaction sometimes known as an aldol condensation The simplest aldol reaction involves two molecules of ethanal

In the reaction the carbon atom next to the carbonyl functional group of one molecule forms a bond with the carbonyl carbon atom of the second molecule

(a) Draw a structural formula for the product formed when propanone is used instead of ethanal in this type of reaction (1)

(b) Name an aldehyde that would not take part in an aldol condensation (1)

(c) Apart from the structure of the reactants suggest what is unusual about applying the term ldquocondensationrdquo to this particular type of reaction (1)

29 Primary secondary and tertiary alkanols can be prepared by the reaction of carbonyl compounds with Grignard reagents

Step 1The Grignard reagent reacts with the carbonyl compound

Step 2The reaction of the product of Step 1 with dilute acid produces the alkanol

(a) Describe the difference between a primary a secondary and a tertiary alkanol

You may wish to include labelled structures in your answer (1)34

(b) Suggest a name for the type of reaction that takes place in Step 1 (1)

(c) The same Grignard reagent can be used to produce the alkanol below

Name the carbonyl compound used in this reaction (1)

30 Hairspray is a mixture of chemicals(a) A primary alcohol 2-methylpropan-1-ol is added to hairspray to help it dry quickly on the hair

Draw a structural formula for a secondary alcohol that is an isomer of2-methylpropan-1-ol (1)

(b) Triethanol amine and triisopropyl amine are bases used to neutralise acidic compounds in the hairspray to prevent damage to the hair

In terms of the intermolecular bonding present explain clearly why triethanol amine has a much higher boiling point than triisopropyl amine (2)

35

36

31 Chocolate contains various compounds(a) Many of the flavour and aroma molecules found in chocolate are aldehydes and

ketones Two examples are shown below

Phenylethanal can be easily oxidised but 13-diphenylpropan-2-one cannot(i) Name a chemical that could be used to distinguish between these two

compounds (1)

(ii) Name the type of organic compound formed when phenylethanal is oxidised (1)

(b) Glycerol monostearate is an emulsifier used in chocolate

(i) Why is glycerol monostearate added to chocolate (1)

(ii) Draw a structural formula for glycerol (1)

(c) Theobromine a compound present in chocolate can cause illness in dogs and cats To decide if treatment is necessary vets must calculate the mass of theobromine consumed 1middot0 g of chocolate contains 1middot4 mg of theobromine Calculate the mass in mg of theobromine in a 17 g biscuit of which 28 is chocolate Show your working clearly (2)

(d) The flavour and texture of chocolate comes from a blend of compoundsUsing your knowledge of chemistry describe how you could show that there are ionic compounds and covalent compounds present in chocolate (3)

37

32 Ethanol has many uses

(a) Ethanol is found at relatively low concentrations in wine

(i) Name the chemical reaction that produces ethanol in wine (1)

(ii) Standard ethanol solutions were used to produce a graph of density against

concentration of ethanol given as a percentage of alcohol by volume ( abv)

What is the concentration of ethanol in units of abv in a solution of density 0middot9818 g cmminus3 (1)

(b) Whisky contains a higher concentration of ethanol

(i) Before 1980 the concentration of alcohol in drinks was measured in terms of degrees proof The concentration of alcohol in two drinks is shown in the table below both as abv and degrees proof

38

A cask strength whisky has an alcohol concentration of 65 abv Calculate the alcohol concentration of this whisky in degrees proof (1)

(ii) A barrel containing 195 litres of cask strength whisky costs pound1300 The cask strength whisky is diluted with water to reduce the concentration of alcohol from 65 abv to 46 abv before it is bottled Calculate the cost of the cask strength whisky needed to produce a 0middot70 litre bottle Show your working clearly (2)

(iii) 5-Butyl-4-methyltetrahydrofuran-2-ol is a flavour compound found in whisky

stored in oak barrels

Write the systematic name for the compound shown below (1) 13 11

33 (a) One test for glucose involves Fehlingrsquos solutionCircle the part of the glucose molecule that reacts with Fehlingrsquos solution (1)

(b) In solution sugar molecules exist in an equilibrium in straight-chain and ring forms

To change from the straight-chain form to the ring form the oxygen of the hydroxyl on carbon number 5 joins to the carbonyl carbon This is shown below for glucose

39

Draw the structure of a ring form for fructose (1)

34 (a) During the free radical chain reaction small molecules join to form large chain molecules

One example of a small molecule used is

Name the functional group circled above (1)

(b)Alcohol wipes are used to finish the varnishing treatment Alcohol wipes contain the alcohol propan-2-olState why propan-2-ol can be described as a secondary alcohol (1)

35 A student was carrying out an investigation into alcohols aldehydes and ketones

(a)The student was given three alcohols labelled as A B and C These alcohols were all isomers with the formula C4H9OH

(i) Draw a structural formula for the secondary alcohol with the formula C4H9OH(1)

(ii) The student set up the following experiment

A Suggest why a water bath is an appropriate method of heating the reaction mixture (1)

B Describe the colour change that would have been observed with alcohols A and C (1)

40

C Alcohol B is not oxidised State the type of alcohol which cannot be oxidised by acidified dichromate solution (1)

(iii) The student set up a second experiment with alcohol A

Hot copper(II) oxide is an oxidising agentA When alcohol A (C4H9OH) is oxidised the product turns the pH paper

redSuggest a name for the product (1)

B Complete the ion-electron equation for the oxidation reaction

C4H9OH rarr C4H8O2 (1)

(b)The student found the following information about the boiling points of some aldehydes

41

(i) Name the aldehyde that has a boiling point of 119 degC (1)(ii) Predict the boiling point in degC of the following molecule (1)

(iii) Using information from the table describe one way in which differences in structure affect the boiling point of isomeric aldehydes (1)

(iv) State what would be observed when an aldehyde is gently heated with Tollensrsquo reagent (1)

(c) Ketones contain a carbonyl groupName the type of intermolecular interaction between ketone molecules (1)

42

25 Soaps Detergents and Emulsions

1 Soaps are produced by the following reaction

This reaction is an example ofA condensationB esterificationC hydrolysisD oxidation

2 Which of the following is the salt of a long-chain fatty acid

A FatB OilC SoapD Glycerol

3 Emulsifiers for use in food are commonly made by reacting edible oils with

A estersB glycerolC fatty acidsD amino acids

4 A fatty acid is a long chain carboxylic acid Examples of fatty acids are shown in the table below

43

(a) What is the systematic name for linolenic acid (1)(b) Stearic acid reacts with sodium hydroxide solution to form sodium stearate

(i) Name the type of reaction taking place when stearic acid reacts with sodium hydroxide (1)

(ii) Explain fully how sodium stearate acts to keep grease and non-polar substances suspended in water during cleaning (3)

5 Small children can find it difficult to swallow tablets or pills so ibuprofen is supplied as an ldquoinfant formulardquo emulsion(a) The emulsifier used is polysorbate 80 Its structure is shown below

Explain why this molecule acts as an emulsifier (2)

(b) The emulsion contains 2 g of ibuprofen in every 100 cm3 of emulsion The recommended dose for treating a 6 month old baby is 0middot050 g Calculate the volume in cm3 of ldquoinfant formulardquo needed to treat a 6 month old baby (1)

6 Occasionally seabirds can become contaminated with hydrocarbons from oil spills This causes problems for birds because their feathers lose their waterproofing making the birds susceptible to temperature changes and

44

affecting their buoyancy If the birds attempt to clean themselves to remove the oil they may swallow the hydrocarbons causing damage to their internal organsContaminated seabirds can be cleaned by rubbing vegetable oil into their feathers and feet before the birds are rinsed with diluted washing-up liquidUsing your knowledge of chemistry comment on the problems created for seabirds by oil spills and the actions taken to treat affected birds (3)

7 Dishwasher tablets contain chemicals which remove dirt from dishesDishwasher tablets include detergents These molecules act like soaps to allow mixing of fat-soluble dirt and water(a)During the cleaning process the detergent molecules combine with fat-

soluble dirtA simplified diagram of a detergent molecule is shown

Complete the diagram below to show how detergent molecules combine with fat-soluble dirt (1)

(b)State the term used to describe the non-polar hydrocarbon tail of a detergent molecule (1)

45

26 Fragrances1 Myrcene is a simple terpene

Terpenes contain at least one isoprene unit Which of the following shows a correctly highlighted isoprene unit

2 Limonene is one of the terpene molecules responsible for the flavour of lemons

How many isoprene units are used in the production of one limonene moleculeA 1B 2C 3D 4

46

3 The structure of caryophyllene which can be extracted from clove oil is

Which of the following would be the best solvent for extracting caryophylleneA HexaneB HexanalC HexanolD Hexanone

4 The structure of isoprene is

Limonene is a terpene molecule present in lemons

How many isoprene units are joined together in a limonene molecule

A 1B 2

47

C 3D 4

5 Essential oils are

A non-water soluble non-volatile compoundsB non-water soluble volatile compoundsC water soluble non-volatile compoundsD water soluble volatile compounds

6 Two typical compounds that are present in many perfumes are shown

(a) Why does geraniol evaporate more slowly than limonene (1)

(b) The structure of one of the first synthetic scents used in perfume is shown below

(i) Name the family of carbonyl compounds to which this synthetic scent belongs (1)

(ii) Complete the structure below to show the product formed when this scent is

oxidised (1)

(c) Traces of a liquid were discovered in a bottle believed to contain perfume belonging to Queen Hatshepsut ruler of Egypt over 3500 years ago

Perfumes were made by dissolving plant extracts containing pleasant smelling terpenes and esters in an edible oil A little ethanol and water may also have been addedUsing your knowledge of chemistry comment on the possible smell(s) when such a bottle is opened after being stored for thousands of years (3)

48

49

7 A team of chemists are developing a fragrance for use in a shower gel for men(a) To give the gel a fruity smell the chemists are considering adding an ester

They synthesise six isomeric esters Volunteers smell each ester and give it a rating out of one hundred depending on how fruity the smell is

(i) Name the ester with the fruit-smell rating of 92 (1)

(ii) Shown below are the structures of three more isomers

Arrange these esters in order of decreasing fruit-smell rating (1)

50

(b) To create a fragrance for men the compound civetone is added

Draw a structural formula for the alcohol that can be oxidised to form civetone (1)

(c) To make the shower gel produce a cold tingling sensation when applied to the skin menthol is added

Like terpenes menthol is formed from isoprene (2-methylbuta-13-diene)Circle an isoprene unit on the menthol structure above (1)

8 Many of the compounds in perfumes are molecules consisting of joined isoprene units

(a) State the name that is given to molecules consisting of joined isoprene units (1)

(b)Geraniol is one of the compounds found in perfume It has the following structural formula and systematic name

Linalool can also be present Its structural formula is shown

51

(i) State the systematic name for linalool (1)(ii) Explain why linalool can be classified as a tertiary alcohol (1)

9 The component molecules found in lavender oils are terpenes or terpenoids(a)A chiral carbon is a carbon atom attached to four different atoms or groups of

atomsAn example is shown below

A molecule of the terpenoid linalool has a chiral carbon Linalool has the following structure

Circle the chiral carbon atom in the linalool structure (1)

(b)Farnesene is a terpene consisting of three isoprene units (2-methylbuta-13-diene) joined togetherWrite the molecular formula of farnesene (1)

52

27 Skin Care

1 Which of the following is not a step in a free radical chain reaction

A ActivationB InitiationC PropagationD Termination

2 Fluorine reacts with methane via a free radical chain reaction Some steps in the chain reaction are shown in the table below

Complete the table by(a) inserting the missing name for the first step (1)

(b) showing another possible termination reaction in the final row of the table (1)

3 Suncreams contain antioxidantsThe antioxidant compound A can prevent damage to skin by reacting with free

radicalssuch as NO2bull

53

Why can compound A be described as a free radical scavenger in the reaction shown above

4 Hydrogen and chlorine gases are used in an experiment to demonstrate a free radical reaction A plastic bottle is wrapped with black tape leaving a ldquowindowrdquo on one sideThe bottle is filled with a mixture of hydrogen and chlorine When bright light shines on the bottle there is an explosion

A free radical chain reaction is initiated when light energy causes chlorine radicals to form as shown below

(a) Complete the equations below showing possible propagation and termination steps

(2)

54

(b) Why is the plastic bottle used in the experiment wrapped in black tape (1)

5 Chloramines can be removed from water using ultraviolet light treatment

One step in the process is the formation of free radicals

(a)State what is meant by the term free radical (1)

(b)Another step in the process is shown below

State the name for this type of step in a free radical reaction (1)

6 Modern shellac nail varnishes are more durable and so last longer than traditional nail polish

The shellac nail varnish is applied in thin layers to the nails and then the fingers are placed under a UV lamp

(a) The Skin Care Foundation has recommended that a sun-block is applied to the fingers and hand before using the lampSuggest why the Skin Care Foundation makes this recommendation (1)

(b) A free radical chain reaction takes place and the varnish hardens (i) State what is meant by the term free radical (1)

(ii) The shellac nail varnish contains a mixture of ingredients that take part in the free radical chain reactionOne of the steps in the free radical chain reaction is

55

State the term used to describe this type of step in a free radical chain reaction(1)

7 Skin care products contain a mixture of polar covalent non-polar covalent and ionic compounds The compounds need to stay mixed within the product Skin care products also need to spread easily and remain on the skin for a period of time as well as provide physical and chemical protection from the sun In order to do this skin care products contain a range of chemicals including water fats and oils antioxidants minerals and sun blockUsing your knowledge of chemistry explain the role of different chemicals in skin care products (3)

General Questions

1 A mixture of carbon monoxide and hydrogen can be converted into water and a mixture of hydrocarbons

nCO + (2n + 1)H2 rarr nH2O + hydrocarbons

What is the general formula for the hydrocarbons producedA CnH2nndash2B CnH2nC CnH2n+1D CnH2n+2

2 Butadiene is the first member of a homologous series of hydrocarbons called dienesWhat is the general formula for this seriesA CnHn+2B CnHn+3C CnH2nD CnH2nndash2

3 Which of the following statements about methanol is falseA It can be made from synthesis gasB It can be dehydrated to form an alkeneC It can be oxidised to give a carboxylic acidD It reacts with acidified potassium dichromate solution

56

4

Which line in the table correctly describes reactions X and Y

5

Which line in the table correctly describes reactions X and Y

6 Which of the following fuels when burned would make no contribution to globalwarming

57

A HydrogenB Natural gasC PetrolD Coal

7 Which of the following hydrocarbons always gives the same product when one of itshydrogen atoms is replaced by a chlorine atomA HexaneB Hex-1-eneC CyclohexaneD Cyclohexene

8 Which of the following compounds does not have isomeric structuresA C2HCl3B C2H4Cl2C PropeneD Propan-1-ol

9 What organic compound is produced by the dehydration of ethanol A EthaneB EtheneC EthanalD Ethanoic acid

10

The above equation representsA hydrationB hydrogenationC condensationD hydrolysis

11

Which of the following compounds is an isomer of the structure shown aboveA ButanalB ButanoneC Butan-1-olD Butanoic acid

58

12 A compound with molecular formula C6H12O2 could beA hexanalB hexan-2-olC hexan-2-oneD hexanoic acid

13 Propan-2-ol can be prepared from propane as follows

Which line in the table correctly describes the types of reaction taking place at Steps 1 and 2

14 Which of the following compounds would be the most water soluble

15 Cyanohydrin compounds can be made from carbonyl compounds by reacting the carbonyl compound with hydrogen cyanide (HCN)

59

Which carbonyl compound would react with hydrogen cyanide (HCN) to form the following compound

16 Ethyne is the first member of the homologous series called the alkynes

Ethyne can undergo addition reactions as shown in the flow diagram

(a) Compound 2 is an isomer of 12-dichloroethaneDraw a structural formula for compound 2 (1)

(b) Reagents A B and C are three different diatomic gasesUsing information in the flow diagram identify reagents A B and C (1)

60

Reagent Gas

A

B

C

17 In 1865 the German chemist Kekuleacute proposed a ring structure for benzene This structure was based on alternating single and double bonds

(a) (i) Describe a chemical test that would indicate that the above chemical structure for benzene is incorrect (1)

(ii) Briefly describe the correct structure for benzene (1)

(b) Benzene can be formed from cyclohexaneC6H12 rarr C6H6 + 3H2

What name is given to this type of reaction (1)18 Infra-red spectroscopy is a technique that can be used to identify the bonds that

arepresent in a molecule Different bonds absorb infra-red radiation of different wavenumbers This is due to differences in the bond lsquostretchrsquo These absorptions are recorded in a spectrumA spectrum for propan-1-ol is shown

61

The correlation table on page 13 of the data booklet shows the wavenumber ranges for the absorptions due to different bonds

(a) Use the correlation table to identify the bonds responsible for the two absorptions x and y that are circled in the propan-1-ol spectrum (1)

(b) Propan-1-ol reacts with ethanoic acid(i) What name is given to this type of reaction (1)(ii) Draw a spectrum that could be obtained for the organic product of this

reaction (1)

19 Paracetamol is a widely used painkiller

(a) Write the molecular formula for paracetamol (1)

(b) One antidote for paracetamol overdose is methionine

62

To what family of organic compounds does methionine belong (1)

(c) The concentration of paracetamol in a solution can be determined by measuring how much UV radiation it absorbs

The graph shows how the absorbance of a sample containing 0middot040 g l ndash1 paracetamol varies with wavelength

The quantity of UV radiation of wavelength 245 nm absorbed is directly proportional to the concentration of paracetamolThe absorbance of a second sample of paracetamol solution measured at 245 nm was 0middot90 What is the concentration in g l ndash1 of this second paracetamol solution (1)

20 Many carbon compounds containing oxygen are very flammableThe table shows information about two families of isomersThe lowest temperature at which a compound will ignite is called its flash point

(a) A compound with the molecular formula C6H14O has a boiling point of 158 degC63

Draw a structural formula for this compound (1)

(b) For a family of isomers in the table write a general statement linking the flash points of the compounds to their structures (1)

21 Hydrogels are used in disposable nappies They are fine powders that can absorb up to 500 times their own weight in waterA hydrogel is a very long molecule with carboxyl groups at regular intervals along its length A short section of a hydrogel molecule is shown below

Hydrogels are extremely good at soaking up water because the water molecules are strongly attracted to them

Using your knowledge of chemistry comment on how suitable hydrogels would be for absorbing liquids or solutions spilled in a chemistry lab (1)

64

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

27

4-hydroxybenzoic acid can react with alcohols to form compounds known asparabens

(a) Name the functional group circled in the structure of 4minushydroxybenzoic acid (1)

(b) Name the type of reaction taking place when parabens are formed (1)

(c) Draw the paraben formed when 4minushydroxybenzoic acid reacts with ethanol (1)

(d) Parabens can be used as preservatives in cosmetics and toiletries Parabens are absorbed into the body through the skin The following table indicates the absorption of some parabens

State a conclusion that can be drawn from the information in the table (1)

9

28 When fats and oils are hydrolysed mixtures of fatty acids are obtained

(a) Name the other product obtained in this reaction (1)

(b)The table below shows the percentage composition of the fatty acid mixtures obtained by hydrolysis of coconut oil and olive oil

(i) One of the fatty acids produced by the hydrolysis of olive oil is linoleic acid C17H31COOHState the class of fatty acid to which linoleic acid belongs (1)

(ii) Hydrolysed coconut oil contains the fatty acid caprylic acid with the formula CH3(CH2)6COOHState the systematic name for caprylic acid (1)

(c) The degree of unsaturation of oil can be tested by adding drops of bromine solution to the oil Bromine adds across carbon to carbon double bonds in the fatty acid chains

The following apparatus can be used to compare the degree ofunsaturation of different oils

10

(i) Describe how this apparatus could be used to show that olive oil has a greater degree of unsaturation than coconut oil (2)

(ii) Suggest why hexane is used as the solvent rather than water (1)

(iii) Coconut oil has a melting point of 25 degC Olive oil has a melting point of minus6C

Give two reasons why coconut oil has a higher melting point than olive oil (2)

29 Traditional nail varnishes use ethyl ethanoate and butyl ethanoate as solvents

(a)Draw a structural formula for butyl ethanoate (1)(b)Ethyl ethanoate can be made in the laboratory using the following apparatus

Suggest why a wet paper towel is wrapped around the test tube (1)

(c) Name the type of reaction that takes place during the formation of ethyl ethanoate (1)

30 Pentyl butanoate is responsible for some of the flavour in apricots and strawberries

(a)Hydrolysis of pentyl butanoate using sodium hydroxide produces an alcohol and the salt of the carboxylic acid

(i) Name the alcohol that would be formed when pentyl butanoate is hydrolysed(1)

(ii) Draw a structural formula for the sodium salt of the carboxylic acid that would be formed (1)

(b)Fats and oils belong to the same class of compounds as pentyl butanoate(i) Name this class of compounds (1)

11

(ii) When a fat is hydrolysed using sodium hydroxide sodium salts of fatty acids are producedState a use for sodium salts of fatty acids (1)

22 Proteins

1 When a protein is denaturedA its overall shape is distortedB its amide links are hydrolysedC it is broken into separate peptide fragmentsD it decomposes into amino acids

2 Which of the following compounds can be classified as proteinsA FatsB OilsC EnzymesD Amino acids

3 The monomer units used to construct enzyme molecules areA alcoholsB estersC amino acidsD fatty acids

4 Amino acids are converted into proteins byA hydrationB hydrolysisC hydrogenationD condensation

5 The arrangement of amino acids in a peptide isZ-X-W-V-Y

where the letters V W X Y and Z represent amino acidsOn partial hydrolysis of the peptide which of the following sets of dipeptides is possibleA V-Y Z-X W-Y X-WB Z-X V-Y W-V X-WC Z-X X-V W-V V-YD X-W X-Z Z-W Y-V

6 Which of the following is an amine

12

7 Which of the following arrangements of atoms shows a peptide link

8 The following molecules are found in herbicides Which of the following contains an amide link

9 In α-amino acids the amino group is on the carbon atom adjacent to the acid group

Which of the following is an α-amino acid

10 A tripeptide X has the structure

Partial hydrolysis of X yields a mixture of dipeptidesWhich of the following dipeptides could be produced on hydrolysing X

13

11 The rate of hydrolysis of protein using an enzyme was studied at different temperatures Which of the following graphs would be obtained

12 The rate of hydrolysis of protein using an enzyme was studied at different temperaturesWhich of the following graphs would be obtained

14

13 Polymers can be classified as natural or synthetic(a) Keratin a natural polymer is a protein found in hair

The hydrolysis of keratin produces different monomers of the type shown

(i) What name is given to monomers like glycine alanine and cysteine (1)(ii) What is meant by a hydrolysis reaction (1)

(b) Dacron a synthetic polymer is used in heart surgery A section of the polymer is shown

What name is given to the link made by the shaded group of atoms in this section of the polymer (1)

14 Chemists have developed cheeses specifically for use in cheeseburgers(a) When ordinary cheddar cheese is grilled the shapes of the protein molecules

change and the proteins and fats separate leaving a chewy solid and an oily liquidWhat name is given to the change in protein structure which occurs when ordinary cheddar is grilled (1)

(b) To make cheese for burgers grated cheddar cheese soluble milk proteins and some water are mixed and heated to no more than 82 degC As the cheese begins to melt an emulsifying agent is added and the mixture is stirred

15

(i) Why would a water bath be used to heat the mixture (1)(ii) A section of the structure of a soluble milk protein is shown below

Draw a structural formula for any one of the amino acids formed when this section of

protein is hydrolysed (1)

(iii) The emulsifier used is trisodium citrate a salt formed when citric acid is neutralised using sodium hydroxide Complete the equation below showing a structural formula for the trisodium citrate formed (1) sp 8

15 Phenylalanine and alanine are both amino acids

(a) Phenylalanine is an essential amino acid

(i) What is meant by an essential amino acid (1)

16

(ii) How many hydrogen atoms are present in a molecule of phenylalanine (1)

(b) Phenylalanine and alanine can react to form the dipeptide shown

Circle the peptide link in this molecule (1)

(c) Draw a structural formula for the other dipeptide that can be formed from phenylalanine and alanine (1)

16 Uncooked egg white is mainly composed of dissolved proteins During cooking processes the proteins become denatured as the protein chains unwind and the egg white solidifies

(a) Explain why the protein chains unwind (1)

(b)The temperature at which the protein becomes denatured is called the melting temperature The melting temperature of a protein can be determined using fluorescence In this technique the protein is mixed with a dye that gives out visible light when it attaches to hydrophobic parts of the protein molecule The hydrophobic parts of the structure are on the inside of the protein and the dye has no access to them unless the protein unwinds

(i) Ovalbumin is a protein found in egg white Part of the structure of unwound ovalbumin is shown below

Circle the part of the structure to which the hydrophobic dye is most likely to attach (1)

17

(ii) Another protein in egg white is conalbumin The temperature of a conalbumindye mixture is gradually increased The fluorescence is measured and a graph is produced

The melting temperature is the temperature at which the fluorescence is halfway between the highest and lowest fluorescence valuesDetermine the melting temperature in ordmC for this protein (1)

(c) Once cooked and eaten the digestive system breaks the protein chains into amino acids with the help of enzymes

(i) State the name of the digestion process where enzymes break down proteins into amino acids (1)

(ii)

(A) State how many amino acid molecules joined to form this section of protein (1)

(B) Draw the structure of one amino acid that would be produced when this section of the protein chain is broken down (1)

17 Peptide molecules can be classified according to the number of amino acid units joined by peptide bonds in the molecule

18

(a) Complete the table to identify the type of peptide with the following amino acid sequence

alanine-glycine-valine-proline-tyrosine-serine (1)

(b) Partial hydrolysis of another pentapeptide molecule gave a mixture of three smaller peptide molecules with the following amino acid sequences

leucine-glycine-valineisoleucine-leucineglycine-valine-serine

Write the amino acid sequence for the original pentapeptide molecule (1)

helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip(c) Some amino acids needed to form polypeptides cannot be produced in the human body

State the term used to describe amino acids that the body cannot make (1)

(d)Paper chromatography is often used to analyse the mixtures of amino acids produced when peptides are broken downOn a chromatogram the retention factor Rf for a substance can be a useful method of identifying the substance

The structure of the pentapeptide methionine enkephalin was investigatedA sample of the pentapeptide was completely hydrolysed into its constituent amino acids and this amino acid mixture was applied to a piece of chromatography paper and placed in a solventThe chromatogram obtained is shown below

19

(i) Suggest why only four spots were obtained on the chromatogram of the hydrolysed pentapeptide (1)

(ii) It is known that this amino acid mixture contains the amino acid methionine The Rf value for methionine in this solvent is 040Draw a circle around the spot on the chromatogram that corresponds to methionine (1)

(e) Over the last decade several families of extremely stable peptide molecules have been discovered where the peptide chain forms a ring

(i) A simple cyclic dipeptide is shown

Draw a structural formula for one of the amino acids that would be formed on complete hydrolysis of the above cyclic dipeptide (1)

(ii) Alpha-amanitin is a highly toxic cyclic peptide found in death cap mushrooms The lethal dose for humans is 100 mg per kg of body mass1middot0 g of death cap mushrooms contains 250 mg of alpha-amanitinCalculate the minimum mass of death cap mushrooms that would contain the lethal dose for a 75 kg adult (2)

18 Dishwasher tablets produce the bleach hydrogen peroxide H2O2 One action of this oxidising agent is to oxidise food

(a)(i) Suggest another action of the bleach produced by the dishwasher tablets (1)

20

(ii) Hydrogen peroxide decomposes to form water and oxygen

2H2O2(ℓ) rarr 2H2O(ℓ) + O2(g)

A dishwasher tablet produces 0middot051 g of hydrogen peroxide (mass of one mole = 34 g)

Calculate the volume of oxygen that would be produced when0middot051 g of hydrogen peroxide decomposesTake the volume of 1 mole of oxygen gas to be 24 litres(3)

(b)Enzymes are commonly added to dishwasher tablets These are used to break down proteins(i) The proteins are broken down into small water-soluble molecules

Name the small water-soluble molecules made when proteins are broken down completely (1)

(ii) The structure of a section of protein chain found in egg white is shown

(A)Name the functional group circled (1)(B)Draw a structural formula for one of the molecules that would be made

when this section of egg white protein chain is completely broken down (1)

(iii) As part of the program in the dishwasher the conditions in the dishwasher change so that the enzyme molecules no longer work because they change shape

21

(A) State the term used to describe the change in shape of enzyme molecules(1)

(B) Suggest a change in conditions which would cause the enzyme molecules to change shape (1)

(d) A bleach activator is frequently added to dishwasher tablets to speed up the bleaching reaction One common bleach activator is TAED TAED could be produced in a process which involves a number of stages

(i) The first stage in producing TAED is shown below

Suggest a name for this type of reaction (1)

(ii) The final stage in the process producing TAED is shown below

Draw a structural formula for TAED (1)

22

23 The Chemistry of Cooking

1 Vanillin and zingerone are flavour molecules

Which line in the table correctly compares the properties of vanillin and zingerone

23

2 Erythrose can be used in the production of a chewing gum that helps prevent tooth decay

Which of the following compounds will be the best solvent for erythrose

3 The following molecules give flavour to food Which of the following flavour molecules would be most likely to be retained in the food when the food is cooked in water

24

4 Cooking involves many chemical reactions Proteins fats oils and esters are some examples of compounds found in food A chemist suggested that cooking food could change compounds from being fat-soluble to water-soluble Use your knowledge of chemistry to comment on the accuracy of this statement(3)

25

24 The Oxidation of Food

1 Apples and bananas turn brown when cut or bruised The first step of the reaction causing

the browning is shown below

Which of the following terms correctly describes this reactionA ReductionB OxidationC DehydrationD Condensation

2 Which of the following reactions can be classified as reductionA CH3CH2OH rarr CH3COOHB CH3 CH(OH)CH3 rarr CH3COCH3C CH3CH2COCH3 rarr CH3CH2CH(OH)CH3D CH3CH2CHO rarr CH3CH2COOH

3 The dehydration of butan-2-ol can produce two isomeric alkenes but-1-ene andbut-2-ene Which of the following alkanols can similarly produce on dehydration a pair of isomeric alkenesA Propan-2-olB Pentan-3-olC Hexan-3-olD Heptan-4-ol

4 Which of the following compounds is an alkanone

26

5 Which of the following is an aldehyde

6 Which of the following compounds would react with sodium hydroxide solution to forma saltA CH3CHOB CH3COOHC CH3COCH3D CH3CH2OH

7 Which line in the table shows the correct functional group for each homologous series

8 Which of the following organic compounds is an isomer of hexanalA 2-MethylbutanalB 3-Methylpentan-2-oneC 22-Dimethylbutan-1-olD 3-Ethylpentanal

27

9 The name of this compound is

A methanolB methanalC methanoic acidD methanone

10 Which alcohol could be oxidised to a carboxylic acid

11 Which of the following structural formulae represents a tertiary alcohol

12 Compound X reacted with hot copper(II) oxide and the organic product did not give acolour change when heated with Fehlingrsquos solution Compound X could beA butan-1-olB butan-2-olC butanoneD butanoic acid

28

13 Which two isomers would each produce an acid when warmed with acidified potassiumdichromate solution

A 1 and 2B 2 and 3C 1 and 4D 3 and 4

14 After heating for several minutes as shown in the diagram the pH indicator solution turned red

Liquid Q could beA propanoneB paraffinC propan-1-olD propan-2-ol

29

15 Enzymes are involved in the browning of cut fruitOne reaction taking place is

Which of the following correctly describes the above reaction

A OxidationB ReductionC HydrolysisD Condensation

16 Which of the following statements is correct for ketones

A They are formed by oxidation of tertiary alcohols

B They contain the group

C They contain a carboxyl groupD They will not react with Fehlingrsquos solution

17 Carvone is a natural product that can be extracted from orange peel

Which line in the table correctly describes the reaction of carvone with bromine solution and with acidified potassium dichromate solution

30

18 Which of the following is an isomer of 22-dimethylpentan-1-ol

A CH3CH2CH2CH(CH3)CH2OHB (CH3)3CCH(CH3)CH2OHC CH3CH2CH2CH2CH2CH2CH2CH2OHD (CH3)2CHC(CH3)2CH2CH2OH

19 The equation for the reduction reaction taking place when ethanal reacts with Tollensrsquo reagent is

A Cu2+(aq) + eminus rarr Cu+(aq)

B Ag+(aq) + eminus rarr Ag(s)

C Cr2O72minus(aq) + 14H+(aq) + 6eminus rarr 2Cr3+(aq) + 7H2O(ℓ)

D MnO4minus(aq) + 8H+(aq) + 5eminus rarr Mn2+(aq) + 4H2O(ℓ)

20 The name of the compound with structure

isA 23-dimethylpentan-4-oneB 23-dimethylpentan-2-alC 34-dimethylpentan-2-oneD 34-dimethylpentan-2-al

21 What is the systematic name for the compound below

A 222-trimethylethanolB 22-dimethylpropan-1-olC 22-dimethylpropan-3-olD 22-dimethylpentan-1-ol

31

22 The structure of a molecule found in olive oil can be represented as shown

(a) Olive oil can be hydrolysed using sodium hydroxide solution to produce sodium salts of fatty acids Name the other product of this reaction (1)

(b) In what way does the structure of a fat molecule differ from that of an oil molecule (1)

(c) Over time open containers of olive oil develop a rancid flavour What substance is reacting with the oil to cause these unwanted changes to take place (1)

23 A student writes the following statement It is incorrect Explain the mistake in the studentrsquos reasoning (1)

Alcohols are alkaline because of their OH groups

24 Carbon compounds take part in a wide variety of chemical reactions (a)

Name this type of chemical reaction (1)

(b)

Draw a structural formula for C3H6O (1)

25 Alkanols can be oxidised to alkanoic acids

32

(a) Why can Step 1 be described as an oxidation reaction (1)

(b) Acidified potassium dichromate solution can be used to oxidise propanal in Step 2 What colour change would be observed in this reaction (1)

26 Amines can be produced by reacting ammonia with an aldehyde or a ketone This reaction an example of reductive amination occurs in two stages

Stage 1 Amination

Stage 2 Reduction

(a) Give another name for the type of reaction taking place in Stage 2

(b) Draw the structural formula for the amine produced when butanal undergoes reductive amination with ammonia

27 Using a cobalt catalyst alkenes react with a mixture of hydrogen and carbon monoxideThe products are two isomeric aldehydes Propene reacts with the mixture as shown

(a) What name is given to a mixture of hydrogen and carbon monoxide (1)

(b) Draw a structural formula for compound B (1)

(c) (i) What would be observed if compound A was gently heated with Tollensrsquo reagent

(1)(ii) How would the reaction mixture be heated (1)

33

(d) Aldehydes can also be formed by the reaction of some alcohols with copper(II) oxideName the type of alcohol that would react with copper(II) oxide to form an aldehyde (1)

28 Aldehydes and ketones can take part in a reaction sometimes known as an aldol condensation The simplest aldol reaction involves two molecules of ethanal

In the reaction the carbon atom next to the carbonyl functional group of one molecule forms a bond with the carbonyl carbon atom of the second molecule

(a) Draw a structural formula for the product formed when propanone is used instead of ethanal in this type of reaction (1)

(b) Name an aldehyde that would not take part in an aldol condensation (1)

(c) Apart from the structure of the reactants suggest what is unusual about applying the term ldquocondensationrdquo to this particular type of reaction (1)

29 Primary secondary and tertiary alkanols can be prepared by the reaction of carbonyl compounds with Grignard reagents

Step 1The Grignard reagent reacts with the carbonyl compound

Step 2The reaction of the product of Step 1 with dilute acid produces the alkanol

(a) Describe the difference between a primary a secondary and a tertiary alkanol

You may wish to include labelled structures in your answer (1)34

(b) Suggest a name for the type of reaction that takes place in Step 1 (1)

(c) The same Grignard reagent can be used to produce the alkanol below

Name the carbonyl compound used in this reaction (1)

30 Hairspray is a mixture of chemicals(a) A primary alcohol 2-methylpropan-1-ol is added to hairspray to help it dry quickly on the hair

Draw a structural formula for a secondary alcohol that is an isomer of2-methylpropan-1-ol (1)

(b) Triethanol amine and triisopropyl amine are bases used to neutralise acidic compounds in the hairspray to prevent damage to the hair

In terms of the intermolecular bonding present explain clearly why triethanol amine has a much higher boiling point than triisopropyl amine (2)

35

36

31 Chocolate contains various compounds(a) Many of the flavour and aroma molecules found in chocolate are aldehydes and

ketones Two examples are shown below

Phenylethanal can be easily oxidised but 13-diphenylpropan-2-one cannot(i) Name a chemical that could be used to distinguish between these two

compounds (1)

(ii) Name the type of organic compound formed when phenylethanal is oxidised (1)

(b) Glycerol monostearate is an emulsifier used in chocolate

(i) Why is glycerol monostearate added to chocolate (1)

(ii) Draw a structural formula for glycerol (1)

(c) Theobromine a compound present in chocolate can cause illness in dogs and cats To decide if treatment is necessary vets must calculate the mass of theobromine consumed 1middot0 g of chocolate contains 1middot4 mg of theobromine Calculate the mass in mg of theobromine in a 17 g biscuit of which 28 is chocolate Show your working clearly (2)

(d) The flavour and texture of chocolate comes from a blend of compoundsUsing your knowledge of chemistry describe how you could show that there are ionic compounds and covalent compounds present in chocolate (3)

37

32 Ethanol has many uses

(a) Ethanol is found at relatively low concentrations in wine

(i) Name the chemical reaction that produces ethanol in wine (1)

(ii) Standard ethanol solutions were used to produce a graph of density against

concentration of ethanol given as a percentage of alcohol by volume ( abv)

What is the concentration of ethanol in units of abv in a solution of density 0middot9818 g cmminus3 (1)

(b) Whisky contains a higher concentration of ethanol

(i) Before 1980 the concentration of alcohol in drinks was measured in terms of degrees proof The concentration of alcohol in two drinks is shown in the table below both as abv and degrees proof

38

A cask strength whisky has an alcohol concentration of 65 abv Calculate the alcohol concentration of this whisky in degrees proof (1)

(ii) A barrel containing 195 litres of cask strength whisky costs pound1300 The cask strength whisky is diluted with water to reduce the concentration of alcohol from 65 abv to 46 abv before it is bottled Calculate the cost of the cask strength whisky needed to produce a 0middot70 litre bottle Show your working clearly (2)

(iii) 5-Butyl-4-methyltetrahydrofuran-2-ol is a flavour compound found in whisky

stored in oak barrels

Write the systematic name for the compound shown below (1) 13 11

33 (a) One test for glucose involves Fehlingrsquos solutionCircle the part of the glucose molecule that reacts with Fehlingrsquos solution (1)

(b) In solution sugar molecules exist in an equilibrium in straight-chain and ring forms

To change from the straight-chain form to the ring form the oxygen of the hydroxyl on carbon number 5 joins to the carbonyl carbon This is shown below for glucose

39

Draw the structure of a ring form for fructose (1)

34 (a) During the free radical chain reaction small molecules join to form large chain molecules

One example of a small molecule used is

Name the functional group circled above (1)

(b)Alcohol wipes are used to finish the varnishing treatment Alcohol wipes contain the alcohol propan-2-olState why propan-2-ol can be described as a secondary alcohol (1)

35 A student was carrying out an investigation into alcohols aldehydes and ketones

(a)The student was given three alcohols labelled as A B and C These alcohols were all isomers with the formula C4H9OH

(i) Draw a structural formula for the secondary alcohol with the formula C4H9OH(1)

(ii) The student set up the following experiment

A Suggest why a water bath is an appropriate method of heating the reaction mixture (1)

B Describe the colour change that would have been observed with alcohols A and C (1)

40

C Alcohol B is not oxidised State the type of alcohol which cannot be oxidised by acidified dichromate solution (1)

(iii) The student set up a second experiment with alcohol A

Hot copper(II) oxide is an oxidising agentA When alcohol A (C4H9OH) is oxidised the product turns the pH paper

redSuggest a name for the product (1)

B Complete the ion-electron equation for the oxidation reaction

C4H9OH rarr C4H8O2 (1)

(b)The student found the following information about the boiling points of some aldehydes

41

(i) Name the aldehyde that has a boiling point of 119 degC (1)(ii) Predict the boiling point in degC of the following molecule (1)

(iii) Using information from the table describe one way in which differences in structure affect the boiling point of isomeric aldehydes (1)

(iv) State what would be observed when an aldehyde is gently heated with Tollensrsquo reagent (1)

(c) Ketones contain a carbonyl groupName the type of intermolecular interaction between ketone molecules (1)

42

25 Soaps Detergents and Emulsions

1 Soaps are produced by the following reaction

This reaction is an example ofA condensationB esterificationC hydrolysisD oxidation

2 Which of the following is the salt of a long-chain fatty acid

A FatB OilC SoapD Glycerol

3 Emulsifiers for use in food are commonly made by reacting edible oils with

A estersB glycerolC fatty acidsD amino acids

4 A fatty acid is a long chain carboxylic acid Examples of fatty acids are shown in the table below

43

(a) What is the systematic name for linolenic acid (1)(b) Stearic acid reacts with sodium hydroxide solution to form sodium stearate

(i) Name the type of reaction taking place when stearic acid reacts with sodium hydroxide (1)

(ii) Explain fully how sodium stearate acts to keep grease and non-polar substances suspended in water during cleaning (3)

5 Small children can find it difficult to swallow tablets or pills so ibuprofen is supplied as an ldquoinfant formulardquo emulsion(a) The emulsifier used is polysorbate 80 Its structure is shown below

Explain why this molecule acts as an emulsifier (2)

(b) The emulsion contains 2 g of ibuprofen in every 100 cm3 of emulsion The recommended dose for treating a 6 month old baby is 0middot050 g Calculate the volume in cm3 of ldquoinfant formulardquo needed to treat a 6 month old baby (1)

6 Occasionally seabirds can become contaminated with hydrocarbons from oil spills This causes problems for birds because their feathers lose their waterproofing making the birds susceptible to temperature changes and

44

affecting their buoyancy If the birds attempt to clean themselves to remove the oil they may swallow the hydrocarbons causing damage to their internal organsContaminated seabirds can be cleaned by rubbing vegetable oil into their feathers and feet before the birds are rinsed with diluted washing-up liquidUsing your knowledge of chemistry comment on the problems created for seabirds by oil spills and the actions taken to treat affected birds (3)

7 Dishwasher tablets contain chemicals which remove dirt from dishesDishwasher tablets include detergents These molecules act like soaps to allow mixing of fat-soluble dirt and water(a)During the cleaning process the detergent molecules combine with fat-

soluble dirtA simplified diagram of a detergent molecule is shown

Complete the diagram below to show how detergent molecules combine with fat-soluble dirt (1)

(b)State the term used to describe the non-polar hydrocarbon tail of a detergent molecule (1)

45

26 Fragrances1 Myrcene is a simple terpene

Terpenes contain at least one isoprene unit Which of the following shows a correctly highlighted isoprene unit

2 Limonene is one of the terpene molecules responsible for the flavour of lemons

How many isoprene units are used in the production of one limonene moleculeA 1B 2C 3D 4

46

3 The structure of caryophyllene which can be extracted from clove oil is

Which of the following would be the best solvent for extracting caryophylleneA HexaneB HexanalC HexanolD Hexanone

4 The structure of isoprene is

Limonene is a terpene molecule present in lemons

How many isoprene units are joined together in a limonene molecule

A 1B 2

47

C 3D 4

5 Essential oils are

A non-water soluble non-volatile compoundsB non-water soluble volatile compoundsC water soluble non-volatile compoundsD water soluble volatile compounds

6 Two typical compounds that are present in many perfumes are shown

(a) Why does geraniol evaporate more slowly than limonene (1)

(b) The structure of one of the first synthetic scents used in perfume is shown below

(i) Name the family of carbonyl compounds to which this synthetic scent belongs (1)

(ii) Complete the structure below to show the product formed when this scent is

oxidised (1)

(c) Traces of a liquid were discovered in a bottle believed to contain perfume belonging to Queen Hatshepsut ruler of Egypt over 3500 years ago

Perfumes were made by dissolving plant extracts containing pleasant smelling terpenes and esters in an edible oil A little ethanol and water may also have been addedUsing your knowledge of chemistry comment on the possible smell(s) when such a bottle is opened after being stored for thousands of years (3)

48

49

7 A team of chemists are developing a fragrance for use in a shower gel for men(a) To give the gel a fruity smell the chemists are considering adding an ester

They synthesise six isomeric esters Volunteers smell each ester and give it a rating out of one hundred depending on how fruity the smell is

(i) Name the ester with the fruit-smell rating of 92 (1)

(ii) Shown below are the structures of three more isomers

Arrange these esters in order of decreasing fruit-smell rating (1)

50

(b) To create a fragrance for men the compound civetone is added

Draw a structural formula for the alcohol that can be oxidised to form civetone (1)

(c) To make the shower gel produce a cold tingling sensation when applied to the skin menthol is added

Like terpenes menthol is formed from isoprene (2-methylbuta-13-diene)Circle an isoprene unit on the menthol structure above (1)

8 Many of the compounds in perfumes are molecules consisting of joined isoprene units

(a) State the name that is given to molecules consisting of joined isoprene units (1)

(b)Geraniol is one of the compounds found in perfume It has the following structural formula and systematic name

Linalool can also be present Its structural formula is shown

51

(i) State the systematic name for linalool (1)(ii) Explain why linalool can be classified as a tertiary alcohol (1)

9 The component molecules found in lavender oils are terpenes or terpenoids(a)A chiral carbon is a carbon atom attached to four different atoms or groups of

atomsAn example is shown below

A molecule of the terpenoid linalool has a chiral carbon Linalool has the following structure

Circle the chiral carbon atom in the linalool structure (1)

(b)Farnesene is a terpene consisting of three isoprene units (2-methylbuta-13-diene) joined togetherWrite the molecular formula of farnesene (1)

52

27 Skin Care

1 Which of the following is not a step in a free radical chain reaction

A ActivationB InitiationC PropagationD Termination

2 Fluorine reacts with methane via a free radical chain reaction Some steps in the chain reaction are shown in the table below

Complete the table by(a) inserting the missing name for the first step (1)

(b) showing another possible termination reaction in the final row of the table (1)

3 Suncreams contain antioxidantsThe antioxidant compound A can prevent damage to skin by reacting with free

radicalssuch as NO2bull

53

Why can compound A be described as a free radical scavenger in the reaction shown above

4 Hydrogen and chlorine gases are used in an experiment to demonstrate a free radical reaction A plastic bottle is wrapped with black tape leaving a ldquowindowrdquo on one sideThe bottle is filled with a mixture of hydrogen and chlorine When bright light shines on the bottle there is an explosion

A free radical chain reaction is initiated when light energy causes chlorine radicals to form as shown below

(a) Complete the equations below showing possible propagation and termination steps

(2)

54

(b) Why is the plastic bottle used in the experiment wrapped in black tape (1)

5 Chloramines can be removed from water using ultraviolet light treatment

One step in the process is the formation of free radicals

(a)State what is meant by the term free radical (1)

(b)Another step in the process is shown below

State the name for this type of step in a free radical reaction (1)

6 Modern shellac nail varnishes are more durable and so last longer than traditional nail polish

The shellac nail varnish is applied in thin layers to the nails and then the fingers are placed under a UV lamp

(a) The Skin Care Foundation has recommended that a sun-block is applied to the fingers and hand before using the lampSuggest why the Skin Care Foundation makes this recommendation (1)

(b) A free radical chain reaction takes place and the varnish hardens (i) State what is meant by the term free radical (1)

(ii) The shellac nail varnish contains a mixture of ingredients that take part in the free radical chain reactionOne of the steps in the free radical chain reaction is

55

State the term used to describe this type of step in a free radical chain reaction(1)

7 Skin care products contain a mixture of polar covalent non-polar covalent and ionic compounds The compounds need to stay mixed within the product Skin care products also need to spread easily and remain on the skin for a period of time as well as provide physical and chemical protection from the sun In order to do this skin care products contain a range of chemicals including water fats and oils antioxidants minerals and sun blockUsing your knowledge of chemistry explain the role of different chemicals in skin care products (3)

General Questions

1 A mixture of carbon monoxide and hydrogen can be converted into water and a mixture of hydrocarbons

nCO + (2n + 1)H2 rarr nH2O + hydrocarbons

What is the general formula for the hydrocarbons producedA CnH2nndash2B CnH2nC CnH2n+1D CnH2n+2

2 Butadiene is the first member of a homologous series of hydrocarbons called dienesWhat is the general formula for this seriesA CnHn+2B CnHn+3C CnH2nD CnH2nndash2

3 Which of the following statements about methanol is falseA It can be made from synthesis gasB It can be dehydrated to form an alkeneC It can be oxidised to give a carboxylic acidD It reacts with acidified potassium dichromate solution

56

4

Which line in the table correctly describes reactions X and Y

5

Which line in the table correctly describes reactions X and Y

6 Which of the following fuels when burned would make no contribution to globalwarming

57

A HydrogenB Natural gasC PetrolD Coal

7 Which of the following hydrocarbons always gives the same product when one of itshydrogen atoms is replaced by a chlorine atomA HexaneB Hex-1-eneC CyclohexaneD Cyclohexene

8 Which of the following compounds does not have isomeric structuresA C2HCl3B C2H4Cl2C PropeneD Propan-1-ol

9 What organic compound is produced by the dehydration of ethanol A EthaneB EtheneC EthanalD Ethanoic acid

10

The above equation representsA hydrationB hydrogenationC condensationD hydrolysis

11

Which of the following compounds is an isomer of the structure shown aboveA ButanalB ButanoneC Butan-1-olD Butanoic acid

58

12 A compound with molecular formula C6H12O2 could beA hexanalB hexan-2-olC hexan-2-oneD hexanoic acid

13 Propan-2-ol can be prepared from propane as follows

Which line in the table correctly describes the types of reaction taking place at Steps 1 and 2

14 Which of the following compounds would be the most water soluble

15 Cyanohydrin compounds can be made from carbonyl compounds by reacting the carbonyl compound with hydrogen cyanide (HCN)

59

Which carbonyl compound would react with hydrogen cyanide (HCN) to form the following compound

16 Ethyne is the first member of the homologous series called the alkynes

Ethyne can undergo addition reactions as shown in the flow diagram

(a) Compound 2 is an isomer of 12-dichloroethaneDraw a structural formula for compound 2 (1)

(b) Reagents A B and C are three different diatomic gasesUsing information in the flow diagram identify reagents A B and C (1)

60

Reagent Gas

A

B

C

17 In 1865 the German chemist Kekuleacute proposed a ring structure for benzene This structure was based on alternating single and double bonds

(a) (i) Describe a chemical test that would indicate that the above chemical structure for benzene is incorrect (1)

(ii) Briefly describe the correct structure for benzene (1)

(b) Benzene can be formed from cyclohexaneC6H12 rarr C6H6 + 3H2

What name is given to this type of reaction (1)18 Infra-red spectroscopy is a technique that can be used to identify the bonds that

arepresent in a molecule Different bonds absorb infra-red radiation of different wavenumbers This is due to differences in the bond lsquostretchrsquo These absorptions are recorded in a spectrumA spectrum for propan-1-ol is shown

61

The correlation table on page 13 of the data booklet shows the wavenumber ranges for the absorptions due to different bonds

(a) Use the correlation table to identify the bonds responsible for the two absorptions x and y that are circled in the propan-1-ol spectrum (1)

(b) Propan-1-ol reacts with ethanoic acid(i) What name is given to this type of reaction (1)(ii) Draw a spectrum that could be obtained for the organic product of this

reaction (1)

19 Paracetamol is a widely used painkiller

(a) Write the molecular formula for paracetamol (1)

(b) One antidote for paracetamol overdose is methionine

62

To what family of organic compounds does methionine belong (1)

(c) The concentration of paracetamol in a solution can be determined by measuring how much UV radiation it absorbs

The graph shows how the absorbance of a sample containing 0middot040 g l ndash1 paracetamol varies with wavelength

The quantity of UV radiation of wavelength 245 nm absorbed is directly proportional to the concentration of paracetamolThe absorbance of a second sample of paracetamol solution measured at 245 nm was 0middot90 What is the concentration in g l ndash1 of this second paracetamol solution (1)

20 Many carbon compounds containing oxygen are very flammableThe table shows information about two families of isomersThe lowest temperature at which a compound will ignite is called its flash point

(a) A compound with the molecular formula C6H14O has a boiling point of 158 degC63

Draw a structural formula for this compound (1)

(b) For a family of isomers in the table write a general statement linking the flash points of the compounds to their structures (1)

21 Hydrogels are used in disposable nappies They are fine powders that can absorb up to 500 times their own weight in waterA hydrogel is a very long molecule with carboxyl groups at regular intervals along its length A short section of a hydrogel molecule is shown below

Hydrogels are extremely good at soaking up water because the water molecules are strongly attracted to them

Using your knowledge of chemistry comment on how suitable hydrogels would be for absorbing liquids or solutions spilled in a chemistry lab (1)

64

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

28 When fats and oils are hydrolysed mixtures of fatty acids are obtained

(a) Name the other product obtained in this reaction (1)

(b)The table below shows the percentage composition of the fatty acid mixtures obtained by hydrolysis of coconut oil and olive oil

(i) One of the fatty acids produced by the hydrolysis of olive oil is linoleic acid C17H31COOHState the class of fatty acid to which linoleic acid belongs (1)

(ii) Hydrolysed coconut oil contains the fatty acid caprylic acid with the formula CH3(CH2)6COOHState the systematic name for caprylic acid (1)

(c) The degree of unsaturation of oil can be tested by adding drops of bromine solution to the oil Bromine adds across carbon to carbon double bonds in the fatty acid chains

The following apparatus can be used to compare the degree ofunsaturation of different oils

10

(i) Describe how this apparatus could be used to show that olive oil has a greater degree of unsaturation than coconut oil (2)

(ii) Suggest why hexane is used as the solvent rather than water (1)

(iii) Coconut oil has a melting point of 25 degC Olive oil has a melting point of minus6C

Give two reasons why coconut oil has a higher melting point than olive oil (2)

29 Traditional nail varnishes use ethyl ethanoate and butyl ethanoate as solvents

(a)Draw a structural formula for butyl ethanoate (1)(b)Ethyl ethanoate can be made in the laboratory using the following apparatus

Suggest why a wet paper towel is wrapped around the test tube (1)

(c) Name the type of reaction that takes place during the formation of ethyl ethanoate (1)

30 Pentyl butanoate is responsible for some of the flavour in apricots and strawberries

(a)Hydrolysis of pentyl butanoate using sodium hydroxide produces an alcohol and the salt of the carboxylic acid

(i) Name the alcohol that would be formed when pentyl butanoate is hydrolysed(1)

(ii) Draw a structural formula for the sodium salt of the carboxylic acid that would be formed (1)

(b)Fats and oils belong to the same class of compounds as pentyl butanoate(i) Name this class of compounds (1)

11

(ii) When a fat is hydrolysed using sodium hydroxide sodium salts of fatty acids are producedState a use for sodium salts of fatty acids (1)

22 Proteins

1 When a protein is denaturedA its overall shape is distortedB its amide links are hydrolysedC it is broken into separate peptide fragmentsD it decomposes into amino acids

2 Which of the following compounds can be classified as proteinsA FatsB OilsC EnzymesD Amino acids

3 The monomer units used to construct enzyme molecules areA alcoholsB estersC amino acidsD fatty acids

4 Amino acids are converted into proteins byA hydrationB hydrolysisC hydrogenationD condensation

5 The arrangement of amino acids in a peptide isZ-X-W-V-Y

where the letters V W X Y and Z represent amino acidsOn partial hydrolysis of the peptide which of the following sets of dipeptides is possibleA V-Y Z-X W-Y X-WB Z-X V-Y W-V X-WC Z-X X-V W-V V-YD X-W X-Z Z-W Y-V

6 Which of the following is an amine

12

7 Which of the following arrangements of atoms shows a peptide link

8 The following molecules are found in herbicides Which of the following contains an amide link

9 In α-amino acids the amino group is on the carbon atom adjacent to the acid group

Which of the following is an α-amino acid

10 A tripeptide X has the structure

Partial hydrolysis of X yields a mixture of dipeptidesWhich of the following dipeptides could be produced on hydrolysing X

13

11 The rate of hydrolysis of protein using an enzyme was studied at different temperatures Which of the following graphs would be obtained

12 The rate of hydrolysis of protein using an enzyme was studied at different temperaturesWhich of the following graphs would be obtained

14

13 Polymers can be classified as natural or synthetic(a) Keratin a natural polymer is a protein found in hair

The hydrolysis of keratin produces different monomers of the type shown

(i) What name is given to monomers like glycine alanine and cysteine (1)(ii) What is meant by a hydrolysis reaction (1)

(b) Dacron a synthetic polymer is used in heart surgery A section of the polymer is shown

What name is given to the link made by the shaded group of atoms in this section of the polymer (1)

14 Chemists have developed cheeses specifically for use in cheeseburgers(a) When ordinary cheddar cheese is grilled the shapes of the protein molecules

change and the proteins and fats separate leaving a chewy solid and an oily liquidWhat name is given to the change in protein structure which occurs when ordinary cheddar is grilled (1)

(b) To make cheese for burgers grated cheddar cheese soluble milk proteins and some water are mixed and heated to no more than 82 degC As the cheese begins to melt an emulsifying agent is added and the mixture is stirred

15

(i) Why would a water bath be used to heat the mixture (1)(ii) A section of the structure of a soluble milk protein is shown below

Draw a structural formula for any one of the amino acids formed when this section of

protein is hydrolysed (1)

(iii) The emulsifier used is trisodium citrate a salt formed when citric acid is neutralised using sodium hydroxide Complete the equation below showing a structural formula for the trisodium citrate formed (1) sp 8

15 Phenylalanine and alanine are both amino acids

(a) Phenylalanine is an essential amino acid

(i) What is meant by an essential amino acid (1)

16

(ii) How many hydrogen atoms are present in a molecule of phenylalanine (1)

(b) Phenylalanine and alanine can react to form the dipeptide shown

Circle the peptide link in this molecule (1)

(c) Draw a structural formula for the other dipeptide that can be formed from phenylalanine and alanine (1)

16 Uncooked egg white is mainly composed of dissolved proteins During cooking processes the proteins become denatured as the protein chains unwind and the egg white solidifies

(a) Explain why the protein chains unwind (1)

(b)The temperature at which the protein becomes denatured is called the melting temperature The melting temperature of a protein can be determined using fluorescence In this technique the protein is mixed with a dye that gives out visible light when it attaches to hydrophobic parts of the protein molecule The hydrophobic parts of the structure are on the inside of the protein and the dye has no access to them unless the protein unwinds

(i) Ovalbumin is a protein found in egg white Part of the structure of unwound ovalbumin is shown below

Circle the part of the structure to which the hydrophobic dye is most likely to attach (1)

17

(ii) Another protein in egg white is conalbumin The temperature of a conalbumindye mixture is gradually increased The fluorescence is measured and a graph is produced

The melting temperature is the temperature at which the fluorescence is halfway between the highest and lowest fluorescence valuesDetermine the melting temperature in ordmC for this protein (1)

(c) Once cooked and eaten the digestive system breaks the protein chains into amino acids with the help of enzymes

(i) State the name of the digestion process where enzymes break down proteins into amino acids (1)

(ii)

(A) State how many amino acid molecules joined to form this section of protein (1)

(B) Draw the structure of one amino acid that would be produced when this section of the protein chain is broken down (1)

17 Peptide molecules can be classified according to the number of amino acid units joined by peptide bonds in the molecule

18

(a) Complete the table to identify the type of peptide with the following amino acid sequence

alanine-glycine-valine-proline-tyrosine-serine (1)

(b) Partial hydrolysis of another pentapeptide molecule gave a mixture of three smaller peptide molecules with the following amino acid sequences

leucine-glycine-valineisoleucine-leucineglycine-valine-serine

Write the amino acid sequence for the original pentapeptide molecule (1)

helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip(c) Some amino acids needed to form polypeptides cannot be produced in the human body

State the term used to describe amino acids that the body cannot make (1)

(d)Paper chromatography is often used to analyse the mixtures of amino acids produced when peptides are broken downOn a chromatogram the retention factor Rf for a substance can be a useful method of identifying the substance

The structure of the pentapeptide methionine enkephalin was investigatedA sample of the pentapeptide was completely hydrolysed into its constituent amino acids and this amino acid mixture was applied to a piece of chromatography paper and placed in a solventThe chromatogram obtained is shown below

19

(i) Suggest why only four spots were obtained on the chromatogram of the hydrolysed pentapeptide (1)

(ii) It is known that this amino acid mixture contains the amino acid methionine The Rf value for methionine in this solvent is 040Draw a circle around the spot on the chromatogram that corresponds to methionine (1)

(e) Over the last decade several families of extremely stable peptide molecules have been discovered where the peptide chain forms a ring

(i) A simple cyclic dipeptide is shown

Draw a structural formula for one of the amino acids that would be formed on complete hydrolysis of the above cyclic dipeptide (1)

(ii) Alpha-amanitin is a highly toxic cyclic peptide found in death cap mushrooms The lethal dose for humans is 100 mg per kg of body mass1middot0 g of death cap mushrooms contains 250 mg of alpha-amanitinCalculate the minimum mass of death cap mushrooms that would contain the lethal dose for a 75 kg adult (2)

18 Dishwasher tablets produce the bleach hydrogen peroxide H2O2 One action of this oxidising agent is to oxidise food

(a)(i) Suggest another action of the bleach produced by the dishwasher tablets (1)

20

(ii) Hydrogen peroxide decomposes to form water and oxygen

2H2O2(ℓ) rarr 2H2O(ℓ) + O2(g)

A dishwasher tablet produces 0middot051 g of hydrogen peroxide (mass of one mole = 34 g)

Calculate the volume of oxygen that would be produced when0middot051 g of hydrogen peroxide decomposesTake the volume of 1 mole of oxygen gas to be 24 litres(3)

(b)Enzymes are commonly added to dishwasher tablets These are used to break down proteins(i) The proteins are broken down into small water-soluble molecules

Name the small water-soluble molecules made when proteins are broken down completely (1)

(ii) The structure of a section of protein chain found in egg white is shown

(A)Name the functional group circled (1)(B)Draw a structural formula for one of the molecules that would be made

when this section of egg white protein chain is completely broken down (1)

(iii) As part of the program in the dishwasher the conditions in the dishwasher change so that the enzyme molecules no longer work because they change shape

21

(A) State the term used to describe the change in shape of enzyme molecules(1)

(B) Suggest a change in conditions which would cause the enzyme molecules to change shape (1)

(d) A bleach activator is frequently added to dishwasher tablets to speed up the bleaching reaction One common bleach activator is TAED TAED could be produced in a process which involves a number of stages

(i) The first stage in producing TAED is shown below

Suggest a name for this type of reaction (1)

(ii) The final stage in the process producing TAED is shown below

Draw a structural formula for TAED (1)

22

23 The Chemistry of Cooking

1 Vanillin and zingerone are flavour molecules

Which line in the table correctly compares the properties of vanillin and zingerone

23

2 Erythrose can be used in the production of a chewing gum that helps prevent tooth decay

Which of the following compounds will be the best solvent for erythrose

3 The following molecules give flavour to food Which of the following flavour molecules would be most likely to be retained in the food when the food is cooked in water

24

4 Cooking involves many chemical reactions Proteins fats oils and esters are some examples of compounds found in food A chemist suggested that cooking food could change compounds from being fat-soluble to water-soluble Use your knowledge of chemistry to comment on the accuracy of this statement(3)

25

24 The Oxidation of Food

1 Apples and bananas turn brown when cut or bruised The first step of the reaction causing

the browning is shown below

Which of the following terms correctly describes this reactionA ReductionB OxidationC DehydrationD Condensation

2 Which of the following reactions can be classified as reductionA CH3CH2OH rarr CH3COOHB CH3 CH(OH)CH3 rarr CH3COCH3C CH3CH2COCH3 rarr CH3CH2CH(OH)CH3D CH3CH2CHO rarr CH3CH2COOH

3 The dehydration of butan-2-ol can produce two isomeric alkenes but-1-ene andbut-2-ene Which of the following alkanols can similarly produce on dehydration a pair of isomeric alkenesA Propan-2-olB Pentan-3-olC Hexan-3-olD Heptan-4-ol

4 Which of the following compounds is an alkanone

26

5 Which of the following is an aldehyde

6 Which of the following compounds would react with sodium hydroxide solution to forma saltA CH3CHOB CH3COOHC CH3COCH3D CH3CH2OH

7 Which line in the table shows the correct functional group for each homologous series

8 Which of the following organic compounds is an isomer of hexanalA 2-MethylbutanalB 3-Methylpentan-2-oneC 22-Dimethylbutan-1-olD 3-Ethylpentanal

27

9 The name of this compound is

A methanolB methanalC methanoic acidD methanone

10 Which alcohol could be oxidised to a carboxylic acid

11 Which of the following structural formulae represents a tertiary alcohol

12 Compound X reacted with hot copper(II) oxide and the organic product did not give acolour change when heated with Fehlingrsquos solution Compound X could beA butan-1-olB butan-2-olC butanoneD butanoic acid

28

13 Which two isomers would each produce an acid when warmed with acidified potassiumdichromate solution

A 1 and 2B 2 and 3C 1 and 4D 3 and 4

14 After heating for several minutes as shown in the diagram the pH indicator solution turned red

Liquid Q could beA propanoneB paraffinC propan-1-olD propan-2-ol

29

15 Enzymes are involved in the browning of cut fruitOne reaction taking place is

Which of the following correctly describes the above reaction

A OxidationB ReductionC HydrolysisD Condensation

16 Which of the following statements is correct for ketones

A They are formed by oxidation of tertiary alcohols

B They contain the group

C They contain a carboxyl groupD They will not react with Fehlingrsquos solution

17 Carvone is a natural product that can be extracted from orange peel

Which line in the table correctly describes the reaction of carvone with bromine solution and with acidified potassium dichromate solution

30

18 Which of the following is an isomer of 22-dimethylpentan-1-ol

A CH3CH2CH2CH(CH3)CH2OHB (CH3)3CCH(CH3)CH2OHC CH3CH2CH2CH2CH2CH2CH2CH2OHD (CH3)2CHC(CH3)2CH2CH2OH

19 The equation for the reduction reaction taking place when ethanal reacts with Tollensrsquo reagent is

A Cu2+(aq) + eminus rarr Cu+(aq)

B Ag+(aq) + eminus rarr Ag(s)

C Cr2O72minus(aq) + 14H+(aq) + 6eminus rarr 2Cr3+(aq) + 7H2O(ℓ)

D MnO4minus(aq) + 8H+(aq) + 5eminus rarr Mn2+(aq) + 4H2O(ℓ)

20 The name of the compound with structure

isA 23-dimethylpentan-4-oneB 23-dimethylpentan-2-alC 34-dimethylpentan-2-oneD 34-dimethylpentan-2-al

21 What is the systematic name for the compound below

A 222-trimethylethanolB 22-dimethylpropan-1-olC 22-dimethylpropan-3-olD 22-dimethylpentan-1-ol

31

22 The structure of a molecule found in olive oil can be represented as shown

(a) Olive oil can be hydrolysed using sodium hydroxide solution to produce sodium salts of fatty acids Name the other product of this reaction (1)

(b) In what way does the structure of a fat molecule differ from that of an oil molecule (1)

(c) Over time open containers of olive oil develop a rancid flavour What substance is reacting with the oil to cause these unwanted changes to take place (1)

23 A student writes the following statement It is incorrect Explain the mistake in the studentrsquos reasoning (1)

Alcohols are alkaline because of their OH groups

24 Carbon compounds take part in a wide variety of chemical reactions (a)

Name this type of chemical reaction (1)

(b)

Draw a structural formula for C3H6O (1)

25 Alkanols can be oxidised to alkanoic acids

32

(a) Why can Step 1 be described as an oxidation reaction (1)

(b) Acidified potassium dichromate solution can be used to oxidise propanal in Step 2 What colour change would be observed in this reaction (1)

26 Amines can be produced by reacting ammonia with an aldehyde or a ketone This reaction an example of reductive amination occurs in two stages

Stage 1 Amination

Stage 2 Reduction

(a) Give another name for the type of reaction taking place in Stage 2

(b) Draw the structural formula for the amine produced when butanal undergoes reductive amination with ammonia

27 Using a cobalt catalyst alkenes react with a mixture of hydrogen and carbon monoxideThe products are two isomeric aldehydes Propene reacts with the mixture as shown

(a) What name is given to a mixture of hydrogen and carbon monoxide (1)

(b) Draw a structural formula for compound B (1)

(c) (i) What would be observed if compound A was gently heated with Tollensrsquo reagent

(1)(ii) How would the reaction mixture be heated (1)

33

(d) Aldehydes can also be formed by the reaction of some alcohols with copper(II) oxideName the type of alcohol that would react with copper(II) oxide to form an aldehyde (1)

28 Aldehydes and ketones can take part in a reaction sometimes known as an aldol condensation The simplest aldol reaction involves two molecules of ethanal

In the reaction the carbon atom next to the carbonyl functional group of one molecule forms a bond with the carbonyl carbon atom of the second molecule

(a) Draw a structural formula for the product formed when propanone is used instead of ethanal in this type of reaction (1)

(b) Name an aldehyde that would not take part in an aldol condensation (1)

(c) Apart from the structure of the reactants suggest what is unusual about applying the term ldquocondensationrdquo to this particular type of reaction (1)

29 Primary secondary and tertiary alkanols can be prepared by the reaction of carbonyl compounds with Grignard reagents

Step 1The Grignard reagent reacts with the carbonyl compound

Step 2The reaction of the product of Step 1 with dilute acid produces the alkanol

(a) Describe the difference between a primary a secondary and a tertiary alkanol

You may wish to include labelled structures in your answer (1)34

(b) Suggest a name for the type of reaction that takes place in Step 1 (1)

(c) The same Grignard reagent can be used to produce the alkanol below

Name the carbonyl compound used in this reaction (1)

30 Hairspray is a mixture of chemicals(a) A primary alcohol 2-methylpropan-1-ol is added to hairspray to help it dry quickly on the hair

Draw a structural formula for a secondary alcohol that is an isomer of2-methylpropan-1-ol (1)

(b) Triethanol amine and triisopropyl amine are bases used to neutralise acidic compounds in the hairspray to prevent damage to the hair

In terms of the intermolecular bonding present explain clearly why triethanol amine has a much higher boiling point than triisopropyl amine (2)

35

36

31 Chocolate contains various compounds(a) Many of the flavour and aroma molecules found in chocolate are aldehydes and

ketones Two examples are shown below

Phenylethanal can be easily oxidised but 13-diphenylpropan-2-one cannot(i) Name a chemical that could be used to distinguish between these two

compounds (1)

(ii) Name the type of organic compound formed when phenylethanal is oxidised (1)

(b) Glycerol monostearate is an emulsifier used in chocolate

(i) Why is glycerol monostearate added to chocolate (1)

(ii) Draw a structural formula for glycerol (1)

(c) Theobromine a compound present in chocolate can cause illness in dogs and cats To decide if treatment is necessary vets must calculate the mass of theobromine consumed 1middot0 g of chocolate contains 1middot4 mg of theobromine Calculate the mass in mg of theobromine in a 17 g biscuit of which 28 is chocolate Show your working clearly (2)

(d) The flavour and texture of chocolate comes from a blend of compoundsUsing your knowledge of chemistry describe how you could show that there are ionic compounds and covalent compounds present in chocolate (3)

37

32 Ethanol has many uses

(a) Ethanol is found at relatively low concentrations in wine

(i) Name the chemical reaction that produces ethanol in wine (1)

(ii) Standard ethanol solutions were used to produce a graph of density against

concentration of ethanol given as a percentage of alcohol by volume ( abv)

What is the concentration of ethanol in units of abv in a solution of density 0middot9818 g cmminus3 (1)

(b) Whisky contains a higher concentration of ethanol

(i) Before 1980 the concentration of alcohol in drinks was measured in terms of degrees proof The concentration of alcohol in two drinks is shown in the table below both as abv and degrees proof

38

A cask strength whisky has an alcohol concentration of 65 abv Calculate the alcohol concentration of this whisky in degrees proof (1)

(ii) A barrel containing 195 litres of cask strength whisky costs pound1300 The cask strength whisky is diluted with water to reduce the concentration of alcohol from 65 abv to 46 abv before it is bottled Calculate the cost of the cask strength whisky needed to produce a 0middot70 litre bottle Show your working clearly (2)

(iii) 5-Butyl-4-methyltetrahydrofuran-2-ol is a flavour compound found in whisky

stored in oak barrels

Write the systematic name for the compound shown below (1) 13 11

33 (a) One test for glucose involves Fehlingrsquos solutionCircle the part of the glucose molecule that reacts with Fehlingrsquos solution (1)

(b) In solution sugar molecules exist in an equilibrium in straight-chain and ring forms

To change from the straight-chain form to the ring form the oxygen of the hydroxyl on carbon number 5 joins to the carbonyl carbon This is shown below for glucose

39

Draw the structure of a ring form for fructose (1)

34 (a) During the free radical chain reaction small molecules join to form large chain molecules

One example of a small molecule used is

Name the functional group circled above (1)

(b)Alcohol wipes are used to finish the varnishing treatment Alcohol wipes contain the alcohol propan-2-olState why propan-2-ol can be described as a secondary alcohol (1)

35 A student was carrying out an investigation into alcohols aldehydes and ketones

(a)The student was given three alcohols labelled as A B and C These alcohols were all isomers with the formula C4H9OH

(i) Draw a structural formula for the secondary alcohol with the formula C4H9OH(1)

(ii) The student set up the following experiment

A Suggest why a water bath is an appropriate method of heating the reaction mixture (1)

B Describe the colour change that would have been observed with alcohols A and C (1)

40

C Alcohol B is not oxidised State the type of alcohol which cannot be oxidised by acidified dichromate solution (1)

(iii) The student set up a second experiment with alcohol A

Hot copper(II) oxide is an oxidising agentA When alcohol A (C4H9OH) is oxidised the product turns the pH paper

redSuggest a name for the product (1)

B Complete the ion-electron equation for the oxidation reaction

C4H9OH rarr C4H8O2 (1)

(b)The student found the following information about the boiling points of some aldehydes

41

(i) Name the aldehyde that has a boiling point of 119 degC (1)(ii) Predict the boiling point in degC of the following molecule (1)

(iii) Using information from the table describe one way in which differences in structure affect the boiling point of isomeric aldehydes (1)

(iv) State what would be observed when an aldehyde is gently heated with Tollensrsquo reagent (1)

(c) Ketones contain a carbonyl groupName the type of intermolecular interaction between ketone molecules (1)

42

25 Soaps Detergents and Emulsions

1 Soaps are produced by the following reaction

This reaction is an example ofA condensationB esterificationC hydrolysisD oxidation

2 Which of the following is the salt of a long-chain fatty acid

A FatB OilC SoapD Glycerol

3 Emulsifiers for use in food are commonly made by reacting edible oils with

A estersB glycerolC fatty acidsD amino acids

4 A fatty acid is a long chain carboxylic acid Examples of fatty acids are shown in the table below

43

(a) What is the systematic name for linolenic acid (1)(b) Stearic acid reacts with sodium hydroxide solution to form sodium stearate

(i) Name the type of reaction taking place when stearic acid reacts with sodium hydroxide (1)

(ii) Explain fully how sodium stearate acts to keep grease and non-polar substances suspended in water during cleaning (3)

5 Small children can find it difficult to swallow tablets or pills so ibuprofen is supplied as an ldquoinfant formulardquo emulsion(a) The emulsifier used is polysorbate 80 Its structure is shown below

Explain why this molecule acts as an emulsifier (2)

(b) The emulsion contains 2 g of ibuprofen in every 100 cm3 of emulsion The recommended dose for treating a 6 month old baby is 0middot050 g Calculate the volume in cm3 of ldquoinfant formulardquo needed to treat a 6 month old baby (1)

6 Occasionally seabirds can become contaminated with hydrocarbons from oil spills This causes problems for birds because their feathers lose their waterproofing making the birds susceptible to temperature changes and

44

affecting their buoyancy If the birds attempt to clean themselves to remove the oil they may swallow the hydrocarbons causing damage to their internal organsContaminated seabirds can be cleaned by rubbing vegetable oil into their feathers and feet before the birds are rinsed with diluted washing-up liquidUsing your knowledge of chemistry comment on the problems created for seabirds by oil spills and the actions taken to treat affected birds (3)

7 Dishwasher tablets contain chemicals which remove dirt from dishesDishwasher tablets include detergents These molecules act like soaps to allow mixing of fat-soluble dirt and water(a)During the cleaning process the detergent molecules combine with fat-

soluble dirtA simplified diagram of a detergent molecule is shown

Complete the diagram below to show how detergent molecules combine with fat-soluble dirt (1)

(b)State the term used to describe the non-polar hydrocarbon tail of a detergent molecule (1)

45

26 Fragrances1 Myrcene is a simple terpene

Terpenes contain at least one isoprene unit Which of the following shows a correctly highlighted isoprene unit

2 Limonene is one of the terpene molecules responsible for the flavour of lemons

How many isoprene units are used in the production of one limonene moleculeA 1B 2C 3D 4

46

3 The structure of caryophyllene which can be extracted from clove oil is

Which of the following would be the best solvent for extracting caryophylleneA HexaneB HexanalC HexanolD Hexanone

4 The structure of isoprene is

Limonene is a terpene molecule present in lemons

How many isoprene units are joined together in a limonene molecule

A 1B 2

47

C 3D 4

5 Essential oils are

A non-water soluble non-volatile compoundsB non-water soluble volatile compoundsC water soluble non-volatile compoundsD water soluble volatile compounds

6 Two typical compounds that are present in many perfumes are shown

(a) Why does geraniol evaporate more slowly than limonene (1)

(b) The structure of one of the first synthetic scents used in perfume is shown below

(i) Name the family of carbonyl compounds to which this synthetic scent belongs (1)

(ii) Complete the structure below to show the product formed when this scent is

oxidised (1)

(c) Traces of a liquid were discovered in a bottle believed to contain perfume belonging to Queen Hatshepsut ruler of Egypt over 3500 years ago

Perfumes were made by dissolving plant extracts containing pleasant smelling terpenes and esters in an edible oil A little ethanol and water may also have been addedUsing your knowledge of chemistry comment on the possible smell(s) when such a bottle is opened after being stored for thousands of years (3)

48

49

7 A team of chemists are developing a fragrance for use in a shower gel for men(a) To give the gel a fruity smell the chemists are considering adding an ester

They synthesise six isomeric esters Volunteers smell each ester and give it a rating out of one hundred depending on how fruity the smell is

(i) Name the ester with the fruit-smell rating of 92 (1)

(ii) Shown below are the structures of three more isomers

Arrange these esters in order of decreasing fruit-smell rating (1)

50

(b) To create a fragrance for men the compound civetone is added

Draw a structural formula for the alcohol that can be oxidised to form civetone (1)

(c) To make the shower gel produce a cold tingling sensation when applied to the skin menthol is added

Like terpenes menthol is formed from isoprene (2-methylbuta-13-diene)Circle an isoprene unit on the menthol structure above (1)

8 Many of the compounds in perfumes are molecules consisting of joined isoprene units

(a) State the name that is given to molecules consisting of joined isoprene units (1)

(b)Geraniol is one of the compounds found in perfume It has the following structural formula and systematic name

Linalool can also be present Its structural formula is shown

51

(i) State the systematic name for linalool (1)(ii) Explain why linalool can be classified as a tertiary alcohol (1)

9 The component molecules found in lavender oils are terpenes or terpenoids(a)A chiral carbon is a carbon atom attached to four different atoms or groups of

atomsAn example is shown below

A molecule of the terpenoid linalool has a chiral carbon Linalool has the following structure

Circle the chiral carbon atom in the linalool structure (1)

(b)Farnesene is a terpene consisting of three isoprene units (2-methylbuta-13-diene) joined togetherWrite the molecular formula of farnesene (1)

52

27 Skin Care

1 Which of the following is not a step in a free radical chain reaction

A ActivationB InitiationC PropagationD Termination

2 Fluorine reacts with methane via a free radical chain reaction Some steps in the chain reaction are shown in the table below

Complete the table by(a) inserting the missing name for the first step (1)

(b) showing another possible termination reaction in the final row of the table (1)

3 Suncreams contain antioxidantsThe antioxidant compound A can prevent damage to skin by reacting with free

radicalssuch as NO2bull

53

Why can compound A be described as a free radical scavenger in the reaction shown above

4 Hydrogen and chlorine gases are used in an experiment to demonstrate a free radical reaction A plastic bottle is wrapped with black tape leaving a ldquowindowrdquo on one sideThe bottle is filled with a mixture of hydrogen and chlorine When bright light shines on the bottle there is an explosion

A free radical chain reaction is initiated when light energy causes chlorine radicals to form as shown below

(a) Complete the equations below showing possible propagation and termination steps

(2)

54

(b) Why is the plastic bottle used in the experiment wrapped in black tape (1)

5 Chloramines can be removed from water using ultraviolet light treatment

One step in the process is the formation of free radicals

(a)State what is meant by the term free radical (1)

(b)Another step in the process is shown below

State the name for this type of step in a free radical reaction (1)

6 Modern shellac nail varnishes are more durable and so last longer than traditional nail polish

The shellac nail varnish is applied in thin layers to the nails and then the fingers are placed under a UV lamp

(a) The Skin Care Foundation has recommended that a sun-block is applied to the fingers and hand before using the lampSuggest why the Skin Care Foundation makes this recommendation (1)

(b) A free radical chain reaction takes place and the varnish hardens (i) State what is meant by the term free radical (1)

(ii) The shellac nail varnish contains a mixture of ingredients that take part in the free radical chain reactionOne of the steps in the free radical chain reaction is

55

State the term used to describe this type of step in a free radical chain reaction(1)

7 Skin care products contain a mixture of polar covalent non-polar covalent and ionic compounds The compounds need to stay mixed within the product Skin care products also need to spread easily and remain on the skin for a period of time as well as provide physical and chemical protection from the sun In order to do this skin care products contain a range of chemicals including water fats and oils antioxidants minerals and sun blockUsing your knowledge of chemistry explain the role of different chemicals in skin care products (3)

General Questions

1 A mixture of carbon monoxide and hydrogen can be converted into water and a mixture of hydrocarbons

nCO + (2n + 1)H2 rarr nH2O + hydrocarbons

What is the general formula for the hydrocarbons producedA CnH2nndash2B CnH2nC CnH2n+1D CnH2n+2

2 Butadiene is the first member of a homologous series of hydrocarbons called dienesWhat is the general formula for this seriesA CnHn+2B CnHn+3C CnH2nD CnH2nndash2

3 Which of the following statements about methanol is falseA It can be made from synthesis gasB It can be dehydrated to form an alkeneC It can be oxidised to give a carboxylic acidD It reacts with acidified potassium dichromate solution

56

4

Which line in the table correctly describes reactions X and Y

5

Which line in the table correctly describes reactions X and Y

6 Which of the following fuels when burned would make no contribution to globalwarming

57

A HydrogenB Natural gasC PetrolD Coal

7 Which of the following hydrocarbons always gives the same product when one of itshydrogen atoms is replaced by a chlorine atomA HexaneB Hex-1-eneC CyclohexaneD Cyclohexene

8 Which of the following compounds does not have isomeric structuresA C2HCl3B C2H4Cl2C PropeneD Propan-1-ol

9 What organic compound is produced by the dehydration of ethanol A EthaneB EtheneC EthanalD Ethanoic acid

10

The above equation representsA hydrationB hydrogenationC condensationD hydrolysis

11

Which of the following compounds is an isomer of the structure shown aboveA ButanalB ButanoneC Butan-1-olD Butanoic acid

58

12 A compound with molecular formula C6H12O2 could beA hexanalB hexan-2-olC hexan-2-oneD hexanoic acid

13 Propan-2-ol can be prepared from propane as follows

Which line in the table correctly describes the types of reaction taking place at Steps 1 and 2

14 Which of the following compounds would be the most water soluble

15 Cyanohydrin compounds can be made from carbonyl compounds by reacting the carbonyl compound with hydrogen cyanide (HCN)

59

Which carbonyl compound would react with hydrogen cyanide (HCN) to form the following compound

16 Ethyne is the first member of the homologous series called the alkynes

Ethyne can undergo addition reactions as shown in the flow diagram

(a) Compound 2 is an isomer of 12-dichloroethaneDraw a structural formula for compound 2 (1)

(b) Reagents A B and C are three different diatomic gasesUsing information in the flow diagram identify reagents A B and C (1)

60

Reagent Gas

A

B

C

17 In 1865 the German chemist Kekuleacute proposed a ring structure for benzene This structure was based on alternating single and double bonds

(a) (i) Describe a chemical test that would indicate that the above chemical structure for benzene is incorrect (1)

(ii) Briefly describe the correct structure for benzene (1)

(b) Benzene can be formed from cyclohexaneC6H12 rarr C6H6 + 3H2

What name is given to this type of reaction (1)18 Infra-red spectroscopy is a technique that can be used to identify the bonds that

arepresent in a molecule Different bonds absorb infra-red radiation of different wavenumbers This is due to differences in the bond lsquostretchrsquo These absorptions are recorded in a spectrumA spectrum for propan-1-ol is shown

61

The correlation table on page 13 of the data booklet shows the wavenumber ranges for the absorptions due to different bonds

(a) Use the correlation table to identify the bonds responsible for the two absorptions x and y that are circled in the propan-1-ol spectrum (1)

(b) Propan-1-ol reacts with ethanoic acid(i) What name is given to this type of reaction (1)(ii) Draw a spectrum that could be obtained for the organic product of this

reaction (1)

19 Paracetamol is a widely used painkiller

(a) Write the molecular formula for paracetamol (1)

(b) One antidote for paracetamol overdose is methionine

62

To what family of organic compounds does methionine belong (1)

(c) The concentration of paracetamol in a solution can be determined by measuring how much UV radiation it absorbs

The graph shows how the absorbance of a sample containing 0middot040 g l ndash1 paracetamol varies with wavelength

The quantity of UV radiation of wavelength 245 nm absorbed is directly proportional to the concentration of paracetamolThe absorbance of a second sample of paracetamol solution measured at 245 nm was 0middot90 What is the concentration in g l ndash1 of this second paracetamol solution (1)

20 Many carbon compounds containing oxygen are very flammableThe table shows information about two families of isomersThe lowest temperature at which a compound will ignite is called its flash point

(a) A compound with the molecular formula C6H14O has a boiling point of 158 degC63

Draw a structural formula for this compound (1)

(b) For a family of isomers in the table write a general statement linking the flash points of the compounds to their structures (1)

21 Hydrogels are used in disposable nappies They are fine powders that can absorb up to 500 times their own weight in waterA hydrogel is a very long molecule with carboxyl groups at regular intervals along its length A short section of a hydrogel molecule is shown below

Hydrogels are extremely good at soaking up water because the water molecules are strongly attracted to them

Using your knowledge of chemistry comment on how suitable hydrogels would be for absorbing liquids or solutions spilled in a chemistry lab (1)

64

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

(i) Describe how this apparatus could be used to show that olive oil has a greater degree of unsaturation than coconut oil (2)

(ii) Suggest why hexane is used as the solvent rather than water (1)

(iii) Coconut oil has a melting point of 25 degC Olive oil has a melting point of minus6C

Give two reasons why coconut oil has a higher melting point than olive oil (2)

29 Traditional nail varnishes use ethyl ethanoate and butyl ethanoate as solvents

(a)Draw a structural formula for butyl ethanoate (1)(b)Ethyl ethanoate can be made in the laboratory using the following apparatus

Suggest why a wet paper towel is wrapped around the test tube (1)

(c) Name the type of reaction that takes place during the formation of ethyl ethanoate (1)

30 Pentyl butanoate is responsible for some of the flavour in apricots and strawberries

(a)Hydrolysis of pentyl butanoate using sodium hydroxide produces an alcohol and the salt of the carboxylic acid

(i) Name the alcohol that would be formed when pentyl butanoate is hydrolysed(1)

(ii) Draw a structural formula for the sodium salt of the carboxylic acid that would be formed (1)

(b)Fats and oils belong to the same class of compounds as pentyl butanoate(i) Name this class of compounds (1)

11

(ii) When a fat is hydrolysed using sodium hydroxide sodium salts of fatty acids are producedState a use for sodium salts of fatty acids (1)

22 Proteins

1 When a protein is denaturedA its overall shape is distortedB its amide links are hydrolysedC it is broken into separate peptide fragmentsD it decomposes into amino acids

2 Which of the following compounds can be classified as proteinsA FatsB OilsC EnzymesD Amino acids

3 The monomer units used to construct enzyme molecules areA alcoholsB estersC amino acidsD fatty acids

4 Amino acids are converted into proteins byA hydrationB hydrolysisC hydrogenationD condensation

5 The arrangement of amino acids in a peptide isZ-X-W-V-Y

where the letters V W X Y and Z represent amino acidsOn partial hydrolysis of the peptide which of the following sets of dipeptides is possibleA V-Y Z-X W-Y X-WB Z-X V-Y W-V X-WC Z-X X-V W-V V-YD X-W X-Z Z-W Y-V

6 Which of the following is an amine

12

7 Which of the following arrangements of atoms shows a peptide link

8 The following molecules are found in herbicides Which of the following contains an amide link

9 In α-amino acids the amino group is on the carbon atom adjacent to the acid group

Which of the following is an α-amino acid

10 A tripeptide X has the structure

Partial hydrolysis of X yields a mixture of dipeptidesWhich of the following dipeptides could be produced on hydrolysing X

13

11 The rate of hydrolysis of protein using an enzyme was studied at different temperatures Which of the following graphs would be obtained

12 The rate of hydrolysis of protein using an enzyme was studied at different temperaturesWhich of the following graphs would be obtained

14

13 Polymers can be classified as natural or synthetic(a) Keratin a natural polymer is a protein found in hair

The hydrolysis of keratin produces different monomers of the type shown

(i) What name is given to monomers like glycine alanine and cysteine (1)(ii) What is meant by a hydrolysis reaction (1)

(b) Dacron a synthetic polymer is used in heart surgery A section of the polymer is shown

What name is given to the link made by the shaded group of atoms in this section of the polymer (1)

14 Chemists have developed cheeses specifically for use in cheeseburgers(a) When ordinary cheddar cheese is grilled the shapes of the protein molecules

change and the proteins and fats separate leaving a chewy solid and an oily liquidWhat name is given to the change in protein structure which occurs when ordinary cheddar is grilled (1)

(b) To make cheese for burgers grated cheddar cheese soluble milk proteins and some water are mixed and heated to no more than 82 degC As the cheese begins to melt an emulsifying agent is added and the mixture is stirred

15

(i) Why would a water bath be used to heat the mixture (1)(ii) A section of the structure of a soluble milk protein is shown below

Draw a structural formula for any one of the amino acids formed when this section of

protein is hydrolysed (1)

(iii) The emulsifier used is trisodium citrate a salt formed when citric acid is neutralised using sodium hydroxide Complete the equation below showing a structural formula for the trisodium citrate formed (1) sp 8

15 Phenylalanine and alanine are both amino acids

(a) Phenylalanine is an essential amino acid

(i) What is meant by an essential amino acid (1)

16

(ii) How many hydrogen atoms are present in a molecule of phenylalanine (1)

(b) Phenylalanine and alanine can react to form the dipeptide shown

Circle the peptide link in this molecule (1)

(c) Draw a structural formula for the other dipeptide that can be formed from phenylalanine and alanine (1)

16 Uncooked egg white is mainly composed of dissolved proteins During cooking processes the proteins become denatured as the protein chains unwind and the egg white solidifies

(a) Explain why the protein chains unwind (1)

(b)The temperature at which the protein becomes denatured is called the melting temperature The melting temperature of a protein can be determined using fluorescence In this technique the protein is mixed with a dye that gives out visible light when it attaches to hydrophobic parts of the protein molecule The hydrophobic parts of the structure are on the inside of the protein and the dye has no access to them unless the protein unwinds

(i) Ovalbumin is a protein found in egg white Part of the structure of unwound ovalbumin is shown below

Circle the part of the structure to which the hydrophobic dye is most likely to attach (1)

17

(ii) Another protein in egg white is conalbumin The temperature of a conalbumindye mixture is gradually increased The fluorescence is measured and a graph is produced

The melting temperature is the temperature at which the fluorescence is halfway between the highest and lowest fluorescence valuesDetermine the melting temperature in ordmC for this protein (1)

(c) Once cooked and eaten the digestive system breaks the protein chains into amino acids with the help of enzymes

(i) State the name of the digestion process where enzymes break down proteins into amino acids (1)

(ii)

(A) State how many amino acid molecules joined to form this section of protein (1)

(B) Draw the structure of one amino acid that would be produced when this section of the protein chain is broken down (1)

17 Peptide molecules can be classified according to the number of amino acid units joined by peptide bonds in the molecule

18

(a) Complete the table to identify the type of peptide with the following amino acid sequence

alanine-glycine-valine-proline-tyrosine-serine (1)

(b) Partial hydrolysis of another pentapeptide molecule gave a mixture of three smaller peptide molecules with the following amino acid sequences

leucine-glycine-valineisoleucine-leucineglycine-valine-serine

Write the amino acid sequence for the original pentapeptide molecule (1)

helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip(c) Some amino acids needed to form polypeptides cannot be produced in the human body

State the term used to describe amino acids that the body cannot make (1)

(d)Paper chromatography is often used to analyse the mixtures of amino acids produced when peptides are broken downOn a chromatogram the retention factor Rf for a substance can be a useful method of identifying the substance

The structure of the pentapeptide methionine enkephalin was investigatedA sample of the pentapeptide was completely hydrolysed into its constituent amino acids and this amino acid mixture was applied to a piece of chromatography paper and placed in a solventThe chromatogram obtained is shown below

19

(i) Suggest why only four spots were obtained on the chromatogram of the hydrolysed pentapeptide (1)

(ii) It is known that this amino acid mixture contains the amino acid methionine The Rf value for methionine in this solvent is 040Draw a circle around the spot on the chromatogram that corresponds to methionine (1)

(e) Over the last decade several families of extremely stable peptide molecules have been discovered where the peptide chain forms a ring

(i) A simple cyclic dipeptide is shown

Draw a structural formula for one of the amino acids that would be formed on complete hydrolysis of the above cyclic dipeptide (1)

(ii) Alpha-amanitin is a highly toxic cyclic peptide found in death cap mushrooms The lethal dose for humans is 100 mg per kg of body mass1middot0 g of death cap mushrooms contains 250 mg of alpha-amanitinCalculate the minimum mass of death cap mushrooms that would contain the lethal dose for a 75 kg adult (2)

18 Dishwasher tablets produce the bleach hydrogen peroxide H2O2 One action of this oxidising agent is to oxidise food

(a)(i) Suggest another action of the bleach produced by the dishwasher tablets (1)

20

(ii) Hydrogen peroxide decomposes to form water and oxygen

2H2O2(ℓ) rarr 2H2O(ℓ) + O2(g)

A dishwasher tablet produces 0middot051 g of hydrogen peroxide (mass of one mole = 34 g)

Calculate the volume of oxygen that would be produced when0middot051 g of hydrogen peroxide decomposesTake the volume of 1 mole of oxygen gas to be 24 litres(3)

(b)Enzymes are commonly added to dishwasher tablets These are used to break down proteins(i) The proteins are broken down into small water-soluble molecules

Name the small water-soluble molecules made when proteins are broken down completely (1)

(ii) The structure of a section of protein chain found in egg white is shown

(A)Name the functional group circled (1)(B)Draw a structural formula for one of the molecules that would be made

when this section of egg white protein chain is completely broken down (1)

(iii) As part of the program in the dishwasher the conditions in the dishwasher change so that the enzyme molecules no longer work because they change shape

21

(A) State the term used to describe the change in shape of enzyme molecules(1)

(B) Suggest a change in conditions which would cause the enzyme molecules to change shape (1)

(d) A bleach activator is frequently added to dishwasher tablets to speed up the bleaching reaction One common bleach activator is TAED TAED could be produced in a process which involves a number of stages

(i) The first stage in producing TAED is shown below

Suggest a name for this type of reaction (1)

(ii) The final stage in the process producing TAED is shown below

Draw a structural formula for TAED (1)

22

23 The Chemistry of Cooking

1 Vanillin and zingerone are flavour molecules

Which line in the table correctly compares the properties of vanillin and zingerone

23

2 Erythrose can be used in the production of a chewing gum that helps prevent tooth decay

Which of the following compounds will be the best solvent for erythrose

3 The following molecules give flavour to food Which of the following flavour molecules would be most likely to be retained in the food when the food is cooked in water

24

4 Cooking involves many chemical reactions Proteins fats oils and esters are some examples of compounds found in food A chemist suggested that cooking food could change compounds from being fat-soluble to water-soluble Use your knowledge of chemistry to comment on the accuracy of this statement(3)

25

24 The Oxidation of Food

1 Apples and bananas turn brown when cut or bruised The first step of the reaction causing

the browning is shown below

Which of the following terms correctly describes this reactionA ReductionB OxidationC DehydrationD Condensation

2 Which of the following reactions can be classified as reductionA CH3CH2OH rarr CH3COOHB CH3 CH(OH)CH3 rarr CH3COCH3C CH3CH2COCH3 rarr CH3CH2CH(OH)CH3D CH3CH2CHO rarr CH3CH2COOH

3 The dehydration of butan-2-ol can produce two isomeric alkenes but-1-ene andbut-2-ene Which of the following alkanols can similarly produce on dehydration a pair of isomeric alkenesA Propan-2-olB Pentan-3-olC Hexan-3-olD Heptan-4-ol

4 Which of the following compounds is an alkanone

26

5 Which of the following is an aldehyde

6 Which of the following compounds would react with sodium hydroxide solution to forma saltA CH3CHOB CH3COOHC CH3COCH3D CH3CH2OH

7 Which line in the table shows the correct functional group for each homologous series

8 Which of the following organic compounds is an isomer of hexanalA 2-MethylbutanalB 3-Methylpentan-2-oneC 22-Dimethylbutan-1-olD 3-Ethylpentanal

27

9 The name of this compound is

A methanolB methanalC methanoic acidD methanone

10 Which alcohol could be oxidised to a carboxylic acid

11 Which of the following structural formulae represents a tertiary alcohol

12 Compound X reacted with hot copper(II) oxide and the organic product did not give acolour change when heated with Fehlingrsquos solution Compound X could beA butan-1-olB butan-2-olC butanoneD butanoic acid

28

13 Which two isomers would each produce an acid when warmed with acidified potassiumdichromate solution

A 1 and 2B 2 and 3C 1 and 4D 3 and 4

14 After heating for several minutes as shown in the diagram the pH indicator solution turned red

Liquid Q could beA propanoneB paraffinC propan-1-olD propan-2-ol

29

15 Enzymes are involved in the browning of cut fruitOne reaction taking place is

Which of the following correctly describes the above reaction

A OxidationB ReductionC HydrolysisD Condensation

16 Which of the following statements is correct for ketones

A They are formed by oxidation of tertiary alcohols

B They contain the group

C They contain a carboxyl groupD They will not react with Fehlingrsquos solution

17 Carvone is a natural product that can be extracted from orange peel

Which line in the table correctly describes the reaction of carvone with bromine solution and with acidified potassium dichromate solution

30

18 Which of the following is an isomer of 22-dimethylpentan-1-ol

A CH3CH2CH2CH(CH3)CH2OHB (CH3)3CCH(CH3)CH2OHC CH3CH2CH2CH2CH2CH2CH2CH2OHD (CH3)2CHC(CH3)2CH2CH2OH

19 The equation for the reduction reaction taking place when ethanal reacts with Tollensrsquo reagent is

A Cu2+(aq) + eminus rarr Cu+(aq)

B Ag+(aq) + eminus rarr Ag(s)

C Cr2O72minus(aq) + 14H+(aq) + 6eminus rarr 2Cr3+(aq) + 7H2O(ℓ)

D MnO4minus(aq) + 8H+(aq) + 5eminus rarr Mn2+(aq) + 4H2O(ℓ)

20 The name of the compound with structure

isA 23-dimethylpentan-4-oneB 23-dimethylpentan-2-alC 34-dimethylpentan-2-oneD 34-dimethylpentan-2-al

21 What is the systematic name for the compound below

A 222-trimethylethanolB 22-dimethylpropan-1-olC 22-dimethylpropan-3-olD 22-dimethylpentan-1-ol

31

22 The structure of a molecule found in olive oil can be represented as shown

(a) Olive oil can be hydrolysed using sodium hydroxide solution to produce sodium salts of fatty acids Name the other product of this reaction (1)

(b) In what way does the structure of a fat molecule differ from that of an oil molecule (1)

(c) Over time open containers of olive oil develop a rancid flavour What substance is reacting with the oil to cause these unwanted changes to take place (1)

23 A student writes the following statement It is incorrect Explain the mistake in the studentrsquos reasoning (1)

Alcohols are alkaline because of their OH groups

24 Carbon compounds take part in a wide variety of chemical reactions (a)

Name this type of chemical reaction (1)

(b)

Draw a structural formula for C3H6O (1)

25 Alkanols can be oxidised to alkanoic acids

32

(a) Why can Step 1 be described as an oxidation reaction (1)

(b) Acidified potassium dichromate solution can be used to oxidise propanal in Step 2 What colour change would be observed in this reaction (1)

26 Amines can be produced by reacting ammonia with an aldehyde or a ketone This reaction an example of reductive amination occurs in two stages

Stage 1 Amination

Stage 2 Reduction

(a) Give another name for the type of reaction taking place in Stage 2

(b) Draw the structural formula for the amine produced when butanal undergoes reductive amination with ammonia

27 Using a cobalt catalyst alkenes react with a mixture of hydrogen and carbon monoxideThe products are two isomeric aldehydes Propene reacts with the mixture as shown

(a) What name is given to a mixture of hydrogen and carbon monoxide (1)

(b) Draw a structural formula for compound B (1)

(c) (i) What would be observed if compound A was gently heated with Tollensrsquo reagent

(1)(ii) How would the reaction mixture be heated (1)

33

(d) Aldehydes can also be formed by the reaction of some alcohols with copper(II) oxideName the type of alcohol that would react with copper(II) oxide to form an aldehyde (1)

28 Aldehydes and ketones can take part in a reaction sometimes known as an aldol condensation The simplest aldol reaction involves two molecules of ethanal

In the reaction the carbon atom next to the carbonyl functional group of one molecule forms a bond with the carbonyl carbon atom of the second molecule

(a) Draw a structural formula for the product formed when propanone is used instead of ethanal in this type of reaction (1)

(b) Name an aldehyde that would not take part in an aldol condensation (1)

(c) Apart from the structure of the reactants suggest what is unusual about applying the term ldquocondensationrdquo to this particular type of reaction (1)

29 Primary secondary and tertiary alkanols can be prepared by the reaction of carbonyl compounds with Grignard reagents

Step 1The Grignard reagent reacts with the carbonyl compound

Step 2The reaction of the product of Step 1 with dilute acid produces the alkanol

(a) Describe the difference between a primary a secondary and a tertiary alkanol

You may wish to include labelled structures in your answer (1)34

(b) Suggest a name for the type of reaction that takes place in Step 1 (1)

(c) The same Grignard reagent can be used to produce the alkanol below

Name the carbonyl compound used in this reaction (1)

30 Hairspray is a mixture of chemicals(a) A primary alcohol 2-methylpropan-1-ol is added to hairspray to help it dry quickly on the hair

Draw a structural formula for a secondary alcohol that is an isomer of2-methylpropan-1-ol (1)

(b) Triethanol amine and triisopropyl amine are bases used to neutralise acidic compounds in the hairspray to prevent damage to the hair

In terms of the intermolecular bonding present explain clearly why triethanol amine has a much higher boiling point than triisopropyl amine (2)

35

36

31 Chocolate contains various compounds(a) Many of the flavour and aroma molecules found in chocolate are aldehydes and

ketones Two examples are shown below

Phenylethanal can be easily oxidised but 13-diphenylpropan-2-one cannot(i) Name a chemical that could be used to distinguish between these two

compounds (1)

(ii) Name the type of organic compound formed when phenylethanal is oxidised (1)

(b) Glycerol monostearate is an emulsifier used in chocolate

(i) Why is glycerol monostearate added to chocolate (1)

(ii) Draw a structural formula for glycerol (1)

(c) Theobromine a compound present in chocolate can cause illness in dogs and cats To decide if treatment is necessary vets must calculate the mass of theobromine consumed 1middot0 g of chocolate contains 1middot4 mg of theobromine Calculate the mass in mg of theobromine in a 17 g biscuit of which 28 is chocolate Show your working clearly (2)

(d) The flavour and texture of chocolate comes from a blend of compoundsUsing your knowledge of chemistry describe how you could show that there are ionic compounds and covalent compounds present in chocolate (3)

37

32 Ethanol has many uses

(a) Ethanol is found at relatively low concentrations in wine

(i) Name the chemical reaction that produces ethanol in wine (1)

(ii) Standard ethanol solutions were used to produce a graph of density against

concentration of ethanol given as a percentage of alcohol by volume ( abv)

What is the concentration of ethanol in units of abv in a solution of density 0middot9818 g cmminus3 (1)

(b) Whisky contains a higher concentration of ethanol

(i) Before 1980 the concentration of alcohol in drinks was measured in terms of degrees proof The concentration of alcohol in two drinks is shown in the table below both as abv and degrees proof

38

A cask strength whisky has an alcohol concentration of 65 abv Calculate the alcohol concentration of this whisky in degrees proof (1)

(ii) A barrel containing 195 litres of cask strength whisky costs pound1300 The cask strength whisky is diluted with water to reduce the concentration of alcohol from 65 abv to 46 abv before it is bottled Calculate the cost of the cask strength whisky needed to produce a 0middot70 litre bottle Show your working clearly (2)

(iii) 5-Butyl-4-methyltetrahydrofuran-2-ol is a flavour compound found in whisky

stored in oak barrels

Write the systematic name for the compound shown below (1) 13 11

33 (a) One test for glucose involves Fehlingrsquos solutionCircle the part of the glucose molecule that reacts with Fehlingrsquos solution (1)

(b) In solution sugar molecules exist in an equilibrium in straight-chain and ring forms

To change from the straight-chain form to the ring form the oxygen of the hydroxyl on carbon number 5 joins to the carbonyl carbon This is shown below for glucose

39

Draw the structure of a ring form for fructose (1)

34 (a) During the free radical chain reaction small molecules join to form large chain molecules

One example of a small molecule used is

Name the functional group circled above (1)

(b)Alcohol wipes are used to finish the varnishing treatment Alcohol wipes contain the alcohol propan-2-olState why propan-2-ol can be described as a secondary alcohol (1)

35 A student was carrying out an investigation into alcohols aldehydes and ketones

(a)The student was given three alcohols labelled as A B and C These alcohols were all isomers with the formula C4H9OH

(i) Draw a structural formula for the secondary alcohol with the formula C4H9OH(1)

(ii) The student set up the following experiment

A Suggest why a water bath is an appropriate method of heating the reaction mixture (1)

B Describe the colour change that would have been observed with alcohols A and C (1)

40

C Alcohol B is not oxidised State the type of alcohol which cannot be oxidised by acidified dichromate solution (1)

(iii) The student set up a second experiment with alcohol A

Hot copper(II) oxide is an oxidising agentA When alcohol A (C4H9OH) is oxidised the product turns the pH paper

redSuggest a name for the product (1)

B Complete the ion-electron equation for the oxidation reaction

C4H9OH rarr C4H8O2 (1)

(b)The student found the following information about the boiling points of some aldehydes

41

(i) Name the aldehyde that has a boiling point of 119 degC (1)(ii) Predict the boiling point in degC of the following molecule (1)

(iii) Using information from the table describe one way in which differences in structure affect the boiling point of isomeric aldehydes (1)

(iv) State what would be observed when an aldehyde is gently heated with Tollensrsquo reagent (1)

(c) Ketones contain a carbonyl groupName the type of intermolecular interaction between ketone molecules (1)

42

25 Soaps Detergents and Emulsions

1 Soaps are produced by the following reaction

This reaction is an example ofA condensationB esterificationC hydrolysisD oxidation

2 Which of the following is the salt of a long-chain fatty acid

A FatB OilC SoapD Glycerol

3 Emulsifiers for use in food are commonly made by reacting edible oils with

A estersB glycerolC fatty acidsD amino acids

4 A fatty acid is a long chain carboxylic acid Examples of fatty acids are shown in the table below

43

(a) What is the systematic name for linolenic acid (1)(b) Stearic acid reacts with sodium hydroxide solution to form sodium stearate

(i) Name the type of reaction taking place when stearic acid reacts with sodium hydroxide (1)

(ii) Explain fully how sodium stearate acts to keep grease and non-polar substances suspended in water during cleaning (3)

5 Small children can find it difficult to swallow tablets or pills so ibuprofen is supplied as an ldquoinfant formulardquo emulsion(a) The emulsifier used is polysorbate 80 Its structure is shown below

Explain why this molecule acts as an emulsifier (2)

(b) The emulsion contains 2 g of ibuprofen in every 100 cm3 of emulsion The recommended dose for treating a 6 month old baby is 0middot050 g Calculate the volume in cm3 of ldquoinfant formulardquo needed to treat a 6 month old baby (1)

6 Occasionally seabirds can become contaminated with hydrocarbons from oil spills This causes problems for birds because their feathers lose their waterproofing making the birds susceptible to temperature changes and

44

affecting their buoyancy If the birds attempt to clean themselves to remove the oil they may swallow the hydrocarbons causing damage to their internal organsContaminated seabirds can be cleaned by rubbing vegetable oil into their feathers and feet before the birds are rinsed with diluted washing-up liquidUsing your knowledge of chemistry comment on the problems created for seabirds by oil spills and the actions taken to treat affected birds (3)

7 Dishwasher tablets contain chemicals which remove dirt from dishesDishwasher tablets include detergents These molecules act like soaps to allow mixing of fat-soluble dirt and water(a)During the cleaning process the detergent molecules combine with fat-

soluble dirtA simplified diagram of a detergent molecule is shown

Complete the diagram below to show how detergent molecules combine with fat-soluble dirt (1)

(b)State the term used to describe the non-polar hydrocarbon tail of a detergent molecule (1)

45

26 Fragrances1 Myrcene is a simple terpene

Terpenes contain at least one isoprene unit Which of the following shows a correctly highlighted isoprene unit

2 Limonene is one of the terpene molecules responsible for the flavour of lemons

How many isoprene units are used in the production of one limonene moleculeA 1B 2C 3D 4

46

3 The structure of caryophyllene which can be extracted from clove oil is

Which of the following would be the best solvent for extracting caryophylleneA HexaneB HexanalC HexanolD Hexanone

4 The structure of isoprene is

Limonene is a terpene molecule present in lemons

How many isoprene units are joined together in a limonene molecule

A 1B 2

47

C 3D 4

5 Essential oils are

A non-water soluble non-volatile compoundsB non-water soluble volatile compoundsC water soluble non-volatile compoundsD water soluble volatile compounds

6 Two typical compounds that are present in many perfumes are shown

(a) Why does geraniol evaporate more slowly than limonene (1)

(b) The structure of one of the first synthetic scents used in perfume is shown below

(i) Name the family of carbonyl compounds to which this synthetic scent belongs (1)

(ii) Complete the structure below to show the product formed when this scent is

oxidised (1)

(c) Traces of a liquid were discovered in a bottle believed to contain perfume belonging to Queen Hatshepsut ruler of Egypt over 3500 years ago

Perfumes were made by dissolving plant extracts containing pleasant smelling terpenes and esters in an edible oil A little ethanol and water may also have been addedUsing your knowledge of chemistry comment on the possible smell(s) when such a bottle is opened after being stored for thousands of years (3)

48

49

7 A team of chemists are developing a fragrance for use in a shower gel for men(a) To give the gel a fruity smell the chemists are considering adding an ester

They synthesise six isomeric esters Volunteers smell each ester and give it a rating out of one hundred depending on how fruity the smell is

(i) Name the ester with the fruit-smell rating of 92 (1)

(ii) Shown below are the structures of three more isomers

Arrange these esters in order of decreasing fruit-smell rating (1)

50

(b) To create a fragrance for men the compound civetone is added

Draw a structural formula for the alcohol that can be oxidised to form civetone (1)

(c) To make the shower gel produce a cold tingling sensation when applied to the skin menthol is added

Like terpenes menthol is formed from isoprene (2-methylbuta-13-diene)Circle an isoprene unit on the menthol structure above (1)

8 Many of the compounds in perfumes are molecules consisting of joined isoprene units

(a) State the name that is given to molecules consisting of joined isoprene units (1)

(b)Geraniol is one of the compounds found in perfume It has the following structural formula and systematic name

Linalool can also be present Its structural formula is shown

51

(i) State the systematic name for linalool (1)(ii) Explain why linalool can be classified as a tertiary alcohol (1)

9 The component molecules found in lavender oils are terpenes or terpenoids(a)A chiral carbon is a carbon atom attached to four different atoms or groups of

atomsAn example is shown below

A molecule of the terpenoid linalool has a chiral carbon Linalool has the following structure

Circle the chiral carbon atom in the linalool structure (1)

(b)Farnesene is a terpene consisting of three isoprene units (2-methylbuta-13-diene) joined togetherWrite the molecular formula of farnesene (1)

52

27 Skin Care

1 Which of the following is not a step in a free radical chain reaction

A ActivationB InitiationC PropagationD Termination

2 Fluorine reacts with methane via a free radical chain reaction Some steps in the chain reaction are shown in the table below

Complete the table by(a) inserting the missing name for the first step (1)

(b) showing another possible termination reaction in the final row of the table (1)

3 Suncreams contain antioxidantsThe antioxidant compound A can prevent damage to skin by reacting with free

radicalssuch as NO2bull

53

Why can compound A be described as a free radical scavenger in the reaction shown above

4 Hydrogen and chlorine gases are used in an experiment to demonstrate a free radical reaction A plastic bottle is wrapped with black tape leaving a ldquowindowrdquo on one sideThe bottle is filled with a mixture of hydrogen and chlorine When bright light shines on the bottle there is an explosion

A free radical chain reaction is initiated when light energy causes chlorine radicals to form as shown below

(a) Complete the equations below showing possible propagation and termination steps

(2)

54

(b) Why is the plastic bottle used in the experiment wrapped in black tape (1)

5 Chloramines can be removed from water using ultraviolet light treatment

One step in the process is the formation of free radicals

(a)State what is meant by the term free radical (1)

(b)Another step in the process is shown below

State the name for this type of step in a free radical reaction (1)

6 Modern shellac nail varnishes are more durable and so last longer than traditional nail polish

The shellac nail varnish is applied in thin layers to the nails and then the fingers are placed under a UV lamp

(a) The Skin Care Foundation has recommended that a sun-block is applied to the fingers and hand before using the lampSuggest why the Skin Care Foundation makes this recommendation (1)

(b) A free radical chain reaction takes place and the varnish hardens (i) State what is meant by the term free radical (1)

(ii) The shellac nail varnish contains a mixture of ingredients that take part in the free radical chain reactionOne of the steps in the free radical chain reaction is

55

State the term used to describe this type of step in a free radical chain reaction(1)

7 Skin care products contain a mixture of polar covalent non-polar covalent and ionic compounds The compounds need to stay mixed within the product Skin care products also need to spread easily and remain on the skin for a period of time as well as provide physical and chemical protection from the sun In order to do this skin care products contain a range of chemicals including water fats and oils antioxidants minerals and sun blockUsing your knowledge of chemistry explain the role of different chemicals in skin care products (3)

General Questions

1 A mixture of carbon monoxide and hydrogen can be converted into water and a mixture of hydrocarbons

nCO + (2n + 1)H2 rarr nH2O + hydrocarbons

What is the general formula for the hydrocarbons producedA CnH2nndash2B CnH2nC CnH2n+1D CnH2n+2

2 Butadiene is the first member of a homologous series of hydrocarbons called dienesWhat is the general formula for this seriesA CnHn+2B CnHn+3C CnH2nD CnH2nndash2

3 Which of the following statements about methanol is falseA It can be made from synthesis gasB It can be dehydrated to form an alkeneC It can be oxidised to give a carboxylic acidD It reacts with acidified potassium dichromate solution

56

4

Which line in the table correctly describes reactions X and Y

5

Which line in the table correctly describes reactions X and Y

6 Which of the following fuels when burned would make no contribution to globalwarming

57

A HydrogenB Natural gasC PetrolD Coal

7 Which of the following hydrocarbons always gives the same product when one of itshydrogen atoms is replaced by a chlorine atomA HexaneB Hex-1-eneC CyclohexaneD Cyclohexene

8 Which of the following compounds does not have isomeric structuresA C2HCl3B C2H4Cl2C PropeneD Propan-1-ol

9 What organic compound is produced by the dehydration of ethanol A EthaneB EtheneC EthanalD Ethanoic acid

10

The above equation representsA hydrationB hydrogenationC condensationD hydrolysis

11

Which of the following compounds is an isomer of the structure shown aboveA ButanalB ButanoneC Butan-1-olD Butanoic acid

58

12 A compound with molecular formula C6H12O2 could beA hexanalB hexan-2-olC hexan-2-oneD hexanoic acid

13 Propan-2-ol can be prepared from propane as follows

Which line in the table correctly describes the types of reaction taking place at Steps 1 and 2

14 Which of the following compounds would be the most water soluble

15 Cyanohydrin compounds can be made from carbonyl compounds by reacting the carbonyl compound with hydrogen cyanide (HCN)

59

Which carbonyl compound would react with hydrogen cyanide (HCN) to form the following compound

16 Ethyne is the first member of the homologous series called the alkynes

Ethyne can undergo addition reactions as shown in the flow diagram

(a) Compound 2 is an isomer of 12-dichloroethaneDraw a structural formula for compound 2 (1)

(b) Reagents A B and C are three different diatomic gasesUsing information in the flow diagram identify reagents A B and C (1)

60

Reagent Gas

A

B

C

17 In 1865 the German chemist Kekuleacute proposed a ring structure for benzene This structure was based on alternating single and double bonds

(a) (i) Describe a chemical test that would indicate that the above chemical structure for benzene is incorrect (1)

(ii) Briefly describe the correct structure for benzene (1)

(b) Benzene can be formed from cyclohexaneC6H12 rarr C6H6 + 3H2

What name is given to this type of reaction (1)18 Infra-red spectroscopy is a technique that can be used to identify the bonds that

arepresent in a molecule Different bonds absorb infra-red radiation of different wavenumbers This is due to differences in the bond lsquostretchrsquo These absorptions are recorded in a spectrumA spectrum for propan-1-ol is shown

61

The correlation table on page 13 of the data booklet shows the wavenumber ranges for the absorptions due to different bonds

(a) Use the correlation table to identify the bonds responsible for the two absorptions x and y that are circled in the propan-1-ol spectrum (1)

(b) Propan-1-ol reacts with ethanoic acid(i) What name is given to this type of reaction (1)(ii) Draw a spectrum that could be obtained for the organic product of this

reaction (1)

19 Paracetamol is a widely used painkiller

(a) Write the molecular formula for paracetamol (1)

(b) One antidote for paracetamol overdose is methionine

62

To what family of organic compounds does methionine belong (1)

(c) The concentration of paracetamol in a solution can be determined by measuring how much UV radiation it absorbs

The graph shows how the absorbance of a sample containing 0middot040 g l ndash1 paracetamol varies with wavelength

The quantity of UV radiation of wavelength 245 nm absorbed is directly proportional to the concentration of paracetamolThe absorbance of a second sample of paracetamol solution measured at 245 nm was 0middot90 What is the concentration in g l ndash1 of this second paracetamol solution (1)

20 Many carbon compounds containing oxygen are very flammableThe table shows information about two families of isomersThe lowest temperature at which a compound will ignite is called its flash point

(a) A compound with the molecular formula C6H14O has a boiling point of 158 degC63

Draw a structural formula for this compound (1)

(b) For a family of isomers in the table write a general statement linking the flash points of the compounds to their structures (1)

21 Hydrogels are used in disposable nappies They are fine powders that can absorb up to 500 times their own weight in waterA hydrogel is a very long molecule with carboxyl groups at regular intervals along its length A short section of a hydrogel molecule is shown below

Hydrogels are extremely good at soaking up water because the water molecules are strongly attracted to them

Using your knowledge of chemistry comment on how suitable hydrogels would be for absorbing liquids or solutions spilled in a chemistry lab (1)

64

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

(ii) When a fat is hydrolysed using sodium hydroxide sodium salts of fatty acids are producedState a use for sodium salts of fatty acids (1)

22 Proteins

1 When a protein is denaturedA its overall shape is distortedB its amide links are hydrolysedC it is broken into separate peptide fragmentsD it decomposes into amino acids

2 Which of the following compounds can be classified as proteinsA FatsB OilsC EnzymesD Amino acids

3 The monomer units used to construct enzyme molecules areA alcoholsB estersC amino acidsD fatty acids

4 Amino acids are converted into proteins byA hydrationB hydrolysisC hydrogenationD condensation

5 The arrangement of amino acids in a peptide isZ-X-W-V-Y

where the letters V W X Y and Z represent amino acidsOn partial hydrolysis of the peptide which of the following sets of dipeptides is possibleA V-Y Z-X W-Y X-WB Z-X V-Y W-V X-WC Z-X X-V W-V V-YD X-W X-Z Z-W Y-V

6 Which of the following is an amine

12

7 Which of the following arrangements of atoms shows a peptide link

8 The following molecules are found in herbicides Which of the following contains an amide link

9 In α-amino acids the amino group is on the carbon atom adjacent to the acid group

Which of the following is an α-amino acid

10 A tripeptide X has the structure

Partial hydrolysis of X yields a mixture of dipeptidesWhich of the following dipeptides could be produced on hydrolysing X

13

11 The rate of hydrolysis of protein using an enzyme was studied at different temperatures Which of the following graphs would be obtained

12 The rate of hydrolysis of protein using an enzyme was studied at different temperaturesWhich of the following graphs would be obtained

14

13 Polymers can be classified as natural or synthetic(a) Keratin a natural polymer is a protein found in hair

The hydrolysis of keratin produces different monomers of the type shown

(i) What name is given to monomers like glycine alanine and cysteine (1)(ii) What is meant by a hydrolysis reaction (1)

(b) Dacron a synthetic polymer is used in heart surgery A section of the polymer is shown

What name is given to the link made by the shaded group of atoms in this section of the polymer (1)

14 Chemists have developed cheeses specifically for use in cheeseburgers(a) When ordinary cheddar cheese is grilled the shapes of the protein molecules

change and the proteins and fats separate leaving a chewy solid and an oily liquidWhat name is given to the change in protein structure which occurs when ordinary cheddar is grilled (1)

(b) To make cheese for burgers grated cheddar cheese soluble milk proteins and some water are mixed and heated to no more than 82 degC As the cheese begins to melt an emulsifying agent is added and the mixture is stirred

15

(i) Why would a water bath be used to heat the mixture (1)(ii) A section of the structure of a soluble milk protein is shown below

Draw a structural formula for any one of the amino acids formed when this section of

protein is hydrolysed (1)

(iii) The emulsifier used is trisodium citrate a salt formed when citric acid is neutralised using sodium hydroxide Complete the equation below showing a structural formula for the trisodium citrate formed (1) sp 8

15 Phenylalanine and alanine are both amino acids

(a) Phenylalanine is an essential amino acid

(i) What is meant by an essential amino acid (1)

16

(ii) How many hydrogen atoms are present in a molecule of phenylalanine (1)

(b) Phenylalanine and alanine can react to form the dipeptide shown

Circle the peptide link in this molecule (1)

(c) Draw a structural formula for the other dipeptide that can be formed from phenylalanine and alanine (1)

16 Uncooked egg white is mainly composed of dissolved proteins During cooking processes the proteins become denatured as the protein chains unwind and the egg white solidifies

(a) Explain why the protein chains unwind (1)

(b)The temperature at which the protein becomes denatured is called the melting temperature The melting temperature of a protein can be determined using fluorescence In this technique the protein is mixed with a dye that gives out visible light when it attaches to hydrophobic parts of the protein molecule The hydrophobic parts of the structure are on the inside of the protein and the dye has no access to them unless the protein unwinds

(i) Ovalbumin is a protein found in egg white Part of the structure of unwound ovalbumin is shown below

Circle the part of the structure to which the hydrophobic dye is most likely to attach (1)

17

(ii) Another protein in egg white is conalbumin The temperature of a conalbumindye mixture is gradually increased The fluorescence is measured and a graph is produced

The melting temperature is the temperature at which the fluorescence is halfway between the highest and lowest fluorescence valuesDetermine the melting temperature in ordmC for this protein (1)

(c) Once cooked and eaten the digestive system breaks the protein chains into amino acids with the help of enzymes

(i) State the name of the digestion process where enzymes break down proteins into amino acids (1)

(ii)

(A) State how many amino acid molecules joined to form this section of protein (1)

(B) Draw the structure of one amino acid that would be produced when this section of the protein chain is broken down (1)

17 Peptide molecules can be classified according to the number of amino acid units joined by peptide bonds in the molecule

18

(a) Complete the table to identify the type of peptide with the following amino acid sequence

alanine-glycine-valine-proline-tyrosine-serine (1)

(b) Partial hydrolysis of another pentapeptide molecule gave a mixture of three smaller peptide molecules with the following amino acid sequences

leucine-glycine-valineisoleucine-leucineglycine-valine-serine

Write the amino acid sequence for the original pentapeptide molecule (1)

helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip(c) Some amino acids needed to form polypeptides cannot be produced in the human body

State the term used to describe amino acids that the body cannot make (1)

(d)Paper chromatography is often used to analyse the mixtures of amino acids produced when peptides are broken downOn a chromatogram the retention factor Rf for a substance can be a useful method of identifying the substance

The structure of the pentapeptide methionine enkephalin was investigatedA sample of the pentapeptide was completely hydrolysed into its constituent amino acids and this amino acid mixture was applied to a piece of chromatography paper and placed in a solventThe chromatogram obtained is shown below

19

(i) Suggest why only four spots were obtained on the chromatogram of the hydrolysed pentapeptide (1)

(ii) It is known that this amino acid mixture contains the amino acid methionine The Rf value for methionine in this solvent is 040Draw a circle around the spot on the chromatogram that corresponds to methionine (1)

(e) Over the last decade several families of extremely stable peptide molecules have been discovered where the peptide chain forms a ring

(i) A simple cyclic dipeptide is shown

Draw a structural formula for one of the amino acids that would be formed on complete hydrolysis of the above cyclic dipeptide (1)

(ii) Alpha-amanitin is a highly toxic cyclic peptide found in death cap mushrooms The lethal dose for humans is 100 mg per kg of body mass1middot0 g of death cap mushrooms contains 250 mg of alpha-amanitinCalculate the minimum mass of death cap mushrooms that would contain the lethal dose for a 75 kg adult (2)

18 Dishwasher tablets produce the bleach hydrogen peroxide H2O2 One action of this oxidising agent is to oxidise food

(a)(i) Suggest another action of the bleach produced by the dishwasher tablets (1)

20

(ii) Hydrogen peroxide decomposes to form water and oxygen

2H2O2(ℓ) rarr 2H2O(ℓ) + O2(g)

A dishwasher tablet produces 0middot051 g of hydrogen peroxide (mass of one mole = 34 g)

Calculate the volume of oxygen that would be produced when0middot051 g of hydrogen peroxide decomposesTake the volume of 1 mole of oxygen gas to be 24 litres(3)

(b)Enzymes are commonly added to dishwasher tablets These are used to break down proteins(i) The proteins are broken down into small water-soluble molecules

Name the small water-soluble molecules made when proteins are broken down completely (1)

(ii) The structure of a section of protein chain found in egg white is shown

(A)Name the functional group circled (1)(B)Draw a structural formula for one of the molecules that would be made

when this section of egg white protein chain is completely broken down (1)

(iii) As part of the program in the dishwasher the conditions in the dishwasher change so that the enzyme molecules no longer work because they change shape

21

(A) State the term used to describe the change in shape of enzyme molecules(1)

(B) Suggest a change in conditions which would cause the enzyme molecules to change shape (1)

(d) A bleach activator is frequently added to dishwasher tablets to speed up the bleaching reaction One common bleach activator is TAED TAED could be produced in a process which involves a number of stages

(i) The first stage in producing TAED is shown below

Suggest a name for this type of reaction (1)

(ii) The final stage in the process producing TAED is shown below

Draw a structural formula for TAED (1)

22

23 The Chemistry of Cooking

1 Vanillin and zingerone are flavour molecules

Which line in the table correctly compares the properties of vanillin and zingerone

23

2 Erythrose can be used in the production of a chewing gum that helps prevent tooth decay

Which of the following compounds will be the best solvent for erythrose

3 The following molecules give flavour to food Which of the following flavour molecules would be most likely to be retained in the food when the food is cooked in water

24

4 Cooking involves many chemical reactions Proteins fats oils and esters are some examples of compounds found in food A chemist suggested that cooking food could change compounds from being fat-soluble to water-soluble Use your knowledge of chemistry to comment on the accuracy of this statement(3)

25

24 The Oxidation of Food

1 Apples and bananas turn brown when cut or bruised The first step of the reaction causing

the browning is shown below

Which of the following terms correctly describes this reactionA ReductionB OxidationC DehydrationD Condensation

2 Which of the following reactions can be classified as reductionA CH3CH2OH rarr CH3COOHB CH3 CH(OH)CH3 rarr CH3COCH3C CH3CH2COCH3 rarr CH3CH2CH(OH)CH3D CH3CH2CHO rarr CH3CH2COOH

3 The dehydration of butan-2-ol can produce two isomeric alkenes but-1-ene andbut-2-ene Which of the following alkanols can similarly produce on dehydration a pair of isomeric alkenesA Propan-2-olB Pentan-3-olC Hexan-3-olD Heptan-4-ol

4 Which of the following compounds is an alkanone

26

5 Which of the following is an aldehyde

6 Which of the following compounds would react with sodium hydroxide solution to forma saltA CH3CHOB CH3COOHC CH3COCH3D CH3CH2OH

7 Which line in the table shows the correct functional group for each homologous series

8 Which of the following organic compounds is an isomer of hexanalA 2-MethylbutanalB 3-Methylpentan-2-oneC 22-Dimethylbutan-1-olD 3-Ethylpentanal

27

9 The name of this compound is

A methanolB methanalC methanoic acidD methanone

10 Which alcohol could be oxidised to a carboxylic acid

11 Which of the following structural formulae represents a tertiary alcohol

12 Compound X reacted with hot copper(II) oxide and the organic product did not give acolour change when heated with Fehlingrsquos solution Compound X could beA butan-1-olB butan-2-olC butanoneD butanoic acid

28

13 Which two isomers would each produce an acid when warmed with acidified potassiumdichromate solution

A 1 and 2B 2 and 3C 1 and 4D 3 and 4

14 After heating for several minutes as shown in the diagram the pH indicator solution turned red

Liquid Q could beA propanoneB paraffinC propan-1-olD propan-2-ol

29

15 Enzymes are involved in the browning of cut fruitOne reaction taking place is

Which of the following correctly describes the above reaction

A OxidationB ReductionC HydrolysisD Condensation

16 Which of the following statements is correct for ketones

A They are formed by oxidation of tertiary alcohols

B They contain the group

C They contain a carboxyl groupD They will not react with Fehlingrsquos solution

17 Carvone is a natural product that can be extracted from orange peel

Which line in the table correctly describes the reaction of carvone with bromine solution and with acidified potassium dichromate solution

30

18 Which of the following is an isomer of 22-dimethylpentan-1-ol

A CH3CH2CH2CH(CH3)CH2OHB (CH3)3CCH(CH3)CH2OHC CH3CH2CH2CH2CH2CH2CH2CH2OHD (CH3)2CHC(CH3)2CH2CH2OH

19 The equation for the reduction reaction taking place when ethanal reacts with Tollensrsquo reagent is

A Cu2+(aq) + eminus rarr Cu+(aq)

B Ag+(aq) + eminus rarr Ag(s)

C Cr2O72minus(aq) + 14H+(aq) + 6eminus rarr 2Cr3+(aq) + 7H2O(ℓ)

D MnO4minus(aq) + 8H+(aq) + 5eminus rarr Mn2+(aq) + 4H2O(ℓ)

20 The name of the compound with structure

isA 23-dimethylpentan-4-oneB 23-dimethylpentan-2-alC 34-dimethylpentan-2-oneD 34-dimethylpentan-2-al

21 What is the systematic name for the compound below

A 222-trimethylethanolB 22-dimethylpropan-1-olC 22-dimethylpropan-3-olD 22-dimethylpentan-1-ol

31

22 The structure of a molecule found in olive oil can be represented as shown

(a) Olive oil can be hydrolysed using sodium hydroxide solution to produce sodium salts of fatty acids Name the other product of this reaction (1)

(b) In what way does the structure of a fat molecule differ from that of an oil molecule (1)

(c) Over time open containers of olive oil develop a rancid flavour What substance is reacting with the oil to cause these unwanted changes to take place (1)

23 A student writes the following statement It is incorrect Explain the mistake in the studentrsquos reasoning (1)

Alcohols are alkaline because of their OH groups

24 Carbon compounds take part in a wide variety of chemical reactions (a)

Name this type of chemical reaction (1)

(b)

Draw a structural formula for C3H6O (1)

25 Alkanols can be oxidised to alkanoic acids

32

(a) Why can Step 1 be described as an oxidation reaction (1)

(b) Acidified potassium dichromate solution can be used to oxidise propanal in Step 2 What colour change would be observed in this reaction (1)

26 Amines can be produced by reacting ammonia with an aldehyde or a ketone This reaction an example of reductive amination occurs in two stages

Stage 1 Amination

Stage 2 Reduction

(a) Give another name for the type of reaction taking place in Stage 2

(b) Draw the structural formula for the amine produced when butanal undergoes reductive amination with ammonia

27 Using a cobalt catalyst alkenes react with a mixture of hydrogen and carbon monoxideThe products are two isomeric aldehydes Propene reacts with the mixture as shown

(a) What name is given to a mixture of hydrogen and carbon monoxide (1)

(b) Draw a structural formula for compound B (1)

(c) (i) What would be observed if compound A was gently heated with Tollensrsquo reagent

(1)(ii) How would the reaction mixture be heated (1)

33

(d) Aldehydes can also be formed by the reaction of some alcohols with copper(II) oxideName the type of alcohol that would react with copper(II) oxide to form an aldehyde (1)

28 Aldehydes and ketones can take part in a reaction sometimes known as an aldol condensation The simplest aldol reaction involves two molecules of ethanal

In the reaction the carbon atom next to the carbonyl functional group of one molecule forms a bond with the carbonyl carbon atom of the second molecule

(a) Draw a structural formula for the product formed when propanone is used instead of ethanal in this type of reaction (1)

(b) Name an aldehyde that would not take part in an aldol condensation (1)

(c) Apart from the structure of the reactants suggest what is unusual about applying the term ldquocondensationrdquo to this particular type of reaction (1)

29 Primary secondary and tertiary alkanols can be prepared by the reaction of carbonyl compounds with Grignard reagents

Step 1The Grignard reagent reacts with the carbonyl compound

Step 2The reaction of the product of Step 1 with dilute acid produces the alkanol

(a) Describe the difference between a primary a secondary and a tertiary alkanol

You may wish to include labelled structures in your answer (1)34

(b) Suggest a name for the type of reaction that takes place in Step 1 (1)

(c) The same Grignard reagent can be used to produce the alkanol below

Name the carbonyl compound used in this reaction (1)

30 Hairspray is a mixture of chemicals(a) A primary alcohol 2-methylpropan-1-ol is added to hairspray to help it dry quickly on the hair

Draw a structural formula for a secondary alcohol that is an isomer of2-methylpropan-1-ol (1)

(b) Triethanol amine and triisopropyl amine are bases used to neutralise acidic compounds in the hairspray to prevent damage to the hair

In terms of the intermolecular bonding present explain clearly why triethanol amine has a much higher boiling point than triisopropyl amine (2)

35

36

31 Chocolate contains various compounds(a) Many of the flavour and aroma molecules found in chocolate are aldehydes and

ketones Two examples are shown below

Phenylethanal can be easily oxidised but 13-diphenylpropan-2-one cannot(i) Name a chemical that could be used to distinguish between these two

compounds (1)

(ii) Name the type of organic compound formed when phenylethanal is oxidised (1)

(b) Glycerol monostearate is an emulsifier used in chocolate

(i) Why is glycerol monostearate added to chocolate (1)

(ii) Draw a structural formula for glycerol (1)

(c) Theobromine a compound present in chocolate can cause illness in dogs and cats To decide if treatment is necessary vets must calculate the mass of theobromine consumed 1middot0 g of chocolate contains 1middot4 mg of theobromine Calculate the mass in mg of theobromine in a 17 g biscuit of which 28 is chocolate Show your working clearly (2)

(d) The flavour and texture of chocolate comes from a blend of compoundsUsing your knowledge of chemistry describe how you could show that there are ionic compounds and covalent compounds present in chocolate (3)

37

32 Ethanol has many uses

(a) Ethanol is found at relatively low concentrations in wine

(i) Name the chemical reaction that produces ethanol in wine (1)

(ii) Standard ethanol solutions were used to produce a graph of density against

concentration of ethanol given as a percentage of alcohol by volume ( abv)

What is the concentration of ethanol in units of abv in a solution of density 0middot9818 g cmminus3 (1)

(b) Whisky contains a higher concentration of ethanol

(i) Before 1980 the concentration of alcohol in drinks was measured in terms of degrees proof The concentration of alcohol in two drinks is shown in the table below both as abv and degrees proof

38

A cask strength whisky has an alcohol concentration of 65 abv Calculate the alcohol concentration of this whisky in degrees proof (1)

(ii) A barrel containing 195 litres of cask strength whisky costs pound1300 The cask strength whisky is diluted with water to reduce the concentration of alcohol from 65 abv to 46 abv before it is bottled Calculate the cost of the cask strength whisky needed to produce a 0middot70 litre bottle Show your working clearly (2)

(iii) 5-Butyl-4-methyltetrahydrofuran-2-ol is a flavour compound found in whisky

stored in oak barrels

Write the systematic name for the compound shown below (1) 13 11

33 (a) One test for glucose involves Fehlingrsquos solutionCircle the part of the glucose molecule that reacts with Fehlingrsquos solution (1)

(b) In solution sugar molecules exist in an equilibrium in straight-chain and ring forms

To change from the straight-chain form to the ring form the oxygen of the hydroxyl on carbon number 5 joins to the carbonyl carbon This is shown below for glucose

39

Draw the structure of a ring form for fructose (1)

34 (a) During the free radical chain reaction small molecules join to form large chain molecules

One example of a small molecule used is

Name the functional group circled above (1)

(b)Alcohol wipes are used to finish the varnishing treatment Alcohol wipes contain the alcohol propan-2-olState why propan-2-ol can be described as a secondary alcohol (1)

35 A student was carrying out an investigation into alcohols aldehydes and ketones

(a)The student was given three alcohols labelled as A B and C These alcohols were all isomers with the formula C4H9OH

(i) Draw a structural formula for the secondary alcohol with the formula C4H9OH(1)

(ii) The student set up the following experiment

A Suggest why a water bath is an appropriate method of heating the reaction mixture (1)

B Describe the colour change that would have been observed with alcohols A and C (1)

40

C Alcohol B is not oxidised State the type of alcohol which cannot be oxidised by acidified dichromate solution (1)

(iii) The student set up a second experiment with alcohol A

Hot copper(II) oxide is an oxidising agentA When alcohol A (C4H9OH) is oxidised the product turns the pH paper

redSuggest a name for the product (1)

B Complete the ion-electron equation for the oxidation reaction

C4H9OH rarr C4H8O2 (1)

(b)The student found the following information about the boiling points of some aldehydes

41

(i) Name the aldehyde that has a boiling point of 119 degC (1)(ii) Predict the boiling point in degC of the following molecule (1)

(iii) Using information from the table describe one way in which differences in structure affect the boiling point of isomeric aldehydes (1)

(iv) State what would be observed when an aldehyde is gently heated with Tollensrsquo reagent (1)

(c) Ketones contain a carbonyl groupName the type of intermolecular interaction between ketone molecules (1)

42

25 Soaps Detergents and Emulsions

1 Soaps are produced by the following reaction

This reaction is an example ofA condensationB esterificationC hydrolysisD oxidation

2 Which of the following is the salt of a long-chain fatty acid

A FatB OilC SoapD Glycerol

3 Emulsifiers for use in food are commonly made by reacting edible oils with

A estersB glycerolC fatty acidsD amino acids

4 A fatty acid is a long chain carboxylic acid Examples of fatty acids are shown in the table below

43

(a) What is the systematic name for linolenic acid (1)(b) Stearic acid reacts with sodium hydroxide solution to form sodium stearate

(i) Name the type of reaction taking place when stearic acid reacts with sodium hydroxide (1)

(ii) Explain fully how sodium stearate acts to keep grease and non-polar substances suspended in water during cleaning (3)

5 Small children can find it difficult to swallow tablets or pills so ibuprofen is supplied as an ldquoinfant formulardquo emulsion(a) The emulsifier used is polysorbate 80 Its structure is shown below

Explain why this molecule acts as an emulsifier (2)

(b) The emulsion contains 2 g of ibuprofen in every 100 cm3 of emulsion The recommended dose for treating a 6 month old baby is 0middot050 g Calculate the volume in cm3 of ldquoinfant formulardquo needed to treat a 6 month old baby (1)

6 Occasionally seabirds can become contaminated with hydrocarbons from oil spills This causes problems for birds because their feathers lose their waterproofing making the birds susceptible to temperature changes and

44

affecting their buoyancy If the birds attempt to clean themselves to remove the oil they may swallow the hydrocarbons causing damage to their internal organsContaminated seabirds can be cleaned by rubbing vegetable oil into their feathers and feet before the birds are rinsed with diluted washing-up liquidUsing your knowledge of chemistry comment on the problems created for seabirds by oil spills and the actions taken to treat affected birds (3)

7 Dishwasher tablets contain chemicals which remove dirt from dishesDishwasher tablets include detergents These molecules act like soaps to allow mixing of fat-soluble dirt and water(a)During the cleaning process the detergent molecules combine with fat-

soluble dirtA simplified diagram of a detergent molecule is shown

Complete the diagram below to show how detergent molecules combine with fat-soluble dirt (1)

(b)State the term used to describe the non-polar hydrocarbon tail of a detergent molecule (1)

45

26 Fragrances1 Myrcene is a simple terpene

Terpenes contain at least one isoprene unit Which of the following shows a correctly highlighted isoprene unit

2 Limonene is one of the terpene molecules responsible for the flavour of lemons

How many isoprene units are used in the production of one limonene moleculeA 1B 2C 3D 4

46

3 The structure of caryophyllene which can be extracted from clove oil is

Which of the following would be the best solvent for extracting caryophylleneA HexaneB HexanalC HexanolD Hexanone

4 The structure of isoprene is

Limonene is a terpene molecule present in lemons

How many isoprene units are joined together in a limonene molecule

A 1B 2

47

C 3D 4

5 Essential oils are

A non-water soluble non-volatile compoundsB non-water soluble volatile compoundsC water soluble non-volatile compoundsD water soluble volatile compounds

6 Two typical compounds that are present in many perfumes are shown

(a) Why does geraniol evaporate more slowly than limonene (1)

(b) The structure of one of the first synthetic scents used in perfume is shown below

(i) Name the family of carbonyl compounds to which this synthetic scent belongs (1)

(ii) Complete the structure below to show the product formed when this scent is

oxidised (1)

(c) Traces of a liquid were discovered in a bottle believed to contain perfume belonging to Queen Hatshepsut ruler of Egypt over 3500 years ago

Perfumes were made by dissolving plant extracts containing pleasant smelling terpenes and esters in an edible oil A little ethanol and water may also have been addedUsing your knowledge of chemistry comment on the possible smell(s) when such a bottle is opened after being stored for thousands of years (3)

48

49

7 A team of chemists are developing a fragrance for use in a shower gel for men(a) To give the gel a fruity smell the chemists are considering adding an ester

They synthesise six isomeric esters Volunteers smell each ester and give it a rating out of one hundred depending on how fruity the smell is

(i) Name the ester with the fruit-smell rating of 92 (1)

(ii) Shown below are the structures of three more isomers

Arrange these esters in order of decreasing fruit-smell rating (1)

50

(b) To create a fragrance for men the compound civetone is added

Draw a structural formula for the alcohol that can be oxidised to form civetone (1)

(c) To make the shower gel produce a cold tingling sensation when applied to the skin menthol is added

Like terpenes menthol is formed from isoprene (2-methylbuta-13-diene)Circle an isoprene unit on the menthol structure above (1)

8 Many of the compounds in perfumes are molecules consisting of joined isoprene units

(a) State the name that is given to molecules consisting of joined isoprene units (1)

(b)Geraniol is one of the compounds found in perfume It has the following structural formula and systematic name

Linalool can also be present Its structural formula is shown

51

(i) State the systematic name for linalool (1)(ii) Explain why linalool can be classified as a tertiary alcohol (1)

9 The component molecules found in lavender oils are terpenes or terpenoids(a)A chiral carbon is a carbon atom attached to four different atoms or groups of

atomsAn example is shown below

A molecule of the terpenoid linalool has a chiral carbon Linalool has the following structure

Circle the chiral carbon atom in the linalool structure (1)

(b)Farnesene is a terpene consisting of three isoprene units (2-methylbuta-13-diene) joined togetherWrite the molecular formula of farnesene (1)

52

27 Skin Care

1 Which of the following is not a step in a free radical chain reaction

A ActivationB InitiationC PropagationD Termination

2 Fluorine reacts with methane via a free radical chain reaction Some steps in the chain reaction are shown in the table below

Complete the table by(a) inserting the missing name for the first step (1)

(b) showing another possible termination reaction in the final row of the table (1)

3 Suncreams contain antioxidantsThe antioxidant compound A can prevent damage to skin by reacting with free

radicalssuch as NO2bull

53

Why can compound A be described as a free radical scavenger in the reaction shown above

4 Hydrogen and chlorine gases are used in an experiment to demonstrate a free radical reaction A plastic bottle is wrapped with black tape leaving a ldquowindowrdquo on one sideThe bottle is filled with a mixture of hydrogen and chlorine When bright light shines on the bottle there is an explosion

A free radical chain reaction is initiated when light energy causes chlorine radicals to form as shown below

(a) Complete the equations below showing possible propagation and termination steps

(2)

54

(b) Why is the plastic bottle used in the experiment wrapped in black tape (1)

5 Chloramines can be removed from water using ultraviolet light treatment

One step in the process is the formation of free radicals

(a)State what is meant by the term free radical (1)

(b)Another step in the process is shown below

State the name for this type of step in a free radical reaction (1)

6 Modern shellac nail varnishes are more durable and so last longer than traditional nail polish

The shellac nail varnish is applied in thin layers to the nails and then the fingers are placed under a UV lamp

(a) The Skin Care Foundation has recommended that a sun-block is applied to the fingers and hand before using the lampSuggest why the Skin Care Foundation makes this recommendation (1)

(b) A free radical chain reaction takes place and the varnish hardens (i) State what is meant by the term free radical (1)

(ii) The shellac nail varnish contains a mixture of ingredients that take part in the free radical chain reactionOne of the steps in the free radical chain reaction is

55

State the term used to describe this type of step in a free radical chain reaction(1)

7 Skin care products contain a mixture of polar covalent non-polar covalent and ionic compounds The compounds need to stay mixed within the product Skin care products also need to spread easily and remain on the skin for a period of time as well as provide physical and chemical protection from the sun In order to do this skin care products contain a range of chemicals including water fats and oils antioxidants minerals and sun blockUsing your knowledge of chemistry explain the role of different chemicals in skin care products (3)

General Questions

1 A mixture of carbon monoxide and hydrogen can be converted into water and a mixture of hydrocarbons

nCO + (2n + 1)H2 rarr nH2O + hydrocarbons

What is the general formula for the hydrocarbons producedA CnH2nndash2B CnH2nC CnH2n+1D CnH2n+2

2 Butadiene is the first member of a homologous series of hydrocarbons called dienesWhat is the general formula for this seriesA CnHn+2B CnHn+3C CnH2nD CnH2nndash2

3 Which of the following statements about methanol is falseA It can be made from synthesis gasB It can be dehydrated to form an alkeneC It can be oxidised to give a carboxylic acidD It reacts with acidified potassium dichromate solution

56

4

Which line in the table correctly describes reactions X and Y

5

Which line in the table correctly describes reactions X and Y

6 Which of the following fuels when burned would make no contribution to globalwarming

57

A HydrogenB Natural gasC PetrolD Coal

7 Which of the following hydrocarbons always gives the same product when one of itshydrogen atoms is replaced by a chlorine atomA HexaneB Hex-1-eneC CyclohexaneD Cyclohexene

8 Which of the following compounds does not have isomeric structuresA C2HCl3B C2H4Cl2C PropeneD Propan-1-ol

9 What organic compound is produced by the dehydration of ethanol A EthaneB EtheneC EthanalD Ethanoic acid

10

The above equation representsA hydrationB hydrogenationC condensationD hydrolysis

11

Which of the following compounds is an isomer of the structure shown aboveA ButanalB ButanoneC Butan-1-olD Butanoic acid

58

12 A compound with molecular formula C6H12O2 could beA hexanalB hexan-2-olC hexan-2-oneD hexanoic acid

13 Propan-2-ol can be prepared from propane as follows

Which line in the table correctly describes the types of reaction taking place at Steps 1 and 2

14 Which of the following compounds would be the most water soluble

15 Cyanohydrin compounds can be made from carbonyl compounds by reacting the carbonyl compound with hydrogen cyanide (HCN)

59

Which carbonyl compound would react with hydrogen cyanide (HCN) to form the following compound

16 Ethyne is the first member of the homologous series called the alkynes

Ethyne can undergo addition reactions as shown in the flow diagram

(a) Compound 2 is an isomer of 12-dichloroethaneDraw a structural formula for compound 2 (1)

(b) Reagents A B and C are three different diatomic gasesUsing information in the flow diagram identify reagents A B and C (1)

60

Reagent Gas

A

B

C

17 In 1865 the German chemist Kekuleacute proposed a ring structure for benzene This structure was based on alternating single and double bonds

(a) (i) Describe a chemical test that would indicate that the above chemical structure for benzene is incorrect (1)

(ii) Briefly describe the correct structure for benzene (1)

(b) Benzene can be formed from cyclohexaneC6H12 rarr C6H6 + 3H2

What name is given to this type of reaction (1)18 Infra-red spectroscopy is a technique that can be used to identify the bonds that

arepresent in a molecule Different bonds absorb infra-red radiation of different wavenumbers This is due to differences in the bond lsquostretchrsquo These absorptions are recorded in a spectrumA spectrum for propan-1-ol is shown

61

The correlation table on page 13 of the data booklet shows the wavenumber ranges for the absorptions due to different bonds

(a) Use the correlation table to identify the bonds responsible for the two absorptions x and y that are circled in the propan-1-ol spectrum (1)

(b) Propan-1-ol reacts with ethanoic acid(i) What name is given to this type of reaction (1)(ii) Draw a spectrum that could be obtained for the organic product of this

reaction (1)

19 Paracetamol is a widely used painkiller

(a) Write the molecular formula for paracetamol (1)

(b) One antidote for paracetamol overdose is methionine

62

To what family of organic compounds does methionine belong (1)

(c) The concentration of paracetamol in a solution can be determined by measuring how much UV radiation it absorbs

The graph shows how the absorbance of a sample containing 0middot040 g l ndash1 paracetamol varies with wavelength

The quantity of UV radiation of wavelength 245 nm absorbed is directly proportional to the concentration of paracetamolThe absorbance of a second sample of paracetamol solution measured at 245 nm was 0middot90 What is the concentration in g l ndash1 of this second paracetamol solution (1)

20 Many carbon compounds containing oxygen are very flammableThe table shows information about two families of isomersThe lowest temperature at which a compound will ignite is called its flash point

(a) A compound with the molecular formula C6H14O has a boiling point of 158 degC63

Draw a structural formula for this compound (1)

(b) For a family of isomers in the table write a general statement linking the flash points of the compounds to their structures (1)

21 Hydrogels are used in disposable nappies They are fine powders that can absorb up to 500 times their own weight in waterA hydrogel is a very long molecule with carboxyl groups at regular intervals along its length A short section of a hydrogel molecule is shown below

Hydrogels are extremely good at soaking up water because the water molecules are strongly attracted to them

Using your knowledge of chemistry comment on how suitable hydrogels would be for absorbing liquids or solutions spilled in a chemistry lab (1)

64

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

7 Which of the following arrangements of atoms shows a peptide link

8 The following molecules are found in herbicides Which of the following contains an amide link

9 In α-amino acids the amino group is on the carbon atom adjacent to the acid group

Which of the following is an α-amino acid

10 A tripeptide X has the structure

Partial hydrolysis of X yields a mixture of dipeptidesWhich of the following dipeptides could be produced on hydrolysing X

13

11 The rate of hydrolysis of protein using an enzyme was studied at different temperatures Which of the following graphs would be obtained

12 The rate of hydrolysis of protein using an enzyme was studied at different temperaturesWhich of the following graphs would be obtained

14

13 Polymers can be classified as natural or synthetic(a) Keratin a natural polymer is a protein found in hair

The hydrolysis of keratin produces different monomers of the type shown

(i) What name is given to monomers like glycine alanine and cysteine (1)(ii) What is meant by a hydrolysis reaction (1)

(b) Dacron a synthetic polymer is used in heart surgery A section of the polymer is shown

What name is given to the link made by the shaded group of atoms in this section of the polymer (1)

14 Chemists have developed cheeses specifically for use in cheeseburgers(a) When ordinary cheddar cheese is grilled the shapes of the protein molecules

change and the proteins and fats separate leaving a chewy solid and an oily liquidWhat name is given to the change in protein structure which occurs when ordinary cheddar is grilled (1)

(b) To make cheese for burgers grated cheddar cheese soluble milk proteins and some water are mixed and heated to no more than 82 degC As the cheese begins to melt an emulsifying agent is added and the mixture is stirred

15

(i) Why would a water bath be used to heat the mixture (1)(ii) A section of the structure of a soluble milk protein is shown below

Draw a structural formula for any one of the amino acids formed when this section of

protein is hydrolysed (1)

(iii) The emulsifier used is trisodium citrate a salt formed when citric acid is neutralised using sodium hydroxide Complete the equation below showing a structural formula for the trisodium citrate formed (1) sp 8

15 Phenylalanine and alanine are both amino acids

(a) Phenylalanine is an essential amino acid

(i) What is meant by an essential amino acid (1)

16

(ii) How many hydrogen atoms are present in a molecule of phenylalanine (1)

(b) Phenylalanine and alanine can react to form the dipeptide shown

Circle the peptide link in this molecule (1)

(c) Draw a structural formula for the other dipeptide that can be formed from phenylalanine and alanine (1)

16 Uncooked egg white is mainly composed of dissolved proteins During cooking processes the proteins become denatured as the protein chains unwind and the egg white solidifies

(a) Explain why the protein chains unwind (1)

(b)The temperature at which the protein becomes denatured is called the melting temperature The melting temperature of a protein can be determined using fluorescence In this technique the protein is mixed with a dye that gives out visible light when it attaches to hydrophobic parts of the protein molecule The hydrophobic parts of the structure are on the inside of the protein and the dye has no access to them unless the protein unwinds

(i) Ovalbumin is a protein found in egg white Part of the structure of unwound ovalbumin is shown below

Circle the part of the structure to which the hydrophobic dye is most likely to attach (1)

17

(ii) Another protein in egg white is conalbumin The temperature of a conalbumindye mixture is gradually increased The fluorescence is measured and a graph is produced

The melting temperature is the temperature at which the fluorescence is halfway between the highest and lowest fluorescence valuesDetermine the melting temperature in ordmC for this protein (1)

(c) Once cooked and eaten the digestive system breaks the protein chains into amino acids with the help of enzymes

(i) State the name of the digestion process where enzymes break down proteins into amino acids (1)

(ii)

(A) State how many amino acid molecules joined to form this section of protein (1)

(B) Draw the structure of one amino acid that would be produced when this section of the protein chain is broken down (1)

17 Peptide molecules can be classified according to the number of amino acid units joined by peptide bonds in the molecule

18

(a) Complete the table to identify the type of peptide with the following amino acid sequence

alanine-glycine-valine-proline-tyrosine-serine (1)

(b) Partial hydrolysis of another pentapeptide molecule gave a mixture of three smaller peptide molecules with the following amino acid sequences

leucine-glycine-valineisoleucine-leucineglycine-valine-serine

Write the amino acid sequence for the original pentapeptide molecule (1)

helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip(c) Some amino acids needed to form polypeptides cannot be produced in the human body

State the term used to describe amino acids that the body cannot make (1)

(d)Paper chromatography is often used to analyse the mixtures of amino acids produced when peptides are broken downOn a chromatogram the retention factor Rf for a substance can be a useful method of identifying the substance

The structure of the pentapeptide methionine enkephalin was investigatedA sample of the pentapeptide was completely hydrolysed into its constituent amino acids and this amino acid mixture was applied to a piece of chromatography paper and placed in a solventThe chromatogram obtained is shown below

19

(i) Suggest why only four spots were obtained on the chromatogram of the hydrolysed pentapeptide (1)

(ii) It is known that this amino acid mixture contains the amino acid methionine The Rf value for methionine in this solvent is 040Draw a circle around the spot on the chromatogram that corresponds to methionine (1)

(e) Over the last decade several families of extremely stable peptide molecules have been discovered where the peptide chain forms a ring

(i) A simple cyclic dipeptide is shown

Draw a structural formula for one of the amino acids that would be formed on complete hydrolysis of the above cyclic dipeptide (1)

(ii) Alpha-amanitin is a highly toxic cyclic peptide found in death cap mushrooms The lethal dose for humans is 100 mg per kg of body mass1middot0 g of death cap mushrooms contains 250 mg of alpha-amanitinCalculate the minimum mass of death cap mushrooms that would contain the lethal dose for a 75 kg adult (2)

18 Dishwasher tablets produce the bleach hydrogen peroxide H2O2 One action of this oxidising agent is to oxidise food

(a)(i) Suggest another action of the bleach produced by the dishwasher tablets (1)

20

(ii) Hydrogen peroxide decomposes to form water and oxygen

2H2O2(ℓ) rarr 2H2O(ℓ) + O2(g)

A dishwasher tablet produces 0middot051 g of hydrogen peroxide (mass of one mole = 34 g)

Calculate the volume of oxygen that would be produced when0middot051 g of hydrogen peroxide decomposesTake the volume of 1 mole of oxygen gas to be 24 litres(3)

(b)Enzymes are commonly added to dishwasher tablets These are used to break down proteins(i) The proteins are broken down into small water-soluble molecules

Name the small water-soluble molecules made when proteins are broken down completely (1)

(ii) The structure of a section of protein chain found in egg white is shown

(A)Name the functional group circled (1)(B)Draw a structural formula for one of the molecules that would be made

when this section of egg white protein chain is completely broken down (1)

(iii) As part of the program in the dishwasher the conditions in the dishwasher change so that the enzyme molecules no longer work because they change shape

21

(A) State the term used to describe the change in shape of enzyme molecules(1)

(B) Suggest a change in conditions which would cause the enzyme molecules to change shape (1)

(d) A bleach activator is frequently added to dishwasher tablets to speed up the bleaching reaction One common bleach activator is TAED TAED could be produced in a process which involves a number of stages

(i) The first stage in producing TAED is shown below

Suggest a name for this type of reaction (1)

(ii) The final stage in the process producing TAED is shown below

Draw a structural formula for TAED (1)

22

23 The Chemistry of Cooking

1 Vanillin and zingerone are flavour molecules

Which line in the table correctly compares the properties of vanillin and zingerone

23

2 Erythrose can be used in the production of a chewing gum that helps prevent tooth decay

Which of the following compounds will be the best solvent for erythrose

3 The following molecules give flavour to food Which of the following flavour molecules would be most likely to be retained in the food when the food is cooked in water

24

4 Cooking involves many chemical reactions Proteins fats oils and esters are some examples of compounds found in food A chemist suggested that cooking food could change compounds from being fat-soluble to water-soluble Use your knowledge of chemistry to comment on the accuracy of this statement(3)

25

24 The Oxidation of Food

1 Apples and bananas turn brown when cut or bruised The first step of the reaction causing

the browning is shown below

Which of the following terms correctly describes this reactionA ReductionB OxidationC DehydrationD Condensation

2 Which of the following reactions can be classified as reductionA CH3CH2OH rarr CH3COOHB CH3 CH(OH)CH3 rarr CH3COCH3C CH3CH2COCH3 rarr CH3CH2CH(OH)CH3D CH3CH2CHO rarr CH3CH2COOH

3 The dehydration of butan-2-ol can produce two isomeric alkenes but-1-ene andbut-2-ene Which of the following alkanols can similarly produce on dehydration a pair of isomeric alkenesA Propan-2-olB Pentan-3-olC Hexan-3-olD Heptan-4-ol

4 Which of the following compounds is an alkanone

26

5 Which of the following is an aldehyde

6 Which of the following compounds would react with sodium hydroxide solution to forma saltA CH3CHOB CH3COOHC CH3COCH3D CH3CH2OH

7 Which line in the table shows the correct functional group for each homologous series

8 Which of the following organic compounds is an isomer of hexanalA 2-MethylbutanalB 3-Methylpentan-2-oneC 22-Dimethylbutan-1-olD 3-Ethylpentanal

27

9 The name of this compound is

A methanolB methanalC methanoic acidD methanone

10 Which alcohol could be oxidised to a carboxylic acid

11 Which of the following structural formulae represents a tertiary alcohol

12 Compound X reacted with hot copper(II) oxide and the organic product did not give acolour change when heated with Fehlingrsquos solution Compound X could beA butan-1-olB butan-2-olC butanoneD butanoic acid

28

13 Which two isomers would each produce an acid when warmed with acidified potassiumdichromate solution

A 1 and 2B 2 and 3C 1 and 4D 3 and 4

14 After heating for several minutes as shown in the diagram the pH indicator solution turned red

Liquid Q could beA propanoneB paraffinC propan-1-olD propan-2-ol

29

15 Enzymes are involved in the browning of cut fruitOne reaction taking place is

Which of the following correctly describes the above reaction

A OxidationB ReductionC HydrolysisD Condensation

16 Which of the following statements is correct for ketones

A They are formed by oxidation of tertiary alcohols

B They contain the group

C They contain a carboxyl groupD They will not react with Fehlingrsquos solution

17 Carvone is a natural product that can be extracted from orange peel

Which line in the table correctly describes the reaction of carvone with bromine solution and with acidified potassium dichromate solution

30

18 Which of the following is an isomer of 22-dimethylpentan-1-ol

A CH3CH2CH2CH(CH3)CH2OHB (CH3)3CCH(CH3)CH2OHC CH3CH2CH2CH2CH2CH2CH2CH2OHD (CH3)2CHC(CH3)2CH2CH2OH

19 The equation for the reduction reaction taking place when ethanal reacts with Tollensrsquo reagent is

A Cu2+(aq) + eminus rarr Cu+(aq)

B Ag+(aq) + eminus rarr Ag(s)

C Cr2O72minus(aq) + 14H+(aq) + 6eminus rarr 2Cr3+(aq) + 7H2O(ℓ)

D MnO4minus(aq) + 8H+(aq) + 5eminus rarr Mn2+(aq) + 4H2O(ℓ)

20 The name of the compound with structure

isA 23-dimethylpentan-4-oneB 23-dimethylpentan-2-alC 34-dimethylpentan-2-oneD 34-dimethylpentan-2-al

21 What is the systematic name for the compound below

A 222-trimethylethanolB 22-dimethylpropan-1-olC 22-dimethylpropan-3-olD 22-dimethylpentan-1-ol

31

22 The structure of a molecule found in olive oil can be represented as shown

(a) Olive oil can be hydrolysed using sodium hydroxide solution to produce sodium salts of fatty acids Name the other product of this reaction (1)

(b) In what way does the structure of a fat molecule differ from that of an oil molecule (1)

(c) Over time open containers of olive oil develop a rancid flavour What substance is reacting with the oil to cause these unwanted changes to take place (1)

23 A student writes the following statement It is incorrect Explain the mistake in the studentrsquos reasoning (1)

Alcohols are alkaline because of their OH groups

24 Carbon compounds take part in a wide variety of chemical reactions (a)

Name this type of chemical reaction (1)

(b)

Draw a structural formula for C3H6O (1)

25 Alkanols can be oxidised to alkanoic acids

32

(a) Why can Step 1 be described as an oxidation reaction (1)

(b) Acidified potassium dichromate solution can be used to oxidise propanal in Step 2 What colour change would be observed in this reaction (1)

26 Amines can be produced by reacting ammonia with an aldehyde or a ketone This reaction an example of reductive amination occurs in two stages

Stage 1 Amination

Stage 2 Reduction

(a) Give another name for the type of reaction taking place in Stage 2

(b) Draw the structural formula for the amine produced when butanal undergoes reductive amination with ammonia

27 Using a cobalt catalyst alkenes react with a mixture of hydrogen and carbon monoxideThe products are two isomeric aldehydes Propene reacts with the mixture as shown

(a) What name is given to a mixture of hydrogen and carbon monoxide (1)

(b) Draw a structural formula for compound B (1)

(c) (i) What would be observed if compound A was gently heated with Tollensrsquo reagent

(1)(ii) How would the reaction mixture be heated (1)

33

(d) Aldehydes can also be formed by the reaction of some alcohols with copper(II) oxideName the type of alcohol that would react with copper(II) oxide to form an aldehyde (1)

28 Aldehydes and ketones can take part in a reaction sometimes known as an aldol condensation The simplest aldol reaction involves two molecules of ethanal

In the reaction the carbon atom next to the carbonyl functional group of one molecule forms a bond with the carbonyl carbon atom of the second molecule

(a) Draw a structural formula for the product formed when propanone is used instead of ethanal in this type of reaction (1)

(b) Name an aldehyde that would not take part in an aldol condensation (1)

(c) Apart from the structure of the reactants suggest what is unusual about applying the term ldquocondensationrdquo to this particular type of reaction (1)

29 Primary secondary and tertiary alkanols can be prepared by the reaction of carbonyl compounds with Grignard reagents

Step 1The Grignard reagent reacts with the carbonyl compound

Step 2The reaction of the product of Step 1 with dilute acid produces the alkanol

(a) Describe the difference between a primary a secondary and a tertiary alkanol

You may wish to include labelled structures in your answer (1)34

(b) Suggest a name for the type of reaction that takes place in Step 1 (1)

(c) The same Grignard reagent can be used to produce the alkanol below

Name the carbonyl compound used in this reaction (1)

30 Hairspray is a mixture of chemicals(a) A primary alcohol 2-methylpropan-1-ol is added to hairspray to help it dry quickly on the hair

Draw a structural formula for a secondary alcohol that is an isomer of2-methylpropan-1-ol (1)

(b) Triethanol amine and triisopropyl amine are bases used to neutralise acidic compounds in the hairspray to prevent damage to the hair

In terms of the intermolecular bonding present explain clearly why triethanol amine has a much higher boiling point than triisopropyl amine (2)

35

36

31 Chocolate contains various compounds(a) Many of the flavour and aroma molecules found in chocolate are aldehydes and

ketones Two examples are shown below

Phenylethanal can be easily oxidised but 13-diphenylpropan-2-one cannot(i) Name a chemical that could be used to distinguish between these two

compounds (1)

(ii) Name the type of organic compound formed when phenylethanal is oxidised (1)

(b) Glycerol monostearate is an emulsifier used in chocolate

(i) Why is glycerol monostearate added to chocolate (1)

(ii) Draw a structural formula for glycerol (1)

(c) Theobromine a compound present in chocolate can cause illness in dogs and cats To decide if treatment is necessary vets must calculate the mass of theobromine consumed 1middot0 g of chocolate contains 1middot4 mg of theobromine Calculate the mass in mg of theobromine in a 17 g biscuit of which 28 is chocolate Show your working clearly (2)

(d) The flavour and texture of chocolate comes from a blend of compoundsUsing your knowledge of chemistry describe how you could show that there are ionic compounds and covalent compounds present in chocolate (3)

37

32 Ethanol has many uses

(a) Ethanol is found at relatively low concentrations in wine

(i) Name the chemical reaction that produces ethanol in wine (1)

(ii) Standard ethanol solutions were used to produce a graph of density against

concentration of ethanol given as a percentage of alcohol by volume ( abv)

What is the concentration of ethanol in units of abv in a solution of density 0middot9818 g cmminus3 (1)

(b) Whisky contains a higher concentration of ethanol

(i) Before 1980 the concentration of alcohol in drinks was measured in terms of degrees proof The concentration of alcohol in two drinks is shown in the table below both as abv and degrees proof

38

A cask strength whisky has an alcohol concentration of 65 abv Calculate the alcohol concentration of this whisky in degrees proof (1)

(ii) A barrel containing 195 litres of cask strength whisky costs pound1300 The cask strength whisky is diluted with water to reduce the concentration of alcohol from 65 abv to 46 abv before it is bottled Calculate the cost of the cask strength whisky needed to produce a 0middot70 litre bottle Show your working clearly (2)

(iii) 5-Butyl-4-methyltetrahydrofuran-2-ol is a flavour compound found in whisky

stored in oak barrels

Write the systematic name for the compound shown below (1) 13 11

33 (a) One test for glucose involves Fehlingrsquos solutionCircle the part of the glucose molecule that reacts with Fehlingrsquos solution (1)

(b) In solution sugar molecules exist in an equilibrium in straight-chain and ring forms

To change from the straight-chain form to the ring form the oxygen of the hydroxyl on carbon number 5 joins to the carbonyl carbon This is shown below for glucose

39

Draw the structure of a ring form for fructose (1)

34 (a) During the free radical chain reaction small molecules join to form large chain molecules

One example of a small molecule used is

Name the functional group circled above (1)

(b)Alcohol wipes are used to finish the varnishing treatment Alcohol wipes contain the alcohol propan-2-olState why propan-2-ol can be described as a secondary alcohol (1)

35 A student was carrying out an investigation into alcohols aldehydes and ketones

(a)The student was given three alcohols labelled as A B and C These alcohols were all isomers with the formula C4H9OH

(i) Draw a structural formula for the secondary alcohol with the formula C4H9OH(1)

(ii) The student set up the following experiment

A Suggest why a water bath is an appropriate method of heating the reaction mixture (1)

B Describe the colour change that would have been observed with alcohols A and C (1)

40

C Alcohol B is not oxidised State the type of alcohol which cannot be oxidised by acidified dichromate solution (1)

(iii) The student set up a second experiment with alcohol A

Hot copper(II) oxide is an oxidising agentA When alcohol A (C4H9OH) is oxidised the product turns the pH paper

redSuggest a name for the product (1)

B Complete the ion-electron equation for the oxidation reaction

C4H9OH rarr C4H8O2 (1)

(b)The student found the following information about the boiling points of some aldehydes

41

(i) Name the aldehyde that has a boiling point of 119 degC (1)(ii) Predict the boiling point in degC of the following molecule (1)

(iii) Using information from the table describe one way in which differences in structure affect the boiling point of isomeric aldehydes (1)

(iv) State what would be observed when an aldehyde is gently heated with Tollensrsquo reagent (1)

(c) Ketones contain a carbonyl groupName the type of intermolecular interaction between ketone molecules (1)

42

25 Soaps Detergents and Emulsions

1 Soaps are produced by the following reaction

This reaction is an example ofA condensationB esterificationC hydrolysisD oxidation

2 Which of the following is the salt of a long-chain fatty acid

A FatB OilC SoapD Glycerol

3 Emulsifiers for use in food are commonly made by reacting edible oils with

A estersB glycerolC fatty acidsD amino acids

4 A fatty acid is a long chain carboxylic acid Examples of fatty acids are shown in the table below

43

(a) What is the systematic name for linolenic acid (1)(b) Stearic acid reacts with sodium hydroxide solution to form sodium stearate

(i) Name the type of reaction taking place when stearic acid reacts with sodium hydroxide (1)

(ii) Explain fully how sodium stearate acts to keep grease and non-polar substances suspended in water during cleaning (3)

5 Small children can find it difficult to swallow tablets or pills so ibuprofen is supplied as an ldquoinfant formulardquo emulsion(a) The emulsifier used is polysorbate 80 Its structure is shown below

Explain why this molecule acts as an emulsifier (2)

(b) The emulsion contains 2 g of ibuprofen in every 100 cm3 of emulsion The recommended dose for treating a 6 month old baby is 0middot050 g Calculate the volume in cm3 of ldquoinfant formulardquo needed to treat a 6 month old baby (1)

6 Occasionally seabirds can become contaminated with hydrocarbons from oil spills This causes problems for birds because their feathers lose their waterproofing making the birds susceptible to temperature changes and

44

affecting their buoyancy If the birds attempt to clean themselves to remove the oil they may swallow the hydrocarbons causing damage to their internal organsContaminated seabirds can be cleaned by rubbing vegetable oil into their feathers and feet before the birds are rinsed with diluted washing-up liquidUsing your knowledge of chemistry comment on the problems created for seabirds by oil spills and the actions taken to treat affected birds (3)

7 Dishwasher tablets contain chemicals which remove dirt from dishesDishwasher tablets include detergents These molecules act like soaps to allow mixing of fat-soluble dirt and water(a)During the cleaning process the detergent molecules combine with fat-

soluble dirtA simplified diagram of a detergent molecule is shown

Complete the diagram below to show how detergent molecules combine with fat-soluble dirt (1)

(b)State the term used to describe the non-polar hydrocarbon tail of a detergent molecule (1)

45

26 Fragrances1 Myrcene is a simple terpene

Terpenes contain at least one isoprene unit Which of the following shows a correctly highlighted isoprene unit

2 Limonene is one of the terpene molecules responsible for the flavour of lemons

How many isoprene units are used in the production of one limonene moleculeA 1B 2C 3D 4

46

3 The structure of caryophyllene which can be extracted from clove oil is

Which of the following would be the best solvent for extracting caryophylleneA HexaneB HexanalC HexanolD Hexanone

4 The structure of isoprene is

Limonene is a terpene molecule present in lemons

How many isoprene units are joined together in a limonene molecule

A 1B 2

47

C 3D 4

5 Essential oils are

A non-water soluble non-volatile compoundsB non-water soluble volatile compoundsC water soluble non-volatile compoundsD water soluble volatile compounds

6 Two typical compounds that are present in many perfumes are shown

(a) Why does geraniol evaporate more slowly than limonene (1)

(b) The structure of one of the first synthetic scents used in perfume is shown below

(i) Name the family of carbonyl compounds to which this synthetic scent belongs (1)

(ii) Complete the structure below to show the product formed when this scent is

oxidised (1)

(c) Traces of a liquid were discovered in a bottle believed to contain perfume belonging to Queen Hatshepsut ruler of Egypt over 3500 years ago

Perfumes were made by dissolving plant extracts containing pleasant smelling terpenes and esters in an edible oil A little ethanol and water may also have been addedUsing your knowledge of chemistry comment on the possible smell(s) when such a bottle is opened after being stored for thousands of years (3)

48

49

7 A team of chemists are developing a fragrance for use in a shower gel for men(a) To give the gel a fruity smell the chemists are considering adding an ester

They synthesise six isomeric esters Volunteers smell each ester and give it a rating out of one hundred depending on how fruity the smell is

(i) Name the ester with the fruit-smell rating of 92 (1)

(ii) Shown below are the structures of three more isomers

Arrange these esters in order of decreasing fruit-smell rating (1)

50

(b) To create a fragrance for men the compound civetone is added

Draw a structural formula for the alcohol that can be oxidised to form civetone (1)

(c) To make the shower gel produce a cold tingling sensation when applied to the skin menthol is added

Like terpenes menthol is formed from isoprene (2-methylbuta-13-diene)Circle an isoprene unit on the menthol structure above (1)

8 Many of the compounds in perfumes are molecules consisting of joined isoprene units

(a) State the name that is given to molecules consisting of joined isoprene units (1)

(b)Geraniol is one of the compounds found in perfume It has the following structural formula and systematic name

Linalool can also be present Its structural formula is shown

51

(i) State the systematic name for linalool (1)(ii) Explain why linalool can be classified as a tertiary alcohol (1)

9 The component molecules found in lavender oils are terpenes or terpenoids(a)A chiral carbon is a carbon atom attached to four different atoms or groups of

atomsAn example is shown below

A molecule of the terpenoid linalool has a chiral carbon Linalool has the following structure

Circle the chiral carbon atom in the linalool structure (1)

(b)Farnesene is a terpene consisting of three isoprene units (2-methylbuta-13-diene) joined togetherWrite the molecular formula of farnesene (1)

52

27 Skin Care

1 Which of the following is not a step in a free radical chain reaction

A ActivationB InitiationC PropagationD Termination

2 Fluorine reacts with methane via a free radical chain reaction Some steps in the chain reaction are shown in the table below

Complete the table by(a) inserting the missing name for the first step (1)

(b) showing another possible termination reaction in the final row of the table (1)

3 Suncreams contain antioxidantsThe antioxidant compound A can prevent damage to skin by reacting with free

radicalssuch as NO2bull

53

Why can compound A be described as a free radical scavenger in the reaction shown above

4 Hydrogen and chlorine gases are used in an experiment to demonstrate a free radical reaction A plastic bottle is wrapped with black tape leaving a ldquowindowrdquo on one sideThe bottle is filled with a mixture of hydrogen and chlorine When bright light shines on the bottle there is an explosion

A free radical chain reaction is initiated when light energy causes chlorine radicals to form as shown below

(a) Complete the equations below showing possible propagation and termination steps

(2)

54

(b) Why is the plastic bottle used in the experiment wrapped in black tape (1)

5 Chloramines can be removed from water using ultraviolet light treatment

One step in the process is the formation of free radicals

(a)State what is meant by the term free radical (1)

(b)Another step in the process is shown below

State the name for this type of step in a free radical reaction (1)

6 Modern shellac nail varnishes are more durable and so last longer than traditional nail polish

The shellac nail varnish is applied in thin layers to the nails and then the fingers are placed under a UV lamp

(a) The Skin Care Foundation has recommended that a sun-block is applied to the fingers and hand before using the lampSuggest why the Skin Care Foundation makes this recommendation (1)

(b) A free radical chain reaction takes place and the varnish hardens (i) State what is meant by the term free radical (1)

(ii) The shellac nail varnish contains a mixture of ingredients that take part in the free radical chain reactionOne of the steps in the free radical chain reaction is

55

State the term used to describe this type of step in a free radical chain reaction(1)

7 Skin care products contain a mixture of polar covalent non-polar covalent and ionic compounds The compounds need to stay mixed within the product Skin care products also need to spread easily and remain on the skin for a period of time as well as provide physical and chemical protection from the sun In order to do this skin care products contain a range of chemicals including water fats and oils antioxidants minerals and sun blockUsing your knowledge of chemistry explain the role of different chemicals in skin care products (3)

General Questions

1 A mixture of carbon monoxide and hydrogen can be converted into water and a mixture of hydrocarbons

nCO + (2n + 1)H2 rarr nH2O + hydrocarbons

What is the general formula for the hydrocarbons producedA CnH2nndash2B CnH2nC CnH2n+1D CnH2n+2

2 Butadiene is the first member of a homologous series of hydrocarbons called dienesWhat is the general formula for this seriesA CnHn+2B CnHn+3C CnH2nD CnH2nndash2

3 Which of the following statements about methanol is falseA It can be made from synthesis gasB It can be dehydrated to form an alkeneC It can be oxidised to give a carboxylic acidD It reacts with acidified potassium dichromate solution

56

4

Which line in the table correctly describes reactions X and Y

5

Which line in the table correctly describes reactions X and Y

6 Which of the following fuels when burned would make no contribution to globalwarming

57

A HydrogenB Natural gasC PetrolD Coal

7 Which of the following hydrocarbons always gives the same product when one of itshydrogen atoms is replaced by a chlorine atomA HexaneB Hex-1-eneC CyclohexaneD Cyclohexene

8 Which of the following compounds does not have isomeric structuresA C2HCl3B C2H4Cl2C PropeneD Propan-1-ol

9 What organic compound is produced by the dehydration of ethanol A EthaneB EtheneC EthanalD Ethanoic acid

10

The above equation representsA hydrationB hydrogenationC condensationD hydrolysis

11

Which of the following compounds is an isomer of the structure shown aboveA ButanalB ButanoneC Butan-1-olD Butanoic acid

58

12 A compound with molecular formula C6H12O2 could beA hexanalB hexan-2-olC hexan-2-oneD hexanoic acid

13 Propan-2-ol can be prepared from propane as follows

Which line in the table correctly describes the types of reaction taking place at Steps 1 and 2

14 Which of the following compounds would be the most water soluble

15 Cyanohydrin compounds can be made from carbonyl compounds by reacting the carbonyl compound with hydrogen cyanide (HCN)

59

Which carbonyl compound would react with hydrogen cyanide (HCN) to form the following compound

16 Ethyne is the first member of the homologous series called the alkynes

Ethyne can undergo addition reactions as shown in the flow diagram

(a) Compound 2 is an isomer of 12-dichloroethaneDraw a structural formula for compound 2 (1)

(b) Reagents A B and C are three different diatomic gasesUsing information in the flow diagram identify reagents A B and C (1)

60

Reagent Gas

A

B

C

17 In 1865 the German chemist Kekuleacute proposed a ring structure for benzene This structure was based on alternating single and double bonds

(a) (i) Describe a chemical test that would indicate that the above chemical structure for benzene is incorrect (1)

(ii) Briefly describe the correct structure for benzene (1)

(b) Benzene can be formed from cyclohexaneC6H12 rarr C6H6 + 3H2

What name is given to this type of reaction (1)18 Infra-red spectroscopy is a technique that can be used to identify the bonds that

arepresent in a molecule Different bonds absorb infra-red radiation of different wavenumbers This is due to differences in the bond lsquostretchrsquo These absorptions are recorded in a spectrumA spectrum for propan-1-ol is shown

61

The correlation table on page 13 of the data booklet shows the wavenumber ranges for the absorptions due to different bonds

(a) Use the correlation table to identify the bonds responsible for the two absorptions x and y that are circled in the propan-1-ol spectrum (1)

(b) Propan-1-ol reacts with ethanoic acid(i) What name is given to this type of reaction (1)(ii) Draw a spectrum that could be obtained for the organic product of this

reaction (1)

19 Paracetamol is a widely used painkiller

(a) Write the molecular formula for paracetamol (1)

(b) One antidote for paracetamol overdose is methionine

62

To what family of organic compounds does methionine belong (1)

(c) The concentration of paracetamol in a solution can be determined by measuring how much UV radiation it absorbs

The graph shows how the absorbance of a sample containing 0middot040 g l ndash1 paracetamol varies with wavelength

The quantity of UV radiation of wavelength 245 nm absorbed is directly proportional to the concentration of paracetamolThe absorbance of a second sample of paracetamol solution measured at 245 nm was 0middot90 What is the concentration in g l ndash1 of this second paracetamol solution (1)

20 Many carbon compounds containing oxygen are very flammableThe table shows information about two families of isomersThe lowest temperature at which a compound will ignite is called its flash point

(a) A compound with the molecular formula C6H14O has a boiling point of 158 degC63

Draw a structural formula for this compound (1)

(b) For a family of isomers in the table write a general statement linking the flash points of the compounds to their structures (1)

21 Hydrogels are used in disposable nappies They are fine powders that can absorb up to 500 times their own weight in waterA hydrogel is a very long molecule with carboxyl groups at regular intervals along its length A short section of a hydrogel molecule is shown below

Hydrogels are extremely good at soaking up water because the water molecules are strongly attracted to them

Using your knowledge of chemistry comment on how suitable hydrogels would be for absorbing liquids or solutions spilled in a chemistry lab (1)

64

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

11 The rate of hydrolysis of protein using an enzyme was studied at different temperatures Which of the following graphs would be obtained

12 The rate of hydrolysis of protein using an enzyme was studied at different temperaturesWhich of the following graphs would be obtained

14

13 Polymers can be classified as natural or synthetic(a) Keratin a natural polymer is a protein found in hair

The hydrolysis of keratin produces different monomers of the type shown

(i) What name is given to monomers like glycine alanine and cysteine (1)(ii) What is meant by a hydrolysis reaction (1)

(b) Dacron a synthetic polymer is used in heart surgery A section of the polymer is shown

What name is given to the link made by the shaded group of atoms in this section of the polymer (1)

14 Chemists have developed cheeses specifically for use in cheeseburgers(a) When ordinary cheddar cheese is grilled the shapes of the protein molecules

change and the proteins and fats separate leaving a chewy solid and an oily liquidWhat name is given to the change in protein structure which occurs when ordinary cheddar is grilled (1)

(b) To make cheese for burgers grated cheddar cheese soluble milk proteins and some water are mixed and heated to no more than 82 degC As the cheese begins to melt an emulsifying agent is added and the mixture is stirred

15

(i) Why would a water bath be used to heat the mixture (1)(ii) A section of the structure of a soluble milk protein is shown below

Draw a structural formula for any one of the amino acids formed when this section of

protein is hydrolysed (1)

(iii) The emulsifier used is trisodium citrate a salt formed when citric acid is neutralised using sodium hydroxide Complete the equation below showing a structural formula for the trisodium citrate formed (1) sp 8

15 Phenylalanine and alanine are both amino acids

(a) Phenylalanine is an essential amino acid

(i) What is meant by an essential amino acid (1)

16

(ii) How many hydrogen atoms are present in a molecule of phenylalanine (1)

(b) Phenylalanine and alanine can react to form the dipeptide shown

Circle the peptide link in this molecule (1)

(c) Draw a structural formula for the other dipeptide that can be formed from phenylalanine and alanine (1)

16 Uncooked egg white is mainly composed of dissolved proteins During cooking processes the proteins become denatured as the protein chains unwind and the egg white solidifies

(a) Explain why the protein chains unwind (1)

(b)The temperature at which the protein becomes denatured is called the melting temperature The melting temperature of a protein can be determined using fluorescence In this technique the protein is mixed with a dye that gives out visible light when it attaches to hydrophobic parts of the protein molecule The hydrophobic parts of the structure are on the inside of the protein and the dye has no access to them unless the protein unwinds

(i) Ovalbumin is a protein found in egg white Part of the structure of unwound ovalbumin is shown below

Circle the part of the structure to which the hydrophobic dye is most likely to attach (1)

17

(ii) Another protein in egg white is conalbumin The temperature of a conalbumindye mixture is gradually increased The fluorescence is measured and a graph is produced

The melting temperature is the temperature at which the fluorescence is halfway between the highest and lowest fluorescence valuesDetermine the melting temperature in ordmC for this protein (1)

(c) Once cooked and eaten the digestive system breaks the protein chains into amino acids with the help of enzymes

(i) State the name of the digestion process where enzymes break down proteins into amino acids (1)

(ii)

(A) State how many amino acid molecules joined to form this section of protein (1)

(B) Draw the structure of one amino acid that would be produced when this section of the protein chain is broken down (1)

17 Peptide molecules can be classified according to the number of amino acid units joined by peptide bonds in the molecule

18

(a) Complete the table to identify the type of peptide with the following amino acid sequence

alanine-glycine-valine-proline-tyrosine-serine (1)

(b) Partial hydrolysis of another pentapeptide molecule gave a mixture of three smaller peptide molecules with the following amino acid sequences

leucine-glycine-valineisoleucine-leucineglycine-valine-serine

Write the amino acid sequence for the original pentapeptide molecule (1)

helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip(c) Some amino acids needed to form polypeptides cannot be produced in the human body

State the term used to describe amino acids that the body cannot make (1)

(d)Paper chromatography is often used to analyse the mixtures of amino acids produced when peptides are broken downOn a chromatogram the retention factor Rf for a substance can be a useful method of identifying the substance

The structure of the pentapeptide methionine enkephalin was investigatedA sample of the pentapeptide was completely hydrolysed into its constituent amino acids and this amino acid mixture was applied to a piece of chromatography paper and placed in a solventThe chromatogram obtained is shown below

19

(i) Suggest why only four spots were obtained on the chromatogram of the hydrolysed pentapeptide (1)

(ii) It is known that this amino acid mixture contains the amino acid methionine The Rf value for methionine in this solvent is 040Draw a circle around the spot on the chromatogram that corresponds to methionine (1)

(e) Over the last decade several families of extremely stable peptide molecules have been discovered where the peptide chain forms a ring

(i) A simple cyclic dipeptide is shown

Draw a structural formula for one of the amino acids that would be formed on complete hydrolysis of the above cyclic dipeptide (1)

(ii) Alpha-amanitin is a highly toxic cyclic peptide found in death cap mushrooms The lethal dose for humans is 100 mg per kg of body mass1middot0 g of death cap mushrooms contains 250 mg of alpha-amanitinCalculate the minimum mass of death cap mushrooms that would contain the lethal dose for a 75 kg adult (2)

18 Dishwasher tablets produce the bleach hydrogen peroxide H2O2 One action of this oxidising agent is to oxidise food

(a)(i) Suggest another action of the bleach produced by the dishwasher tablets (1)

20

(ii) Hydrogen peroxide decomposes to form water and oxygen

2H2O2(ℓ) rarr 2H2O(ℓ) + O2(g)

A dishwasher tablet produces 0middot051 g of hydrogen peroxide (mass of one mole = 34 g)

Calculate the volume of oxygen that would be produced when0middot051 g of hydrogen peroxide decomposesTake the volume of 1 mole of oxygen gas to be 24 litres(3)

(b)Enzymes are commonly added to dishwasher tablets These are used to break down proteins(i) The proteins are broken down into small water-soluble molecules

Name the small water-soluble molecules made when proteins are broken down completely (1)

(ii) The structure of a section of protein chain found in egg white is shown

(A)Name the functional group circled (1)(B)Draw a structural formula for one of the molecules that would be made

when this section of egg white protein chain is completely broken down (1)

(iii) As part of the program in the dishwasher the conditions in the dishwasher change so that the enzyme molecules no longer work because they change shape

21

(A) State the term used to describe the change in shape of enzyme molecules(1)

(B) Suggest a change in conditions which would cause the enzyme molecules to change shape (1)

(d) A bleach activator is frequently added to dishwasher tablets to speed up the bleaching reaction One common bleach activator is TAED TAED could be produced in a process which involves a number of stages

(i) The first stage in producing TAED is shown below

Suggest a name for this type of reaction (1)

(ii) The final stage in the process producing TAED is shown below

Draw a structural formula for TAED (1)

22

23 The Chemistry of Cooking

1 Vanillin and zingerone are flavour molecules

Which line in the table correctly compares the properties of vanillin and zingerone

23

2 Erythrose can be used in the production of a chewing gum that helps prevent tooth decay

Which of the following compounds will be the best solvent for erythrose

3 The following molecules give flavour to food Which of the following flavour molecules would be most likely to be retained in the food when the food is cooked in water

24

4 Cooking involves many chemical reactions Proteins fats oils and esters are some examples of compounds found in food A chemist suggested that cooking food could change compounds from being fat-soluble to water-soluble Use your knowledge of chemistry to comment on the accuracy of this statement(3)

25

24 The Oxidation of Food

1 Apples and bananas turn brown when cut or bruised The first step of the reaction causing

the browning is shown below

Which of the following terms correctly describes this reactionA ReductionB OxidationC DehydrationD Condensation

2 Which of the following reactions can be classified as reductionA CH3CH2OH rarr CH3COOHB CH3 CH(OH)CH3 rarr CH3COCH3C CH3CH2COCH3 rarr CH3CH2CH(OH)CH3D CH3CH2CHO rarr CH3CH2COOH

3 The dehydration of butan-2-ol can produce two isomeric alkenes but-1-ene andbut-2-ene Which of the following alkanols can similarly produce on dehydration a pair of isomeric alkenesA Propan-2-olB Pentan-3-olC Hexan-3-olD Heptan-4-ol

4 Which of the following compounds is an alkanone

26

5 Which of the following is an aldehyde

6 Which of the following compounds would react with sodium hydroxide solution to forma saltA CH3CHOB CH3COOHC CH3COCH3D CH3CH2OH

7 Which line in the table shows the correct functional group for each homologous series

8 Which of the following organic compounds is an isomer of hexanalA 2-MethylbutanalB 3-Methylpentan-2-oneC 22-Dimethylbutan-1-olD 3-Ethylpentanal

27

9 The name of this compound is

A methanolB methanalC methanoic acidD methanone

10 Which alcohol could be oxidised to a carboxylic acid

11 Which of the following structural formulae represents a tertiary alcohol

12 Compound X reacted with hot copper(II) oxide and the organic product did not give acolour change when heated with Fehlingrsquos solution Compound X could beA butan-1-olB butan-2-olC butanoneD butanoic acid

28

13 Which two isomers would each produce an acid when warmed with acidified potassiumdichromate solution

A 1 and 2B 2 and 3C 1 and 4D 3 and 4

14 After heating for several minutes as shown in the diagram the pH indicator solution turned red

Liquid Q could beA propanoneB paraffinC propan-1-olD propan-2-ol

29

15 Enzymes are involved in the browning of cut fruitOne reaction taking place is

Which of the following correctly describes the above reaction

A OxidationB ReductionC HydrolysisD Condensation

16 Which of the following statements is correct for ketones

A They are formed by oxidation of tertiary alcohols

B They contain the group

C They contain a carboxyl groupD They will not react with Fehlingrsquos solution

17 Carvone is a natural product that can be extracted from orange peel

Which line in the table correctly describes the reaction of carvone with bromine solution and with acidified potassium dichromate solution

30

18 Which of the following is an isomer of 22-dimethylpentan-1-ol

A CH3CH2CH2CH(CH3)CH2OHB (CH3)3CCH(CH3)CH2OHC CH3CH2CH2CH2CH2CH2CH2CH2OHD (CH3)2CHC(CH3)2CH2CH2OH

19 The equation for the reduction reaction taking place when ethanal reacts with Tollensrsquo reagent is

A Cu2+(aq) + eminus rarr Cu+(aq)

B Ag+(aq) + eminus rarr Ag(s)

C Cr2O72minus(aq) + 14H+(aq) + 6eminus rarr 2Cr3+(aq) + 7H2O(ℓ)

D MnO4minus(aq) + 8H+(aq) + 5eminus rarr Mn2+(aq) + 4H2O(ℓ)

20 The name of the compound with structure

isA 23-dimethylpentan-4-oneB 23-dimethylpentan-2-alC 34-dimethylpentan-2-oneD 34-dimethylpentan-2-al

21 What is the systematic name for the compound below

A 222-trimethylethanolB 22-dimethylpropan-1-olC 22-dimethylpropan-3-olD 22-dimethylpentan-1-ol

31

22 The structure of a molecule found in olive oil can be represented as shown

(a) Olive oil can be hydrolysed using sodium hydroxide solution to produce sodium salts of fatty acids Name the other product of this reaction (1)

(b) In what way does the structure of a fat molecule differ from that of an oil molecule (1)

(c) Over time open containers of olive oil develop a rancid flavour What substance is reacting with the oil to cause these unwanted changes to take place (1)

23 A student writes the following statement It is incorrect Explain the mistake in the studentrsquos reasoning (1)

Alcohols are alkaline because of their OH groups

24 Carbon compounds take part in a wide variety of chemical reactions (a)

Name this type of chemical reaction (1)

(b)

Draw a structural formula for C3H6O (1)

25 Alkanols can be oxidised to alkanoic acids

32

(a) Why can Step 1 be described as an oxidation reaction (1)

(b) Acidified potassium dichromate solution can be used to oxidise propanal in Step 2 What colour change would be observed in this reaction (1)

26 Amines can be produced by reacting ammonia with an aldehyde or a ketone This reaction an example of reductive amination occurs in two stages

Stage 1 Amination

Stage 2 Reduction

(a) Give another name for the type of reaction taking place in Stage 2

(b) Draw the structural formula for the amine produced when butanal undergoes reductive amination with ammonia

27 Using a cobalt catalyst alkenes react with a mixture of hydrogen and carbon monoxideThe products are two isomeric aldehydes Propene reacts with the mixture as shown

(a) What name is given to a mixture of hydrogen and carbon monoxide (1)

(b) Draw a structural formula for compound B (1)

(c) (i) What would be observed if compound A was gently heated with Tollensrsquo reagent

(1)(ii) How would the reaction mixture be heated (1)

33

(d) Aldehydes can also be formed by the reaction of some alcohols with copper(II) oxideName the type of alcohol that would react with copper(II) oxide to form an aldehyde (1)

28 Aldehydes and ketones can take part in a reaction sometimes known as an aldol condensation The simplest aldol reaction involves two molecules of ethanal

In the reaction the carbon atom next to the carbonyl functional group of one molecule forms a bond with the carbonyl carbon atom of the second molecule

(a) Draw a structural formula for the product formed when propanone is used instead of ethanal in this type of reaction (1)

(b) Name an aldehyde that would not take part in an aldol condensation (1)

(c) Apart from the structure of the reactants suggest what is unusual about applying the term ldquocondensationrdquo to this particular type of reaction (1)

29 Primary secondary and tertiary alkanols can be prepared by the reaction of carbonyl compounds with Grignard reagents

Step 1The Grignard reagent reacts with the carbonyl compound

Step 2The reaction of the product of Step 1 with dilute acid produces the alkanol

(a) Describe the difference between a primary a secondary and a tertiary alkanol

You may wish to include labelled structures in your answer (1)34

(b) Suggest a name for the type of reaction that takes place in Step 1 (1)

(c) The same Grignard reagent can be used to produce the alkanol below

Name the carbonyl compound used in this reaction (1)

30 Hairspray is a mixture of chemicals(a) A primary alcohol 2-methylpropan-1-ol is added to hairspray to help it dry quickly on the hair

Draw a structural formula for a secondary alcohol that is an isomer of2-methylpropan-1-ol (1)

(b) Triethanol amine and triisopropyl amine are bases used to neutralise acidic compounds in the hairspray to prevent damage to the hair

In terms of the intermolecular bonding present explain clearly why triethanol amine has a much higher boiling point than triisopropyl amine (2)

35

36

31 Chocolate contains various compounds(a) Many of the flavour and aroma molecules found in chocolate are aldehydes and

ketones Two examples are shown below

Phenylethanal can be easily oxidised but 13-diphenylpropan-2-one cannot(i) Name a chemical that could be used to distinguish between these two

compounds (1)

(ii) Name the type of organic compound formed when phenylethanal is oxidised (1)

(b) Glycerol monostearate is an emulsifier used in chocolate

(i) Why is glycerol monostearate added to chocolate (1)

(ii) Draw a structural formula for glycerol (1)

(c) Theobromine a compound present in chocolate can cause illness in dogs and cats To decide if treatment is necessary vets must calculate the mass of theobromine consumed 1middot0 g of chocolate contains 1middot4 mg of theobromine Calculate the mass in mg of theobromine in a 17 g biscuit of which 28 is chocolate Show your working clearly (2)

(d) The flavour and texture of chocolate comes from a blend of compoundsUsing your knowledge of chemistry describe how you could show that there are ionic compounds and covalent compounds present in chocolate (3)

37

32 Ethanol has many uses

(a) Ethanol is found at relatively low concentrations in wine

(i) Name the chemical reaction that produces ethanol in wine (1)

(ii) Standard ethanol solutions were used to produce a graph of density against

concentration of ethanol given as a percentage of alcohol by volume ( abv)

What is the concentration of ethanol in units of abv in a solution of density 0middot9818 g cmminus3 (1)

(b) Whisky contains a higher concentration of ethanol

(i) Before 1980 the concentration of alcohol in drinks was measured in terms of degrees proof The concentration of alcohol in two drinks is shown in the table below both as abv and degrees proof

38

A cask strength whisky has an alcohol concentration of 65 abv Calculate the alcohol concentration of this whisky in degrees proof (1)

(ii) A barrel containing 195 litres of cask strength whisky costs pound1300 The cask strength whisky is diluted with water to reduce the concentration of alcohol from 65 abv to 46 abv before it is bottled Calculate the cost of the cask strength whisky needed to produce a 0middot70 litre bottle Show your working clearly (2)

(iii) 5-Butyl-4-methyltetrahydrofuran-2-ol is a flavour compound found in whisky

stored in oak barrels

Write the systematic name for the compound shown below (1) 13 11

33 (a) One test for glucose involves Fehlingrsquos solutionCircle the part of the glucose molecule that reacts with Fehlingrsquos solution (1)

(b) In solution sugar molecules exist in an equilibrium in straight-chain and ring forms

To change from the straight-chain form to the ring form the oxygen of the hydroxyl on carbon number 5 joins to the carbonyl carbon This is shown below for glucose

39

Draw the structure of a ring form for fructose (1)

34 (a) During the free radical chain reaction small molecules join to form large chain molecules

One example of a small molecule used is

Name the functional group circled above (1)

(b)Alcohol wipes are used to finish the varnishing treatment Alcohol wipes contain the alcohol propan-2-olState why propan-2-ol can be described as a secondary alcohol (1)

35 A student was carrying out an investigation into alcohols aldehydes and ketones

(a)The student was given three alcohols labelled as A B and C These alcohols were all isomers with the formula C4H9OH

(i) Draw a structural formula for the secondary alcohol with the formula C4H9OH(1)

(ii) The student set up the following experiment

A Suggest why a water bath is an appropriate method of heating the reaction mixture (1)

B Describe the colour change that would have been observed with alcohols A and C (1)

40

C Alcohol B is not oxidised State the type of alcohol which cannot be oxidised by acidified dichromate solution (1)

(iii) The student set up a second experiment with alcohol A

Hot copper(II) oxide is an oxidising agentA When alcohol A (C4H9OH) is oxidised the product turns the pH paper

redSuggest a name for the product (1)

B Complete the ion-electron equation for the oxidation reaction

C4H9OH rarr C4H8O2 (1)

(b)The student found the following information about the boiling points of some aldehydes

41

(i) Name the aldehyde that has a boiling point of 119 degC (1)(ii) Predict the boiling point in degC of the following molecule (1)

(iii) Using information from the table describe one way in which differences in structure affect the boiling point of isomeric aldehydes (1)

(iv) State what would be observed when an aldehyde is gently heated with Tollensrsquo reagent (1)

(c) Ketones contain a carbonyl groupName the type of intermolecular interaction between ketone molecules (1)

42

25 Soaps Detergents and Emulsions

1 Soaps are produced by the following reaction

This reaction is an example ofA condensationB esterificationC hydrolysisD oxidation

2 Which of the following is the salt of a long-chain fatty acid

A FatB OilC SoapD Glycerol

3 Emulsifiers for use in food are commonly made by reacting edible oils with

A estersB glycerolC fatty acidsD amino acids

4 A fatty acid is a long chain carboxylic acid Examples of fatty acids are shown in the table below

43

(a) What is the systematic name for linolenic acid (1)(b) Stearic acid reacts with sodium hydroxide solution to form sodium stearate

(i) Name the type of reaction taking place when stearic acid reacts with sodium hydroxide (1)

(ii) Explain fully how sodium stearate acts to keep grease and non-polar substances suspended in water during cleaning (3)

5 Small children can find it difficult to swallow tablets or pills so ibuprofen is supplied as an ldquoinfant formulardquo emulsion(a) The emulsifier used is polysorbate 80 Its structure is shown below

Explain why this molecule acts as an emulsifier (2)

(b) The emulsion contains 2 g of ibuprofen in every 100 cm3 of emulsion The recommended dose for treating a 6 month old baby is 0middot050 g Calculate the volume in cm3 of ldquoinfant formulardquo needed to treat a 6 month old baby (1)

6 Occasionally seabirds can become contaminated with hydrocarbons from oil spills This causes problems for birds because their feathers lose their waterproofing making the birds susceptible to temperature changes and

44

affecting their buoyancy If the birds attempt to clean themselves to remove the oil they may swallow the hydrocarbons causing damage to their internal organsContaminated seabirds can be cleaned by rubbing vegetable oil into their feathers and feet before the birds are rinsed with diluted washing-up liquidUsing your knowledge of chemistry comment on the problems created for seabirds by oil spills and the actions taken to treat affected birds (3)

7 Dishwasher tablets contain chemicals which remove dirt from dishesDishwasher tablets include detergents These molecules act like soaps to allow mixing of fat-soluble dirt and water(a)During the cleaning process the detergent molecules combine with fat-

soluble dirtA simplified diagram of a detergent molecule is shown

Complete the diagram below to show how detergent molecules combine with fat-soluble dirt (1)

(b)State the term used to describe the non-polar hydrocarbon tail of a detergent molecule (1)

45

26 Fragrances1 Myrcene is a simple terpene

Terpenes contain at least one isoprene unit Which of the following shows a correctly highlighted isoprene unit

2 Limonene is one of the terpene molecules responsible for the flavour of lemons

How many isoprene units are used in the production of one limonene moleculeA 1B 2C 3D 4

46

3 The structure of caryophyllene which can be extracted from clove oil is

Which of the following would be the best solvent for extracting caryophylleneA HexaneB HexanalC HexanolD Hexanone

4 The structure of isoprene is

Limonene is a terpene molecule present in lemons

How many isoprene units are joined together in a limonene molecule

A 1B 2

47

C 3D 4

5 Essential oils are

A non-water soluble non-volatile compoundsB non-water soluble volatile compoundsC water soluble non-volatile compoundsD water soluble volatile compounds

6 Two typical compounds that are present in many perfumes are shown

(a) Why does geraniol evaporate more slowly than limonene (1)

(b) The structure of one of the first synthetic scents used in perfume is shown below

(i) Name the family of carbonyl compounds to which this synthetic scent belongs (1)

(ii) Complete the structure below to show the product formed when this scent is

oxidised (1)

(c) Traces of a liquid were discovered in a bottle believed to contain perfume belonging to Queen Hatshepsut ruler of Egypt over 3500 years ago

Perfumes were made by dissolving plant extracts containing pleasant smelling terpenes and esters in an edible oil A little ethanol and water may also have been addedUsing your knowledge of chemistry comment on the possible smell(s) when such a bottle is opened after being stored for thousands of years (3)

48

49

7 A team of chemists are developing a fragrance for use in a shower gel for men(a) To give the gel a fruity smell the chemists are considering adding an ester

They synthesise six isomeric esters Volunteers smell each ester and give it a rating out of one hundred depending on how fruity the smell is

(i) Name the ester with the fruit-smell rating of 92 (1)

(ii) Shown below are the structures of three more isomers

Arrange these esters in order of decreasing fruit-smell rating (1)

50

(b) To create a fragrance for men the compound civetone is added

Draw a structural formula for the alcohol that can be oxidised to form civetone (1)

(c) To make the shower gel produce a cold tingling sensation when applied to the skin menthol is added

Like terpenes menthol is formed from isoprene (2-methylbuta-13-diene)Circle an isoprene unit on the menthol structure above (1)

8 Many of the compounds in perfumes are molecules consisting of joined isoprene units

(a) State the name that is given to molecules consisting of joined isoprene units (1)

(b)Geraniol is one of the compounds found in perfume It has the following structural formula and systematic name

Linalool can also be present Its structural formula is shown

51

(i) State the systematic name for linalool (1)(ii) Explain why linalool can be classified as a tertiary alcohol (1)

9 The component molecules found in lavender oils are terpenes or terpenoids(a)A chiral carbon is a carbon atom attached to four different atoms or groups of

atomsAn example is shown below

A molecule of the terpenoid linalool has a chiral carbon Linalool has the following structure

Circle the chiral carbon atom in the linalool structure (1)

(b)Farnesene is a terpene consisting of three isoprene units (2-methylbuta-13-diene) joined togetherWrite the molecular formula of farnesene (1)

52

27 Skin Care

1 Which of the following is not a step in a free radical chain reaction

A ActivationB InitiationC PropagationD Termination

2 Fluorine reacts with methane via a free radical chain reaction Some steps in the chain reaction are shown in the table below

Complete the table by(a) inserting the missing name for the first step (1)

(b) showing another possible termination reaction in the final row of the table (1)

3 Suncreams contain antioxidantsThe antioxidant compound A can prevent damage to skin by reacting with free

radicalssuch as NO2bull

53

Why can compound A be described as a free radical scavenger in the reaction shown above

4 Hydrogen and chlorine gases are used in an experiment to demonstrate a free radical reaction A plastic bottle is wrapped with black tape leaving a ldquowindowrdquo on one sideThe bottle is filled with a mixture of hydrogen and chlorine When bright light shines on the bottle there is an explosion

A free radical chain reaction is initiated when light energy causes chlorine radicals to form as shown below

(a) Complete the equations below showing possible propagation and termination steps

(2)

54

(b) Why is the plastic bottle used in the experiment wrapped in black tape (1)

5 Chloramines can be removed from water using ultraviolet light treatment

One step in the process is the formation of free radicals

(a)State what is meant by the term free radical (1)

(b)Another step in the process is shown below

State the name for this type of step in a free radical reaction (1)

6 Modern shellac nail varnishes are more durable and so last longer than traditional nail polish

The shellac nail varnish is applied in thin layers to the nails and then the fingers are placed under a UV lamp

(a) The Skin Care Foundation has recommended that a sun-block is applied to the fingers and hand before using the lampSuggest why the Skin Care Foundation makes this recommendation (1)

(b) A free radical chain reaction takes place and the varnish hardens (i) State what is meant by the term free radical (1)

(ii) The shellac nail varnish contains a mixture of ingredients that take part in the free radical chain reactionOne of the steps in the free radical chain reaction is

55

State the term used to describe this type of step in a free radical chain reaction(1)

7 Skin care products contain a mixture of polar covalent non-polar covalent and ionic compounds The compounds need to stay mixed within the product Skin care products also need to spread easily and remain on the skin for a period of time as well as provide physical and chemical protection from the sun In order to do this skin care products contain a range of chemicals including water fats and oils antioxidants minerals and sun blockUsing your knowledge of chemistry explain the role of different chemicals in skin care products (3)

General Questions

1 A mixture of carbon monoxide and hydrogen can be converted into water and a mixture of hydrocarbons

nCO + (2n + 1)H2 rarr nH2O + hydrocarbons

What is the general formula for the hydrocarbons producedA CnH2nndash2B CnH2nC CnH2n+1D CnH2n+2

2 Butadiene is the first member of a homologous series of hydrocarbons called dienesWhat is the general formula for this seriesA CnHn+2B CnHn+3C CnH2nD CnH2nndash2

3 Which of the following statements about methanol is falseA It can be made from synthesis gasB It can be dehydrated to form an alkeneC It can be oxidised to give a carboxylic acidD It reacts with acidified potassium dichromate solution

56

4

Which line in the table correctly describes reactions X and Y

5

Which line in the table correctly describes reactions X and Y

6 Which of the following fuels when burned would make no contribution to globalwarming

57

A HydrogenB Natural gasC PetrolD Coal

7 Which of the following hydrocarbons always gives the same product when one of itshydrogen atoms is replaced by a chlorine atomA HexaneB Hex-1-eneC CyclohexaneD Cyclohexene

8 Which of the following compounds does not have isomeric structuresA C2HCl3B C2H4Cl2C PropeneD Propan-1-ol

9 What organic compound is produced by the dehydration of ethanol A EthaneB EtheneC EthanalD Ethanoic acid

10

The above equation representsA hydrationB hydrogenationC condensationD hydrolysis

11

Which of the following compounds is an isomer of the structure shown aboveA ButanalB ButanoneC Butan-1-olD Butanoic acid

58

12 A compound with molecular formula C6H12O2 could beA hexanalB hexan-2-olC hexan-2-oneD hexanoic acid

13 Propan-2-ol can be prepared from propane as follows

Which line in the table correctly describes the types of reaction taking place at Steps 1 and 2

14 Which of the following compounds would be the most water soluble

15 Cyanohydrin compounds can be made from carbonyl compounds by reacting the carbonyl compound with hydrogen cyanide (HCN)

59

Which carbonyl compound would react with hydrogen cyanide (HCN) to form the following compound

16 Ethyne is the first member of the homologous series called the alkynes

Ethyne can undergo addition reactions as shown in the flow diagram

(a) Compound 2 is an isomer of 12-dichloroethaneDraw a structural formula for compound 2 (1)

(b) Reagents A B and C are three different diatomic gasesUsing information in the flow diagram identify reagents A B and C (1)

60

Reagent Gas

A

B

C

17 In 1865 the German chemist Kekuleacute proposed a ring structure for benzene This structure was based on alternating single and double bonds

(a) (i) Describe a chemical test that would indicate that the above chemical structure for benzene is incorrect (1)

(ii) Briefly describe the correct structure for benzene (1)

(b) Benzene can be formed from cyclohexaneC6H12 rarr C6H6 + 3H2

What name is given to this type of reaction (1)18 Infra-red spectroscopy is a technique that can be used to identify the bonds that

arepresent in a molecule Different bonds absorb infra-red radiation of different wavenumbers This is due to differences in the bond lsquostretchrsquo These absorptions are recorded in a spectrumA spectrum for propan-1-ol is shown

61

The correlation table on page 13 of the data booklet shows the wavenumber ranges for the absorptions due to different bonds

(a) Use the correlation table to identify the bonds responsible for the two absorptions x and y that are circled in the propan-1-ol spectrum (1)

(b) Propan-1-ol reacts with ethanoic acid(i) What name is given to this type of reaction (1)(ii) Draw a spectrum that could be obtained for the organic product of this

reaction (1)

19 Paracetamol is a widely used painkiller

(a) Write the molecular formula for paracetamol (1)

(b) One antidote for paracetamol overdose is methionine

62

To what family of organic compounds does methionine belong (1)

(c) The concentration of paracetamol in a solution can be determined by measuring how much UV radiation it absorbs

The graph shows how the absorbance of a sample containing 0middot040 g l ndash1 paracetamol varies with wavelength

The quantity of UV radiation of wavelength 245 nm absorbed is directly proportional to the concentration of paracetamolThe absorbance of a second sample of paracetamol solution measured at 245 nm was 0middot90 What is the concentration in g l ndash1 of this second paracetamol solution (1)

20 Many carbon compounds containing oxygen are very flammableThe table shows information about two families of isomersThe lowest temperature at which a compound will ignite is called its flash point

(a) A compound with the molecular formula C6H14O has a boiling point of 158 degC63

Draw a structural formula for this compound (1)

(b) For a family of isomers in the table write a general statement linking the flash points of the compounds to their structures (1)

21 Hydrogels are used in disposable nappies They are fine powders that can absorb up to 500 times their own weight in waterA hydrogel is a very long molecule with carboxyl groups at regular intervals along its length A short section of a hydrogel molecule is shown below

Hydrogels are extremely good at soaking up water because the water molecules are strongly attracted to them

Using your knowledge of chemistry comment on how suitable hydrogels would be for absorbing liquids or solutions spilled in a chemistry lab (1)

64

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

13 Polymers can be classified as natural or synthetic(a) Keratin a natural polymer is a protein found in hair

The hydrolysis of keratin produces different monomers of the type shown

(i) What name is given to monomers like glycine alanine and cysteine (1)(ii) What is meant by a hydrolysis reaction (1)

(b) Dacron a synthetic polymer is used in heart surgery A section of the polymer is shown

What name is given to the link made by the shaded group of atoms in this section of the polymer (1)

14 Chemists have developed cheeses specifically for use in cheeseburgers(a) When ordinary cheddar cheese is grilled the shapes of the protein molecules

change and the proteins and fats separate leaving a chewy solid and an oily liquidWhat name is given to the change in protein structure which occurs when ordinary cheddar is grilled (1)

(b) To make cheese for burgers grated cheddar cheese soluble milk proteins and some water are mixed and heated to no more than 82 degC As the cheese begins to melt an emulsifying agent is added and the mixture is stirred

15

(i) Why would a water bath be used to heat the mixture (1)(ii) A section of the structure of a soluble milk protein is shown below

Draw a structural formula for any one of the amino acids formed when this section of

protein is hydrolysed (1)

(iii) The emulsifier used is trisodium citrate a salt formed when citric acid is neutralised using sodium hydroxide Complete the equation below showing a structural formula for the trisodium citrate formed (1) sp 8

15 Phenylalanine and alanine are both amino acids

(a) Phenylalanine is an essential amino acid

(i) What is meant by an essential amino acid (1)

16

(ii) How many hydrogen atoms are present in a molecule of phenylalanine (1)

(b) Phenylalanine and alanine can react to form the dipeptide shown

Circle the peptide link in this molecule (1)

(c) Draw a structural formula for the other dipeptide that can be formed from phenylalanine and alanine (1)

16 Uncooked egg white is mainly composed of dissolved proteins During cooking processes the proteins become denatured as the protein chains unwind and the egg white solidifies

(a) Explain why the protein chains unwind (1)

(b)The temperature at which the protein becomes denatured is called the melting temperature The melting temperature of a protein can be determined using fluorescence In this technique the protein is mixed with a dye that gives out visible light when it attaches to hydrophobic parts of the protein molecule The hydrophobic parts of the structure are on the inside of the protein and the dye has no access to them unless the protein unwinds

(i) Ovalbumin is a protein found in egg white Part of the structure of unwound ovalbumin is shown below

Circle the part of the structure to which the hydrophobic dye is most likely to attach (1)

17

(ii) Another protein in egg white is conalbumin The temperature of a conalbumindye mixture is gradually increased The fluorescence is measured and a graph is produced

The melting temperature is the temperature at which the fluorescence is halfway between the highest and lowest fluorescence valuesDetermine the melting temperature in ordmC for this protein (1)

(c) Once cooked and eaten the digestive system breaks the protein chains into amino acids with the help of enzymes

(i) State the name of the digestion process where enzymes break down proteins into amino acids (1)

(ii)

(A) State how many amino acid molecules joined to form this section of protein (1)

(B) Draw the structure of one amino acid that would be produced when this section of the protein chain is broken down (1)

17 Peptide molecules can be classified according to the number of amino acid units joined by peptide bonds in the molecule

18

(a) Complete the table to identify the type of peptide with the following amino acid sequence

alanine-glycine-valine-proline-tyrosine-serine (1)

(b) Partial hydrolysis of another pentapeptide molecule gave a mixture of three smaller peptide molecules with the following amino acid sequences

leucine-glycine-valineisoleucine-leucineglycine-valine-serine

Write the amino acid sequence for the original pentapeptide molecule (1)

helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip(c) Some amino acids needed to form polypeptides cannot be produced in the human body

State the term used to describe amino acids that the body cannot make (1)

(d)Paper chromatography is often used to analyse the mixtures of amino acids produced when peptides are broken downOn a chromatogram the retention factor Rf for a substance can be a useful method of identifying the substance

The structure of the pentapeptide methionine enkephalin was investigatedA sample of the pentapeptide was completely hydrolysed into its constituent amino acids and this amino acid mixture was applied to a piece of chromatography paper and placed in a solventThe chromatogram obtained is shown below

19

(i) Suggest why only four spots were obtained on the chromatogram of the hydrolysed pentapeptide (1)

(ii) It is known that this amino acid mixture contains the amino acid methionine The Rf value for methionine in this solvent is 040Draw a circle around the spot on the chromatogram that corresponds to methionine (1)

(e) Over the last decade several families of extremely stable peptide molecules have been discovered where the peptide chain forms a ring

(i) A simple cyclic dipeptide is shown

Draw a structural formula for one of the amino acids that would be formed on complete hydrolysis of the above cyclic dipeptide (1)

(ii) Alpha-amanitin is a highly toxic cyclic peptide found in death cap mushrooms The lethal dose for humans is 100 mg per kg of body mass1middot0 g of death cap mushrooms contains 250 mg of alpha-amanitinCalculate the minimum mass of death cap mushrooms that would contain the lethal dose for a 75 kg adult (2)

18 Dishwasher tablets produce the bleach hydrogen peroxide H2O2 One action of this oxidising agent is to oxidise food

(a)(i) Suggest another action of the bleach produced by the dishwasher tablets (1)

20

(ii) Hydrogen peroxide decomposes to form water and oxygen

2H2O2(ℓ) rarr 2H2O(ℓ) + O2(g)

A dishwasher tablet produces 0middot051 g of hydrogen peroxide (mass of one mole = 34 g)

Calculate the volume of oxygen that would be produced when0middot051 g of hydrogen peroxide decomposesTake the volume of 1 mole of oxygen gas to be 24 litres(3)

(b)Enzymes are commonly added to dishwasher tablets These are used to break down proteins(i) The proteins are broken down into small water-soluble molecules

Name the small water-soluble molecules made when proteins are broken down completely (1)

(ii) The structure of a section of protein chain found in egg white is shown

(A)Name the functional group circled (1)(B)Draw a structural formula for one of the molecules that would be made

when this section of egg white protein chain is completely broken down (1)

(iii) As part of the program in the dishwasher the conditions in the dishwasher change so that the enzyme molecules no longer work because they change shape

21

(A) State the term used to describe the change in shape of enzyme molecules(1)

(B) Suggest a change in conditions which would cause the enzyme molecules to change shape (1)

(d) A bleach activator is frequently added to dishwasher tablets to speed up the bleaching reaction One common bleach activator is TAED TAED could be produced in a process which involves a number of stages

(i) The first stage in producing TAED is shown below

Suggest a name for this type of reaction (1)

(ii) The final stage in the process producing TAED is shown below

Draw a structural formula for TAED (1)

22

23 The Chemistry of Cooking

1 Vanillin and zingerone are flavour molecules

Which line in the table correctly compares the properties of vanillin and zingerone

23

2 Erythrose can be used in the production of a chewing gum that helps prevent tooth decay

Which of the following compounds will be the best solvent for erythrose

3 The following molecules give flavour to food Which of the following flavour molecules would be most likely to be retained in the food when the food is cooked in water

24

4 Cooking involves many chemical reactions Proteins fats oils and esters are some examples of compounds found in food A chemist suggested that cooking food could change compounds from being fat-soluble to water-soluble Use your knowledge of chemistry to comment on the accuracy of this statement(3)

25

24 The Oxidation of Food

1 Apples and bananas turn brown when cut or bruised The first step of the reaction causing

the browning is shown below

Which of the following terms correctly describes this reactionA ReductionB OxidationC DehydrationD Condensation

2 Which of the following reactions can be classified as reductionA CH3CH2OH rarr CH3COOHB CH3 CH(OH)CH3 rarr CH3COCH3C CH3CH2COCH3 rarr CH3CH2CH(OH)CH3D CH3CH2CHO rarr CH3CH2COOH

3 The dehydration of butan-2-ol can produce two isomeric alkenes but-1-ene andbut-2-ene Which of the following alkanols can similarly produce on dehydration a pair of isomeric alkenesA Propan-2-olB Pentan-3-olC Hexan-3-olD Heptan-4-ol

4 Which of the following compounds is an alkanone

26

5 Which of the following is an aldehyde

6 Which of the following compounds would react with sodium hydroxide solution to forma saltA CH3CHOB CH3COOHC CH3COCH3D CH3CH2OH

7 Which line in the table shows the correct functional group for each homologous series

8 Which of the following organic compounds is an isomer of hexanalA 2-MethylbutanalB 3-Methylpentan-2-oneC 22-Dimethylbutan-1-olD 3-Ethylpentanal

27

9 The name of this compound is

A methanolB methanalC methanoic acidD methanone

10 Which alcohol could be oxidised to a carboxylic acid

11 Which of the following structural formulae represents a tertiary alcohol

12 Compound X reacted with hot copper(II) oxide and the organic product did not give acolour change when heated with Fehlingrsquos solution Compound X could beA butan-1-olB butan-2-olC butanoneD butanoic acid

28

13 Which two isomers would each produce an acid when warmed with acidified potassiumdichromate solution

A 1 and 2B 2 and 3C 1 and 4D 3 and 4

14 After heating for several minutes as shown in the diagram the pH indicator solution turned red

Liquid Q could beA propanoneB paraffinC propan-1-olD propan-2-ol

29

15 Enzymes are involved in the browning of cut fruitOne reaction taking place is

Which of the following correctly describes the above reaction

A OxidationB ReductionC HydrolysisD Condensation

16 Which of the following statements is correct for ketones

A They are formed by oxidation of tertiary alcohols

B They contain the group

C They contain a carboxyl groupD They will not react with Fehlingrsquos solution

17 Carvone is a natural product that can be extracted from orange peel

Which line in the table correctly describes the reaction of carvone with bromine solution and with acidified potassium dichromate solution

30

18 Which of the following is an isomer of 22-dimethylpentan-1-ol

A CH3CH2CH2CH(CH3)CH2OHB (CH3)3CCH(CH3)CH2OHC CH3CH2CH2CH2CH2CH2CH2CH2OHD (CH3)2CHC(CH3)2CH2CH2OH

19 The equation for the reduction reaction taking place when ethanal reacts with Tollensrsquo reagent is

A Cu2+(aq) + eminus rarr Cu+(aq)

B Ag+(aq) + eminus rarr Ag(s)

C Cr2O72minus(aq) + 14H+(aq) + 6eminus rarr 2Cr3+(aq) + 7H2O(ℓ)

D MnO4minus(aq) + 8H+(aq) + 5eminus rarr Mn2+(aq) + 4H2O(ℓ)

20 The name of the compound with structure

isA 23-dimethylpentan-4-oneB 23-dimethylpentan-2-alC 34-dimethylpentan-2-oneD 34-dimethylpentan-2-al

21 What is the systematic name for the compound below

A 222-trimethylethanolB 22-dimethylpropan-1-olC 22-dimethylpropan-3-olD 22-dimethylpentan-1-ol

31

22 The structure of a molecule found in olive oil can be represented as shown

(a) Olive oil can be hydrolysed using sodium hydroxide solution to produce sodium salts of fatty acids Name the other product of this reaction (1)

(b) In what way does the structure of a fat molecule differ from that of an oil molecule (1)

(c) Over time open containers of olive oil develop a rancid flavour What substance is reacting with the oil to cause these unwanted changes to take place (1)

23 A student writes the following statement It is incorrect Explain the mistake in the studentrsquos reasoning (1)

Alcohols are alkaline because of their OH groups

24 Carbon compounds take part in a wide variety of chemical reactions (a)

Name this type of chemical reaction (1)

(b)

Draw a structural formula for C3H6O (1)

25 Alkanols can be oxidised to alkanoic acids

32

(a) Why can Step 1 be described as an oxidation reaction (1)

(b) Acidified potassium dichromate solution can be used to oxidise propanal in Step 2 What colour change would be observed in this reaction (1)

26 Amines can be produced by reacting ammonia with an aldehyde or a ketone This reaction an example of reductive amination occurs in two stages

Stage 1 Amination

Stage 2 Reduction

(a) Give another name for the type of reaction taking place in Stage 2

(b) Draw the structural formula for the amine produced when butanal undergoes reductive amination with ammonia

27 Using a cobalt catalyst alkenes react with a mixture of hydrogen and carbon monoxideThe products are two isomeric aldehydes Propene reacts with the mixture as shown

(a) What name is given to a mixture of hydrogen and carbon monoxide (1)

(b) Draw a structural formula for compound B (1)

(c) (i) What would be observed if compound A was gently heated with Tollensrsquo reagent

(1)(ii) How would the reaction mixture be heated (1)

33

(d) Aldehydes can also be formed by the reaction of some alcohols with copper(II) oxideName the type of alcohol that would react with copper(II) oxide to form an aldehyde (1)

28 Aldehydes and ketones can take part in a reaction sometimes known as an aldol condensation The simplest aldol reaction involves two molecules of ethanal

In the reaction the carbon atom next to the carbonyl functional group of one molecule forms a bond with the carbonyl carbon atom of the second molecule

(a) Draw a structural formula for the product formed when propanone is used instead of ethanal in this type of reaction (1)

(b) Name an aldehyde that would not take part in an aldol condensation (1)

(c) Apart from the structure of the reactants suggest what is unusual about applying the term ldquocondensationrdquo to this particular type of reaction (1)

29 Primary secondary and tertiary alkanols can be prepared by the reaction of carbonyl compounds with Grignard reagents

Step 1The Grignard reagent reacts with the carbonyl compound

Step 2The reaction of the product of Step 1 with dilute acid produces the alkanol

(a) Describe the difference between a primary a secondary and a tertiary alkanol

You may wish to include labelled structures in your answer (1)34

(b) Suggest a name for the type of reaction that takes place in Step 1 (1)

(c) The same Grignard reagent can be used to produce the alkanol below

Name the carbonyl compound used in this reaction (1)

30 Hairspray is a mixture of chemicals(a) A primary alcohol 2-methylpropan-1-ol is added to hairspray to help it dry quickly on the hair

Draw a structural formula for a secondary alcohol that is an isomer of2-methylpropan-1-ol (1)

(b) Triethanol amine and triisopropyl amine are bases used to neutralise acidic compounds in the hairspray to prevent damage to the hair

In terms of the intermolecular bonding present explain clearly why triethanol amine has a much higher boiling point than triisopropyl amine (2)

35

36

31 Chocolate contains various compounds(a) Many of the flavour and aroma molecules found in chocolate are aldehydes and

ketones Two examples are shown below

Phenylethanal can be easily oxidised but 13-diphenylpropan-2-one cannot(i) Name a chemical that could be used to distinguish between these two

compounds (1)

(ii) Name the type of organic compound formed when phenylethanal is oxidised (1)

(b) Glycerol monostearate is an emulsifier used in chocolate

(i) Why is glycerol monostearate added to chocolate (1)

(ii) Draw a structural formula for glycerol (1)

(c) Theobromine a compound present in chocolate can cause illness in dogs and cats To decide if treatment is necessary vets must calculate the mass of theobromine consumed 1middot0 g of chocolate contains 1middot4 mg of theobromine Calculate the mass in mg of theobromine in a 17 g biscuit of which 28 is chocolate Show your working clearly (2)

(d) The flavour and texture of chocolate comes from a blend of compoundsUsing your knowledge of chemistry describe how you could show that there are ionic compounds and covalent compounds present in chocolate (3)

37

32 Ethanol has many uses

(a) Ethanol is found at relatively low concentrations in wine

(i) Name the chemical reaction that produces ethanol in wine (1)

(ii) Standard ethanol solutions were used to produce a graph of density against

concentration of ethanol given as a percentage of alcohol by volume ( abv)

What is the concentration of ethanol in units of abv in a solution of density 0middot9818 g cmminus3 (1)

(b) Whisky contains a higher concentration of ethanol

(i) Before 1980 the concentration of alcohol in drinks was measured in terms of degrees proof The concentration of alcohol in two drinks is shown in the table below both as abv and degrees proof

38

A cask strength whisky has an alcohol concentration of 65 abv Calculate the alcohol concentration of this whisky in degrees proof (1)

(ii) A barrel containing 195 litres of cask strength whisky costs pound1300 The cask strength whisky is diluted with water to reduce the concentration of alcohol from 65 abv to 46 abv before it is bottled Calculate the cost of the cask strength whisky needed to produce a 0middot70 litre bottle Show your working clearly (2)

(iii) 5-Butyl-4-methyltetrahydrofuran-2-ol is a flavour compound found in whisky

stored in oak barrels

Write the systematic name for the compound shown below (1) 13 11

33 (a) One test for glucose involves Fehlingrsquos solutionCircle the part of the glucose molecule that reacts with Fehlingrsquos solution (1)

(b) In solution sugar molecules exist in an equilibrium in straight-chain and ring forms

To change from the straight-chain form to the ring form the oxygen of the hydroxyl on carbon number 5 joins to the carbonyl carbon This is shown below for glucose

39

Draw the structure of a ring form for fructose (1)

34 (a) During the free radical chain reaction small molecules join to form large chain molecules

One example of a small molecule used is

Name the functional group circled above (1)

(b)Alcohol wipes are used to finish the varnishing treatment Alcohol wipes contain the alcohol propan-2-olState why propan-2-ol can be described as a secondary alcohol (1)

35 A student was carrying out an investigation into alcohols aldehydes and ketones

(a)The student was given three alcohols labelled as A B and C These alcohols were all isomers with the formula C4H9OH

(i) Draw a structural formula for the secondary alcohol with the formula C4H9OH(1)

(ii) The student set up the following experiment

A Suggest why a water bath is an appropriate method of heating the reaction mixture (1)

B Describe the colour change that would have been observed with alcohols A and C (1)

40

C Alcohol B is not oxidised State the type of alcohol which cannot be oxidised by acidified dichromate solution (1)

(iii) The student set up a second experiment with alcohol A

Hot copper(II) oxide is an oxidising agentA When alcohol A (C4H9OH) is oxidised the product turns the pH paper

redSuggest a name for the product (1)

B Complete the ion-electron equation for the oxidation reaction

C4H9OH rarr C4H8O2 (1)

(b)The student found the following information about the boiling points of some aldehydes

41

(i) Name the aldehyde that has a boiling point of 119 degC (1)(ii) Predict the boiling point in degC of the following molecule (1)

(iii) Using information from the table describe one way in which differences in structure affect the boiling point of isomeric aldehydes (1)

(iv) State what would be observed when an aldehyde is gently heated with Tollensrsquo reagent (1)

(c) Ketones contain a carbonyl groupName the type of intermolecular interaction between ketone molecules (1)

42

25 Soaps Detergents and Emulsions

1 Soaps are produced by the following reaction

This reaction is an example ofA condensationB esterificationC hydrolysisD oxidation

2 Which of the following is the salt of a long-chain fatty acid

A FatB OilC SoapD Glycerol

3 Emulsifiers for use in food are commonly made by reacting edible oils with

A estersB glycerolC fatty acidsD amino acids

4 A fatty acid is a long chain carboxylic acid Examples of fatty acids are shown in the table below

43

(a) What is the systematic name for linolenic acid (1)(b) Stearic acid reacts with sodium hydroxide solution to form sodium stearate

(i) Name the type of reaction taking place when stearic acid reacts with sodium hydroxide (1)

(ii) Explain fully how sodium stearate acts to keep grease and non-polar substances suspended in water during cleaning (3)

5 Small children can find it difficult to swallow tablets or pills so ibuprofen is supplied as an ldquoinfant formulardquo emulsion(a) The emulsifier used is polysorbate 80 Its structure is shown below

Explain why this molecule acts as an emulsifier (2)

(b) The emulsion contains 2 g of ibuprofen in every 100 cm3 of emulsion The recommended dose for treating a 6 month old baby is 0middot050 g Calculate the volume in cm3 of ldquoinfant formulardquo needed to treat a 6 month old baby (1)

6 Occasionally seabirds can become contaminated with hydrocarbons from oil spills This causes problems for birds because their feathers lose their waterproofing making the birds susceptible to temperature changes and

44

affecting their buoyancy If the birds attempt to clean themselves to remove the oil they may swallow the hydrocarbons causing damage to their internal organsContaminated seabirds can be cleaned by rubbing vegetable oil into their feathers and feet before the birds are rinsed with diluted washing-up liquidUsing your knowledge of chemistry comment on the problems created for seabirds by oil spills and the actions taken to treat affected birds (3)

7 Dishwasher tablets contain chemicals which remove dirt from dishesDishwasher tablets include detergents These molecules act like soaps to allow mixing of fat-soluble dirt and water(a)During the cleaning process the detergent molecules combine with fat-

soluble dirtA simplified diagram of a detergent molecule is shown

Complete the diagram below to show how detergent molecules combine with fat-soluble dirt (1)

(b)State the term used to describe the non-polar hydrocarbon tail of a detergent molecule (1)

45

26 Fragrances1 Myrcene is a simple terpene

Terpenes contain at least one isoprene unit Which of the following shows a correctly highlighted isoprene unit

2 Limonene is one of the terpene molecules responsible for the flavour of lemons

How many isoprene units are used in the production of one limonene moleculeA 1B 2C 3D 4

46

3 The structure of caryophyllene which can be extracted from clove oil is

Which of the following would be the best solvent for extracting caryophylleneA HexaneB HexanalC HexanolD Hexanone

4 The structure of isoprene is

Limonene is a terpene molecule present in lemons

How many isoprene units are joined together in a limonene molecule

A 1B 2

47

C 3D 4

5 Essential oils are

A non-water soluble non-volatile compoundsB non-water soluble volatile compoundsC water soluble non-volatile compoundsD water soluble volatile compounds

6 Two typical compounds that are present in many perfumes are shown

(a) Why does geraniol evaporate more slowly than limonene (1)

(b) The structure of one of the first synthetic scents used in perfume is shown below

(i) Name the family of carbonyl compounds to which this synthetic scent belongs (1)

(ii) Complete the structure below to show the product formed when this scent is

oxidised (1)

(c) Traces of a liquid were discovered in a bottle believed to contain perfume belonging to Queen Hatshepsut ruler of Egypt over 3500 years ago

Perfumes were made by dissolving plant extracts containing pleasant smelling terpenes and esters in an edible oil A little ethanol and water may also have been addedUsing your knowledge of chemistry comment on the possible smell(s) when such a bottle is opened after being stored for thousands of years (3)

48

49

7 A team of chemists are developing a fragrance for use in a shower gel for men(a) To give the gel a fruity smell the chemists are considering adding an ester

They synthesise six isomeric esters Volunteers smell each ester and give it a rating out of one hundred depending on how fruity the smell is

(i) Name the ester with the fruit-smell rating of 92 (1)

(ii) Shown below are the structures of three more isomers

Arrange these esters in order of decreasing fruit-smell rating (1)

50

(b) To create a fragrance for men the compound civetone is added

Draw a structural formula for the alcohol that can be oxidised to form civetone (1)

(c) To make the shower gel produce a cold tingling sensation when applied to the skin menthol is added

Like terpenes menthol is formed from isoprene (2-methylbuta-13-diene)Circle an isoprene unit on the menthol structure above (1)

8 Many of the compounds in perfumes are molecules consisting of joined isoprene units

(a) State the name that is given to molecules consisting of joined isoprene units (1)

(b)Geraniol is one of the compounds found in perfume It has the following structural formula and systematic name

Linalool can also be present Its structural formula is shown

51

(i) State the systematic name for linalool (1)(ii) Explain why linalool can be classified as a tertiary alcohol (1)

9 The component molecules found in lavender oils are terpenes or terpenoids(a)A chiral carbon is a carbon atom attached to four different atoms or groups of

atomsAn example is shown below

A molecule of the terpenoid linalool has a chiral carbon Linalool has the following structure

Circle the chiral carbon atom in the linalool structure (1)

(b)Farnesene is a terpene consisting of three isoprene units (2-methylbuta-13-diene) joined togetherWrite the molecular formula of farnesene (1)

52

27 Skin Care

1 Which of the following is not a step in a free radical chain reaction

A ActivationB InitiationC PropagationD Termination

2 Fluorine reacts with methane via a free radical chain reaction Some steps in the chain reaction are shown in the table below

Complete the table by(a) inserting the missing name for the first step (1)

(b) showing another possible termination reaction in the final row of the table (1)

3 Suncreams contain antioxidantsThe antioxidant compound A can prevent damage to skin by reacting with free

radicalssuch as NO2bull

53

Why can compound A be described as a free radical scavenger in the reaction shown above

4 Hydrogen and chlorine gases are used in an experiment to demonstrate a free radical reaction A plastic bottle is wrapped with black tape leaving a ldquowindowrdquo on one sideThe bottle is filled with a mixture of hydrogen and chlorine When bright light shines on the bottle there is an explosion

A free radical chain reaction is initiated when light energy causes chlorine radicals to form as shown below

(a) Complete the equations below showing possible propagation and termination steps

(2)

54

(b) Why is the plastic bottle used in the experiment wrapped in black tape (1)

5 Chloramines can be removed from water using ultraviolet light treatment

One step in the process is the formation of free radicals

(a)State what is meant by the term free radical (1)

(b)Another step in the process is shown below

State the name for this type of step in a free radical reaction (1)

6 Modern shellac nail varnishes are more durable and so last longer than traditional nail polish

The shellac nail varnish is applied in thin layers to the nails and then the fingers are placed under a UV lamp

(a) The Skin Care Foundation has recommended that a sun-block is applied to the fingers and hand before using the lampSuggest why the Skin Care Foundation makes this recommendation (1)

(b) A free radical chain reaction takes place and the varnish hardens (i) State what is meant by the term free radical (1)

(ii) The shellac nail varnish contains a mixture of ingredients that take part in the free radical chain reactionOne of the steps in the free radical chain reaction is

55

State the term used to describe this type of step in a free radical chain reaction(1)

7 Skin care products contain a mixture of polar covalent non-polar covalent and ionic compounds The compounds need to stay mixed within the product Skin care products also need to spread easily and remain on the skin for a period of time as well as provide physical and chemical protection from the sun In order to do this skin care products contain a range of chemicals including water fats and oils antioxidants minerals and sun blockUsing your knowledge of chemistry explain the role of different chemicals in skin care products (3)

General Questions

1 A mixture of carbon monoxide and hydrogen can be converted into water and a mixture of hydrocarbons

nCO + (2n + 1)H2 rarr nH2O + hydrocarbons

What is the general formula for the hydrocarbons producedA CnH2nndash2B CnH2nC CnH2n+1D CnH2n+2

2 Butadiene is the first member of a homologous series of hydrocarbons called dienesWhat is the general formula for this seriesA CnHn+2B CnHn+3C CnH2nD CnH2nndash2

3 Which of the following statements about methanol is falseA It can be made from synthesis gasB It can be dehydrated to form an alkeneC It can be oxidised to give a carboxylic acidD It reacts with acidified potassium dichromate solution

56

4

Which line in the table correctly describes reactions X and Y

5

Which line in the table correctly describes reactions X and Y

6 Which of the following fuels when burned would make no contribution to globalwarming

57

A HydrogenB Natural gasC PetrolD Coal

7 Which of the following hydrocarbons always gives the same product when one of itshydrogen atoms is replaced by a chlorine atomA HexaneB Hex-1-eneC CyclohexaneD Cyclohexene

8 Which of the following compounds does not have isomeric structuresA C2HCl3B C2H4Cl2C PropeneD Propan-1-ol

9 What organic compound is produced by the dehydration of ethanol A EthaneB EtheneC EthanalD Ethanoic acid

10

The above equation representsA hydrationB hydrogenationC condensationD hydrolysis

11

Which of the following compounds is an isomer of the structure shown aboveA ButanalB ButanoneC Butan-1-olD Butanoic acid

58

12 A compound with molecular formula C6H12O2 could beA hexanalB hexan-2-olC hexan-2-oneD hexanoic acid

13 Propan-2-ol can be prepared from propane as follows

Which line in the table correctly describes the types of reaction taking place at Steps 1 and 2

14 Which of the following compounds would be the most water soluble

15 Cyanohydrin compounds can be made from carbonyl compounds by reacting the carbonyl compound with hydrogen cyanide (HCN)

59

Which carbonyl compound would react with hydrogen cyanide (HCN) to form the following compound

16 Ethyne is the first member of the homologous series called the alkynes

Ethyne can undergo addition reactions as shown in the flow diagram

(a) Compound 2 is an isomer of 12-dichloroethaneDraw a structural formula for compound 2 (1)

(b) Reagents A B and C are three different diatomic gasesUsing information in the flow diagram identify reagents A B and C (1)

60

Reagent Gas

A

B

C

17 In 1865 the German chemist Kekuleacute proposed a ring structure for benzene This structure was based on alternating single and double bonds

(a) (i) Describe a chemical test that would indicate that the above chemical structure for benzene is incorrect (1)

(ii) Briefly describe the correct structure for benzene (1)

(b) Benzene can be formed from cyclohexaneC6H12 rarr C6H6 + 3H2

What name is given to this type of reaction (1)18 Infra-red spectroscopy is a technique that can be used to identify the bonds that

arepresent in a molecule Different bonds absorb infra-red radiation of different wavenumbers This is due to differences in the bond lsquostretchrsquo These absorptions are recorded in a spectrumA spectrum for propan-1-ol is shown

61

The correlation table on page 13 of the data booklet shows the wavenumber ranges for the absorptions due to different bonds

(a) Use the correlation table to identify the bonds responsible for the two absorptions x and y that are circled in the propan-1-ol spectrum (1)

(b) Propan-1-ol reacts with ethanoic acid(i) What name is given to this type of reaction (1)(ii) Draw a spectrum that could be obtained for the organic product of this

reaction (1)

19 Paracetamol is a widely used painkiller

(a) Write the molecular formula for paracetamol (1)

(b) One antidote for paracetamol overdose is methionine

62

To what family of organic compounds does methionine belong (1)

(c) The concentration of paracetamol in a solution can be determined by measuring how much UV radiation it absorbs

The graph shows how the absorbance of a sample containing 0middot040 g l ndash1 paracetamol varies with wavelength

The quantity of UV radiation of wavelength 245 nm absorbed is directly proportional to the concentration of paracetamolThe absorbance of a second sample of paracetamol solution measured at 245 nm was 0middot90 What is the concentration in g l ndash1 of this second paracetamol solution (1)

20 Many carbon compounds containing oxygen are very flammableThe table shows information about two families of isomersThe lowest temperature at which a compound will ignite is called its flash point

(a) A compound with the molecular formula C6H14O has a boiling point of 158 degC63

Draw a structural formula for this compound (1)

(b) For a family of isomers in the table write a general statement linking the flash points of the compounds to their structures (1)

21 Hydrogels are used in disposable nappies They are fine powders that can absorb up to 500 times their own weight in waterA hydrogel is a very long molecule with carboxyl groups at regular intervals along its length A short section of a hydrogel molecule is shown below

Hydrogels are extremely good at soaking up water because the water molecules are strongly attracted to them

Using your knowledge of chemistry comment on how suitable hydrogels would be for absorbing liquids or solutions spilled in a chemistry lab (1)

64

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

(i) Why would a water bath be used to heat the mixture (1)(ii) A section of the structure of a soluble milk protein is shown below

Draw a structural formula for any one of the amino acids formed when this section of

protein is hydrolysed (1)

(iii) The emulsifier used is trisodium citrate a salt formed when citric acid is neutralised using sodium hydroxide Complete the equation below showing a structural formula for the trisodium citrate formed (1) sp 8

15 Phenylalanine and alanine are both amino acids

(a) Phenylalanine is an essential amino acid

(i) What is meant by an essential amino acid (1)

16

(ii) How many hydrogen atoms are present in a molecule of phenylalanine (1)

(b) Phenylalanine and alanine can react to form the dipeptide shown

Circle the peptide link in this molecule (1)

(c) Draw a structural formula for the other dipeptide that can be formed from phenylalanine and alanine (1)

16 Uncooked egg white is mainly composed of dissolved proteins During cooking processes the proteins become denatured as the protein chains unwind and the egg white solidifies

(a) Explain why the protein chains unwind (1)

(b)The temperature at which the protein becomes denatured is called the melting temperature The melting temperature of a protein can be determined using fluorescence In this technique the protein is mixed with a dye that gives out visible light when it attaches to hydrophobic parts of the protein molecule The hydrophobic parts of the structure are on the inside of the protein and the dye has no access to them unless the protein unwinds

(i) Ovalbumin is a protein found in egg white Part of the structure of unwound ovalbumin is shown below

Circle the part of the structure to which the hydrophobic dye is most likely to attach (1)

17

(ii) Another protein in egg white is conalbumin The temperature of a conalbumindye mixture is gradually increased The fluorescence is measured and a graph is produced

The melting temperature is the temperature at which the fluorescence is halfway between the highest and lowest fluorescence valuesDetermine the melting temperature in ordmC for this protein (1)

(c) Once cooked and eaten the digestive system breaks the protein chains into amino acids with the help of enzymes

(i) State the name of the digestion process where enzymes break down proteins into amino acids (1)

(ii)

(A) State how many amino acid molecules joined to form this section of protein (1)

(B) Draw the structure of one amino acid that would be produced when this section of the protein chain is broken down (1)

17 Peptide molecules can be classified according to the number of amino acid units joined by peptide bonds in the molecule

18

(a) Complete the table to identify the type of peptide with the following amino acid sequence

alanine-glycine-valine-proline-tyrosine-serine (1)

(b) Partial hydrolysis of another pentapeptide molecule gave a mixture of three smaller peptide molecules with the following amino acid sequences

leucine-glycine-valineisoleucine-leucineglycine-valine-serine

Write the amino acid sequence for the original pentapeptide molecule (1)

helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip(c) Some amino acids needed to form polypeptides cannot be produced in the human body

State the term used to describe amino acids that the body cannot make (1)

(d)Paper chromatography is often used to analyse the mixtures of amino acids produced when peptides are broken downOn a chromatogram the retention factor Rf for a substance can be a useful method of identifying the substance

The structure of the pentapeptide methionine enkephalin was investigatedA sample of the pentapeptide was completely hydrolysed into its constituent amino acids and this amino acid mixture was applied to a piece of chromatography paper and placed in a solventThe chromatogram obtained is shown below

19

(i) Suggest why only four spots were obtained on the chromatogram of the hydrolysed pentapeptide (1)

(ii) It is known that this amino acid mixture contains the amino acid methionine The Rf value for methionine in this solvent is 040Draw a circle around the spot on the chromatogram that corresponds to methionine (1)

(e) Over the last decade several families of extremely stable peptide molecules have been discovered where the peptide chain forms a ring

(i) A simple cyclic dipeptide is shown

Draw a structural formula for one of the amino acids that would be formed on complete hydrolysis of the above cyclic dipeptide (1)

(ii) Alpha-amanitin is a highly toxic cyclic peptide found in death cap mushrooms The lethal dose for humans is 100 mg per kg of body mass1middot0 g of death cap mushrooms contains 250 mg of alpha-amanitinCalculate the minimum mass of death cap mushrooms that would contain the lethal dose for a 75 kg adult (2)

18 Dishwasher tablets produce the bleach hydrogen peroxide H2O2 One action of this oxidising agent is to oxidise food

(a)(i) Suggest another action of the bleach produced by the dishwasher tablets (1)

20

(ii) Hydrogen peroxide decomposes to form water and oxygen

2H2O2(ℓ) rarr 2H2O(ℓ) + O2(g)

A dishwasher tablet produces 0middot051 g of hydrogen peroxide (mass of one mole = 34 g)

Calculate the volume of oxygen that would be produced when0middot051 g of hydrogen peroxide decomposesTake the volume of 1 mole of oxygen gas to be 24 litres(3)

(b)Enzymes are commonly added to dishwasher tablets These are used to break down proteins(i) The proteins are broken down into small water-soluble molecules

Name the small water-soluble molecules made when proteins are broken down completely (1)

(ii) The structure of a section of protein chain found in egg white is shown

(A)Name the functional group circled (1)(B)Draw a structural formula for one of the molecules that would be made

when this section of egg white protein chain is completely broken down (1)

(iii) As part of the program in the dishwasher the conditions in the dishwasher change so that the enzyme molecules no longer work because they change shape

21

(A) State the term used to describe the change in shape of enzyme molecules(1)

(B) Suggest a change in conditions which would cause the enzyme molecules to change shape (1)

(d) A bleach activator is frequently added to dishwasher tablets to speed up the bleaching reaction One common bleach activator is TAED TAED could be produced in a process which involves a number of stages

(i) The first stage in producing TAED is shown below

Suggest a name for this type of reaction (1)

(ii) The final stage in the process producing TAED is shown below

Draw a structural formula for TAED (1)

22

23 The Chemistry of Cooking

1 Vanillin and zingerone are flavour molecules

Which line in the table correctly compares the properties of vanillin and zingerone

23

2 Erythrose can be used in the production of a chewing gum that helps prevent tooth decay

Which of the following compounds will be the best solvent for erythrose

3 The following molecules give flavour to food Which of the following flavour molecules would be most likely to be retained in the food when the food is cooked in water

24

4 Cooking involves many chemical reactions Proteins fats oils and esters are some examples of compounds found in food A chemist suggested that cooking food could change compounds from being fat-soluble to water-soluble Use your knowledge of chemistry to comment on the accuracy of this statement(3)

25

24 The Oxidation of Food

1 Apples and bananas turn brown when cut or bruised The first step of the reaction causing

the browning is shown below

Which of the following terms correctly describes this reactionA ReductionB OxidationC DehydrationD Condensation

2 Which of the following reactions can be classified as reductionA CH3CH2OH rarr CH3COOHB CH3 CH(OH)CH3 rarr CH3COCH3C CH3CH2COCH3 rarr CH3CH2CH(OH)CH3D CH3CH2CHO rarr CH3CH2COOH

3 The dehydration of butan-2-ol can produce two isomeric alkenes but-1-ene andbut-2-ene Which of the following alkanols can similarly produce on dehydration a pair of isomeric alkenesA Propan-2-olB Pentan-3-olC Hexan-3-olD Heptan-4-ol

4 Which of the following compounds is an alkanone

26

5 Which of the following is an aldehyde

6 Which of the following compounds would react with sodium hydroxide solution to forma saltA CH3CHOB CH3COOHC CH3COCH3D CH3CH2OH

7 Which line in the table shows the correct functional group for each homologous series

8 Which of the following organic compounds is an isomer of hexanalA 2-MethylbutanalB 3-Methylpentan-2-oneC 22-Dimethylbutan-1-olD 3-Ethylpentanal

27

9 The name of this compound is

A methanolB methanalC methanoic acidD methanone

10 Which alcohol could be oxidised to a carboxylic acid

11 Which of the following structural formulae represents a tertiary alcohol

12 Compound X reacted with hot copper(II) oxide and the organic product did not give acolour change when heated with Fehlingrsquos solution Compound X could beA butan-1-olB butan-2-olC butanoneD butanoic acid

28

13 Which two isomers would each produce an acid when warmed with acidified potassiumdichromate solution

A 1 and 2B 2 and 3C 1 and 4D 3 and 4

14 After heating for several minutes as shown in the diagram the pH indicator solution turned red

Liquid Q could beA propanoneB paraffinC propan-1-olD propan-2-ol

29

15 Enzymes are involved in the browning of cut fruitOne reaction taking place is

Which of the following correctly describes the above reaction

A OxidationB ReductionC HydrolysisD Condensation

16 Which of the following statements is correct for ketones

A They are formed by oxidation of tertiary alcohols

B They contain the group

C They contain a carboxyl groupD They will not react with Fehlingrsquos solution

17 Carvone is a natural product that can be extracted from orange peel

Which line in the table correctly describes the reaction of carvone with bromine solution and with acidified potassium dichromate solution

30

18 Which of the following is an isomer of 22-dimethylpentan-1-ol

A CH3CH2CH2CH(CH3)CH2OHB (CH3)3CCH(CH3)CH2OHC CH3CH2CH2CH2CH2CH2CH2CH2OHD (CH3)2CHC(CH3)2CH2CH2OH

19 The equation for the reduction reaction taking place when ethanal reacts with Tollensrsquo reagent is

A Cu2+(aq) + eminus rarr Cu+(aq)

B Ag+(aq) + eminus rarr Ag(s)

C Cr2O72minus(aq) + 14H+(aq) + 6eminus rarr 2Cr3+(aq) + 7H2O(ℓ)

D MnO4minus(aq) + 8H+(aq) + 5eminus rarr Mn2+(aq) + 4H2O(ℓ)

20 The name of the compound with structure

isA 23-dimethylpentan-4-oneB 23-dimethylpentan-2-alC 34-dimethylpentan-2-oneD 34-dimethylpentan-2-al

21 What is the systematic name for the compound below

A 222-trimethylethanolB 22-dimethylpropan-1-olC 22-dimethylpropan-3-olD 22-dimethylpentan-1-ol

31

22 The structure of a molecule found in olive oil can be represented as shown

(a) Olive oil can be hydrolysed using sodium hydroxide solution to produce sodium salts of fatty acids Name the other product of this reaction (1)

(b) In what way does the structure of a fat molecule differ from that of an oil molecule (1)

(c) Over time open containers of olive oil develop a rancid flavour What substance is reacting with the oil to cause these unwanted changes to take place (1)

23 A student writes the following statement It is incorrect Explain the mistake in the studentrsquos reasoning (1)

Alcohols are alkaline because of their OH groups

24 Carbon compounds take part in a wide variety of chemical reactions (a)

Name this type of chemical reaction (1)

(b)

Draw a structural formula for C3H6O (1)

25 Alkanols can be oxidised to alkanoic acids

32

(a) Why can Step 1 be described as an oxidation reaction (1)

(b) Acidified potassium dichromate solution can be used to oxidise propanal in Step 2 What colour change would be observed in this reaction (1)

26 Amines can be produced by reacting ammonia with an aldehyde or a ketone This reaction an example of reductive amination occurs in two stages

Stage 1 Amination

Stage 2 Reduction

(a) Give another name for the type of reaction taking place in Stage 2

(b) Draw the structural formula for the amine produced when butanal undergoes reductive amination with ammonia

27 Using a cobalt catalyst alkenes react with a mixture of hydrogen and carbon monoxideThe products are two isomeric aldehydes Propene reacts with the mixture as shown

(a) What name is given to a mixture of hydrogen and carbon monoxide (1)

(b) Draw a structural formula for compound B (1)

(c) (i) What would be observed if compound A was gently heated with Tollensrsquo reagent

(1)(ii) How would the reaction mixture be heated (1)

33

(d) Aldehydes can also be formed by the reaction of some alcohols with copper(II) oxideName the type of alcohol that would react with copper(II) oxide to form an aldehyde (1)

28 Aldehydes and ketones can take part in a reaction sometimes known as an aldol condensation The simplest aldol reaction involves two molecules of ethanal

In the reaction the carbon atom next to the carbonyl functional group of one molecule forms a bond with the carbonyl carbon atom of the second molecule

(a) Draw a structural formula for the product formed when propanone is used instead of ethanal in this type of reaction (1)

(b) Name an aldehyde that would not take part in an aldol condensation (1)

(c) Apart from the structure of the reactants suggest what is unusual about applying the term ldquocondensationrdquo to this particular type of reaction (1)

29 Primary secondary and tertiary alkanols can be prepared by the reaction of carbonyl compounds with Grignard reagents

Step 1The Grignard reagent reacts with the carbonyl compound

Step 2The reaction of the product of Step 1 with dilute acid produces the alkanol

(a) Describe the difference between a primary a secondary and a tertiary alkanol

You may wish to include labelled structures in your answer (1)34

(b) Suggest a name for the type of reaction that takes place in Step 1 (1)

(c) The same Grignard reagent can be used to produce the alkanol below

Name the carbonyl compound used in this reaction (1)

30 Hairspray is a mixture of chemicals(a) A primary alcohol 2-methylpropan-1-ol is added to hairspray to help it dry quickly on the hair

Draw a structural formula for a secondary alcohol that is an isomer of2-methylpropan-1-ol (1)

(b) Triethanol amine and triisopropyl amine are bases used to neutralise acidic compounds in the hairspray to prevent damage to the hair

In terms of the intermolecular bonding present explain clearly why triethanol amine has a much higher boiling point than triisopropyl amine (2)

35

36

31 Chocolate contains various compounds(a) Many of the flavour and aroma molecules found in chocolate are aldehydes and

ketones Two examples are shown below

Phenylethanal can be easily oxidised but 13-diphenylpropan-2-one cannot(i) Name a chemical that could be used to distinguish between these two

compounds (1)

(ii) Name the type of organic compound formed when phenylethanal is oxidised (1)

(b) Glycerol monostearate is an emulsifier used in chocolate

(i) Why is glycerol monostearate added to chocolate (1)

(ii) Draw a structural formula for glycerol (1)

(c) Theobromine a compound present in chocolate can cause illness in dogs and cats To decide if treatment is necessary vets must calculate the mass of theobromine consumed 1middot0 g of chocolate contains 1middot4 mg of theobromine Calculate the mass in mg of theobromine in a 17 g biscuit of which 28 is chocolate Show your working clearly (2)

(d) The flavour and texture of chocolate comes from a blend of compoundsUsing your knowledge of chemistry describe how you could show that there are ionic compounds and covalent compounds present in chocolate (3)

37

32 Ethanol has many uses

(a) Ethanol is found at relatively low concentrations in wine

(i) Name the chemical reaction that produces ethanol in wine (1)

(ii) Standard ethanol solutions were used to produce a graph of density against

concentration of ethanol given as a percentage of alcohol by volume ( abv)

What is the concentration of ethanol in units of abv in a solution of density 0middot9818 g cmminus3 (1)

(b) Whisky contains a higher concentration of ethanol

(i) Before 1980 the concentration of alcohol in drinks was measured in terms of degrees proof The concentration of alcohol in two drinks is shown in the table below both as abv and degrees proof

38

A cask strength whisky has an alcohol concentration of 65 abv Calculate the alcohol concentration of this whisky in degrees proof (1)

(ii) A barrel containing 195 litres of cask strength whisky costs pound1300 The cask strength whisky is diluted with water to reduce the concentration of alcohol from 65 abv to 46 abv before it is bottled Calculate the cost of the cask strength whisky needed to produce a 0middot70 litre bottle Show your working clearly (2)

(iii) 5-Butyl-4-methyltetrahydrofuran-2-ol is a flavour compound found in whisky

stored in oak barrels

Write the systematic name for the compound shown below (1) 13 11

33 (a) One test for glucose involves Fehlingrsquos solutionCircle the part of the glucose molecule that reacts with Fehlingrsquos solution (1)

(b) In solution sugar molecules exist in an equilibrium in straight-chain and ring forms

To change from the straight-chain form to the ring form the oxygen of the hydroxyl on carbon number 5 joins to the carbonyl carbon This is shown below for glucose

39

Draw the structure of a ring form for fructose (1)

34 (a) During the free radical chain reaction small molecules join to form large chain molecules

One example of a small molecule used is

Name the functional group circled above (1)

(b)Alcohol wipes are used to finish the varnishing treatment Alcohol wipes contain the alcohol propan-2-olState why propan-2-ol can be described as a secondary alcohol (1)

35 A student was carrying out an investigation into alcohols aldehydes and ketones

(a)The student was given three alcohols labelled as A B and C These alcohols were all isomers with the formula C4H9OH

(i) Draw a structural formula for the secondary alcohol with the formula C4H9OH(1)

(ii) The student set up the following experiment

A Suggest why a water bath is an appropriate method of heating the reaction mixture (1)

B Describe the colour change that would have been observed with alcohols A and C (1)

40

C Alcohol B is not oxidised State the type of alcohol which cannot be oxidised by acidified dichromate solution (1)

(iii) The student set up a second experiment with alcohol A

Hot copper(II) oxide is an oxidising agentA When alcohol A (C4H9OH) is oxidised the product turns the pH paper

redSuggest a name for the product (1)

B Complete the ion-electron equation for the oxidation reaction

C4H9OH rarr C4H8O2 (1)

(b)The student found the following information about the boiling points of some aldehydes

41

(i) Name the aldehyde that has a boiling point of 119 degC (1)(ii) Predict the boiling point in degC of the following molecule (1)

(iii) Using information from the table describe one way in which differences in structure affect the boiling point of isomeric aldehydes (1)

(iv) State what would be observed when an aldehyde is gently heated with Tollensrsquo reagent (1)

(c) Ketones contain a carbonyl groupName the type of intermolecular interaction between ketone molecules (1)

42

25 Soaps Detergents and Emulsions

1 Soaps are produced by the following reaction

This reaction is an example ofA condensationB esterificationC hydrolysisD oxidation

2 Which of the following is the salt of a long-chain fatty acid

A FatB OilC SoapD Glycerol

3 Emulsifiers for use in food are commonly made by reacting edible oils with

A estersB glycerolC fatty acidsD amino acids

4 A fatty acid is a long chain carboxylic acid Examples of fatty acids are shown in the table below

43

(a) What is the systematic name for linolenic acid (1)(b) Stearic acid reacts with sodium hydroxide solution to form sodium stearate

(i) Name the type of reaction taking place when stearic acid reacts with sodium hydroxide (1)

(ii) Explain fully how sodium stearate acts to keep grease and non-polar substances suspended in water during cleaning (3)

5 Small children can find it difficult to swallow tablets or pills so ibuprofen is supplied as an ldquoinfant formulardquo emulsion(a) The emulsifier used is polysorbate 80 Its structure is shown below

Explain why this molecule acts as an emulsifier (2)

(b) The emulsion contains 2 g of ibuprofen in every 100 cm3 of emulsion The recommended dose for treating a 6 month old baby is 0middot050 g Calculate the volume in cm3 of ldquoinfant formulardquo needed to treat a 6 month old baby (1)

6 Occasionally seabirds can become contaminated with hydrocarbons from oil spills This causes problems for birds because their feathers lose their waterproofing making the birds susceptible to temperature changes and

44

affecting their buoyancy If the birds attempt to clean themselves to remove the oil they may swallow the hydrocarbons causing damage to their internal organsContaminated seabirds can be cleaned by rubbing vegetable oil into their feathers and feet before the birds are rinsed with diluted washing-up liquidUsing your knowledge of chemistry comment on the problems created for seabirds by oil spills and the actions taken to treat affected birds (3)

7 Dishwasher tablets contain chemicals which remove dirt from dishesDishwasher tablets include detergents These molecules act like soaps to allow mixing of fat-soluble dirt and water(a)During the cleaning process the detergent molecules combine with fat-

soluble dirtA simplified diagram of a detergent molecule is shown

Complete the diagram below to show how detergent molecules combine with fat-soluble dirt (1)

(b)State the term used to describe the non-polar hydrocarbon tail of a detergent molecule (1)

45

26 Fragrances1 Myrcene is a simple terpene

Terpenes contain at least one isoprene unit Which of the following shows a correctly highlighted isoprene unit

2 Limonene is one of the terpene molecules responsible for the flavour of lemons

How many isoprene units are used in the production of one limonene moleculeA 1B 2C 3D 4

46

3 The structure of caryophyllene which can be extracted from clove oil is

Which of the following would be the best solvent for extracting caryophylleneA HexaneB HexanalC HexanolD Hexanone

4 The structure of isoprene is

Limonene is a terpene molecule present in lemons

How many isoprene units are joined together in a limonene molecule

A 1B 2

47

C 3D 4

5 Essential oils are

A non-water soluble non-volatile compoundsB non-water soluble volatile compoundsC water soluble non-volatile compoundsD water soluble volatile compounds

6 Two typical compounds that are present in many perfumes are shown

(a) Why does geraniol evaporate more slowly than limonene (1)

(b) The structure of one of the first synthetic scents used in perfume is shown below

(i) Name the family of carbonyl compounds to which this synthetic scent belongs (1)

(ii) Complete the structure below to show the product formed when this scent is

oxidised (1)

(c) Traces of a liquid were discovered in a bottle believed to contain perfume belonging to Queen Hatshepsut ruler of Egypt over 3500 years ago

Perfumes were made by dissolving plant extracts containing pleasant smelling terpenes and esters in an edible oil A little ethanol and water may also have been addedUsing your knowledge of chemistry comment on the possible smell(s) when such a bottle is opened after being stored for thousands of years (3)

48

49

7 A team of chemists are developing a fragrance for use in a shower gel for men(a) To give the gel a fruity smell the chemists are considering adding an ester

They synthesise six isomeric esters Volunteers smell each ester and give it a rating out of one hundred depending on how fruity the smell is

(i) Name the ester with the fruit-smell rating of 92 (1)

(ii) Shown below are the structures of three more isomers

Arrange these esters in order of decreasing fruit-smell rating (1)

50

(b) To create a fragrance for men the compound civetone is added

Draw a structural formula for the alcohol that can be oxidised to form civetone (1)

(c) To make the shower gel produce a cold tingling sensation when applied to the skin menthol is added

Like terpenes menthol is formed from isoprene (2-methylbuta-13-diene)Circle an isoprene unit on the menthol structure above (1)

8 Many of the compounds in perfumes are molecules consisting of joined isoprene units

(a) State the name that is given to molecules consisting of joined isoprene units (1)

(b)Geraniol is one of the compounds found in perfume It has the following structural formula and systematic name

Linalool can also be present Its structural formula is shown

51

(i) State the systematic name for linalool (1)(ii) Explain why linalool can be classified as a tertiary alcohol (1)

9 The component molecules found in lavender oils are terpenes or terpenoids(a)A chiral carbon is a carbon atom attached to four different atoms or groups of

atomsAn example is shown below

A molecule of the terpenoid linalool has a chiral carbon Linalool has the following structure

Circle the chiral carbon atom in the linalool structure (1)

(b)Farnesene is a terpene consisting of three isoprene units (2-methylbuta-13-diene) joined togetherWrite the molecular formula of farnesene (1)

52

27 Skin Care

1 Which of the following is not a step in a free radical chain reaction

A ActivationB InitiationC PropagationD Termination

2 Fluorine reacts with methane via a free radical chain reaction Some steps in the chain reaction are shown in the table below

Complete the table by(a) inserting the missing name for the first step (1)

(b) showing another possible termination reaction in the final row of the table (1)

3 Suncreams contain antioxidantsThe antioxidant compound A can prevent damage to skin by reacting with free

radicalssuch as NO2bull

53

Why can compound A be described as a free radical scavenger in the reaction shown above

4 Hydrogen and chlorine gases are used in an experiment to demonstrate a free radical reaction A plastic bottle is wrapped with black tape leaving a ldquowindowrdquo on one sideThe bottle is filled with a mixture of hydrogen and chlorine When bright light shines on the bottle there is an explosion

A free radical chain reaction is initiated when light energy causes chlorine radicals to form as shown below

(a) Complete the equations below showing possible propagation and termination steps

(2)

54

(b) Why is the plastic bottle used in the experiment wrapped in black tape (1)

5 Chloramines can be removed from water using ultraviolet light treatment

One step in the process is the formation of free radicals

(a)State what is meant by the term free radical (1)

(b)Another step in the process is shown below

State the name for this type of step in a free radical reaction (1)

6 Modern shellac nail varnishes are more durable and so last longer than traditional nail polish

The shellac nail varnish is applied in thin layers to the nails and then the fingers are placed under a UV lamp

(a) The Skin Care Foundation has recommended that a sun-block is applied to the fingers and hand before using the lampSuggest why the Skin Care Foundation makes this recommendation (1)

(b) A free radical chain reaction takes place and the varnish hardens (i) State what is meant by the term free radical (1)

(ii) The shellac nail varnish contains a mixture of ingredients that take part in the free radical chain reactionOne of the steps in the free radical chain reaction is

55

State the term used to describe this type of step in a free radical chain reaction(1)

7 Skin care products contain a mixture of polar covalent non-polar covalent and ionic compounds The compounds need to stay mixed within the product Skin care products also need to spread easily and remain on the skin for a period of time as well as provide physical and chemical protection from the sun In order to do this skin care products contain a range of chemicals including water fats and oils antioxidants minerals and sun blockUsing your knowledge of chemistry explain the role of different chemicals in skin care products (3)

General Questions

1 A mixture of carbon monoxide and hydrogen can be converted into water and a mixture of hydrocarbons

nCO + (2n + 1)H2 rarr nH2O + hydrocarbons

What is the general formula for the hydrocarbons producedA CnH2nndash2B CnH2nC CnH2n+1D CnH2n+2

2 Butadiene is the first member of a homologous series of hydrocarbons called dienesWhat is the general formula for this seriesA CnHn+2B CnHn+3C CnH2nD CnH2nndash2

3 Which of the following statements about methanol is falseA It can be made from synthesis gasB It can be dehydrated to form an alkeneC It can be oxidised to give a carboxylic acidD It reacts with acidified potassium dichromate solution

56

4

Which line in the table correctly describes reactions X and Y

5

Which line in the table correctly describes reactions X and Y

6 Which of the following fuels when burned would make no contribution to globalwarming

57

A HydrogenB Natural gasC PetrolD Coal

7 Which of the following hydrocarbons always gives the same product when one of itshydrogen atoms is replaced by a chlorine atomA HexaneB Hex-1-eneC CyclohexaneD Cyclohexene

8 Which of the following compounds does not have isomeric structuresA C2HCl3B C2H4Cl2C PropeneD Propan-1-ol

9 What organic compound is produced by the dehydration of ethanol A EthaneB EtheneC EthanalD Ethanoic acid

10

The above equation representsA hydrationB hydrogenationC condensationD hydrolysis

11

Which of the following compounds is an isomer of the structure shown aboveA ButanalB ButanoneC Butan-1-olD Butanoic acid

58

12 A compound with molecular formula C6H12O2 could beA hexanalB hexan-2-olC hexan-2-oneD hexanoic acid

13 Propan-2-ol can be prepared from propane as follows

Which line in the table correctly describes the types of reaction taking place at Steps 1 and 2

14 Which of the following compounds would be the most water soluble

15 Cyanohydrin compounds can be made from carbonyl compounds by reacting the carbonyl compound with hydrogen cyanide (HCN)

59

Which carbonyl compound would react with hydrogen cyanide (HCN) to form the following compound

16 Ethyne is the first member of the homologous series called the alkynes

Ethyne can undergo addition reactions as shown in the flow diagram

(a) Compound 2 is an isomer of 12-dichloroethaneDraw a structural formula for compound 2 (1)

(b) Reagents A B and C are three different diatomic gasesUsing information in the flow diagram identify reagents A B and C (1)

60

Reagent Gas

A

B

C

17 In 1865 the German chemist Kekuleacute proposed a ring structure for benzene This structure was based on alternating single and double bonds

(a) (i) Describe a chemical test that would indicate that the above chemical structure for benzene is incorrect (1)

(ii) Briefly describe the correct structure for benzene (1)

(b) Benzene can be formed from cyclohexaneC6H12 rarr C6H6 + 3H2

What name is given to this type of reaction (1)18 Infra-red spectroscopy is a technique that can be used to identify the bonds that

arepresent in a molecule Different bonds absorb infra-red radiation of different wavenumbers This is due to differences in the bond lsquostretchrsquo These absorptions are recorded in a spectrumA spectrum for propan-1-ol is shown

61

The correlation table on page 13 of the data booklet shows the wavenumber ranges for the absorptions due to different bonds

(a) Use the correlation table to identify the bonds responsible for the two absorptions x and y that are circled in the propan-1-ol spectrum (1)

(b) Propan-1-ol reacts with ethanoic acid(i) What name is given to this type of reaction (1)(ii) Draw a spectrum that could be obtained for the organic product of this

reaction (1)

19 Paracetamol is a widely used painkiller

(a) Write the molecular formula for paracetamol (1)

(b) One antidote for paracetamol overdose is methionine

62

To what family of organic compounds does methionine belong (1)

(c) The concentration of paracetamol in a solution can be determined by measuring how much UV radiation it absorbs

The graph shows how the absorbance of a sample containing 0middot040 g l ndash1 paracetamol varies with wavelength

The quantity of UV radiation of wavelength 245 nm absorbed is directly proportional to the concentration of paracetamolThe absorbance of a second sample of paracetamol solution measured at 245 nm was 0middot90 What is the concentration in g l ndash1 of this second paracetamol solution (1)

20 Many carbon compounds containing oxygen are very flammableThe table shows information about two families of isomersThe lowest temperature at which a compound will ignite is called its flash point

(a) A compound with the molecular formula C6H14O has a boiling point of 158 degC63

Draw a structural formula for this compound (1)

(b) For a family of isomers in the table write a general statement linking the flash points of the compounds to their structures (1)

21 Hydrogels are used in disposable nappies They are fine powders that can absorb up to 500 times their own weight in waterA hydrogel is a very long molecule with carboxyl groups at regular intervals along its length A short section of a hydrogel molecule is shown below

Hydrogels are extremely good at soaking up water because the water molecules are strongly attracted to them

Using your knowledge of chemistry comment on how suitable hydrogels would be for absorbing liquids or solutions spilled in a chemistry lab (1)

64

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

(ii) How many hydrogen atoms are present in a molecule of phenylalanine (1)

(b) Phenylalanine and alanine can react to form the dipeptide shown

Circle the peptide link in this molecule (1)

(c) Draw a structural formula for the other dipeptide that can be formed from phenylalanine and alanine (1)

16 Uncooked egg white is mainly composed of dissolved proteins During cooking processes the proteins become denatured as the protein chains unwind and the egg white solidifies

(a) Explain why the protein chains unwind (1)

(b)The temperature at which the protein becomes denatured is called the melting temperature The melting temperature of a protein can be determined using fluorescence In this technique the protein is mixed with a dye that gives out visible light when it attaches to hydrophobic parts of the protein molecule The hydrophobic parts of the structure are on the inside of the protein and the dye has no access to them unless the protein unwinds

(i) Ovalbumin is a protein found in egg white Part of the structure of unwound ovalbumin is shown below

Circle the part of the structure to which the hydrophobic dye is most likely to attach (1)

17

(ii) Another protein in egg white is conalbumin The temperature of a conalbumindye mixture is gradually increased The fluorescence is measured and a graph is produced

The melting temperature is the temperature at which the fluorescence is halfway between the highest and lowest fluorescence valuesDetermine the melting temperature in ordmC for this protein (1)

(c) Once cooked and eaten the digestive system breaks the protein chains into amino acids with the help of enzymes

(i) State the name of the digestion process where enzymes break down proteins into amino acids (1)

(ii)

(A) State how many amino acid molecules joined to form this section of protein (1)

(B) Draw the structure of one amino acid that would be produced when this section of the protein chain is broken down (1)

17 Peptide molecules can be classified according to the number of amino acid units joined by peptide bonds in the molecule

18

(a) Complete the table to identify the type of peptide with the following amino acid sequence

alanine-glycine-valine-proline-tyrosine-serine (1)

(b) Partial hydrolysis of another pentapeptide molecule gave a mixture of three smaller peptide molecules with the following amino acid sequences

leucine-glycine-valineisoleucine-leucineglycine-valine-serine

Write the amino acid sequence for the original pentapeptide molecule (1)

helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip(c) Some amino acids needed to form polypeptides cannot be produced in the human body

State the term used to describe amino acids that the body cannot make (1)

(d)Paper chromatography is often used to analyse the mixtures of amino acids produced when peptides are broken downOn a chromatogram the retention factor Rf for a substance can be a useful method of identifying the substance

The structure of the pentapeptide methionine enkephalin was investigatedA sample of the pentapeptide was completely hydrolysed into its constituent amino acids and this amino acid mixture was applied to a piece of chromatography paper and placed in a solventThe chromatogram obtained is shown below

19

(i) Suggest why only four spots were obtained on the chromatogram of the hydrolysed pentapeptide (1)

(ii) It is known that this amino acid mixture contains the amino acid methionine The Rf value for methionine in this solvent is 040Draw a circle around the spot on the chromatogram that corresponds to methionine (1)

(e) Over the last decade several families of extremely stable peptide molecules have been discovered where the peptide chain forms a ring

(i) A simple cyclic dipeptide is shown

Draw a structural formula for one of the amino acids that would be formed on complete hydrolysis of the above cyclic dipeptide (1)

(ii) Alpha-amanitin is a highly toxic cyclic peptide found in death cap mushrooms The lethal dose for humans is 100 mg per kg of body mass1middot0 g of death cap mushrooms contains 250 mg of alpha-amanitinCalculate the minimum mass of death cap mushrooms that would contain the lethal dose for a 75 kg adult (2)

18 Dishwasher tablets produce the bleach hydrogen peroxide H2O2 One action of this oxidising agent is to oxidise food

(a)(i) Suggest another action of the bleach produced by the dishwasher tablets (1)

20

(ii) Hydrogen peroxide decomposes to form water and oxygen

2H2O2(ℓ) rarr 2H2O(ℓ) + O2(g)

A dishwasher tablet produces 0middot051 g of hydrogen peroxide (mass of one mole = 34 g)

Calculate the volume of oxygen that would be produced when0middot051 g of hydrogen peroxide decomposesTake the volume of 1 mole of oxygen gas to be 24 litres(3)

(b)Enzymes are commonly added to dishwasher tablets These are used to break down proteins(i) The proteins are broken down into small water-soluble molecules

Name the small water-soluble molecules made when proteins are broken down completely (1)

(ii) The structure of a section of protein chain found in egg white is shown

(A)Name the functional group circled (1)(B)Draw a structural formula for one of the molecules that would be made

when this section of egg white protein chain is completely broken down (1)

(iii) As part of the program in the dishwasher the conditions in the dishwasher change so that the enzyme molecules no longer work because they change shape

21

(A) State the term used to describe the change in shape of enzyme molecules(1)

(B) Suggest a change in conditions which would cause the enzyme molecules to change shape (1)

(d) A bleach activator is frequently added to dishwasher tablets to speed up the bleaching reaction One common bleach activator is TAED TAED could be produced in a process which involves a number of stages

(i) The first stage in producing TAED is shown below

Suggest a name for this type of reaction (1)

(ii) The final stage in the process producing TAED is shown below

Draw a structural formula for TAED (1)

22

23 The Chemistry of Cooking

1 Vanillin and zingerone are flavour molecules

Which line in the table correctly compares the properties of vanillin and zingerone

23

2 Erythrose can be used in the production of a chewing gum that helps prevent tooth decay

Which of the following compounds will be the best solvent for erythrose

3 The following molecules give flavour to food Which of the following flavour molecules would be most likely to be retained in the food when the food is cooked in water

24

4 Cooking involves many chemical reactions Proteins fats oils and esters are some examples of compounds found in food A chemist suggested that cooking food could change compounds from being fat-soluble to water-soluble Use your knowledge of chemistry to comment on the accuracy of this statement(3)

25

24 The Oxidation of Food

1 Apples and bananas turn brown when cut or bruised The first step of the reaction causing

the browning is shown below

Which of the following terms correctly describes this reactionA ReductionB OxidationC DehydrationD Condensation

2 Which of the following reactions can be classified as reductionA CH3CH2OH rarr CH3COOHB CH3 CH(OH)CH3 rarr CH3COCH3C CH3CH2COCH3 rarr CH3CH2CH(OH)CH3D CH3CH2CHO rarr CH3CH2COOH

3 The dehydration of butan-2-ol can produce two isomeric alkenes but-1-ene andbut-2-ene Which of the following alkanols can similarly produce on dehydration a pair of isomeric alkenesA Propan-2-olB Pentan-3-olC Hexan-3-olD Heptan-4-ol

4 Which of the following compounds is an alkanone

26

5 Which of the following is an aldehyde

6 Which of the following compounds would react with sodium hydroxide solution to forma saltA CH3CHOB CH3COOHC CH3COCH3D CH3CH2OH

7 Which line in the table shows the correct functional group for each homologous series

8 Which of the following organic compounds is an isomer of hexanalA 2-MethylbutanalB 3-Methylpentan-2-oneC 22-Dimethylbutan-1-olD 3-Ethylpentanal

27

9 The name of this compound is

A methanolB methanalC methanoic acidD methanone

10 Which alcohol could be oxidised to a carboxylic acid

11 Which of the following structural formulae represents a tertiary alcohol

12 Compound X reacted with hot copper(II) oxide and the organic product did not give acolour change when heated with Fehlingrsquos solution Compound X could beA butan-1-olB butan-2-olC butanoneD butanoic acid

28

13 Which two isomers would each produce an acid when warmed with acidified potassiumdichromate solution

A 1 and 2B 2 and 3C 1 and 4D 3 and 4

14 After heating for several minutes as shown in the diagram the pH indicator solution turned red

Liquid Q could beA propanoneB paraffinC propan-1-olD propan-2-ol

29

15 Enzymes are involved in the browning of cut fruitOne reaction taking place is

Which of the following correctly describes the above reaction

A OxidationB ReductionC HydrolysisD Condensation

16 Which of the following statements is correct for ketones

A They are formed by oxidation of tertiary alcohols

B They contain the group

C They contain a carboxyl groupD They will not react with Fehlingrsquos solution

17 Carvone is a natural product that can be extracted from orange peel

Which line in the table correctly describes the reaction of carvone with bromine solution and with acidified potassium dichromate solution

30

18 Which of the following is an isomer of 22-dimethylpentan-1-ol

A CH3CH2CH2CH(CH3)CH2OHB (CH3)3CCH(CH3)CH2OHC CH3CH2CH2CH2CH2CH2CH2CH2OHD (CH3)2CHC(CH3)2CH2CH2OH

19 The equation for the reduction reaction taking place when ethanal reacts with Tollensrsquo reagent is

A Cu2+(aq) + eminus rarr Cu+(aq)

B Ag+(aq) + eminus rarr Ag(s)

C Cr2O72minus(aq) + 14H+(aq) + 6eminus rarr 2Cr3+(aq) + 7H2O(ℓ)

D MnO4minus(aq) + 8H+(aq) + 5eminus rarr Mn2+(aq) + 4H2O(ℓ)

20 The name of the compound with structure

isA 23-dimethylpentan-4-oneB 23-dimethylpentan-2-alC 34-dimethylpentan-2-oneD 34-dimethylpentan-2-al

21 What is the systematic name for the compound below

A 222-trimethylethanolB 22-dimethylpropan-1-olC 22-dimethylpropan-3-olD 22-dimethylpentan-1-ol

31

22 The structure of a molecule found in olive oil can be represented as shown

(a) Olive oil can be hydrolysed using sodium hydroxide solution to produce sodium salts of fatty acids Name the other product of this reaction (1)

(b) In what way does the structure of a fat molecule differ from that of an oil molecule (1)

(c) Over time open containers of olive oil develop a rancid flavour What substance is reacting with the oil to cause these unwanted changes to take place (1)

23 A student writes the following statement It is incorrect Explain the mistake in the studentrsquos reasoning (1)

Alcohols are alkaline because of their OH groups

24 Carbon compounds take part in a wide variety of chemical reactions (a)

Name this type of chemical reaction (1)

(b)

Draw a structural formula for C3H6O (1)

25 Alkanols can be oxidised to alkanoic acids

32

(a) Why can Step 1 be described as an oxidation reaction (1)

(b) Acidified potassium dichromate solution can be used to oxidise propanal in Step 2 What colour change would be observed in this reaction (1)

26 Amines can be produced by reacting ammonia with an aldehyde or a ketone This reaction an example of reductive amination occurs in two stages

Stage 1 Amination

Stage 2 Reduction

(a) Give another name for the type of reaction taking place in Stage 2

(b) Draw the structural formula for the amine produced when butanal undergoes reductive amination with ammonia

27 Using a cobalt catalyst alkenes react with a mixture of hydrogen and carbon monoxideThe products are two isomeric aldehydes Propene reacts with the mixture as shown

(a) What name is given to a mixture of hydrogen and carbon monoxide (1)

(b) Draw a structural formula for compound B (1)

(c) (i) What would be observed if compound A was gently heated with Tollensrsquo reagent

(1)(ii) How would the reaction mixture be heated (1)

33

(d) Aldehydes can also be formed by the reaction of some alcohols with copper(II) oxideName the type of alcohol that would react with copper(II) oxide to form an aldehyde (1)

28 Aldehydes and ketones can take part in a reaction sometimes known as an aldol condensation The simplest aldol reaction involves two molecules of ethanal

In the reaction the carbon atom next to the carbonyl functional group of one molecule forms a bond with the carbonyl carbon atom of the second molecule

(a) Draw a structural formula for the product formed when propanone is used instead of ethanal in this type of reaction (1)

(b) Name an aldehyde that would not take part in an aldol condensation (1)

(c) Apart from the structure of the reactants suggest what is unusual about applying the term ldquocondensationrdquo to this particular type of reaction (1)

29 Primary secondary and tertiary alkanols can be prepared by the reaction of carbonyl compounds with Grignard reagents

Step 1The Grignard reagent reacts with the carbonyl compound

Step 2The reaction of the product of Step 1 with dilute acid produces the alkanol

(a) Describe the difference between a primary a secondary and a tertiary alkanol

You may wish to include labelled structures in your answer (1)34

(b) Suggest a name for the type of reaction that takes place in Step 1 (1)

(c) The same Grignard reagent can be used to produce the alkanol below

Name the carbonyl compound used in this reaction (1)

30 Hairspray is a mixture of chemicals(a) A primary alcohol 2-methylpropan-1-ol is added to hairspray to help it dry quickly on the hair

Draw a structural formula for a secondary alcohol that is an isomer of2-methylpropan-1-ol (1)

(b) Triethanol amine and triisopropyl amine are bases used to neutralise acidic compounds in the hairspray to prevent damage to the hair

In terms of the intermolecular bonding present explain clearly why triethanol amine has a much higher boiling point than triisopropyl amine (2)

35

36

31 Chocolate contains various compounds(a) Many of the flavour and aroma molecules found in chocolate are aldehydes and

ketones Two examples are shown below

Phenylethanal can be easily oxidised but 13-diphenylpropan-2-one cannot(i) Name a chemical that could be used to distinguish between these two

compounds (1)

(ii) Name the type of organic compound formed when phenylethanal is oxidised (1)

(b) Glycerol monostearate is an emulsifier used in chocolate

(i) Why is glycerol monostearate added to chocolate (1)

(ii) Draw a structural formula for glycerol (1)

(c) Theobromine a compound present in chocolate can cause illness in dogs and cats To decide if treatment is necessary vets must calculate the mass of theobromine consumed 1middot0 g of chocolate contains 1middot4 mg of theobromine Calculate the mass in mg of theobromine in a 17 g biscuit of which 28 is chocolate Show your working clearly (2)

(d) The flavour and texture of chocolate comes from a blend of compoundsUsing your knowledge of chemistry describe how you could show that there are ionic compounds and covalent compounds present in chocolate (3)

37

32 Ethanol has many uses

(a) Ethanol is found at relatively low concentrations in wine

(i) Name the chemical reaction that produces ethanol in wine (1)

(ii) Standard ethanol solutions were used to produce a graph of density against

concentration of ethanol given as a percentage of alcohol by volume ( abv)

What is the concentration of ethanol in units of abv in a solution of density 0middot9818 g cmminus3 (1)

(b) Whisky contains a higher concentration of ethanol

(i) Before 1980 the concentration of alcohol in drinks was measured in terms of degrees proof The concentration of alcohol in two drinks is shown in the table below both as abv and degrees proof

38

A cask strength whisky has an alcohol concentration of 65 abv Calculate the alcohol concentration of this whisky in degrees proof (1)

(ii) A barrel containing 195 litres of cask strength whisky costs pound1300 The cask strength whisky is diluted with water to reduce the concentration of alcohol from 65 abv to 46 abv before it is bottled Calculate the cost of the cask strength whisky needed to produce a 0middot70 litre bottle Show your working clearly (2)

(iii) 5-Butyl-4-methyltetrahydrofuran-2-ol is a flavour compound found in whisky

stored in oak barrels

Write the systematic name for the compound shown below (1) 13 11

33 (a) One test for glucose involves Fehlingrsquos solutionCircle the part of the glucose molecule that reacts with Fehlingrsquos solution (1)

(b) In solution sugar molecules exist in an equilibrium in straight-chain and ring forms

To change from the straight-chain form to the ring form the oxygen of the hydroxyl on carbon number 5 joins to the carbonyl carbon This is shown below for glucose

39

Draw the structure of a ring form for fructose (1)

34 (a) During the free radical chain reaction small molecules join to form large chain molecules

One example of a small molecule used is

Name the functional group circled above (1)

(b)Alcohol wipes are used to finish the varnishing treatment Alcohol wipes contain the alcohol propan-2-olState why propan-2-ol can be described as a secondary alcohol (1)

35 A student was carrying out an investigation into alcohols aldehydes and ketones

(a)The student was given three alcohols labelled as A B and C These alcohols were all isomers with the formula C4H9OH

(i) Draw a structural formula for the secondary alcohol with the formula C4H9OH(1)

(ii) The student set up the following experiment

A Suggest why a water bath is an appropriate method of heating the reaction mixture (1)

B Describe the colour change that would have been observed with alcohols A and C (1)

40

C Alcohol B is not oxidised State the type of alcohol which cannot be oxidised by acidified dichromate solution (1)

(iii) The student set up a second experiment with alcohol A

Hot copper(II) oxide is an oxidising agentA When alcohol A (C4H9OH) is oxidised the product turns the pH paper

redSuggest a name for the product (1)

B Complete the ion-electron equation for the oxidation reaction

C4H9OH rarr C4H8O2 (1)

(b)The student found the following information about the boiling points of some aldehydes

41

(i) Name the aldehyde that has a boiling point of 119 degC (1)(ii) Predict the boiling point in degC of the following molecule (1)

(iii) Using information from the table describe one way in which differences in structure affect the boiling point of isomeric aldehydes (1)

(iv) State what would be observed when an aldehyde is gently heated with Tollensrsquo reagent (1)

(c) Ketones contain a carbonyl groupName the type of intermolecular interaction between ketone molecules (1)

42

25 Soaps Detergents and Emulsions

1 Soaps are produced by the following reaction

This reaction is an example ofA condensationB esterificationC hydrolysisD oxidation

2 Which of the following is the salt of a long-chain fatty acid

A FatB OilC SoapD Glycerol

3 Emulsifiers for use in food are commonly made by reacting edible oils with

A estersB glycerolC fatty acidsD amino acids

4 A fatty acid is a long chain carboxylic acid Examples of fatty acids are shown in the table below

43

(a) What is the systematic name for linolenic acid (1)(b) Stearic acid reacts with sodium hydroxide solution to form sodium stearate

(i) Name the type of reaction taking place when stearic acid reacts with sodium hydroxide (1)

(ii) Explain fully how sodium stearate acts to keep grease and non-polar substances suspended in water during cleaning (3)

5 Small children can find it difficult to swallow tablets or pills so ibuprofen is supplied as an ldquoinfant formulardquo emulsion(a) The emulsifier used is polysorbate 80 Its structure is shown below

Explain why this molecule acts as an emulsifier (2)

(b) The emulsion contains 2 g of ibuprofen in every 100 cm3 of emulsion The recommended dose for treating a 6 month old baby is 0middot050 g Calculate the volume in cm3 of ldquoinfant formulardquo needed to treat a 6 month old baby (1)

6 Occasionally seabirds can become contaminated with hydrocarbons from oil spills This causes problems for birds because their feathers lose their waterproofing making the birds susceptible to temperature changes and

44

affecting their buoyancy If the birds attempt to clean themselves to remove the oil they may swallow the hydrocarbons causing damage to their internal organsContaminated seabirds can be cleaned by rubbing vegetable oil into their feathers and feet before the birds are rinsed with diluted washing-up liquidUsing your knowledge of chemistry comment on the problems created for seabirds by oil spills and the actions taken to treat affected birds (3)

7 Dishwasher tablets contain chemicals which remove dirt from dishesDishwasher tablets include detergents These molecules act like soaps to allow mixing of fat-soluble dirt and water(a)During the cleaning process the detergent molecules combine with fat-

soluble dirtA simplified diagram of a detergent molecule is shown

Complete the diagram below to show how detergent molecules combine with fat-soluble dirt (1)

(b)State the term used to describe the non-polar hydrocarbon tail of a detergent molecule (1)

45

26 Fragrances1 Myrcene is a simple terpene

Terpenes contain at least one isoprene unit Which of the following shows a correctly highlighted isoprene unit

2 Limonene is one of the terpene molecules responsible for the flavour of lemons

How many isoprene units are used in the production of one limonene moleculeA 1B 2C 3D 4

46

3 The structure of caryophyllene which can be extracted from clove oil is

Which of the following would be the best solvent for extracting caryophylleneA HexaneB HexanalC HexanolD Hexanone

4 The structure of isoprene is

Limonene is a terpene molecule present in lemons

How many isoprene units are joined together in a limonene molecule

A 1B 2

47

C 3D 4

5 Essential oils are

A non-water soluble non-volatile compoundsB non-water soluble volatile compoundsC water soluble non-volatile compoundsD water soluble volatile compounds

6 Two typical compounds that are present in many perfumes are shown

(a) Why does geraniol evaporate more slowly than limonene (1)

(b) The structure of one of the first synthetic scents used in perfume is shown below

(i) Name the family of carbonyl compounds to which this synthetic scent belongs (1)

(ii) Complete the structure below to show the product formed when this scent is

oxidised (1)

(c) Traces of a liquid were discovered in a bottle believed to contain perfume belonging to Queen Hatshepsut ruler of Egypt over 3500 years ago

Perfumes were made by dissolving plant extracts containing pleasant smelling terpenes and esters in an edible oil A little ethanol and water may also have been addedUsing your knowledge of chemistry comment on the possible smell(s) when such a bottle is opened after being stored for thousands of years (3)

48

49

7 A team of chemists are developing a fragrance for use in a shower gel for men(a) To give the gel a fruity smell the chemists are considering adding an ester

They synthesise six isomeric esters Volunteers smell each ester and give it a rating out of one hundred depending on how fruity the smell is

(i) Name the ester with the fruit-smell rating of 92 (1)

(ii) Shown below are the structures of three more isomers

Arrange these esters in order of decreasing fruit-smell rating (1)

50

(b) To create a fragrance for men the compound civetone is added

Draw a structural formula for the alcohol that can be oxidised to form civetone (1)

(c) To make the shower gel produce a cold tingling sensation when applied to the skin menthol is added

Like terpenes menthol is formed from isoprene (2-methylbuta-13-diene)Circle an isoprene unit on the menthol structure above (1)

8 Many of the compounds in perfumes are molecules consisting of joined isoprene units

(a) State the name that is given to molecules consisting of joined isoprene units (1)

(b)Geraniol is one of the compounds found in perfume It has the following structural formula and systematic name

Linalool can also be present Its structural formula is shown

51

(i) State the systematic name for linalool (1)(ii) Explain why linalool can be classified as a tertiary alcohol (1)

9 The component molecules found in lavender oils are terpenes or terpenoids(a)A chiral carbon is a carbon atom attached to four different atoms or groups of

atomsAn example is shown below

A molecule of the terpenoid linalool has a chiral carbon Linalool has the following structure

Circle the chiral carbon atom in the linalool structure (1)

(b)Farnesene is a terpene consisting of three isoprene units (2-methylbuta-13-diene) joined togetherWrite the molecular formula of farnesene (1)

52

27 Skin Care

1 Which of the following is not a step in a free radical chain reaction

A ActivationB InitiationC PropagationD Termination

2 Fluorine reacts with methane via a free radical chain reaction Some steps in the chain reaction are shown in the table below

Complete the table by(a) inserting the missing name for the first step (1)

(b) showing another possible termination reaction in the final row of the table (1)

3 Suncreams contain antioxidantsThe antioxidant compound A can prevent damage to skin by reacting with free

radicalssuch as NO2bull

53

Why can compound A be described as a free radical scavenger in the reaction shown above

4 Hydrogen and chlorine gases are used in an experiment to demonstrate a free radical reaction A plastic bottle is wrapped with black tape leaving a ldquowindowrdquo on one sideThe bottle is filled with a mixture of hydrogen and chlorine When bright light shines on the bottle there is an explosion

A free radical chain reaction is initiated when light energy causes chlorine radicals to form as shown below

(a) Complete the equations below showing possible propagation and termination steps

(2)

54

(b) Why is the plastic bottle used in the experiment wrapped in black tape (1)

5 Chloramines can be removed from water using ultraviolet light treatment

One step in the process is the formation of free radicals

(a)State what is meant by the term free radical (1)

(b)Another step in the process is shown below

State the name for this type of step in a free radical reaction (1)

6 Modern shellac nail varnishes are more durable and so last longer than traditional nail polish

The shellac nail varnish is applied in thin layers to the nails and then the fingers are placed under a UV lamp

(a) The Skin Care Foundation has recommended that a sun-block is applied to the fingers and hand before using the lampSuggest why the Skin Care Foundation makes this recommendation (1)

(b) A free radical chain reaction takes place and the varnish hardens (i) State what is meant by the term free radical (1)

(ii) The shellac nail varnish contains a mixture of ingredients that take part in the free radical chain reactionOne of the steps in the free radical chain reaction is

55

State the term used to describe this type of step in a free radical chain reaction(1)

7 Skin care products contain a mixture of polar covalent non-polar covalent and ionic compounds The compounds need to stay mixed within the product Skin care products also need to spread easily and remain on the skin for a period of time as well as provide physical and chemical protection from the sun In order to do this skin care products contain a range of chemicals including water fats and oils antioxidants minerals and sun blockUsing your knowledge of chemistry explain the role of different chemicals in skin care products (3)

General Questions

1 A mixture of carbon monoxide and hydrogen can be converted into water and a mixture of hydrocarbons

nCO + (2n + 1)H2 rarr nH2O + hydrocarbons

What is the general formula for the hydrocarbons producedA CnH2nndash2B CnH2nC CnH2n+1D CnH2n+2

2 Butadiene is the first member of a homologous series of hydrocarbons called dienesWhat is the general formula for this seriesA CnHn+2B CnHn+3C CnH2nD CnH2nndash2

3 Which of the following statements about methanol is falseA It can be made from synthesis gasB It can be dehydrated to form an alkeneC It can be oxidised to give a carboxylic acidD It reacts with acidified potassium dichromate solution

56

4

Which line in the table correctly describes reactions X and Y

5

Which line in the table correctly describes reactions X and Y

6 Which of the following fuels when burned would make no contribution to globalwarming

57

A HydrogenB Natural gasC PetrolD Coal

7 Which of the following hydrocarbons always gives the same product when one of itshydrogen atoms is replaced by a chlorine atomA HexaneB Hex-1-eneC CyclohexaneD Cyclohexene

8 Which of the following compounds does not have isomeric structuresA C2HCl3B C2H4Cl2C PropeneD Propan-1-ol

9 What organic compound is produced by the dehydration of ethanol A EthaneB EtheneC EthanalD Ethanoic acid

10

The above equation representsA hydrationB hydrogenationC condensationD hydrolysis

11

Which of the following compounds is an isomer of the structure shown aboveA ButanalB ButanoneC Butan-1-olD Butanoic acid

58

12 A compound with molecular formula C6H12O2 could beA hexanalB hexan-2-olC hexan-2-oneD hexanoic acid

13 Propan-2-ol can be prepared from propane as follows

Which line in the table correctly describes the types of reaction taking place at Steps 1 and 2

14 Which of the following compounds would be the most water soluble

15 Cyanohydrin compounds can be made from carbonyl compounds by reacting the carbonyl compound with hydrogen cyanide (HCN)

59

Which carbonyl compound would react with hydrogen cyanide (HCN) to form the following compound

16 Ethyne is the first member of the homologous series called the alkynes

Ethyne can undergo addition reactions as shown in the flow diagram

(a) Compound 2 is an isomer of 12-dichloroethaneDraw a structural formula for compound 2 (1)

(b) Reagents A B and C are three different diatomic gasesUsing information in the flow diagram identify reagents A B and C (1)

60

Reagent Gas

A

B

C

17 In 1865 the German chemist Kekuleacute proposed a ring structure for benzene This structure was based on alternating single and double bonds

(a) (i) Describe a chemical test that would indicate that the above chemical structure for benzene is incorrect (1)

(ii) Briefly describe the correct structure for benzene (1)

(b) Benzene can be formed from cyclohexaneC6H12 rarr C6H6 + 3H2

What name is given to this type of reaction (1)18 Infra-red spectroscopy is a technique that can be used to identify the bonds that

arepresent in a molecule Different bonds absorb infra-red radiation of different wavenumbers This is due to differences in the bond lsquostretchrsquo These absorptions are recorded in a spectrumA spectrum for propan-1-ol is shown

61

The correlation table on page 13 of the data booklet shows the wavenumber ranges for the absorptions due to different bonds

(a) Use the correlation table to identify the bonds responsible for the two absorptions x and y that are circled in the propan-1-ol spectrum (1)

(b) Propan-1-ol reacts with ethanoic acid(i) What name is given to this type of reaction (1)(ii) Draw a spectrum that could be obtained for the organic product of this

reaction (1)

19 Paracetamol is a widely used painkiller

(a) Write the molecular formula for paracetamol (1)

(b) One antidote for paracetamol overdose is methionine

62

To what family of organic compounds does methionine belong (1)

(c) The concentration of paracetamol in a solution can be determined by measuring how much UV radiation it absorbs

The graph shows how the absorbance of a sample containing 0middot040 g l ndash1 paracetamol varies with wavelength

The quantity of UV radiation of wavelength 245 nm absorbed is directly proportional to the concentration of paracetamolThe absorbance of a second sample of paracetamol solution measured at 245 nm was 0middot90 What is the concentration in g l ndash1 of this second paracetamol solution (1)

20 Many carbon compounds containing oxygen are very flammableThe table shows information about two families of isomersThe lowest temperature at which a compound will ignite is called its flash point

(a) A compound with the molecular formula C6H14O has a boiling point of 158 degC63

Draw a structural formula for this compound (1)

(b) For a family of isomers in the table write a general statement linking the flash points of the compounds to their structures (1)

21 Hydrogels are used in disposable nappies They are fine powders that can absorb up to 500 times their own weight in waterA hydrogel is a very long molecule with carboxyl groups at regular intervals along its length A short section of a hydrogel molecule is shown below

Hydrogels are extremely good at soaking up water because the water molecules are strongly attracted to them

Using your knowledge of chemistry comment on how suitable hydrogels would be for absorbing liquids or solutions spilled in a chemistry lab (1)

64

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

(ii) Another protein in egg white is conalbumin The temperature of a conalbumindye mixture is gradually increased The fluorescence is measured and a graph is produced

The melting temperature is the temperature at which the fluorescence is halfway between the highest and lowest fluorescence valuesDetermine the melting temperature in ordmC for this protein (1)

(c) Once cooked and eaten the digestive system breaks the protein chains into amino acids with the help of enzymes

(i) State the name of the digestion process where enzymes break down proteins into amino acids (1)

(ii)

(A) State how many amino acid molecules joined to form this section of protein (1)

(B) Draw the structure of one amino acid that would be produced when this section of the protein chain is broken down (1)

17 Peptide molecules can be classified according to the number of amino acid units joined by peptide bonds in the molecule

18

(a) Complete the table to identify the type of peptide with the following amino acid sequence

alanine-glycine-valine-proline-tyrosine-serine (1)

(b) Partial hydrolysis of another pentapeptide molecule gave a mixture of three smaller peptide molecules with the following amino acid sequences

leucine-glycine-valineisoleucine-leucineglycine-valine-serine

Write the amino acid sequence for the original pentapeptide molecule (1)

helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip(c) Some amino acids needed to form polypeptides cannot be produced in the human body

State the term used to describe amino acids that the body cannot make (1)

(d)Paper chromatography is often used to analyse the mixtures of amino acids produced when peptides are broken downOn a chromatogram the retention factor Rf for a substance can be a useful method of identifying the substance

The structure of the pentapeptide methionine enkephalin was investigatedA sample of the pentapeptide was completely hydrolysed into its constituent amino acids and this amino acid mixture was applied to a piece of chromatography paper and placed in a solventThe chromatogram obtained is shown below

19

(i) Suggest why only four spots were obtained on the chromatogram of the hydrolysed pentapeptide (1)

(ii) It is known that this amino acid mixture contains the amino acid methionine The Rf value for methionine in this solvent is 040Draw a circle around the spot on the chromatogram that corresponds to methionine (1)

(e) Over the last decade several families of extremely stable peptide molecules have been discovered where the peptide chain forms a ring

(i) A simple cyclic dipeptide is shown

Draw a structural formula for one of the amino acids that would be formed on complete hydrolysis of the above cyclic dipeptide (1)

(ii) Alpha-amanitin is a highly toxic cyclic peptide found in death cap mushrooms The lethal dose for humans is 100 mg per kg of body mass1middot0 g of death cap mushrooms contains 250 mg of alpha-amanitinCalculate the minimum mass of death cap mushrooms that would contain the lethal dose for a 75 kg adult (2)

18 Dishwasher tablets produce the bleach hydrogen peroxide H2O2 One action of this oxidising agent is to oxidise food

(a)(i) Suggest another action of the bleach produced by the dishwasher tablets (1)

20

(ii) Hydrogen peroxide decomposes to form water and oxygen

2H2O2(ℓ) rarr 2H2O(ℓ) + O2(g)

A dishwasher tablet produces 0middot051 g of hydrogen peroxide (mass of one mole = 34 g)

Calculate the volume of oxygen that would be produced when0middot051 g of hydrogen peroxide decomposesTake the volume of 1 mole of oxygen gas to be 24 litres(3)

(b)Enzymes are commonly added to dishwasher tablets These are used to break down proteins(i) The proteins are broken down into small water-soluble molecules

Name the small water-soluble molecules made when proteins are broken down completely (1)

(ii) The structure of a section of protein chain found in egg white is shown

(A)Name the functional group circled (1)(B)Draw a structural formula for one of the molecules that would be made

when this section of egg white protein chain is completely broken down (1)

(iii) As part of the program in the dishwasher the conditions in the dishwasher change so that the enzyme molecules no longer work because they change shape

21

(A) State the term used to describe the change in shape of enzyme molecules(1)

(B) Suggest a change in conditions which would cause the enzyme molecules to change shape (1)

(d) A bleach activator is frequently added to dishwasher tablets to speed up the bleaching reaction One common bleach activator is TAED TAED could be produced in a process which involves a number of stages

(i) The first stage in producing TAED is shown below

Suggest a name for this type of reaction (1)

(ii) The final stage in the process producing TAED is shown below

Draw a structural formula for TAED (1)

22

23 The Chemistry of Cooking

1 Vanillin and zingerone are flavour molecules

Which line in the table correctly compares the properties of vanillin and zingerone

23

2 Erythrose can be used in the production of a chewing gum that helps prevent tooth decay

Which of the following compounds will be the best solvent for erythrose

3 The following molecules give flavour to food Which of the following flavour molecules would be most likely to be retained in the food when the food is cooked in water

24

4 Cooking involves many chemical reactions Proteins fats oils and esters are some examples of compounds found in food A chemist suggested that cooking food could change compounds from being fat-soluble to water-soluble Use your knowledge of chemistry to comment on the accuracy of this statement(3)

25

24 The Oxidation of Food

1 Apples and bananas turn brown when cut or bruised The first step of the reaction causing

the browning is shown below

Which of the following terms correctly describes this reactionA ReductionB OxidationC DehydrationD Condensation

2 Which of the following reactions can be classified as reductionA CH3CH2OH rarr CH3COOHB CH3 CH(OH)CH3 rarr CH3COCH3C CH3CH2COCH3 rarr CH3CH2CH(OH)CH3D CH3CH2CHO rarr CH3CH2COOH

3 The dehydration of butan-2-ol can produce two isomeric alkenes but-1-ene andbut-2-ene Which of the following alkanols can similarly produce on dehydration a pair of isomeric alkenesA Propan-2-olB Pentan-3-olC Hexan-3-olD Heptan-4-ol

4 Which of the following compounds is an alkanone

26

5 Which of the following is an aldehyde

6 Which of the following compounds would react with sodium hydroxide solution to forma saltA CH3CHOB CH3COOHC CH3COCH3D CH3CH2OH

7 Which line in the table shows the correct functional group for each homologous series

8 Which of the following organic compounds is an isomer of hexanalA 2-MethylbutanalB 3-Methylpentan-2-oneC 22-Dimethylbutan-1-olD 3-Ethylpentanal

27

9 The name of this compound is

A methanolB methanalC methanoic acidD methanone

10 Which alcohol could be oxidised to a carboxylic acid

11 Which of the following structural formulae represents a tertiary alcohol

12 Compound X reacted with hot copper(II) oxide and the organic product did not give acolour change when heated with Fehlingrsquos solution Compound X could beA butan-1-olB butan-2-olC butanoneD butanoic acid

28

13 Which two isomers would each produce an acid when warmed with acidified potassiumdichromate solution

A 1 and 2B 2 and 3C 1 and 4D 3 and 4

14 After heating for several minutes as shown in the diagram the pH indicator solution turned red

Liquid Q could beA propanoneB paraffinC propan-1-olD propan-2-ol

29

15 Enzymes are involved in the browning of cut fruitOne reaction taking place is

Which of the following correctly describes the above reaction

A OxidationB ReductionC HydrolysisD Condensation

16 Which of the following statements is correct for ketones

A They are formed by oxidation of tertiary alcohols

B They contain the group

C They contain a carboxyl groupD They will not react with Fehlingrsquos solution

17 Carvone is a natural product that can be extracted from orange peel

Which line in the table correctly describes the reaction of carvone with bromine solution and with acidified potassium dichromate solution

30

18 Which of the following is an isomer of 22-dimethylpentan-1-ol

A CH3CH2CH2CH(CH3)CH2OHB (CH3)3CCH(CH3)CH2OHC CH3CH2CH2CH2CH2CH2CH2CH2OHD (CH3)2CHC(CH3)2CH2CH2OH

19 The equation for the reduction reaction taking place when ethanal reacts with Tollensrsquo reagent is

A Cu2+(aq) + eminus rarr Cu+(aq)

B Ag+(aq) + eminus rarr Ag(s)

C Cr2O72minus(aq) + 14H+(aq) + 6eminus rarr 2Cr3+(aq) + 7H2O(ℓ)

D MnO4minus(aq) + 8H+(aq) + 5eminus rarr Mn2+(aq) + 4H2O(ℓ)

20 The name of the compound with structure

isA 23-dimethylpentan-4-oneB 23-dimethylpentan-2-alC 34-dimethylpentan-2-oneD 34-dimethylpentan-2-al

21 What is the systematic name for the compound below

A 222-trimethylethanolB 22-dimethylpropan-1-olC 22-dimethylpropan-3-olD 22-dimethylpentan-1-ol

31

22 The structure of a molecule found in olive oil can be represented as shown

(a) Olive oil can be hydrolysed using sodium hydroxide solution to produce sodium salts of fatty acids Name the other product of this reaction (1)

(b) In what way does the structure of a fat molecule differ from that of an oil molecule (1)

(c) Over time open containers of olive oil develop a rancid flavour What substance is reacting with the oil to cause these unwanted changes to take place (1)

23 A student writes the following statement It is incorrect Explain the mistake in the studentrsquos reasoning (1)

Alcohols are alkaline because of their OH groups

24 Carbon compounds take part in a wide variety of chemical reactions (a)

Name this type of chemical reaction (1)

(b)

Draw a structural formula for C3H6O (1)

25 Alkanols can be oxidised to alkanoic acids

32

(a) Why can Step 1 be described as an oxidation reaction (1)

(b) Acidified potassium dichromate solution can be used to oxidise propanal in Step 2 What colour change would be observed in this reaction (1)

26 Amines can be produced by reacting ammonia with an aldehyde or a ketone This reaction an example of reductive amination occurs in two stages

Stage 1 Amination

Stage 2 Reduction

(a) Give another name for the type of reaction taking place in Stage 2

(b) Draw the structural formula for the amine produced when butanal undergoes reductive amination with ammonia

27 Using a cobalt catalyst alkenes react with a mixture of hydrogen and carbon monoxideThe products are two isomeric aldehydes Propene reacts with the mixture as shown

(a) What name is given to a mixture of hydrogen and carbon monoxide (1)

(b) Draw a structural formula for compound B (1)

(c) (i) What would be observed if compound A was gently heated with Tollensrsquo reagent

(1)(ii) How would the reaction mixture be heated (1)

33

(d) Aldehydes can also be formed by the reaction of some alcohols with copper(II) oxideName the type of alcohol that would react with copper(II) oxide to form an aldehyde (1)

28 Aldehydes and ketones can take part in a reaction sometimes known as an aldol condensation The simplest aldol reaction involves two molecules of ethanal

In the reaction the carbon atom next to the carbonyl functional group of one molecule forms a bond with the carbonyl carbon atom of the second molecule

(a) Draw a structural formula for the product formed when propanone is used instead of ethanal in this type of reaction (1)

(b) Name an aldehyde that would not take part in an aldol condensation (1)

(c) Apart from the structure of the reactants suggest what is unusual about applying the term ldquocondensationrdquo to this particular type of reaction (1)

29 Primary secondary and tertiary alkanols can be prepared by the reaction of carbonyl compounds with Grignard reagents

Step 1The Grignard reagent reacts with the carbonyl compound

Step 2The reaction of the product of Step 1 with dilute acid produces the alkanol

(a) Describe the difference between a primary a secondary and a tertiary alkanol

You may wish to include labelled structures in your answer (1)34

(b) Suggest a name for the type of reaction that takes place in Step 1 (1)

(c) The same Grignard reagent can be used to produce the alkanol below

Name the carbonyl compound used in this reaction (1)

30 Hairspray is a mixture of chemicals(a) A primary alcohol 2-methylpropan-1-ol is added to hairspray to help it dry quickly on the hair

Draw a structural formula for a secondary alcohol that is an isomer of2-methylpropan-1-ol (1)

(b) Triethanol amine and triisopropyl amine are bases used to neutralise acidic compounds in the hairspray to prevent damage to the hair

In terms of the intermolecular bonding present explain clearly why triethanol amine has a much higher boiling point than triisopropyl amine (2)

35

36

31 Chocolate contains various compounds(a) Many of the flavour and aroma molecules found in chocolate are aldehydes and

ketones Two examples are shown below

Phenylethanal can be easily oxidised but 13-diphenylpropan-2-one cannot(i) Name a chemical that could be used to distinguish between these two

compounds (1)

(ii) Name the type of organic compound formed when phenylethanal is oxidised (1)

(b) Glycerol monostearate is an emulsifier used in chocolate

(i) Why is glycerol monostearate added to chocolate (1)

(ii) Draw a structural formula for glycerol (1)

(c) Theobromine a compound present in chocolate can cause illness in dogs and cats To decide if treatment is necessary vets must calculate the mass of theobromine consumed 1middot0 g of chocolate contains 1middot4 mg of theobromine Calculate the mass in mg of theobromine in a 17 g biscuit of which 28 is chocolate Show your working clearly (2)

(d) The flavour and texture of chocolate comes from a blend of compoundsUsing your knowledge of chemistry describe how you could show that there are ionic compounds and covalent compounds present in chocolate (3)

37

32 Ethanol has many uses

(a) Ethanol is found at relatively low concentrations in wine

(i) Name the chemical reaction that produces ethanol in wine (1)

(ii) Standard ethanol solutions were used to produce a graph of density against

concentration of ethanol given as a percentage of alcohol by volume ( abv)

What is the concentration of ethanol in units of abv in a solution of density 0middot9818 g cmminus3 (1)

(b) Whisky contains a higher concentration of ethanol

(i) Before 1980 the concentration of alcohol in drinks was measured in terms of degrees proof The concentration of alcohol in two drinks is shown in the table below both as abv and degrees proof

38

A cask strength whisky has an alcohol concentration of 65 abv Calculate the alcohol concentration of this whisky in degrees proof (1)

(ii) A barrel containing 195 litres of cask strength whisky costs pound1300 The cask strength whisky is diluted with water to reduce the concentration of alcohol from 65 abv to 46 abv before it is bottled Calculate the cost of the cask strength whisky needed to produce a 0middot70 litre bottle Show your working clearly (2)

(iii) 5-Butyl-4-methyltetrahydrofuran-2-ol is a flavour compound found in whisky

stored in oak barrels

Write the systematic name for the compound shown below (1) 13 11

33 (a) One test for glucose involves Fehlingrsquos solutionCircle the part of the glucose molecule that reacts with Fehlingrsquos solution (1)

(b) In solution sugar molecules exist in an equilibrium in straight-chain and ring forms

To change from the straight-chain form to the ring form the oxygen of the hydroxyl on carbon number 5 joins to the carbonyl carbon This is shown below for glucose

39

Draw the structure of a ring form for fructose (1)

34 (a) During the free radical chain reaction small molecules join to form large chain molecules

One example of a small molecule used is

Name the functional group circled above (1)

(b)Alcohol wipes are used to finish the varnishing treatment Alcohol wipes contain the alcohol propan-2-olState why propan-2-ol can be described as a secondary alcohol (1)

35 A student was carrying out an investigation into alcohols aldehydes and ketones

(a)The student was given three alcohols labelled as A B and C These alcohols were all isomers with the formula C4H9OH

(i) Draw a structural formula for the secondary alcohol with the formula C4H9OH(1)

(ii) The student set up the following experiment

A Suggest why a water bath is an appropriate method of heating the reaction mixture (1)

B Describe the colour change that would have been observed with alcohols A and C (1)

40

C Alcohol B is not oxidised State the type of alcohol which cannot be oxidised by acidified dichromate solution (1)

(iii) The student set up a second experiment with alcohol A

Hot copper(II) oxide is an oxidising agentA When alcohol A (C4H9OH) is oxidised the product turns the pH paper

redSuggest a name for the product (1)

B Complete the ion-electron equation for the oxidation reaction

C4H9OH rarr C4H8O2 (1)

(b)The student found the following information about the boiling points of some aldehydes

41

(i) Name the aldehyde that has a boiling point of 119 degC (1)(ii) Predict the boiling point in degC of the following molecule (1)

(iii) Using information from the table describe one way in which differences in structure affect the boiling point of isomeric aldehydes (1)

(iv) State what would be observed when an aldehyde is gently heated with Tollensrsquo reagent (1)

(c) Ketones contain a carbonyl groupName the type of intermolecular interaction between ketone molecules (1)

42

25 Soaps Detergents and Emulsions

1 Soaps are produced by the following reaction

This reaction is an example ofA condensationB esterificationC hydrolysisD oxidation

2 Which of the following is the salt of a long-chain fatty acid

A FatB OilC SoapD Glycerol

3 Emulsifiers for use in food are commonly made by reacting edible oils with

A estersB glycerolC fatty acidsD amino acids

4 A fatty acid is a long chain carboxylic acid Examples of fatty acids are shown in the table below

43

(a) What is the systematic name for linolenic acid (1)(b) Stearic acid reacts with sodium hydroxide solution to form sodium stearate

(i) Name the type of reaction taking place when stearic acid reacts with sodium hydroxide (1)

(ii) Explain fully how sodium stearate acts to keep grease and non-polar substances suspended in water during cleaning (3)

5 Small children can find it difficult to swallow tablets or pills so ibuprofen is supplied as an ldquoinfant formulardquo emulsion(a) The emulsifier used is polysorbate 80 Its structure is shown below

Explain why this molecule acts as an emulsifier (2)

(b) The emulsion contains 2 g of ibuprofen in every 100 cm3 of emulsion The recommended dose for treating a 6 month old baby is 0middot050 g Calculate the volume in cm3 of ldquoinfant formulardquo needed to treat a 6 month old baby (1)

6 Occasionally seabirds can become contaminated with hydrocarbons from oil spills This causes problems for birds because their feathers lose their waterproofing making the birds susceptible to temperature changes and

44

affecting their buoyancy If the birds attempt to clean themselves to remove the oil they may swallow the hydrocarbons causing damage to their internal organsContaminated seabirds can be cleaned by rubbing vegetable oil into their feathers and feet before the birds are rinsed with diluted washing-up liquidUsing your knowledge of chemistry comment on the problems created for seabirds by oil spills and the actions taken to treat affected birds (3)

7 Dishwasher tablets contain chemicals which remove dirt from dishesDishwasher tablets include detergents These molecules act like soaps to allow mixing of fat-soluble dirt and water(a)During the cleaning process the detergent molecules combine with fat-

soluble dirtA simplified diagram of a detergent molecule is shown

Complete the diagram below to show how detergent molecules combine with fat-soluble dirt (1)

(b)State the term used to describe the non-polar hydrocarbon tail of a detergent molecule (1)

45

26 Fragrances1 Myrcene is a simple terpene

Terpenes contain at least one isoprene unit Which of the following shows a correctly highlighted isoprene unit

2 Limonene is one of the terpene molecules responsible for the flavour of lemons

How many isoprene units are used in the production of one limonene moleculeA 1B 2C 3D 4

46

3 The structure of caryophyllene which can be extracted from clove oil is

Which of the following would be the best solvent for extracting caryophylleneA HexaneB HexanalC HexanolD Hexanone

4 The structure of isoprene is

Limonene is a terpene molecule present in lemons

How many isoprene units are joined together in a limonene molecule

A 1B 2

47

C 3D 4

5 Essential oils are

A non-water soluble non-volatile compoundsB non-water soluble volatile compoundsC water soluble non-volatile compoundsD water soluble volatile compounds

6 Two typical compounds that are present in many perfumes are shown

(a) Why does geraniol evaporate more slowly than limonene (1)

(b) The structure of one of the first synthetic scents used in perfume is shown below

(i) Name the family of carbonyl compounds to which this synthetic scent belongs (1)

(ii) Complete the structure below to show the product formed when this scent is

oxidised (1)

(c) Traces of a liquid were discovered in a bottle believed to contain perfume belonging to Queen Hatshepsut ruler of Egypt over 3500 years ago

Perfumes were made by dissolving plant extracts containing pleasant smelling terpenes and esters in an edible oil A little ethanol and water may also have been addedUsing your knowledge of chemistry comment on the possible smell(s) when such a bottle is opened after being stored for thousands of years (3)

48

49

7 A team of chemists are developing a fragrance for use in a shower gel for men(a) To give the gel a fruity smell the chemists are considering adding an ester

They synthesise six isomeric esters Volunteers smell each ester and give it a rating out of one hundred depending on how fruity the smell is

(i) Name the ester with the fruit-smell rating of 92 (1)

(ii) Shown below are the structures of three more isomers

Arrange these esters in order of decreasing fruit-smell rating (1)

50

(b) To create a fragrance for men the compound civetone is added

Draw a structural formula for the alcohol that can be oxidised to form civetone (1)

(c) To make the shower gel produce a cold tingling sensation when applied to the skin menthol is added

Like terpenes menthol is formed from isoprene (2-methylbuta-13-diene)Circle an isoprene unit on the menthol structure above (1)

8 Many of the compounds in perfumes are molecules consisting of joined isoprene units

(a) State the name that is given to molecules consisting of joined isoprene units (1)

(b)Geraniol is one of the compounds found in perfume It has the following structural formula and systematic name

Linalool can also be present Its structural formula is shown

51

(i) State the systematic name for linalool (1)(ii) Explain why linalool can be classified as a tertiary alcohol (1)

9 The component molecules found in lavender oils are terpenes or terpenoids(a)A chiral carbon is a carbon atom attached to four different atoms or groups of

atomsAn example is shown below

A molecule of the terpenoid linalool has a chiral carbon Linalool has the following structure

Circle the chiral carbon atom in the linalool structure (1)

(b)Farnesene is a terpene consisting of three isoprene units (2-methylbuta-13-diene) joined togetherWrite the molecular formula of farnesene (1)

52

27 Skin Care

1 Which of the following is not a step in a free radical chain reaction

A ActivationB InitiationC PropagationD Termination

2 Fluorine reacts with methane via a free radical chain reaction Some steps in the chain reaction are shown in the table below

Complete the table by(a) inserting the missing name for the first step (1)

(b) showing another possible termination reaction in the final row of the table (1)

3 Suncreams contain antioxidantsThe antioxidant compound A can prevent damage to skin by reacting with free

radicalssuch as NO2bull

53

Why can compound A be described as a free radical scavenger in the reaction shown above

4 Hydrogen and chlorine gases are used in an experiment to demonstrate a free radical reaction A plastic bottle is wrapped with black tape leaving a ldquowindowrdquo on one sideThe bottle is filled with a mixture of hydrogen and chlorine When bright light shines on the bottle there is an explosion

A free radical chain reaction is initiated when light energy causes chlorine radicals to form as shown below

(a) Complete the equations below showing possible propagation and termination steps

(2)

54

(b) Why is the plastic bottle used in the experiment wrapped in black tape (1)

5 Chloramines can be removed from water using ultraviolet light treatment

One step in the process is the formation of free radicals

(a)State what is meant by the term free radical (1)

(b)Another step in the process is shown below

State the name for this type of step in a free radical reaction (1)

6 Modern shellac nail varnishes are more durable and so last longer than traditional nail polish

The shellac nail varnish is applied in thin layers to the nails and then the fingers are placed under a UV lamp

(a) The Skin Care Foundation has recommended that a sun-block is applied to the fingers and hand before using the lampSuggest why the Skin Care Foundation makes this recommendation (1)

(b) A free radical chain reaction takes place and the varnish hardens (i) State what is meant by the term free radical (1)

(ii) The shellac nail varnish contains a mixture of ingredients that take part in the free radical chain reactionOne of the steps in the free radical chain reaction is

55

State the term used to describe this type of step in a free radical chain reaction(1)

7 Skin care products contain a mixture of polar covalent non-polar covalent and ionic compounds The compounds need to stay mixed within the product Skin care products also need to spread easily and remain on the skin for a period of time as well as provide physical and chemical protection from the sun In order to do this skin care products contain a range of chemicals including water fats and oils antioxidants minerals and sun blockUsing your knowledge of chemistry explain the role of different chemicals in skin care products (3)

General Questions

1 A mixture of carbon monoxide and hydrogen can be converted into water and a mixture of hydrocarbons

nCO + (2n + 1)H2 rarr nH2O + hydrocarbons

What is the general formula for the hydrocarbons producedA CnH2nndash2B CnH2nC CnH2n+1D CnH2n+2

2 Butadiene is the first member of a homologous series of hydrocarbons called dienesWhat is the general formula for this seriesA CnHn+2B CnHn+3C CnH2nD CnH2nndash2

3 Which of the following statements about methanol is falseA It can be made from synthesis gasB It can be dehydrated to form an alkeneC It can be oxidised to give a carboxylic acidD It reacts with acidified potassium dichromate solution

56

4

Which line in the table correctly describes reactions X and Y

5

Which line in the table correctly describes reactions X and Y

6 Which of the following fuels when burned would make no contribution to globalwarming

57

A HydrogenB Natural gasC PetrolD Coal

7 Which of the following hydrocarbons always gives the same product when one of itshydrogen atoms is replaced by a chlorine atomA HexaneB Hex-1-eneC CyclohexaneD Cyclohexene

8 Which of the following compounds does not have isomeric structuresA C2HCl3B C2H4Cl2C PropeneD Propan-1-ol

9 What organic compound is produced by the dehydration of ethanol A EthaneB EtheneC EthanalD Ethanoic acid

10

The above equation representsA hydrationB hydrogenationC condensationD hydrolysis

11

Which of the following compounds is an isomer of the structure shown aboveA ButanalB ButanoneC Butan-1-olD Butanoic acid

58

12 A compound with molecular formula C6H12O2 could beA hexanalB hexan-2-olC hexan-2-oneD hexanoic acid

13 Propan-2-ol can be prepared from propane as follows

Which line in the table correctly describes the types of reaction taking place at Steps 1 and 2

14 Which of the following compounds would be the most water soluble

15 Cyanohydrin compounds can be made from carbonyl compounds by reacting the carbonyl compound with hydrogen cyanide (HCN)

59

Which carbonyl compound would react with hydrogen cyanide (HCN) to form the following compound

16 Ethyne is the first member of the homologous series called the alkynes

Ethyne can undergo addition reactions as shown in the flow diagram

(a) Compound 2 is an isomer of 12-dichloroethaneDraw a structural formula for compound 2 (1)

(b) Reagents A B and C are three different diatomic gasesUsing information in the flow diagram identify reagents A B and C (1)

60

Reagent Gas

A

B

C

17 In 1865 the German chemist Kekuleacute proposed a ring structure for benzene This structure was based on alternating single and double bonds

(a) (i) Describe a chemical test that would indicate that the above chemical structure for benzene is incorrect (1)

(ii) Briefly describe the correct structure for benzene (1)

(b) Benzene can be formed from cyclohexaneC6H12 rarr C6H6 + 3H2

What name is given to this type of reaction (1)18 Infra-red spectroscopy is a technique that can be used to identify the bonds that

arepresent in a molecule Different bonds absorb infra-red radiation of different wavenumbers This is due to differences in the bond lsquostretchrsquo These absorptions are recorded in a spectrumA spectrum for propan-1-ol is shown

61

The correlation table on page 13 of the data booklet shows the wavenumber ranges for the absorptions due to different bonds

(a) Use the correlation table to identify the bonds responsible for the two absorptions x and y that are circled in the propan-1-ol spectrum (1)

(b) Propan-1-ol reacts with ethanoic acid(i) What name is given to this type of reaction (1)(ii) Draw a spectrum that could be obtained for the organic product of this

reaction (1)

19 Paracetamol is a widely used painkiller

(a) Write the molecular formula for paracetamol (1)

(b) One antidote for paracetamol overdose is methionine

62

To what family of organic compounds does methionine belong (1)

(c) The concentration of paracetamol in a solution can be determined by measuring how much UV radiation it absorbs

The graph shows how the absorbance of a sample containing 0middot040 g l ndash1 paracetamol varies with wavelength

The quantity of UV radiation of wavelength 245 nm absorbed is directly proportional to the concentration of paracetamolThe absorbance of a second sample of paracetamol solution measured at 245 nm was 0middot90 What is the concentration in g l ndash1 of this second paracetamol solution (1)

20 Many carbon compounds containing oxygen are very flammableThe table shows information about two families of isomersThe lowest temperature at which a compound will ignite is called its flash point

(a) A compound with the molecular formula C6H14O has a boiling point of 158 degC63

Draw a structural formula for this compound (1)

(b) For a family of isomers in the table write a general statement linking the flash points of the compounds to their structures (1)

21 Hydrogels are used in disposable nappies They are fine powders that can absorb up to 500 times their own weight in waterA hydrogel is a very long molecule with carboxyl groups at regular intervals along its length A short section of a hydrogel molecule is shown below

Hydrogels are extremely good at soaking up water because the water molecules are strongly attracted to them

Using your knowledge of chemistry comment on how suitable hydrogels would be for absorbing liquids or solutions spilled in a chemistry lab (1)

64

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

(a) Complete the table to identify the type of peptide with the following amino acid sequence

alanine-glycine-valine-proline-tyrosine-serine (1)

(b) Partial hydrolysis of another pentapeptide molecule gave a mixture of three smaller peptide molecules with the following amino acid sequences

leucine-glycine-valineisoleucine-leucineglycine-valine-serine

Write the amino acid sequence for the original pentapeptide molecule (1)

helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip--helliphelliphelliphelliphelliphelliphelliphelliphellip(c) Some amino acids needed to form polypeptides cannot be produced in the human body

State the term used to describe amino acids that the body cannot make (1)

(d)Paper chromatography is often used to analyse the mixtures of amino acids produced when peptides are broken downOn a chromatogram the retention factor Rf for a substance can be a useful method of identifying the substance

The structure of the pentapeptide methionine enkephalin was investigatedA sample of the pentapeptide was completely hydrolysed into its constituent amino acids and this amino acid mixture was applied to a piece of chromatography paper and placed in a solventThe chromatogram obtained is shown below

19

(i) Suggest why only four spots were obtained on the chromatogram of the hydrolysed pentapeptide (1)

(ii) It is known that this amino acid mixture contains the amino acid methionine The Rf value for methionine in this solvent is 040Draw a circle around the spot on the chromatogram that corresponds to methionine (1)

(e) Over the last decade several families of extremely stable peptide molecules have been discovered where the peptide chain forms a ring

(i) A simple cyclic dipeptide is shown

Draw a structural formula for one of the amino acids that would be formed on complete hydrolysis of the above cyclic dipeptide (1)

(ii) Alpha-amanitin is a highly toxic cyclic peptide found in death cap mushrooms The lethal dose for humans is 100 mg per kg of body mass1middot0 g of death cap mushrooms contains 250 mg of alpha-amanitinCalculate the minimum mass of death cap mushrooms that would contain the lethal dose for a 75 kg adult (2)

18 Dishwasher tablets produce the bleach hydrogen peroxide H2O2 One action of this oxidising agent is to oxidise food

(a)(i) Suggest another action of the bleach produced by the dishwasher tablets (1)

20

(ii) Hydrogen peroxide decomposes to form water and oxygen

2H2O2(ℓ) rarr 2H2O(ℓ) + O2(g)

A dishwasher tablet produces 0middot051 g of hydrogen peroxide (mass of one mole = 34 g)

Calculate the volume of oxygen that would be produced when0middot051 g of hydrogen peroxide decomposesTake the volume of 1 mole of oxygen gas to be 24 litres(3)

(b)Enzymes are commonly added to dishwasher tablets These are used to break down proteins(i) The proteins are broken down into small water-soluble molecules

Name the small water-soluble molecules made when proteins are broken down completely (1)

(ii) The structure of a section of protein chain found in egg white is shown

(A)Name the functional group circled (1)(B)Draw a structural formula for one of the molecules that would be made

when this section of egg white protein chain is completely broken down (1)

(iii) As part of the program in the dishwasher the conditions in the dishwasher change so that the enzyme molecules no longer work because they change shape

21

(A) State the term used to describe the change in shape of enzyme molecules(1)

(B) Suggest a change in conditions which would cause the enzyme molecules to change shape (1)

(d) A bleach activator is frequently added to dishwasher tablets to speed up the bleaching reaction One common bleach activator is TAED TAED could be produced in a process which involves a number of stages

(i) The first stage in producing TAED is shown below

Suggest a name for this type of reaction (1)

(ii) The final stage in the process producing TAED is shown below

Draw a structural formula for TAED (1)

22

23 The Chemistry of Cooking

1 Vanillin and zingerone are flavour molecules

Which line in the table correctly compares the properties of vanillin and zingerone

23

2 Erythrose can be used in the production of a chewing gum that helps prevent tooth decay

Which of the following compounds will be the best solvent for erythrose

3 The following molecules give flavour to food Which of the following flavour molecules would be most likely to be retained in the food when the food is cooked in water

24

4 Cooking involves many chemical reactions Proteins fats oils and esters are some examples of compounds found in food A chemist suggested that cooking food could change compounds from being fat-soluble to water-soluble Use your knowledge of chemistry to comment on the accuracy of this statement(3)

25

24 The Oxidation of Food

1 Apples and bananas turn brown when cut or bruised The first step of the reaction causing

the browning is shown below

Which of the following terms correctly describes this reactionA ReductionB OxidationC DehydrationD Condensation

2 Which of the following reactions can be classified as reductionA CH3CH2OH rarr CH3COOHB CH3 CH(OH)CH3 rarr CH3COCH3C CH3CH2COCH3 rarr CH3CH2CH(OH)CH3D CH3CH2CHO rarr CH3CH2COOH

3 The dehydration of butan-2-ol can produce two isomeric alkenes but-1-ene andbut-2-ene Which of the following alkanols can similarly produce on dehydration a pair of isomeric alkenesA Propan-2-olB Pentan-3-olC Hexan-3-olD Heptan-4-ol

4 Which of the following compounds is an alkanone

26

5 Which of the following is an aldehyde

6 Which of the following compounds would react with sodium hydroxide solution to forma saltA CH3CHOB CH3COOHC CH3COCH3D CH3CH2OH

7 Which line in the table shows the correct functional group for each homologous series

8 Which of the following organic compounds is an isomer of hexanalA 2-MethylbutanalB 3-Methylpentan-2-oneC 22-Dimethylbutan-1-olD 3-Ethylpentanal

27

9 The name of this compound is

A methanolB methanalC methanoic acidD methanone

10 Which alcohol could be oxidised to a carboxylic acid

11 Which of the following structural formulae represents a tertiary alcohol

12 Compound X reacted with hot copper(II) oxide and the organic product did not give acolour change when heated with Fehlingrsquos solution Compound X could beA butan-1-olB butan-2-olC butanoneD butanoic acid

28

13 Which two isomers would each produce an acid when warmed with acidified potassiumdichromate solution

A 1 and 2B 2 and 3C 1 and 4D 3 and 4

14 After heating for several minutes as shown in the diagram the pH indicator solution turned red

Liquid Q could beA propanoneB paraffinC propan-1-olD propan-2-ol

29

15 Enzymes are involved in the browning of cut fruitOne reaction taking place is

Which of the following correctly describes the above reaction

A OxidationB ReductionC HydrolysisD Condensation

16 Which of the following statements is correct for ketones

A They are formed by oxidation of tertiary alcohols

B They contain the group

C They contain a carboxyl groupD They will not react with Fehlingrsquos solution

17 Carvone is a natural product that can be extracted from orange peel

Which line in the table correctly describes the reaction of carvone with bromine solution and with acidified potassium dichromate solution

30

18 Which of the following is an isomer of 22-dimethylpentan-1-ol

A CH3CH2CH2CH(CH3)CH2OHB (CH3)3CCH(CH3)CH2OHC CH3CH2CH2CH2CH2CH2CH2CH2OHD (CH3)2CHC(CH3)2CH2CH2OH

19 The equation for the reduction reaction taking place when ethanal reacts with Tollensrsquo reagent is

A Cu2+(aq) + eminus rarr Cu+(aq)

B Ag+(aq) + eminus rarr Ag(s)

C Cr2O72minus(aq) + 14H+(aq) + 6eminus rarr 2Cr3+(aq) + 7H2O(ℓ)

D MnO4minus(aq) + 8H+(aq) + 5eminus rarr Mn2+(aq) + 4H2O(ℓ)

20 The name of the compound with structure

isA 23-dimethylpentan-4-oneB 23-dimethylpentan-2-alC 34-dimethylpentan-2-oneD 34-dimethylpentan-2-al

21 What is the systematic name for the compound below

A 222-trimethylethanolB 22-dimethylpropan-1-olC 22-dimethylpropan-3-olD 22-dimethylpentan-1-ol

31

22 The structure of a molecule found in olive oil can be represented as shown

(a) Olive oil can be hydrolysed using sodium hydroxide solution to produce sodium salts of fatty acids Name the other product of this reaction (1)

(b) In what way does the structure of a fat molecule differ from that of an oil molecule (1)

(c) Over time open containers of olive oil develop a rancid flavour What substance is reacting with the oil to cause these unwanted changes to take place (1)

23 A student writes the following statement It is incorrect Explain the mistake in the studentrsquos reasoning (1)

Alcohols are alkaline because of their OH groups

24 Carbon compounds take part in a wide variety of chemical reactions (a)

Name this type of chemical reaction (1)

(b)

Draw a structural formula for C3H6O (1)

25 Alkanols can be oxidised to alkanoic acids

32

(a) Why can Step 1 be described as an oxidation reaction (1)

(b) Acidified potassium dichromate solution can be used to oxidise propanal in Step 2 What colour change would be observed in this reaction (1)

26 Amines can be produced by reacting ammonia with an aldehyde or a ketone This reaction an example of reductive amination occurs in two stages

Stage 1 Amination

Stage 2 Reduction

(a) Give another name for the type of reaction taking place in Stage 2

(b) Draw the structural formula for the amine produced when butanal undergoes reductive amination with ammonia

27 Using a cobalt catalyst alkenes react with a mixture of hydrogen and carbon monoxideThe products are two isomeric aldehydes Propene reacts with the mixture as shown

(a) What name is given to a mixture of hydrogen and carbon monoxide (1)

(b) Draw a structural formula for compound B (1)

(c) (i) What would be observed if compound A was gently heated with Tollensrsquo reagent

(1)(ii) How would the reaction mixture be heated (1)

33

(d) Aldehydes can also be formed by the reaction of some alcohols with copper(II) oxideName the type of alcohol that would react with copper(II) oxide to form an aldehyde (1)

28 Aldehydes and ketones can take part in a reaction sometimes known as an aldol condensation The simplest aldol reaction involves two molecules of ethanal

In the reaction the carbon atom next to the carbonyl functional group of one molecule forms a bond with the carbonyl carbon atom of the second molecule

(a) Draw a structural formula for the product formed when propanone is used instead of ethanal in this type of reaction (1)

(b) Name an aldehyde that would not take part in an aldol condensation (1)

(c) Apart from the structure of the reactants suggest what is unusual about applying the term ldquocondensationrdquo to this particular type of reaction (1)

29 Primary secondary and tertiary alkanols can be prepared by the reaction of carbonyl compounds with Grignard reagents

Step 1The Grignard reagent reacts with the carbonyl compound

Step 2The reaction of the product of Step 1 with dilute acid produces the alkanol

(a) Describe the difference between a primary a secondary and a tertiary alkanol

You may wish to include labelled structures in your answer (1)34

(b) Suggest a name for the type of reaction that takes place in Step 1 (1)

(c) The same Grignard reagent can be used to produce the alkanol below

Name the carbonyl compound used in this reaction (1)

30 Hairspray is a mixture of chemicals(a) A primary alcohol 2-methylpropan-1-ol is added to hairspray to help it dry quickly on the hair

Draw a structural formula for a secondary alcohol that is an isomer of2-methylpropan-1-ol (1)

(b) Triethanol amine and triisopropyl amine are bases used to neutralise acidic compounds in the hairspray to prevent damage to the hair

In terms of the intermolecular bonding present explain clearly why triethanol amine has a much higher boiling point than triisopropyl amine (2)

35

36

31 Chocolate contains various compounds(a) Many of the flavour and aroma molecules found in chocolate are aldehydes and

ketones Two examples are shown below

Phenylethanal can be easily oxidised but 13-diphenylpropan-2-one cannot(i) Name a chemical that could be used to distinguish between these two

compounds (1)

(ii) Name the type of organic compound formed when phenylethanal is oxidised (1)

(b) Glycerol monostearate is an emulsifier used in chocolate

(i) Why is glycerol monostearate added to chocolate (1)

(ii) Draw a structural formula for glycerol (1)

(c) Theobromine a compound present in chocolate can cause illness in dogs and cats To decide if treatment is necessary vets must calculate the mass of theobromine consumed 1middot0 g of chocolate contains 1middot4 mg of theobromine Calculate the mass in mg of theobromine in a 17 g biscuit of which 28 is chocolate Show your working clearly (2)

(d) The flavour and texture of chocolate comes from a blend of compoundsUsing your knowledge of chemistry describe how you could show that there are ionic compounds and covalent compounds present in chocolate (3)

37

32 Ethanol has many uses

(a) Ethanol is found at relatively low concentrations in wine

(i) Name the chemical reaction that produces ethanol in wine (1)

(ii) Standard ethanol solutions were used to produce a graph of density against

concentration of ethanol given as a percentage of alcohol by volume ( abv)

What is the concentration of ethanol in units of abv in a solution of density 0middot9818 g cmminus3 (1)

(b) Whisky contains a higher concentration of ethanol

(i) Before 1980 the concentration of alcohol in drinks was measured in terms of degrees proof The concentration of alcohol in two drinks is shown in the table below both as abv and degrees proof

38

A cask strength whisky has an alcohol concentration of 65 abv Calculate the alcohol concentration of this whisky in degrees proof (1)

(ii) A barrel containing 195 litres of cask strength whisky costs pound1300 The cask strength whisky is diluted with water to reduce the concentration of alcohol from 65 abv to 46 abv before it is bottled Calculate the cost of the cask strength whisky needed to produce a 0middot70 litre bottle Show your working clearly (2)

(iii) 5-Butyl-4-methyltetrahydrofuran-2-ol is a flavour compound found in whisky

stored in oak barrels

Write the systematic name for the compound shown below (1) 13 11

33 (a) One test for glucose involves Fehlingrsquos solutionCircle the part of the glucose molecule that reacts with Fehlingrsquos solution (1)

(b) In solution sugar molecules exist in an equilibrium in straight-chain and ring forms

To change from the straight-chain form to the ring form the oxygen of the hydroxyl on carbon number 5 joins to the carbonyl carbon This is shown below for glucose

39

Draw the structure of a ring form for fructose (1)

34 (a) During the free radical chain reaction small molecules join to form large chain molecules

One example of a small molecule used is

Name the functional group circled above (1)

(b)Alcohol wipes are used to finish the varnishing treatment Alcohol wipes contain the alcohol propan-2-olState why propan-2-ol can be described as a secondary alcohol (1)

35 A student was carrying out an investigation into alcohols aldehydes and ketones

(a)The student was given three alcohols labelled as A B and C These alcohols were all isomers with the formula C4H9OH

(i) Draw a structural formula for the secondary alcohol with the formula C4H9OH(1)

(ii) The student set up the following experiment

A Suggest why a water bath is an appropriate method of heating the reaction mixture (1)

B Describe the colour change that would have been observed with alcohols A and C (1)

40

C Alcohol B is not oxidised State the type of alcohol which cannot be oxidised by acidified dichromate solution (1)

(iii) The student set up a second experiment with alcohol A

Hot copper(II) oxide is an oxidising agentA When alcohol A (C4H9OH) is oxidised the product turns the pH paper

redSuggest a name for the product (1)

B Complete the ion-electron equation for the oxidation reaction

C4H9OH rarr C4H8O2 (1)

(b)The student found the following information about the boiling points of some aldehydes

41

(i) Name the aldehyde that has a boiling point of 119 degC (1)(ii) Predict the boiling point in degC of the following molecule (1)

(iii) Using information from the table describe one way in which differences in structure affect the boiling point of isomeric aldehydes (1)

(iv) State what would be observed when an aldehyde is gently heated with Tollensrsquo reagent (1)

(c) Ketones contain a carbonyl groupName the type of intermolecular interaction between ketone molecules (1)

42

25 Soaps Detergents and Emulsions

1 Soaps are produced by the following reaction

This reaction is an example ofA condensationB esterificationC hydrolysisD oxidation

2 Which of the following is the salt of a long-chain fatty acid

A FatB OilC SoapD Glycerol

3 Emulsifiers for use in food are commonly made by reacting edible oils with

A estersB glycerolC fatty acidsD amino acids

4 A fatty acid is a long chain carboxylic acid Examples of fatty acids are shown in the table below

43

(a) What is the systematic name for linolenic acid (1)(b) Stearic acid reacts with sodium hydroxide solution to form sodium stearate

(i) Name the type of reaction taking place when stearic acid reacts with sodium hydroxide (1)

(ii) Explain fully how sodium stearate acts to keep grease and non-polar substances suspended in water during cleaning (3)

5 Small children can find it difficult to swallow tablets or pills so ibuprofen is supplied as an ldquoinfant formulardquo emulsion(a) The emulsifier used is polysorbate 80 Its structure is shown below

Explain why this molecule acts as an emulsifier (2)

(b) The emulsion contains 2 g of ibuprofen in every 100 cm3 of emulsion The recommended dose for treating a 6 month old baby is 0middot050 g Calculate the volume in cm3 of ldquoinfant formulardquo needed to treat a 6 month old baby (1)

6 Occasionally seabirds can become contaminated with hydrocarbons from oil spills This causes problems for birds because their feathers lose their waterproofing making the birds susceptible to temperature changes and

44

affecting their buoyancy If the birds attempt to clean themselves to remove the oil they may swallow the hydrocarbons causing damage to their internal organsContaminated seabirds can be cleaned by rubbing vegetable oil into their feathers and feet before the birds are rinsed with diluted washing-up liquidUsing your knowledge of chemistry comment on the problems created for seabirds by oil spills and the actions taken to treat affected birds (3)

7 Dishwasher tablets contain chemicals which remove dirt from dishesDishwasher tablets include detergents These molecules act like soaps to allow mixing of fat-soluble dirt and water(a)During the cleaning process the detergent molecules combine with fat-

soluble dirtA simplified diagram of a detergent molecule is shown

Complete the diagram below to show how detergent molecules combine with fat-soluble dirt (1)

(b)State the term used to describe the non-polar hydrocarbon tail of a detergent molecule (1)

45

26 Fragrances1 Myrcene is a simple terpene

Terpenes contain at least one isoprene unit Which of the following shows a correctly highlighted isoprene unit

2 Limonene is one of the terpene molecules responsible for the flavour of lemons

How many isoprene units are used in the production of one limonene moleculeA 1B 2C 3D 4

46

3 The structure of caryophyllene which can be extracted from clove oil is

Which of the following would be the best solvent for extracting caryophylleneA HexaneB HexanalC HexanolD Hexanone

4 The structure of isoprene is

Limonene is a terpene molecule present in lemons

How many isoprene units are joined together in a limonene molecule

A 1B 2

47

C 3D 4

5 Essential oils are

A non-water soluble non-volatile compoundsB non-water soluble volatile compoundsC water soluble non-volatile compoundsD water soluble volatile compounds

6 Two typical compounds that are present in many perfumes are shown

(a) Why does geraniol evaporate more slowly than limonene (1)

(b) The structure of one of the first synthetic scents used in perfume is shown below

(i) Name the family of carbonyl compounds to which this synthetic scent belongs (1)

(ii) Complete the structure below to show the product formed when this scent is

oxidised (1)

(c) Traces of a liquid were discovered in a bottle believed to contain perfume belonging to Queen Hatshepsut ruler of Egypt over 3500 years ago

Perfumes were made by dissolving plant extracts containing pleasant smelling terpenes and esters in an edible oil A little ethanol and water may also have been addedUsing your knowledge of chemistry comment on the possible smell(s) when such a bottle is opened after being stored for thousands of years (3)

48

49

7 A team of chemists are developing a fragrance for use in a shower gel for men(a) To give the gel a fruity smell the chemists are considering adding an ester

They synthesise six isomeric esters Volunteers smell each ester and give it a rating out of one hundred depending on how fruity the smell is

(i) Name the ester with the fruit-smell rating of 92 (1)

(ii) Shown below are the structures of three more isomers

Arrange these esters in order of decreasing fruit-smell rating (1)

50

(b) To create a fragrance for men the compound civetone is added

Draw a structural formula for the alcohol that can be oxidised to form civetone (1)

(c) To make the shower gel produce a cold tingling sensation when applied to the skin menthol is added

Like terpenes menthol is formed from isoprene (2-methylbuta-13-diene)Circle an isoprene unit on the menthol structure above (1)

8 Many of the compounds in perfumes are molecules consisting of joined isoprene units

(a) State the name that is given to molecules consisting of joined isoprene units (1)

(b)Geraniol is one of the compounds found in perfume It has the following structural formula and systematic name

Linalool can also be present Its structural formula is shown

51

(i) State the systematic name for linalool (1)(ii) Explain why linalool can be classified as a tertiary alcohol (1)

9 The component molecules found in lavender oils are terpenes or terpenoids(a)A chiral carbon is a carbon atom attached to four different atoms or groups of

atomsAn example is shown below

A molecule of the terpenoid linalool has a chiral carbon Linalool has the following structure

Circle the chiral carbon atom in the linalool structure (1)

(b)Farnesene is a terpene consisting of three isoprene units (2-methylbuta-13-diene) joined togetherWrite the molecular formula of farnesene (1)

52

27 Skin Care

1 Which of the following is not a step in a free radical chain reaction

A ActivationB InitiationC PropagationD Termination

2 Fluorine reacts with methane via a free radical chain reaction Some steps in the chain reaction are shown in the table below

Complete the table by(a) inserting the missing name for the first step (1)

(b) showing another possible termination reaction in the final row of the table (1)

3 Suncreams contain antioxidantsThe antioxidant compound A can prevent damage to skin by reacting with free

radicalssuch as NO2bull

53

Why can compound A be described as a free radical scavenger in the reaction shown above

4 Hydrogen and chlorine gases are used in an experiment to demonstrate a free radical reaction A plastic bottle is wrapped with black tape leaving a ldquowindowrdquo on one sideThe bottle is filled with a mixture of hydrogen and chlorine When bright light shines on the bottle there is an explosion

A free radical chain reaction is initiated when light energy causes chlorine radicals to form as shown below

(a) Complete the equations below showing possible propagation and termination steps

(2)

54

(b) Why is the plastic bottle used in the experiment wrapped in black tape (1)

5 Chloramines can be removed from water using ultraviolet light treatment

One step in the process is the formation of free radicals

(a)State what is meant by the term free radical (1)

(b)Another step in the process is shown below

State the name for this type of step in a free radical reaction (1)

6 Modern shellac nail varnishes are more durable and so last longer than traditional nail polish

The shellac nail varnish is applied in thin layers to the nails and then the fingers are placed under a UV lamp

(a) The Skin Care Foundation has recommended that a sun-block is applied to the fingers and hand before using the lampSuggest why the Skin Care Foundation makes this recommendation (1)

(b) A free radical chain reaction takes place and the varnish hardens (i) State what is meant by the term free radical (1)

(ii) The shellac nail varnish contains a mixture of ingredients that take part in the free radical chain reactionOne of the steps in the free radical chain reaction is

55

State the term used to describe this type of step in a free radical chain reaction(1)

7 Skin care products contain a mixture of polar covalent non-polar covalent and ionic compounds The compounds need to stay mixed within the product Skin care products also need to spread easily and remain on the skin for a period of time as well as provide physical and chemical protection from the sun In order to do this skin care products contain a range of chemicals including water fats and oils antioxidants minerals and sun blockUsing your knowledge of chemistry explain the role of different chemicals in skin care products (3)

General Questions

1 A mixture of carbon monoxide and hydrogen can be converted into water and a mixture of hydrocarbons

nCO + (2n + 1)H2 rarr nH2O + hydrocarbons

What is the general formula for the hydrocarbons producedA CnH2nndash2B CnH2nC CnH2n+1D CnH2n+2

2 Butadiene is the first member of a homologous series of hydrocarbons called dienesWhat is the general formula for this seriesA CnHn+2B CnHn+3C CnH2nD CnH2nndash2

3 Which of the following statements about methanol is falseA It can be made from synthesis gasB It can be dehydrated to form an alkeneC It can be oxidised to give a carboxylic acidD It reacts with acidified potassium dichromate solution

56

4

Which line in the table correctly describes reactions X and Y

5

Which line in the table correctly describes reactions X and Y

6 Which of the following fuels when burned would make no contribution to globalwarming

57

A HydrogenB Natural gasC PetrolD Coal

7 Which of the following hydrocarbons always gives the same product when one of itshydrogen atoms is replaced by a chlorine atomA HexaneB Hex-1-eneC CyclohexaneD Cyclohexene

8 Which of the following compounds does not have isomeric structuresA C2HCl3B C2H4Cl2C PropeneD Propan-1-ol

9 What organic compound is produced by the dehydration of ethanol A EthaneB EtheneC EthanalD Ethanoic acid

10

The above equation representsA hydrationB hydrogenationC condensationD hydrolysis

11

Which of the following compounds is an isomer of the structure shown aboveA ButanalB ButanoneC Butan-1-olD Butanoic acid

58

12 A compound with molecular formula C6H12O2 could beA hexanalB hexan-2-olC hexan-2-oneD hexanoic acid

13 Propan-2-ol can be prepared from propane as follows

Which line in the table correctly describes the types of reaction taking place at Steps 1 and 2

14 Which of the following compounds would be the most water soluble

15 Cyanohydrin compounds can be made from carbonyl compounds by reacting the carbonyl compound with hydrogen cyanide (HCN)

59

Which carbonyl compound would react with hydrogen cyanide (HCN) to form the following compound

16 Ethyne is the first member of the homologous series called the alkynes

Ethyne can undergo addition reactions as shown in the flow diagram

(a) Compound 2 is an isomer of 12-dichloroethaneDraw a structural formula for compound 2 (1)

(b) Reagents A B and C are three different diatomic gasesUsing information in the flow diagram identify reagents A B and C (1)

60

Reagent Gas

A

B

C

17 In 1865 the German chemist Kekuleacute proposed a ring structure for benzene This structure was based on alternating single and double bonds

(a) (i) Describe a chemical test that would indicate that the above chemical structure for benzene is incorrect (1)

(ii) Briefly describe the correct structure for benzene (1)

(b) Benzene can be formed from cyclohexaneC6H12 rarr C6H6 + 3H2

What name is given to this type of reaction (1)18 Infra-red spectroscopy is a technique that can be used to identify the bonds that

arepresent in a molecule Different bonds absorb infra-red radiation of different wavenumbers This is due to differences in the bond lsquostretchrsquo These absorptions are recorded in a spectrumA spectrum for propan-1-ol is shown

61

The correlation table on page 13 of the data booklet shows the wavenumber ranges for the absorptions due to different bonds

(a) Use the correlation table to identify the bonds responsible for the two absorptions x and y that are circled in the propan-1-ol spectrum (1)

(b) Propan-1-ol reacts with ethanoic acid(i) What name is given to this type of reaction (1)(ii) Draw a spectrum that could be obtained for the organic product of this

reaction (1)

19 Paracetamol is a widely used painkiller

(a) Write the molecular formula for paracetamol (1)

(b) One antidote for paracetamol overdose is methionine

62

To what family of organic compounds does methionine belong (1)

(c) The concentration of paracetamol in a solution can be determined by measuring how much UV radiation it absorbs

The graph shows how the absorbance of a sample containing 0middot040 g l ndash1 paracetamol varies with wavelength

The quantity of UV radiation of wavelength 245 nm absorbed is directly proportional to the concentration of paracetamolThe absorbance of a second sample of paracetamol solution measured at 245 nm was 0middot90 What is the concentration in g l ndash1 of this second paracetamol solution (1)

20 Many carbon compounds containing oxygen are very flammableThe table shows information about two families of isomersThe lowest temperature at which a compound will ignite is called its flash point

(a) A compound with the molecular formula C6H14O has a boiling point of 158 degC63

Draw a structural formula for this compound (1)

(b) For a family of isomers in the table write a general statement linking the flash points of the compounds to their structures (1)

21 Hydrogels are used in disposable nappies They are fine powders that can absorb up to 500 times their own weight in waterA hydrogel is a very long molecule with carboxyl groups at regular intervals along its length A short section of a hydrogel molecule is shown below

Hydrogels are extremely good at soaking up water because the water molecules are strongly attracted to them

Using your knowledge of chemistry comment on how suitable hydrogels would be for absorbing liquids or solutions spilled in a chemistry lab (1)

64

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

(i) Suggest why only four spots were obtained on the chromatogram of the hydrolysed pentapeptide (1)

(ii) It is known that this amino acid mixture contains the amino acid methionine The Rf value for methionine in this solvent is 040Draw a circle around the spot on the chromatogram that corresponds to methionine (1)

(e) Over the last decade several families of extremely stable peptide molecules have been discovered where the peptide chain forms a ring

(i) A simple cyclic dipeptide is shown

Draw a structural formula for one of the amino acids that would be formed on complete hydrolysis of the above cyclic dipeptide (1)

(ii) Alpha-amanitin is a highly toxic cyclic peptide found in death cap mushrooms The lethal dose for humans is 100 mg per kg of body mass1middot0 g of death cap mushrooms contains 250 mg of alpha-amanitinCalculate the minimum mass of death cap mushrooms that would contain the lethal dose for a 75 kg adult (2)

18 Dishwasher tablets produce the bleach hydrogen peroxide H2O2 One action of this oxidising agent is to oxidise food

(a)(i) Suggest another action of the bleach produced by the dishwasher tablets (1)

20

(ii) Hydrogen peroxide decomposes to form water and oxygen

2H2O2(ℓ) rarr 2H2O(ℓ) + O2(g)

A dishwasher tablet produces 0middot051 g of hydrogen peroxide (mass of one mole = 34 g)

Calculate the volume of oxygen that would be produced when0middot051 g of hydrogen peroxide decomposesTake the volume of 1 mole of oxygen gas to be 24 litres(3)

(b)Enzymes are commonly added to dishwasher tablets These are used to break down proteins(i) The proteins are broken down into small water-soluble molecules

Name the small water-soluble molecules made when proteins are broken down completely (1)

(ii) The structure of a section of protein chain found in egg white is shown

(A)Name the functional group circled (1)(B)Draw a structural formula for one of the molecules that would be made

when this section of egg white protein chain is completely broken down (1)

(iii) As part of the program in the dishwasher the conditions in the dishwasher change so that the enzyme molecules no longer work because they change shape

21

(A) State the term used to describe the change in shape of enzyme molecules(1)

(B) Suggest a change in conditions which would cause the enzyme molecules to change shape (1)

(d) A bleach activator is frequently added to dishwasher tablets to speed up the bleaching reaction One common bleach activator is TAED TAED could be produced in a process which involves a number of stages

(i) The first stage in producing TAED is shown below

Suggest a name for this type of reaction (1)

(ii) The final stage in the process producing TAED is shown below

Draw a structural formula for TAED (1)

22

23 The Chemistry of Cooking

1 Vanillin and zingerone are flavour molecules

Which line in the table correctly compares the properties of vanillin and zingerone

23

2 Erythrose can be used in the production of a chewing gum that helps prevent tooth decay

Which of the following compounds will be the best solvent for erythrose

3 The following molecules give flavour to food Which of the following flavour molecules would be most likely to be retained in the food when the food is cooked in water

24

4 Cooking involves many chemical reactions Proteins fats oils and esters are some examples of compounds found in food A chemist suggested that cooking food could change compounds from being fat-soluble to water-soluble Use your knowledge of chemistry to comment on the accuracy of this statement(3)

25

24 The Oxidation of Food

1 Apples and bananas turn brown when cut or bruised The first step of the reaction causing

the browning is shown below

Which of the following terms correctly describes this reactionA ReductionB OxidationC DehydrationD Condensation

2 Which of the following reactions can be classified as reductionA CH3CH2OH rarr CH3COOHB CH3 CH(OH)CH3 rarr CH3COCH3C CH3CH2COCH3 rarr CH3CH2CH(OH)CH3D CH3CH2CHO rarr CH3CH2COOH

3 The dehydration of butan-2-ol can produce two isomeric alkenes but-1-ene andbut-2-ene Which of the following alkanols can similarly produce on dehydration a pair of isomeric alkenesA Propan-2-olB Pentan-3-olC Hexan-3-olD Heptan-4-ol

4 Which of the following compounds is an alkanone

26

5 Which of the following is an aldehyde

6 Which of the following compounds would react with sodium hydroxide solution to forma saltA CH3CHOB CH3COOHC CH3COCH3D CH3CH2OH

7 Which line in the table shows the correct functional group for each homologous series

8 Which of the following organic compounds is an isomer of hexanalA 2-MethylbutanalB 3-Methylpentan-2-oneC 22-Dimethylbutan-1-olD 3-Ethylpentanal

27

9 The name of this compound is

A methanolB methanalC methanoic acidD methanone

10 Which alcohol could be oxidised to a carboxylic acid

11 Which of the following structural formulae represents a tertiary alcohol

12 Compound X reacted with hot copper(II) oxide and the organic product did not give acolour change when heated with Fehlingrsquos solution Compound X could beA butan-1-olB butan-2-olC butanoneD butanoic acid

28

13 Which two isomers would each produce an acid when warmed with acidified potassiumdichromate solution

A 1 and 2B 2 and 3C 1 and 4D 3 and 4

14 After heating for several minutes as shown in the diagram the pH indicator solution turned red

Liquid Q could beA propanoneB paraffinC propan-1-olD propan-2-ol

29

15 Enzymes are involved in the browning of cut fruitOne reaction taking place is

Which of the following correctly describes the above reaction

A OxidationB ReductionC HydrolysisD Condensation

16 Which of the following statements is correct for ketones

A They are formed by oxidation of tertiary alcohols

B They contain the group

C They contain a carboxyl groupD They will not react with Fehlingrsquos solution

17 Carvone is a natural product that can be extracted from orange peel

Which line in the table correctly describes the reaction of carvone with bromine solution and with acidified potassium dichromate solution

30

18 Which of the following is an isomer of 22-dimethylpentan-1-ol

A CH3CH2CH2CH(CH3)CH2OHB (CH3)3CCH(CH3)CH2OHC CH3CH2CH2CH2CH2CH2CH2CH2OHD (CH3)2CHC(CH3)2CH2CH2OH

19 The equation for the reduction reaction taking place when ethanal reacts with Tollensrsquo reagent is

A Cu2+(aq) + eminus rarr Cu+(aq)

B Ag+(aq) + eminus rarr Ag(s)

C Cr2O72minus(aq) + 14H+(aq) + 6eminus rarr 2Cr3+(aq) + 7H2O(ℓ)

D MnO4minus(aq) + 8H+(aq) + 5eminus rarr Mn2+(aq) + 4H2O(ℓ)

20 The name of the compound with structure

isA 23-dimethylpentan-4-oneB 23-dimethylpentan-2-alC 34-dimethylpentan-2-oneD 34-dimethylpentan-2-al

21 What is the systematic name for the compound below

A 222-trimethylethanolB 22-dimethylpropan-1-olC 22-dimethylpropan-3-olD 22-dimethylpentan-1-ol

31

22 The structure of a molecule found in olive oil can be represented as shown

(a) Olive oil can be hydrolysed using sodium hydroxide solution to produce sodium salts of fatty acids Name the other product of this reaction (1)

(b) In what way does the structure of a fat molecule differ from that of an oil molecule (1)

(c) Over time open containers of olive oil develop a rancid flavour What substance is reacting with the oil to cause these unwanted changes to take place (1)

23 A student writes the following statement It is incorrect Explain the mistake in the studentrsquos reasoning (1)

Alcohols are alkaline because of their OH groups

24 Carbon compounds take part in a wide variety of chemical reactions (a)

Name this type of chemical reaction (1)

(b)

Draw a structural formula for C3H6O (1)

25 Alkanols can be oxidised to alkanoic acids

32

(a) Why can Step 1 be described as an oxidation reaction (1)

(b) Acidified potassium dichromate solution can be used to oxidise propanal in Step 2 What colour change would be observed in this reaction (1)

26 Amines can be produced by reacting ammonia with an aldehyde or a ketone This reaction an example of reductive amination occurs in two stages

Stage 1 Amination

Stage 2 Reduction

(a) Give another name for the type of reaction taking place in Stage 2

(b) Draw the structural formula for the amine produced when butanal undergoes reductive amination with ammonia

27 Using a cobalt catalyst alkenes react with a mixture of hydrogen and carbon monoxideThe products are two isomeric aldehydes Propene reacts with the mixture as shown

(a) What name is given to a mixture of hydrogen and carbon monoxide (1)

(b) Draw a structural formula for compound B (1)

(c) (i) What would be observed if compound A was gently heated with Tollensrsquo reagent

(1)(ii) How would the reaction mixture be heated (1)

33

(d) Aldehydes can also be formed by the reaction of some alcohols with copper(II) oxideName the type of alcohol that would react with copper(II) oxide to form an aldehyde (1)

28 Aldehydes and ketones can take part in a reaction sometimes known as an aldol condensation The simplest aldol reaction involves two molecules of ethanal

In the reaction the carbon atom next to the carbonyl functional group of one molecule forms a bond with the carbonyl carbon atom of the second molecule

(a) Draw a structural formula for the product formed when propanone is used instead of ethanal in this type of reaction (1)

(b) Name an aldehyde that would not take part in an aldol condensation (1)

(c) Apart from the structure of the reactants suggest what is unusual about applying the term ldquocondensationrdquo to this particular type of reaction (1)

29 Primary secondary and tertiary alkanols can be prepared by the reaction of carbonyl compounds with Grignard reagents

Step 1The Grignard reagent reacts with the carbonyl compound

Step 2The reaction of the product of Step 1 with dilute acid produces the alkanol

(a) Describe the difference between a primary a secondary and a tertiary alkanol

You may wish to include labelled structures in your answer (1)34

(b) Suggest a name for the type of reaction that takes place in Step 1 (1)

(c) The same Grignard reagent can be used to produce the alkanol below

Name the carbonyl compound used in this reaction (1)

30 Hairspray is a mixture of chemicals(a) A primary alcohol 2-methylpropan-1-ol is added to hairspray to help it dry quickly on the hair

Draw a structural formula for a secondary alcohol that is an isomer of2-methylpropan-1-ol (1)

(b) Triethanol amine and triisopropyl amine are bases used to neutralise acidic compounds in the hairspray to prevent damage to the hair

In terms of the intermolecular bonding present explain clearly why triethanol amine has a much higher boiling point than triisopropyl amine (2)

35

36

31 Chocolate contains various compounds(a) Many of the flavour and aroma molecules found in chocolate are aldehydes and

ketones Two examples are shown below

Phenylethanal can be easily oxidised but 13-diphenylpropan-2-one cannot(i) Name a chemical that could be used to distinguish between these two

compounds (1)

(ii) Name the type of organic compound formed when phenylethanal is oxidised (1)

(b) Glycerol monostearate is an emulsifier used in chocolate

(i) Why is glycerol monostearate added to chocolate (1)

(ii) Draw a structural formula for glycerol (1)

(c) Theobromine a compound present in chocolate can cause illness in dogs and cats To decide if treatment is necessary vets must calculate the mass of theobromine consumed 1middot0 g of chocolate contains 1middot4 mg of theobromine Calculate the mass in mg of theobromine in a 17 g biscuit of which 28 is chocolate Show your working clearly (2)

(d) The flavour and texture of chocolate comes from a blend of compoundsUsing your knowledge of chemistry describe how you could show that there are ionic compounds and covalent compounds present in chocolate (3)

37

32 Ethanol has many uses

(a) Ethanol is found at relatively low concentrations in wine

(i) Name the chemical reaction that produces ethanol in wine (1)

(ii) Standard ethanol solutions were used to produce a graph of density against

concentration of ethanol given as a percentage of alcohol by volume ( abv)

What is the concentration of ethanol in units of abv in a solution of density 0middot9818 g cmminus3 (1)

(b) Whisky contains a higher concentration of ethanol

(i) Before 1980 the concentration of alcohol in drinks was measured in terms of degrees proof The concentration of alcohol in two drinks is shown in the table below both as abv and degrees proof

38

A cask strength whisky has an alcohol concentration of 65 abv Calculate the alcohol concentration of this whisky in degrees proof (1)

(ii) A barrel containing 195 litres of cask strength whisky costs pound1300 The cask strength whisky is diluted with water to reduce the concentration of alcohol from 65 abv to 46 abv before it is bottled Calculate the cost of the cask strength whisky needed to produce a 0middot70 litre bottle Show your working clearly (2)

(iii) 5-Butyl-4-methyltetrahydrofuran-2-ol is a flavour compound found in whisky

stored in oak barrels

Write the systematic name for the compound shown below (1) 13 11

33 (a) One test for glucose involves Fehlingrsquos solutionCircle the part of the glucose molecule that reacts with Fehlingrsquos solution (1)

(b) In solution sugar molecules exist in an equilibrium in straight-chain and ring forms

To change from the straight-chain form to the ring form the oxygen of the hydroxyl on carbon number 5 joins to the carbonyl carbon This is shown below for glucose

39

Draw the structure of a ring form for fructose (1)

34 (a) During the free radical chain reaction small molecules join to form large chain molecules

One example of a small molecule used is

Name the functional group circled above (1)

(b)Alcohol wipes are used to finish the varnishing treatment Alcohol wipes contain the alcohol propan-2-olState why propan-2-ol can be described as a secondary alcohol (1)

35 A student was carrying out an investigation into alcohols aldehydes and ketones

(a)The student was given three alcohols labelled as A B and C These alcohols were all isomers with the formula C4H9OH

(i) Draw a structural formula for the secondary alcohol with the formula C4H9OH(1)

(ii) The student set up the following experiment

A Suggest why a water bath is an appropriate method of heating the reaction mixture (1)

B Describe the colour change that would have been observed with alcohols A and C (1)

40

C Alcohol B is not oxidised State the type of alcohol which cannot be oxidised by acidified dichromate solution (1)

(iii) The student set up a second experiment with alcohol A

Hot copper(II) oxide is an oxidising agentA When alcohol A (C4H9OH) is oxidised the product turns the pH paper

redSuggest a name for the product (1)

B Complete the ion-electron equation for the oxidation reaction

C4H9OH rarr C4H8O2 (1)

(b)The student found the following information about the boiling points of some aldehydes

41

(i) Name the aldehyde that has a boiling point of 119 degC (1)(ii) Predict the boiling point in degC of the following molecule (1)

(iii) Using information from the table describe one way in which differences in structure affect the boiling point of isomeric aldehydes (1)

(iv) State what would be observed when an aldehyde is gently heated with Tollensrsquo reagent (1)

(c) Ketones contain a carbonyl groupName the type of intermolecular interaction between ketone molecules (1)

42

25 Soaps Detergents and Emulsions

1 Soaps are produced by the following reaction

This reaction is an example ofA condensationB esterificationC hydrolysisD oxidation

2 Which of the following is the salt of a long-chain fatty acid

A FatB OilC SoapD Glycerol

3 Emulsifiers for use in food are commonly made by reacting edible oils with

A estersB glycerolC fatty acidsD amino acids

4 A fatty acid is a long chain carboxylic acid Examples of fatty acids are shown in the table below

43

(a) What is the systematic name for linolenic acid (1)(b) Stearic acid reacts with sodium hydroxide solution to form sodium stearate

(i) Name the type of reaction taking place when stearic acid reacts with sodium hydroxide (1)

(ii) Explain fully how sodium stearate acts to keep grease and non-polar substances suspended in water during cleaning (3)

5 Small children can find it difficult to swallow tablets or pills so ibuprofen is supplied as an ldquoinfant formulardquo emulsion(a) The emulsifier used is polysorbate 80 Its structure is shown below

Explain why this molecule acts as an emulsifier (2)

(b) The emulsion contains 2 g of ibuprofen in every 100 cm3 of emulsion The recommended dose for treating a 6 month old baby is 0middot050 g Calculate the volume in cm3 of ldquoinfant formulardquo needed to treat a 6 month old baby (1)

6 Occasionally seabirds can become contaminated with hydrocarbons from oil spills This causes problems for birds because their feathers lose their waterproofing making the birds susceptible to temperature changes and

44

affecting their buoyancy If the birds attempt to clean themselves to remove the oil they may swallow the hydrocarbons causing damage to their internal organsContaminated seabirds can be cleaned by rubbing vegetable oil into their feathers and feet before the birds are rinsed with diluted washing-up liquidUsing your knowledge of chemistry comment on the problems created for seabirds by oil spills and the actions taken to treat affected birds (3)

7 Dishwasher tablets contain chemicals which remove dirt from dishesDishwasher tablets include detergents These molecules act like soaps to allow mixing of fat-soluble dirt and water(a)During the cleaning process the detergent molecules combine with fat-

soluble dirtA simplified diagram of a detergent molecule is shown

Complete the diagram below to show how detergent molecules combine with fat-soluble dirt (1)

(b)State the term used to describe the non-polar hydrocarbon tail of a detergent molecule (1)

45

26 Fragrances1 Myrcene is a simple terpene

Terpenes contain at least one isoprene unit Which of the following shows a correctly highlighted isoprene unit

2 Limonene is one of the terpene molecules responsible for the flavour of lemons

How many isoprene units are used in the production of one limonene moleculeA 1B 2C 3D 4

46

3 The structure of caryophyllene which can be extracted from clove oil is

Which of the following would be the best solvent for extracting caryophylleneA HexaneB HexanalC HexanolD Hexanone

4 The structure of isoprene is

Limonene is a terpene molecule present in lemons

How many isoprene units are joined together in a limonene molecule

A 1B 2

47

C 3D 4

5 Essential oils are

A non-water soluble non-volatile compoundsB non-water soluble volatile compoundsC water soluble non-volatile compoundsD water soluble volatile compounds

6 Two typical compounds that are present in many perfumes are shown

(a) Why does geraniol evaporate more slowly than limonene (1)

(b) The structure of one of the first synthetic scents used in perfume is shown below

(i) Name the family of carbonyl compounds to which this synthetic scent belongs (1)

(ii) Complete the structure below to show the product formed when this scent is

oxidised (1)

(c) Traces of a liquid were discovered in a bottle believed to contain perfume belonging to Queen Hatshepsut ruler of Egypt over 3500 years ago

Perfumes were made by dissolving plant extracts containing pleasant smelling terpenes and esters in an edible oil A little ethanol and water may also have been addedUsing your knowledge of chemistry comment on the possible smell(s) when such a bottle is opened after being stored for thousands of years (3)

48

49

7 A team of chemists are developing a fragrance for use in a shower gel for men(a) To give the gel a fruity smell the chemists are considering adding an ester

They synthesise six isomeric esters Volunteers smell each ester and give it a rating out of one hundred depending on how fruity the smell is

(i) Name the ester with the fruit-smell rating of 92 (1)

(ii) Shown below are the structures of three more isomers

Arrange these esters in order of decreasing fruit-smell rating (1)

50

(b) To create a fragrance for men the compound civetone is added

Draw a structural formula for the alcohol that can be oxidised to form civetone (1)

(c) To make the shower gel produce a cold tingling sensation when applied to the skin menthol is added

Like terpenes menthol is formed from isoprene (2-methylbuta-13-diene)Circle an isoprene unit on the menthol structure above (1)

8 Many of the compounds in perfumes are molecules consisting of joined isoprene units

(a) State the name that is given to molecules consisting of joined isoprene units (1)

(b)Geraniol is one of the compounds found in perfume It has the following structural formula and systematic name

Linalool can also be present Its structural formula is shown

51

(i) State the systematic name for linalool (1)(ii) Explain why linalool can be classified as a tertiary alcohol (1)

9 The component molecules found in lavender oils are terpenes or terpenoids(a)A chiral carbon is a carbon atom attached to four different atoms or groups of

atomsAn example is shown below

A molecule of the terpenoid linalool has a chiral carbon Linalool has the following structure

Circle the chiral carbon atom in the linalool structure (1)

(b)Farnesene is a terpene consisting of three isoprene units (2-methylbuta-13-diene) joined togetherWrite the molecular formula of farnesene (1)

52

27 Skin Care

1 Which of the following is not a step in a free radical chain reaction

A ActivationB InitiationC PropagationD Termination

2 Fluorine reacts with methane via a free radical chain reaction Some steps in the chain reaction are shown in the table below

Complete the table by(a) inserting the missing name for the first step (1)

(b) showing another possible termination reaction in the final row of the table (1)

3 Suncreams contain antioxidantsThe antioxidant compound A can prevent damage to skin by reacting with free

radicalssuch as NO2bull

53

Why can compound A be described as a free radical scavenger in the reaction shown above

4 Hydrogen and chlorine gases are used in an experiment to demonstrate a free radical reaction A plastic bottle is wrapped with black tape leaving a ldquowindowrdquo on one sideThe bottle is filled with a mixture of hydrogen and chlorine When bright light shines on the bottle there is an explosion

A free radical chain reaction is initiated when light energy causes chlorine radicals to form as shown below

(a) Complete the equations below showing possible propagation and termination steps

(2)

54

(b) Why is the plastic bottle used in the experiment wrapped in black tape (1)

5 Chloramines can be removed from water using ultraviolet light treatment

One step in the process is the formation of free radicals

(a)State what is meant by the term free radical (1)

(b)Another step in the process is shown below

State the name for this type of step in a free radical reaction (1)

6 Modern shellac nail varnishes are more durable and so last longer than traditional nail polish

The shellac nail varnish is applied in thin layers to the nails and then the fingers are placed under a UV lamp

(a) The Skin Care Foundation has recommended that a sun-block is applied to the fingers and hand before using the lampSuggest why the Skin Care Foundation makes this recommendation (1)

(b) A free radical chain reaction takes place and the varnish hardens (i) State what is meant by the term free radical (1)

(ii) The shellac nail varnish contains a mixture of ingredients that take part in the free radical chain reactionOne of the steps in the free radical chain reaction is

55

State the term used to describe this type of step in a free radical chain reaction(1)

7 Skin care products contain a mixture of polar covalent non-polar covalent and ionic compounds The compounds need to stay mixed within the product Skin care products also need to spread easily and remain on the skin for a period of time as well as provide physical and chemical protection from the sun In order to do this skin care products contain a range of chemicals including water fats and oils antioxidants minerals and sun blockUsing your knowledge of chemistry explain the role of different chemicals in skin care products (3)

General Questions

1 A mixture of carbon monoxide and hydrogen can be converted into water and a mixture of hydrocarbons

nCO + (2n + 1)H2 rarr nH2O + hydrocarbons

What is the general formula for the hydrocarbons producedA CnH2nndash2B CnH2nC CnH2n+1D CnH2n+2

2 Butadiene is the first member of a homologous series of hydrocarbons called dienesWhat is the general formula for this seriesA CnHn+2B CnHn+3C CnH2nD CnH2nndash2

3 Which of the following statements about methanol is falseA It can be made from synthesis gasB It can be dehydrated to form an alkeneC It can be oxidised to give a carboxylic acidD It reacts with acidified potassium dichromate solution

56

4

Which line in the table correctly describes reactions X and Y

5

Which line in the table correctly describes reactions X and Y

6 Which of the following fuels when burned would make no contribution to globalwarming

57

A HydrogenB Natural gasC PetrolD Coal

7 Which of the following hydrocarbons always gives the same product when one of itshydrogen atoms is replaced by a chlorine atomA HexaneB Hex-1-eneC CyclohexaneD Cyclohexene

8 Which of the following compounds does not have isomeric structuresA C2HCl3B C2H4Cl2C PropeneD Propan-1-ol

9 What organic compound is produced by the dehydration of ethanol A EthaneB EtheneC EthanalD Ethanoic acid

10

The above equation representsA hydrationB hydrogenationC condensationD hydrolysis

11

Which of the following compounds is an isomer of the structure shown aboveA ButanalB ButanoneC Butan-1-olD Butanoic acid

58

12 A compound with molecular formula C6H12O2 could beA hexanalB hexan-2-olC hexan-2-oneD hexanoic acid

13 Propan-2-ol can be prepared from propane as follows

Which line in the table correctly describes the types of reaction taking place at Steps 1 and 2

14 Which of the following compounds would be the most water soluble

15 Cyanohydrin compounds can be made from carbonyl compounds by reacting the carbonyl compound with hydrogen cyanide (HCN)

59

Which carbonyl compound would react with hydrogen cyanide (HCN) to form the following compound

16 Ethyne is the first member of the homologous series called the alkynes

Ethyne can undergo addition reactions as shown in the flow diagram

(a) Compound 2 is an isomer of 12-dichloroethaneDraw a structural formula for compound 2 (1)

(b) Reagents A B and C are three different diatomic gasesUsing information in the flow diagram identify reagents A B and C (1)

60

Reagent Gas

A

B

C

17 In 1865 the German chemist Kekuleacute proposed a ring structure for benzene This structure was based on alternating single and double bonds

(a) (i) Describe a chemical test that would indicate that the above chemical structure for benzene is incorrect (1)

(ii) Briefly describe the correct structure for benzene (1)

(b) Benzene can be formed from cyclohexaneC6H12 rarr C6H6 + 3H2

What name is given to this type of reaction (1)18 Infra-red spectroscopy is a technique that can be used to identify the bonds that

arepresent in a molecule Different bonds absorb infra-red radiation of different wavenumbers This is due to differences in the bond lsquostretchrsquo These absorptions are recorded in a spectrumA spectrum for propan-1-ol is shown

61

The correlation table on page 13 of the data booklet shows the wavenumber ranges for the absorptions due to different bonds

(a) Use the correlation table to identify the bonds responsible for the two absorptions x and y that are circled in the propan-1-ol spectrum (1)

(b) Propan-1-ol reacts with ethanoic acid(i) What name is given to this type of reaction (1)(ii) Draw a spectrum that could be obtained for the organic product of this

reaction (1)

19 Paracetamol is a widely used painkiller

(a) Write the molecular formula for paracetamol (1)

(b) One antidote for paracetamol overdose is methionine

62

To what family of organic compounds does methionine belong (1)

(c) The concentration of paracetamol in a solution can be determined by measuring how much UV radiation it absorbs

The graph shows how the absorbance of a sample containing 0middot040 g l ndash1 paracetamol varies with wavelength

The quantity of UV radiation of wavelength 245 nm absorbed is directly proportional to the concentration of paracetamolThe absorbance of a second sample of paracetamol solution measured at 245 nm was 0middot90 What is the concentration in g l ndash1 of this second paracetamol solution (1)

20 Many carbon compounds containing oxygen are very flammableThe table shows information about two families of isomersThe lowest temperature at which a compound will ignite is called its flash point

(a) A compound with the molecular formula C6H14O has a boiling point of 158 degC63

Draw a structural formula for this compound (1)

(b) For a family of isomers in the table write a general statement linking the flash points of the compounds to their structures (1)

21 Hydrogels are used in disposable nappies They are fine powders that can absorb up to 500 times their own weight in waterA hydrogel is a very long molecule with carboxyl groups at regular intervals along its length A short section of a hydrogel molecule is shown below

Hydrogels are extremely good at soaking up water because the water molecules are strongly attracted to them

Using your knowledge of chemistry comment on how suitable hydrogels would be for absorbing liquids or solutions spilled in a chemistry lab (1)

64

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

(ii) Hydrogen peroxide decomposes to form water and oxygen

2H2O2(ℓ) rarr 2H2O(ℓ) + O2(g)

A dishwasher tablet produces 0middot051 g of hydrogen peroxide (mass of one mole = 34 g)

Calculate the volume of oxygen that would be produced when0middot051 g of hydrogen peroxide decomposesTake the volume of 1 mole of oxygen gas to be 24 litres(3)

(b)Enzymes are commonly added to dishwasher tablets These are used to break down proteins(i) The proteins are broken down into small water-soluble molecules

Name the small water-soluble molecules made when proteins are broken down completely (1)

(ii) The structure of a section of protein chain found in egg white is shown

(A)Name the functional group circled (1)(B)Draw a structural formula for one of the molecules that would be made

when this section of egg white protein chain is completely broken down (1)

(iii) As part of the program in the dishwasher the conditions in the dishwasher change so that the enzyme molecules no longer work because they change shape

21

(A) State the term used to describe the change in shape of enzyme molecules(1)

(B) Suggest a change in conditions which would cause the enzyme molecules to change shape (1)

(d) A bleach activator is frequently added to dishwasher tablets to speed up the bleaching reaction One common bleach activator is TAED TAED could be produced in a process which involves a number of stages

(i) The first stage in producing TAED is shown below

Suggest a name for this type of reaction (1)

(ii) The final stage in the process producing TAED is shown below

Draw a structural formula for TAED (1)

22

23 The Chemistry of Cooking

1 Vanillin and zingerone are flavour molecules

Which line in the table correctly compares the properties of vanillin and zingerone

23

2 Erythrose can be used in the production of a chewing gum that helps prevent tooth decay

Which of the following compounds will be the best solvent for erythrose

3 The following molecules give flavour to food Which of the following flavour molecules would be most likely to be retained in the food when the food is cooked in water

24

4 Cooking involves many chemical reactions Proteins fats oils and esters are some examples of compounds found in food A chemist suggested that cooking food could change compounds from being fat-soluble to water-soluble Use your knowledge of chemistry to comment on the accuracy of this statement(3)

25

24 The Oxidation of Food

1 Apples and bananas turn brown when cut or bruised The first step of the reaction causing

the browning is shown below

Which of the following terms correctly describes this reactionA ReductionB OxidationC DehydrationD Condensation

2 Which of the following reactions can be classified as reductionA CH3CH2OH rarr CH3COOHB CH3 CH(OH)CH3 rarr CH3COCH3C CH3CH2COCH3 rarr CH3CH2CH(OH)CH3D CH3CH2CHO rarr CH3CH2COOH

3 The dehydration of butan-2-ol can produce two isomeric alkenes but-1-ene andbut-2-ene Which of the following alkanols can similarly produce on dehydration a pair of isomeric alkenesA Propan-2-olB Pentan-3-olC Hexan-3-olD Heptan-4-ol

4 Which of the following compounds is an alkanone

26

5 Which of the following is an aldehyde

6 Which of the following compounds would react with sodium hydroxide solution to forma saltA CH3CHOB CH3COOHC CH3COCH3D CH3CH2OH

7 Which line in the table shows the correct functional group for each homologous series

8 Which of the following organic compounds is an isomer of hexanalA 2-MethylbutanalB 3-Methylpentan-2-oneC 22-Dimethylbutan-1-olD 3-Ethylpentanal

27

9 The name of this compound is

A methanolB methanalC methanoic acidD methanone

10 Which alcohol could be oxidised to a carboxylic acid

11 Which of the following structural formulae represents a tertiary alcohol

12 Compound X reacted with hot copper(II) oxide and the organic product did not give acolour change when heated with Fehlingrsquos solution Compound X could beA butan-1-olB butan-2-olC butanoneD butanoic acid

28

13 Which two isomers would each produce an acid when warmed with acidified potassiumdichromate solution

A 1 and 2B 2 and 3C 1 and 4D 3 and 4

14 After heating for several minutes as shown in the diagram the pH indicator solution turned red

Liquid Q could beA propanoneB paraffinC propan-1-olD propan-2-ol

29

15 Enzymes are involved in the browning of cut fruitOne reaction taking place is

Which of the following correctly describes the above reaction

A OxidationB ReductionC HydrolysisD Condensation

16 Which of the following statements is correct for ketones

A They are formed by oxidation of tertiary alcohols

B They contain the group

C They contain a carboxyl groupD They will not react with Fehlingrsquos solution

17 Carvone is a natural product that can be extracted from orange peel

Which line in the table correctly describes the reaction of carvone with bromine solution and with acidified potassium dichromate solution

30

18 Which of the following is an isomer of 22-dimethylpentan-1-ol

A CH3CH2CH2CH(CH3)CH2OHB (CH3)3CCH(CH3)CH2OHC CH3CH2CH2CH2CH2CH2CH2CH2OHD (CH3)2CHC(CH3)2CH2CH2OH

19 The equation for the reduction reaction taking place when ethanal reacts with Tollensrsquo reagent is

A Cu2+(aq) + eminus rarr Cu+(aq)

B Ag+(aq) + eminus rarr Ag(s)

C Cr2O72minus(aq) + 14H+(aq) + 6eminus rarr 2Cr3+(aq) + 7H2O(ℓ)

D MnO4minus(aq) + 8H+(aq) + 5eminus rarr Mn2+(aq) + 4H2O(ℓ)

20 The name of the compound with structure

isA 23-dimethylpentan-4-oneB 23-dimethylpentan-2-alC 34-dimethylpentan-2-oneD 34-dimethylpentan-2-al

21 What is the systematic name for the compound below

A 222-trimethylethanolB 22-dimethylpropan-1-olC 22-dimethylpropan-3-olD 22-dimethylpentan-1-ol

31

22 The structure of a molecule found in olive oil can be represented as shown

(a) Olive oil can be hydrolysed using sodium hydroxide solution to produce sodium salts of fatty acids Name the other product of this reaction (1)

(b) In what way does the structure of a fat molecule differ from that of an oil molecule (1)

(c) Over time open containers of olive oil develop a rancid flavour What substance is reacting with the oil to cause these unwanted changes to take place (1)

23 A student writes the following statement It is incorrect Explain the mistake in the studentrsquos reasoning (1)

Alcohols are alkaline because of their OH groups

24 Carbon compounds take part in a wide variety of chemical reactions (a)

Name this type of chemical reaction (1)

(b)

Draw a structural formula for C3H6O (1)

25 Alkanols can be oxidised to alkanoic acids

32

(a) Why can Step 1 be described as an oxidation reaction (1)

(b) Acidified potassium dichromate solution can be used to oxidise propanal in Step 2 What colour change would be observed in this reaction (1)

26 Amines can be produced by reacting ammonia with an aldehyde or a ketone This reaction an example of reductive amination occurs in two stages

Stage 1 Amination

Stage 2 Reduction

(a) Give another name for the type of reaction taking place in Stage 2

(b) Draw the structural formula for the amine produced when butanal undergoes reductive amination with ammonia

27 Using a cobalt catalyst alkenes react with a mixture of hydrogen and carbon monoxideThe products are two isomeric aldehydes Propene reacts with the mixture as shown

(a) What name is given to a mixture of hydrogen and carbon monoxide (1)

(b) Draw a structural formula for compound B (1)

(c) (i) What would be observed if compound A was gently heated with Tollensrsquo reagent

(1)(ii) How would the reaction mixture be heated (1)

33

(d) Aldehydes can also be formed by the reaction of some alcohols with copper(II) oxideName the type of alcohol that would react with copper(II) oxide to form an aldehyde (1)

28 Aldehydes and ketones can take part in a reaction sometimes known as an aldol condensation The simplest aldol reaction involves two molecules of ethanal

In the reaction the carbon atom next to the carbonyl functional group of one molecule forms a bond with the carbonyl carbon atom of the second molecule

(a) Draw a structural formula for the product formed when propanone is used instead of ethanal in this type of reaction (1)

(b) Name an aldehyde that would not take part in an aldol condensation (1)

(c) Apart from the structure of the reactants suggest what is unusual about applying the term ldquocondensationrdquo to this particular type of reaction (1)

29 Primary secondary and tertiary alkanols can be prepared by the reaction of carbonyl compounds with Grignard reagents

Step 1The Grignard reagent reacts with the carbonyl compound

Step 2The reaction of the product of Step 1 with dilute acid produces the alkanol

(a) Describe the difference between a primary a secondary and a tertiary alkanol

You may wish to include labelled structures in your answer (1)34

(b) Suggest a name for the type of reaction that takes place in Step 1 (1)

(c) The same Grignard reagent can be used to produce the alkanol below

Name the carbonyl compound used in this reaction (1)

30 Hairspray is a mixture of chemicals(a) A primary alcohol 2-methylpropan-1-ol is added to hairspray to help it dry quickly on the hair

Draw a structural formula for a secondary alcohol that is an isomer of2-methylpropan-1-ol (1)

(b) Triethanol amine and triisopropyl amine are bases used to neutralise acidic compounds in the hairspray to prevent damage to the hair

In terms of the intermolecular bonding present explain clearly why triethanol amine has a much higher boiling point than triisopropyl amine (2)

35

36

31 Chocolate contains various compounds(a) Many of the flavour and aroma molecules found in chocolate are aldehydes and

ketones Two examples are shown below

Phenylethanal can be easily oxidised but 13-diphenylpropan-2-one cannot(i) Name a chemical that could be used to distinguish between these two

compounds (1)

(ii) Name the type of organic compound formed when phenylethanal is oxidised (1)

(b) Glycerol monostearate is an emulsifier used in chocolate

(i) Why is glycerol monostearate added to chocolate (1)

(ii) Draw a structural formula for glycerol (1)

(c) Theobromine a compound present in chocolate can cause illness in dogs and cats To decide if treatment is necessary vets must calculate the mass of theobromine consumed 1middot0 g of chocolate contains 1middot4 mg of theobromine Calculate the mass in mg of theobromine in a 17 g biscuit of which 28 is chocolate Show your working clearly (2)

(d) The flavour and texture of chocolate comes from a blend of compoundsUsing your knowledge of chemistry describe how you could show that there are ionic compounds and covalent compounds present in chocolate (3)

37

32 Ethanol has many uses

(a) Ethanol is found at relatively low concentrations in wine

(i) Name the chemical reaction that produces ethanol in wine (1)

(ii) Standard ethanol solutions were used to produce a graph of density against

concentration of ethanol given as a percentage of alcohol by volume ( abv)

What is the concentration of ethanol in units of abv in a solution of density 0middot9818 g cmminus3 (1)

(b) Whisky contains a higher concentration of ethanol

(i) Before 1980 the concentration of alcohol in drinks was measured in terms of degrees proof The concentration of alcohol in two drinks is shown in the table below both as abv and degrees proof

38

A cask strength whisky has an alcohol concentration of 65 abv Calculate the alcohol concentration of this whisky in degrees proof (1)

(ii) A barrel containing 195 litres of cask strength whisky costs pound1300 The cask strength whisky is diluted with water to reduce the concentration of alcohol from 65 abv to 46 abv before it is bottled Calculate the cost of the cask strength whisky needed to produce a 0middot70 litre bottle Show your working clearly (2)

(iii) 5-Butyl-4-methyltetrahydrofuran-2-ol is a flavour compound found in whisky

stored in oak barrels

Write the systematic name for the compound shown below (1) 13 11

33 (a) One test for glucose involves Fehlingrsquos solutionCircle the part of the glucose molecule that reacts with Fehlingrsquos solution (1)

(b) In solution sugar molecules exist in an equilibrium in straight-chain and ring forms

To change from the straight-chain form to the ring form the oxygen of the hydroxyl on carbon number 5 joins to the carbonyl carbon This is shown below for glucose

39

Draw the structure of a ring form for fructose (1)

34 (a) During the free radical chain reaction small molecules join to form large chain molecules

One example of a small molecule used is

Name the functional group circled above (1)

(b)Alcohol wipes are used to finish the varnishing treatment Alcohol wipes contain the alcohol propan-2-olState why propan-2-ol can be described as a secondary alcohol (1)

35 A student was carrying out an investigation into alcohols aldehydes and ketones

(a)The student was given three alcohols labelled as A B and C These alcohols were all isomers with the formula C4H9OH

(i) Draw a structural formula for the secondary alcohol with the formula C4H9OH(1)

(ii) The student set up the following experiment

A Suggest why a water bath is an appropriate method of heating the reaction mixture (1)

B Describe the colour change that would have been observed with alcohols A and C (1)

40

C Alcohol B is not oxidised State the type of alcohol which cannot be oxidised by acidified dichromate solution (1)

(iii) The student set up a second experiment with alcohol A

Hot copper(II) oxide is an oxidising agentA When alcohol A (C4H9OH) is oxidised the product turns the pH paper

redSuggest a name for the product (1)

B Complete the ion-electron equation for the oxidation reaction

C4H9OH rarr C4H8O2 (1)

(b)The student found the following information about the boiling points of some aldehydes

41

(i) Name the aldehyde that has a boiling point of 119 degC (1)(ii) Predict the boiling point in degC of the following molecule (1)

(iii) Using information from the table describe one way in which differences in structure affect the boiling point of isomeric aldehydes (1)

(iv) State what would be observed when an aldehyde is gently heated with Tollensrsquo reagent (1)

(c) Ketones contain a carbonyl groupName the type of intermolecular interaction between ketone molecules (1)

42

25 Soaps Detergents and Emulsions

1 Soaps are produced by the following reaction

This reaction is an example ofA condensationB esterificationC hydrolysisD oxidation

2 Which of the following is the salt of a long-chain fatty acid

A FatB OilC SoapD Glycerol

3 Emulsifiers for use in food are commonly made by reacting edible oils with

A estersB glycerolC fatty acidsD amino acids

4 A fatty acid is a long chain carboxylic acid Examples of fatty acids are shown in the table below

43

(a) What is the systematic name for linolenic acid (1)(b) Stearic acid reacts with sodium hydroxide solution to form sodium stearate

(i) Name the type of reaction taking place when stearic acid reacts with sodium hydroxide (1)

(ii) Explain fully how sodium stearate acts to keep grease and non-polar substances suspended in water during cleaning (3)

5 Small children can find it difficult to swallow tablets or pills so ibuprofen is supplied as an ldquoinfant formulardquo emulsion(a) The emulsifier used is polysorbate 80 Its structure is shown below

Explain why this molecule acts as an emulsifier (2)

(b) The emulsion contains 2 g of ibuprofen in every 100 cm3 of emulsion The recommended dose for treating a 6 month old baby is 0middot050 g Calculate the volume in cm3 of ldquoinfant formulardquo needed to treat a 6 month old baby (1)

6 Occasionally seabirds can become contaminated with hydrocarbons from oil spills This causes problems for birds because their feathers lose their waterproofing making the birds susceptible to temperature changes and

44

affecting their buoyancy If the birds attempt to clean themselves to remove the oil they may swallow the hydrocarbons causing damage to their internal organsContaminated seabirds can be cleaned by rubbing vegetable oil into their feathers and feet before the birds are rinsed with diluted washing-up liquidUsing your knowledge of chemistry comment on the problems created for seabirds by oil spills and the actions taken to treat affected birds (3)

7 Dishwasher tablets contain chemicals which remove dirt from dishesDishwasher tablets include detergents These molecules act like soaps to allow mixing of fat-soluble dirt and water(a)During the cleaning process the detergent molecules combine with fat-

soluble dirtA simplified diagram of a detergent molecule is shown

Complete the diagram below to show how detergent molecules combine with fat-soluble dirt (1)

(b)State the term used to describe the non-polar hydrocarbon tail of a detergent molecule (1)

45

26 Fragrances1 Myrcene is a simple terpene

Terpenes contain at least one isoprene unit Which of the following shows a correctly highlighted isoprene unit

2 Limonene is one of the terpene molecules responsible for the flavour of lemons

How many isoprene units are used in the production of one limonene moleculeA 1B 2C 3D 4

46

3 The structure of caryophyllene which can be extracted from clove oil is

Which of the following would be the best solvent for extracting caryophylleneA HexaneB HexanalC HexanolD Hexanone

4 The structure of isoprene is

Limonene is a terpene molecule present in lemons

How many isoprene units are joined together in a limonene molecule

A 1B 2

47

C 3D 4

5 Essential oils are

A non-water soluble non-volatile compoundsB non-water soluble volatile compoundsC water soluble non-volatile compoundsD water soluble volatile compounds

6 Two typical compounds that are present in many perfumes are shown

(a) Why does geraniol evaporate more slowly than limonene (1)

(b) The structure of one of the first synthetic scents used in perfume is shown below

(i) Name the family of carbonyl compounds to which this synthetic scent belongs (1)

(ii) Complete the structure below to show the product formed when this scent is

oxidised (1)

(c) Traces of a liquid were discovered in a bottle believed to contain perfume belonging to Queen Hatshepsut ruler of Egypt over 3500 years ago

Perfumes were made by dissolving plant extracts containing pleasant smelling terpenes and esters in an edible oil A little ethanol and water may also have been addedUsing your knowledge of chemistry comment on the possible smell(s) when such a bottle is opened after being stored for thousands of years (3)

48

49

7 A team of chemists are developing a fragrance for use in a shower gel for men(a) To give the gel a fruity smell the chemists are considering adding an ester

They synthesise six isomeric esters Volunteers smell each ester and give it a rating out of one hundred depending on how fruity the smell is

(i) Name the ester with the fruit-smell rating of 92 (1)

(ii) Shown below are the structures of three more isomers

Arrange these esters in order of decreasing fruit-smell rating (1)

50

(b) To create a fragrance for men the compound civetone is added

Draw a structural formula for the alcohol that can be oxidised to form civetone (1)

(c) To make the shower gel produce a cold tingling sensation when applied to the skin menthol is added

Like terpenes menthol is formed from isoprene (2-methylbuta-13-diene)Circle an isoprene unit on the menthol structure above (1)

8 Many of the compounds in perfumes are molecules consisting of joined isoprene units

(a) State the name that is given to molecules consisting of joined isoprene units (1)

(b)Geraniol is one of the compounds found in perfume It has the following structural formula and systematic name

Linalool can also be present Its structural formula is shown

51

(i) State the systematic name for linalool (1)(ii) Explain why linalool can be classified as a tertiary alcohol (1)

9 The component molecules found in lavender oils are terpenes or terpenoids(a)A chiral carbon is a carbon atom attached to four different atoms or groups of

atomsAn example is shown below

A molecule of the terpenoid linalool has a chiral carbon Linalool has the following structure

Circle the chiral carbon atom in the linalool structure (1)

(b)Farnesene is a terpene consisting of three isoprene units (2-methylbuta-13-diene) joined togetherWrite the molecular formula of farnesene (1)

52

27 Skin Care

1 Which of the following is not a step in a free radical chain reaction

A ActivationB InitiationC PropagationD Termination

2 Fluorine reacts with methane via a free radical chain reaction Some steps in the chain reaction are shown in the table below

Complete the table by(a) inserting the missing name for the first step (1)

(b) showing another possible termination reaction in the final row of the table (1)

3 Suncreams contain antioxidantsThe antioxidant compound A can prevent damage to skin by reacting with free

radicalssuch as NO2bull

53

Why can compound A be described as a free radical scavenger in the reaction shown above

4 Hydrogen and chlorine gases are used in an experiment to demonstrate a free radical reaction A plastic bottle is wrapped with black tape leaving a ldquowindowrdquo on one sideThe bottle is filled with a mixture of hydrogen and chlorine When bright light shines on the bottle there is an explosion

A free radical chain reaction is initiated when light energy causes chlorine radicals to form as shown below

(a) Complete the equations below showing possible propagation and termination steps

(2)

54

(b) Why is the plastic bottle used in the experiment wrapped in black tape (1)

5 Chloramines can be removed from water using ultraviolet light treatment

One step in the process is the formation of free radicals

(a)State what is meant by the term free radical (1)

(b)Another step in the process is shown below

State the name for this type of step in a free radical reaction (1)

6 Modern shellac nail varnishes are more durable and so last longer than traditional nail polish

The shellac nail varnish is applied in thin layers to the nails and then the fingers are placed under a UV lamp

(a) The Skin Care Foundation has recommended that a sun-block is applied to the fingers and hand before using the lampSuggest why the Skin Care Foundation makes this recommendation (1)

(b) A free radical chain reaction takes place and the varnish hardens (i) State what is meant by the term free radical (1)

(ii) The shellac nail varnish contains a mixture of ingredients that take part in the free radical chain reactionOne of the steps in the free radical chain reaction is

55

State the term used to describe this type of step in a free radical chain reaction(1)

7 Skin care products contain a mixture of polar covalent non-polar covalent and ionic compounds The compounds need to stay mixed within the product Skin care products also need to spread easily and remain on the skin for a period of time as well as provide physical and chemical protection from the sun In order to do this skin care products contain a range of chemicals including water fats and oils antioxidants minerals and sun blockUsing your knowledge of chemistry explain the role of different chemicals in skin care products (3)

General Questions

1 A mixture of carbon monoxide and hydrogen can be converted into water and a mixture of hydrocarbons

nCO + (2n + 1)H2 rarr nH2O + hydrocarbons

What is the general formula for the hydrocarbons producedA CnH2nndash2B CnH2nC CnH2n+1D CnH2n+2

2 Butadiene is the first member of a homologous series of hydrocarbons called dienesWhat is the general formula for this seriesA CnHn+2B CnHn+3C CnH2nD CnH2nndash2

3 Which of the following statements about methanol is falseA It can be made from synthesis gasB It can be dehydrated to form an alkeneC It can be oxidised to give a carboxylic acidD It reacts with acidified potassium dichromate solution

56

4

Which line in the table correctly describes reactions X and Y

5

Which line in the table correctly describes reactions X and Y

6 Which of the following fuels when burned would make no contribution to globalwarming

57

A HydrogenB Natural gasC PetrolD Coal

7 Which of the following hydrocarbons always gives the same product when one of itshydrogen atoms is replaced by a chlorine atomA HexaneB Hex-1-eneC CyclohexaneD Cyclohexene

8 Which of the following compounds does not have isomeric structuresA C2HCl3B C2H4Cl2C PropeneD Propan-1-ol

9 What organic compound is produced by the dehydration of ethanol A EthaneB EtheneC EthanalD Ethanoic acid

10

The above equation representsA hydrationB hydrogenationC condensationD hydrolysis

11

Which of the following compounds is an isomer of the structure shown aboveA ButanalB ButanoneC Butan-1-olD Butanoic acid

58

12 A compound with molecular formula C6H12O2 could beA hexanalB hexan-2-olC hexan-2-oneD hexanoic acid

13 Propan-2-ol can be prepared from propane as follows

Which line in the table correctly describes the types of reaction taking place at Steps 1 and 2

14 Which of the following compounds would be the most water soluble

15 Cyanohydrin compounds can be made from carbonyl compounds by reacting the carbonyl compound with hydrogen cyanide (HCN)

59

Which carbonyl compound would react with hydrogen cyanide (HCN) to form the following compound

16 Ethyne is the first member of the homologous series called the alkynes

Ethyne can undergo addition reactions as shown in the flow diagram

(a) Compound 2 is an isomer of 12-dichloroethaneDraw a structural formula for compound 2 (1)

(b) Reagents A B and C are three different diatomic gasesUsing information in the flow diagram identify reagents A B and C (1)

60

Reagent Gas

A

B

C

17 In 1865 the German chemist Kekuleacute proposed a ring structure for benzene This structure was based on alternating single and double bonds

(a) (i) Describe a chemical test that would indicate that the above chemical structure for benzene is incorrect (1)

(ii) Briefly describe the correct structure for benzene (1)

(b) Benzene can be formed from cyclohexaneC6H12 rarr C6H6 + 3H2

What name is given to this type of reaction (1)18 Infra-red spectroscopy is a technique that can be used to identify the bonds that

arepresent in a molecule Different bonds absorb infra-red radiation of different wavenumbers This is due to differences in the bond lsquostretchrsquo These absorptions are recorded in a spectrumA spectrum for propan-1-ol is shown

61

The correlation table on page 13 of the data booklet shows the wavenumber ranges for the absorptions due to different bonds

(a) Use the correlation table to identify the bonds responsible for the two absorptions x and y that are circled in the propan-1-ol spectrum (1)

(b) Propan-1-ol reacts with ethanoic acid(i) What name is given to this type of reaction (1)(ii) Draw a spectrum that could be obtained for the organic product of this

reaction (1)

19 Paracetamol is a widely used painkiller

(a) Write the molecular formula for paracetamol (1)

(b) One antidote for paracetamol overdose is methionine

62

To what family of organic compounds does methionine belong (1)

(c) The concentration of paracetamol in a solution can be determined by measuring how much UV radiation it absorbs

The graph shows how the absorbance of a sample containing 0middot040 g l ndash1 paracetamol varies with wavelength

The quantity of UV radiation of wavelength 245 nm absorbed is directly proportional to the concentration of paracetamolThe absorbance of a second sample of paracetamol solution measured at 245 nm was 0middot90 What is the concentration in g l ndash1 of this second paracetamol solution (1)

20 Many carbon compounds containing oxygen are very flammableThe table shows information about two families of isomersThe lowest temperature at which a compound will ignite is called its flash point

(a) A compound with the molecular formula C6H14O has a boiling point of 158 degC63

Draw a structural formula for this compound (1)

(b) For a family of isomers in the table write a general statement linking the flash points of the compounds to their structures (1)

21 Hydrogels are used in disposable nappies They are fine powders that can absorb up to 500 times their own weight in waterA hydrogel is a very long molecule with carboxyl groups at regular intervals along its length A short section of a hydrogel molecule is shown below

Hydrogels are extremely good at soaking up water because the water molecules are strongly attracted to them

Using your knowledge of chemistry comment on how suitable hydrogels would be for absorbing liquids or solutions spilled in a chemistry lab (1)

64

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

(A) State the term used to describe the change in shape of enzyme molecules(1)

(B) Suggest a change in conditions which would cause the enzyme molecules to change shape (1)

(d) A bleach activator is frequently added to dishwasher tablets to speed up the bleaching reaction One common bleach activator is TAED TAED could be produced in a process which involves a number of stages

(i) The first stage in producing TAED is shown below

Suggest a name for this type of reaction (1)

(ii) The final stage in the process producing TAED is shown below

Draw a structural formula for TAED (1)

22

23 The Chemistry of Cooking

1 Vanillin and zingerone are flavour molecules

Which line in the table correctly compares the properties of vanillin and zingerone

23

2 Erythrose can be used in the production of a chewing gum that helps prevent tooth decay

Which of the following compounds will be the best solvent for erythrose

3 The following molecules give flavour to food Which of the following flavour molecules would be most likely to be retained in the food when the food is cooked in water

24

4 Cooking involves many chemical reactions Proteins fats oils and esters are some examples of compounds found in food A chemist suggested that cooking food could change compounds from being fat-soluble to water-soluble Use your knowledge of chemistry to comment on the accuracy of this statement(3)

25

24 The Oxidation of Food

1 Apples and bananas turn brown when cut or bruised The first step of the reaction causing

the browning is shown below

Which of the following terms correctly describes this reactionA ReductionB OxidationC DehydrationD Condensation

2 Which of the following reactions can be classified as reductionA CH3CH2OH rarr CH3COOHB CH3 CH(OH)CH3 rarr CH3COCH3C CH3CH2COCH3 rarr CH3CH2CH(OH)CH3D CH3CH2CHO rarr CH3CH2COOH

3 The dehydration of butan-2-ol can produce two isomeric alkenes but-1-ene andbut-2-ene Which of the following alkanols can similarly produce on dehydration a pair of isomeric alkenesA Propan-2-olB Pentan-3-olC Hexan-3-olD Heptan-4-ol

4 Which of the following compounds is an alkanone

26

5 Which of the following is an aldehyde

6 Which of the following compounds would react with sodium hydroxide solution to forma saltA CH3CHOB CH3COOHC CH3COCH3D CH3CH2OH

7 Which line in the table shows the correct functional group for each homologous series

8 Which of the following organic compounds is an isomer of hexanalA 2-MethylbutanalB 3-Methylpentan-2-oneC 22-Dimethylbutan-1-olD 3-Ethylpentanal

27

9 The name of this compound is

A methanolB methanalC methanoic acidD methanone

10 Which alcohol could be oxidised to a carboxylic acid

11 Which of the following structural formulae represents a tertiary alcohol

12 Compound X reacted with hot copper(II) oxide and the organic product did not give acolour change when heated with Fehlingrsquos solution Compound X could beA butan-1-olB butan-2-olC butanoneD butanoic acid

28

13 Which two isomers would each produce an acid when warmed with acidified potassiumdichromate solution

A 1 and 2B 2 and 3C 1 and 4D 3 and 4

14 After heating for several minutes as shown in the diagram the pH indicator solution turned red

Liquid Q could beA propanoneB paraffinC propan-1-olD propan-2-ol

29

15 Enzymes are involved in the browning of cut fruitOne reaction taking place is

Which of the following correctly describes the above reaction

A OxidationB ReductionC HydrolysisD Condensation

16 Which of the following statements is correct for ketones

A They are formed by oxidation of tertiary alcohols

B They contain the group

C They contain a carboxyl groupD They will not react with Fehlingrsquos solution

17 Carvone is a natural product that can be extracted from orange peel

Which line in the table correctly describes the reaction of carvone with bromine solution and with acidified potassium dichromate solution

30

18 Which of the following is an isomer of 22-dimethylpentan-1-ol

A CH3CH2CH2CH(CH3)CH2OHB (CH3)3CCH(CH3)CH2OHC CH3CH2CH2CH2CH2CH2CH2CH2OHD (CH3)2CHC(CH3)2CH2CH2OH

19 The equation for the reduction reaction taking place when ethanal reacts with Tollensrsquo reagent is

A Cu2+(aq) + eminus rarr Cu+(aq)

B Ag+(aq) + eminus rarr Ag(s)

C Cr2O72minus(aq) + 14H+(aq) + 6eminus rarr 2Cr3+(aq) + 7H2O(ℓ)

D MnO4minus(aq) + 8H+(aq) + 5eminus rarr Mn2+(aq) + 4H2O(ℓ)

20 The name of the compound with structure

isA 23-dimethylpentan-4-oneB 23-dimethylpentan-2-alC 34-dimethylpentan-2-oneD 34-dimethylpentan-2-al

21 What is the systematic name for the compound below

A 222-trimethylethanolB 22-dimethylpropan-1-olC 22-dimethylpropan-3-olD 22-dimethylpentan-1-ol

31

22 The structure of a molecule found in olive oil can be represented as shown

(a) Olive oil can be hydrolysed using sodium hydroxide solution to produce sodium salts of fatty acids Name the other product of this reaction (1)

(b) In what way does the structure of a fat molecule differ from that of an oil molecule (1)

(c) Over time open containers of olive oil develop a rancid flavour What substance is reacting with the oil to cause these unwanted changes to take place (1)

23 A student writes the following statement It is incorrect Explain the mistake in the studentrsquos reasoning (1)

Alcohols are alkaline because of their OH groups

24 Carbon compounds take part in a wide variety of chemical reactions (a)

Name this type of chemical reaction (1)

(b)

Draw a structural formula for C3H6O (1)

25 Alkanols can be oxidised to alkanoic acids

32

(a) Why can Step 1 be described as an oxidation reaction (1)

(b) Acidified potassium dichromate solution can be used to oxidise propanal in Step 2 What colour change would be observed in this reaction (1)

26 Amines can be produced by reacting ammonia with an aldehyde or a ketone This reaction an example of reductive amination occurs in two stages

Stage 1 Amination

Stage 2 Reduction

(a) Give another name for the type of reaction taking place in Stage 2

(b) Draw the structural formula for the amine produced when butanal undergoes reductive amination with ammonia

27 Using a cobalt catalyst alkenes react with a mixture of hydrogen and carbon monoxideThe products are two isomeric aldehydes Propene reacts with the mixture as shown

(a) What name is given to a mixture of hydrogen and carbon monoxide (1)

(b) Draw a structural formula for compound B (1)

(c) (i) What would be observed if compound A was gently heated with Tollensrsquo reagent

(1)(ii) How would the reaction mixture be heated (1)

33

(d) Aldehydes can also be formed by the reaction of some alcohols with copper(II) oxideName the type of alcohol that would react with copper(II) oxide to form an aldehyde (1)

28 Aldehydes and ketones can take part in a reaction sometimes known as an aldol condensation The simplest aldol reaction involves two molecules of ethanal

In the reaction the carbon atom next to the carbonyl functional group of one molecule forms a bond with the carbonyl carbon atom of the second molecule

(a) Draw a structural formula for the product formed when propanone is used instead of ethanal in this type of reaction (1)

(b) Name an aldehyde that would not take part in an aldol condensation (1)

(c) Apart from the structure of the reactants suggest what is unusual about applying the term ldquocondensationrdquo to this particular type of reaction (1)

29 Primary secondary and tertiary alkanols can be prepared by the reaction of carbonyl compounds with Grignard reagents

Step 1The Grignard reagent reacts with the carbonyl compound

Step 2The reaction of the product of Step 1 with dilute acid produces the alkanol

(a) Describe the difference between a primary a secondary and a tertiary alkanol

You may wish to include labelled structures in your answer (1)34

(b) Suggest a name for the type of reaction that takes place in Step 1 (1)

(c) The same Grignard reagent can be used to produce the alkanol below

Name the carbonyl compound used in this reaction (1)

30 Hairspray is a mixture of chemicals(a) A primary alcohol 2-methylpropan-1-ol is added to hairspray to help it dry quickly on the hair

Draw a structural formula for a secondary alcohol that is an isomer of2-methylpropan-1-ol (1)

(b) Triethanol amine and triisopropyl amine are bases used to neutralise acidic compounds in the hairspray to prevent damage to the hair

In terms of the intermolecular bonding present explain clearly why triethanol amine has a much higher boiling point than triisopropyl amine (2)

35

36

31 Chocolate contains various compounds(a) Many of the flavour and aroma molecules found in chocolate are aldehydes and

ketones Two examples are shown below

Phenylethanal can be easily oxidised but 13-diphenylpropan-2-one cannot(i) Name a chemical that could be used to distinguish between these two

compounds (1)

(ii) Name the type of organic compound formed when phenylethanal is oxidised (1)

(b) Glycerol monostearate is an emulsifier used in chocolate

(i) Why is glycerol monostearate added to chocolate (1)

(ii) Draw a structural formula for glycerol (1)

(c) Theobromine a compound present in chocolate can cause illness in dogs and cats To decide if treatment is necessary vets must calculate the mass of theobromine consumed 1middot0 g of chocolate contains 1middot4 mg of theobromine Calculate the mass in mg of theobromine in a 17 g biscuit of which 28 is chocolate Show your working clearly (2)

(d) The flavour and texture of chocolate comes from a blend of compoundsUsing your knowledge of chemistry describe how you could show that there are ionic compounds and covalent compounds present in chocolate (3)

37

32 Ethanol has many uses

(a) Ethanol is found at relatively low concentrations in wine

(i) Name the chemical reaction that produces ethanol in wine (1)

(ii) Standard ethanol solutions were used to produce a graph of density against

concentration of ethanol given as a percentage of alcohol by volume ( abv)

What is the concentration of ethanol in units of abv in a solution of density 0middot9818 g cmminus3 (1)

(b) Whisky contains a higher concentration of ethanol

(i) Before 1980 the concentration of alcohol in drinks was measured in terms of degrees proof The concentration of alcohol in two drinks is shown in the table below both as abv and degrees proof

38

A cask strength whisky has an alcohol concentration of 65 abv Calculate the alcohol concentration of this whisky in degrees proof (1)

(ii) A barrel containing 195 litres of cask strength whisky costs pound1300 The cask strength whisky is diluted with water to reduce the concentration of alcohol from 65 abv to 46 abv before it is bottled Calculate the cost of the cask strength whisky needed to produce a 0middot70 litre bottle Show your working clearly (2)

(iii) 5-Butyl-4-methyltetrahydrofuran-2-ol is a flavour compound found in whisky

stored in oak barrels

Write the systematic name for the compound shown below (1) 13 11

33 (a) One test for glucose involves Fehlingrsquos solutionCircle the part of the glucose molecule that reacts with Fehlingrsquos solution (1)

(b) In solution sugar molecules exist in an equilibrium in straight-chain and ring forms

To change from the straight-chain form to the ring form the oxygen of the hydroxyl on carbon number 5 joins to the carbonyl carbon This is shown below for glucose

39

Draw the structure of a ring form for fructose (1)

34 (a) During the free radical chain reaction small molecules join to form large chain molecules

One example of a small molecule used is

Name the functional group circled above (1)

(b)Alcohol wipes are used to finish the varnishing treatment Alcohol wipes contain the alcohol propan-2-olState why propan-2-ol can be described as a secondary alcohol (1)

35 A student was carrying out an investigation into alcohols aldehydes and ketones

(a)The student was given three alcohols labelled as A B and C These alcohols were all isomers with the formula C4H9OH

(i) Draw a structural formula for the secondary alcohol with the formula C4H9OH(1)

(ii) The student set up the following experiment

A Suggest why a water bath is an appropriate method of heating the reaction mixture (1)

B Describe the colour change that would have been observed with alcohols A and C (1)

40

C Alcohol B is not oxidised State the type of alcohol which cannot be oxidised by acidified dichromate solution (1)

(iii) The student set up a second experiment with alcohol A

Hot copper(II) oxide is an oxidising agentA When alcohol A (C4H9OH) is oxidised the product turns the pH paper

redSuggest a name for the product (1)

B Complete the ion-electron equation for the oxidation reaction

C4H9OH rarr C4H8O2 (1)

(b)The student found the following information about the boiling points of some aldehydes

41

(i) Name the aldehyde that has a boiling point of 119 degC (1)(ii) Predict the boiling point in degC of the following molecule (1)

(iii) Using information from the table describe one way in which differences in structure affect the boiling point of isomeric aldehydes (1)

(iv) State what would be observed when an aldehyde is gently heated with Tollensrsquo reagent (1)

(c) Ketones contain a carbonyl groupName the type of intermolecular interaction between ketone molecules (1)

42

25 Soaps Detergents and Emulsions

1 Soaps are produced by the following reaction

This reaction is an example ofA condensationB esterificationC hydrolysisD oxidation

2 Which of the following is the salt of a long-chain fatty acid

A FatB OilC SoapD Glycerol

3 Emulsifiers for use in food are commonly made by reacting edible oils with

A estersB glycerolC fatty acidsD amino acids

4 A fatty acid is a long chain carboxylic acid Examples of fatty acids are shown in the table below

43

(a) What is the systematic name for linolenic acid (1)(b) Stearic acid reacts with sodium hydroxide solution to form sodium stearate

(i) Name the type of reaction taking place when stearic acid reacts with sodium hydroxide (1)

(ii) Explain fully how sodium stearate acts to keep grease and non-polar substances suspended in water during cleaning (3)

5 Small children can find it difficult to swallow tablets or pills so ibuprofen is supplied as an ldquoinfant formulardquo emulsion(a) The emulsifier used is polysorbate 80 Its structure is shown below

Explain why this molecule acts as an emulsifier (2)

(b) The emulsion contains 2 g of ibuprofen in every 100 cm3 of emulsion The recommended dose for treating a 6 month old baby is 0middot050 g Calculate the volume in cm3 of ldquoinfant formulardquo needed to treat a 6 month old baby (1)

6 Occasionally seabirds can become contaminated with hydrocarbons from oil spills This causes problems for birds because their feathers lose their waterproofing making the birds susceptible to temperature changes and

44

affecting their buoyancy If the birds attempt to clean themselves to remove the oil they may swallow the hydrocarbons causing damage to their internal organsContaminated seabirds can be cleaned by rubbing vegetable oil into their feathers and feet before the birds are rinsed with diluted washing-up liquidUsing your knowledge of chemistry comment on the problems created for seabirds by oil spills and the actions taken to treat affected birds (3)

7 Dishwasher tablets contain chemicals which remove dirt from dishesDishwasher tablets include detergents These molecules act like soaps to allow mixing of fat-soluble dirt and water(a)During the cleaning process the detergent molecules combine with fat-

soluble dirtA simplified diagram of a detergent molecule is shown

Complete the diagram below to show how detergent molecules combine with fat-soluble dirt (1)

(b)State the term used to describe the non-polar hydrocarbon tail of a detergent molecule (1)

45

26 Fragrances1 Myrcene is a simple terpene

Terpenes contain at least one isoprene unit Which of the following shows a correctly highlighted isoprene unit

2 Limonene is one of the terpene molecules responsible for the flavour of lemons

How many isoprene units are used in the production of one limonene moleculeA 1B 2C 3D 4

46

3 The structure of caryophyllene which can be extracted from clove oil is

Which of the following would be the best solvent for extracting caryophylleneA HexaneB HexanalC HexanolD Hexanone

4 The structure of isoprene is

Limonene is a terpene molecule present in lemons

How many isoprene units are joined together in a limonene molecule

A 1B 2

47

C 3D 4

5 Essential oils are

A non-water soluble non-volatile compoundsB non-water soluble volatile compoundsC water soluble non-volatile compoundsD water soluble volatile compounds

6 Two typical compounds that are present in many perfumes are shown

(a) Why does geraniol evaporate more slowly than limonene (1)

(b) The structure of one of the first synthetic scents used in perfume is shown below

(i) Name the family of carbonyl compounds to which this synthetic scent belongs (1)

(ii) Complete the structure below to show the product formed when this scent is

oxidised (1)

(c) Traces of a liquid were discovered in a bottle believed to contain perfume belonging to Queen Hatshepsut ruler of Egypt over 3500 years ago

Perfumes were made by dissolving plant extracts containing pleasant smelling terpenes and esters in an edible oil A little ethanol and water may also have been addedUsing your knowledge of chemistry comment on the possible smell(s) when such a bottle is opened after being stored for thousands of years (3)

48

49

7 A team of chemists are developing a fragrance for use in a shower gel for men(a) To give the gel a fruity smell the chemists are considering adding an ester

They synthesise six isomeric esters Volunteers smell each ester and give it a rating out of one hundred depending on how fruity the smell is

(i) Name the ester with the fruit-smell rating of 92 (1)

(ii) Shown below are the structures of three more isomers

Arrange these esters in order of decreasing fruit-smell rating (1)

50

(b) To create a fragrance for men the compound civetone is added

Draw a structural formula for the alcohol that can be oxidised to form civetone (1)

(c) To make the shower gel produce a cold tingling sensation when applied to the skin menthol is added

Like terpenes menthol is formed from isoprene (2-methylbuta-13-diene)Circle an isoprene unit on the menthol structure above (1)

8 Many of the compounds in perfumes are molecules consisting of joined isoprene units

(a) State the name that is given to molecules consisting of joined isoprene units (1)

(b)Geraniol is one of the compounds found in perfume It has the following structural formula and systematic name

Linalool can also be present Its structural formula is shown

51

(i) State the systematic name for linalool (1)(ii) Explain why linalool can be classified as a tertiary alcohol (1)

9 The component molecules found in lavender oils are terpenes or terpenoids(a)A chiral carbon is a carbon atom attached to four different atoms or groups of

atomsAn example is shown below

A molecule of the terpenoid linalool has a chiral carbon Linalool has the following structure

Circle the chiral carbon atom in the linalool structure (1)

(b)Farnesene is a terpene consisting of three isoprene units (2-methylbuta-13-diene) joined togetherWrite the molecular formula of farnesene (1)

52

27 Skin Care

1 Which of the following is not a step in a free radical chain reaction

A ActivationB InitiationC PropagationD Termination

2 Fluorine reacts with methane via a free radical chain reaction Some steps in the chain reaction are shown in the table below

Complete the table by(a) inserting the missing name for the first step (1)

(b) showing another possible termination reaction in the final row of the table (1)

3 Suncreams contain antioxidantsThe antioxidant compound A can prevent damage to skin by reacting with free

radicalssuch as NO2bull

53

Why can compound A be described as a free radical scavenger in the reaction shown above

4 Hydrogen and chlorine gases are used in an experiment to demonstrate a free radical reaction A plastic bottle is wrapped with black tape leaving a ldquowindowrdquo on one sideThe bottle is filled with a mixture of hydrogen and chlorine When bright light shines on the bottle there is an explosion

A free radical chain reaction is initiated when light energy causes chlorine radicals to form as shown below

(a) Complete the equations below showing possible propagation and termination steps

(2)

54

(b) Why is the plastic bottle used in the experiment wrapped in black tape (1)

5 Chloramines can be removed from water using ultraviolet light treatment

One step in the process is the formation of free radicals

(a)State what is meant by the term free radical (1)

(b)Another step in the process is shown below

State the name for this type of step in a free radical reaction (1)

6 Modern shellac nail varnishes are more durable and so last longer than traditional nail polish

The shellac nail varnish is applied in thin layers to the nails and then the fingers are placed under a UV lamp

(a) The Skin Care Foundation has recommended that a sun-block is applied to the fingers and hand before using the lampSuggest why the Skin Care Foundation makes this recommendation (1)

(b) A free radical chain reaction takes place and the varnish hardens (i) State what is meant by the term free radical (1)

(ii) The shellac nail varnish contains a mixture of ingredients that take part in the free radical chain reactionOne of the steps in the free radical chain reaction is

55

State the term used to describe this type of step in a free radical chain reaction(1)

7 Skin care products contain a mixture of polar covalent non-polar covalent and ionic compounds The compounds need to stay mixed within the product Skin care products also need to spread easily and remain on the skin for a period of time as well as provide physical and chemical protection from the sun In order to do this skin care products contain a range of chemicals including water fats and oils antioxidants minerals and sun blockUsing your knowledge of chemistry explain the role of different chemicals in skin care products (3)

General Questions

1 A mixture of carbon monoxide and hydrogen can be converted into water and a mixture of hydrocarbons

nCO + (2n + 1)H2 rarr nH2O + hydrocarbons

What is the general formula for the hydrocarbons producedA CnH2nndash2B CnH2nC CnH2n+1D CnH2n+2

2 Butadiene is the first member of a homologous series of hydrocarbons called dienesWhat is the general formula for this seriesA CnHn+2B CnHn+3C CnH2nD CnH2nndash2

3 Which of the following statements about methanol is falseA It can be made from synthesis gasB It can be dehydrated to form an alkeneC It can be oxidised to give a carboxylic acidD It reacts with acidified potassium dichromate solution

56

4

Which line in the table correctly describes reactions X and Y

5

Which line in the table correctly describes reactions X and Y

6 Which of the following fuels when burned would make no contribution to globalwarming

57

A HydrogenB Natural gasC PetrolD Coal

7 Which of the following hydrocarbons always gives the same product when one of itshydrogen atoms is replaced by a chlorine atomA HexaneB Hex-1-eneC CyclohexaneD Cyclohexene

8 Which of the following compounds does not have isomeric structuresA C2HCl3B C2H4Cl2C PropeneD Propan-1-ol

9 What organic compound is produced by the dehydration of ethanol A EthaneB EtheneC EthanalD Ethanoic acid

10

The above equation representsA hydrationB hydrogenationC condensationD hydrolysis

11

Which of the following compounds is an isomer of the structure shown aboveA ButanalB ButanoneC Butan-1-olD Butanoic acid

58

12 A compound with molecular formula C6H12O2 could beA hexanalB hexan-2-olC hexan-2-oneD hexanoic acid

13 Propan-2-ol can be prepared from propane as follows

Which line in the table correctly describes the types of reaction taking place at Steps 1 and 2

14 Which of the following compounds would be the most water soluble

15 Cyanohydrin compounds can be made from carbonyl compounds by reacting the carbonyl compound with hydrogen cyanide (HCN)

59

Which carbonyl compound would react with hydrogen cyanide (HCN) to form the following compound

16 Ethyne is the first member of the homologous series called the alkynes

Ethyne can undergo addition reactions as shown in the flow diagram

(a) Compound 2 is an isomer of 12-dichloroethaneDraw a structural formula for compound 2 (1)

(b) Reagents A B and C are three different diatomic gasesUsing information in the flow diagram identify reagents A B and C (1)

60

Reagent Gas

A

B

C

17 In 1865 the German chemist Kekuleacute proposed a ring structure for benzene This structure was based on alternating single and double bonds

(a) (i) Describe a chemical test that would indicate that the above chemical structure for benzene is incorrect (1)

(ii) Briefly describe the correct structure for benzene (1)

(b) Benzene can be formed from cyclohexaneC6H12 rarr C6H6 + 3H2

What name is given to this type of reaction (1)18 Infra-red spectroscopy is a technique that can be used to identify the bonds that

arepresent in a molecule Different bonds absorb infra-red radiation of different wavenumbers This is due to differences in the bond lsquostretchrsquo These absorptions are recorded in a spectrumA spectrum for propan-1-ol is shown

61

The correlation table on page 13 of the data booklet shows the wavenumber ranges for the absorptions due to different bonds

(a) Use the correlation table to identify the bonds responsible for the two absorptions x and y that are circled in the propan-1-ol spectrum (1)

(b) Propan-1-ol reacts with ethanoic acid(i) What name is given to this type of reaction (1)(ii) Draw a spectrum that could be obtained for the organic product of this

reaction (1)

19 Paracetamol is a widely used painkiller

(a) Write the molecular formula for paracetamol (1)

(b) One antidote for paracetamol overdose is methionine

62

To what family of organic compounds does methionine belong (1)

(c) The concentration of paracetamol in a solution can be determined by measuring how much UV radiation it absorbs

The graph shows how the absorbance of a sample containing 0middot040 g l ndash1 paracetamol varies with wavelength

The quantity of UV radiation of wavelength 245 nm absorbed is directly proportional to the concentration of paracetamolThe absorbance of a second sample of paracetamol solution measured at 245 nm was 0middot90 What is the concentration in g l ndash1 of this second paracetamol solution (1)

20 Many carbon compounds containing oxygen are very flammableThe table shows information about two families of isomersThe lowest temperature at which a compound will ignite is called its flash point

(a) A compound with the molecular formula C6H14O has a boiling point of 158 degC63

Draw a structural formula for this compound (1)

(b) For a family of isomers in the table write a general statement linking the flash points of the compounds to their structures (1)

21 Hydrogels are used in disposable nappies They are fine powders that can absorb up to 500 times their own weight in waterA hydrogel is a very long molecule with carboxyl groups at regular intervals along its length A short section of a hydrogel molecule is shown below

Hydrogels are extremely good at soaking up water because the water molecules are strongly attracted to them

Using your knowledge of chemistry comment on how suitable hydrogels would be for absorbing liquids or solutions spilled in a chemistry lab (1)

64

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

23 The Chemistry of Cooking

1 Vanillin and zingerone are flavour molecules

Which line in the table correctly compares the properties of vanillin and zingerone

23

2 Erythrose can be used in the production of a chewing gum that helps prevent tooth decay

Which of the following compounds will be the best solvent for erythrose

3 The following molecules give flavour to food Which of the following flavour molecules would be most likely to be retained in the food when the food is cooked in water

24

4 Cooking involves many chemical reactions Proteins fats oils and esters are some examples of compounds found in food A chemist suggested that cooking food could change compounds from being fat-soluble to water-soluble Use your knowledge of chemistry to comment on the accuracy of this statement(3)

25

24 The Oxidation of Food

1 Apples and bananas turn brown when cut or bruised The first step of the reaction causing

the browning is shown below

Which of the following terms correctly describes this reactionA ReductionB OxidationC DehydrationD Condensation

2 Which of the following reactions can be classified as reductionA CH3CH2OH rarr CH3COOHB CH3 CH(OH)CH3 rarr CH3COCH3C CH3CH2COCH3 rarr CH3CH2CH(OH)CH3D CH3CH2CHO rarr CH3CH2COOH

3 The dehydration of butan-2-ol can produce two isomeric alkenes but-1-ene andbut-2-ene Which of the following alkanols can similarly produce on dehydration a pair of isomeric alkenesA Propan-2-olB Pentan-3-olC Hexan-3-olD Heptan-4-ol

4 Which of the following compounds is an alkanone

26

5 Which of the following is an aldehyde

6 Which of the following compounds would react with sodium hydroxide solution to forma saltA CH3CHOB CH3COOHC CH3COCH3D CH3CH2OH

7 Which line in the table shows the correct functional group for each homologous series

8 Which of the following organic compounds is an isomer of hexanalA 2-MethylbutanalB 3-Methylpentan-2-oneC 22-Dimethylbutan-1-olD 3-Ethylpentanal

27

9 The name of this compound is

A methanolB methanalC methanoic acidD methanone

10 Which alcohol could be oxidised to a carboxylic acid

11 Which of the following structural formulae represents a tertiary alcohol

12 Compound X reacted with hot copper(II) oxide and the organic product did not give acolour change when heated with Fehlingrsquos solution Compound X could beA butan-1-olB butan-2-olC butanoneD butanoic acid

28

13 Which two isomers would each produce an acid when warmed with acidified potassiumdichromate solution

A 1 and 2B 2 and 3C 1 and 4D 3 and 4

14 After heating for several minutes as shown in the diagram the pH indicator solution turned red

Liquid Q could beA propanoneB paraffinC propan-1-olD propan-2-ol

29

15 Enzymes are involved in the browning of cut fruitOne reaction taking place is

Which of the following correctly describes the above reaction

A OxidationB ReductionC HydrolysisD Condensation

16 Which of the following statements is correct for ketones

A They are formed by oxidation of tertiary alcohols

B They contain the group

C They contain a carboxyl groupD They will not react with Fehlingrsquos solution

17 Carvone is a natural product that can be extracted from orange peel

Which line in the table correctly describes the reaction of carvone with bromine solution and with acidified potassium dichromate solution

30

18 Which of the following is an isomer of 22-dimethylpentan-1-ol

A CH3CH2CH2CH(CH3)CH2OHB (CH3)3CCH(CH3)CH2OHC CH3CH2CH2CH2CH2CH2CH2CH2OHD (CH3)2CHC(CH3)2CH2CH2OH

19 The equation for the reduction reaction taking place when ethanal reacts with Tollensrsquo reagent is

A Cu2+(aq) + eminus rarr Cu+(aq)

B Ag+(aq) + eminus rarr Ag(s)

C Cr2O72minus(aq) + 14H+(aq) + 6eminus rarr 2Cr3+(aq) + 7H2O(ℓ)

D MnO4minus(aq) + 8H+(aq) + 5eminus rarr Mn2+(aq) + 4H2O(ℓ)

20 The name of the compound with structure

isA 23-dimethylpentan-4-oneB 23-dimethylpentan-2-alC 34-dimethylpentan-2-oneD 34-dimethylpentan-2-al

21 What is the systematic name for the compound below

A 222-trimethylethanolB 22-dimethylpropan-1-olC 22-dimethylpropan-3-olD 22-dimethylpentan-1-ol

31

22 The structure of a molecule found in olive oil can be represented as shown

(a) Olive oil can be hydrolysed using sodium hydroxide solution to produce sodium salts of fatty acids Name the other product of this reaction (1)

(b) In what way does the structure of a fat molecule differ from that of an oil molecule (1)

(c) Over time open containers of olive oil develop a rancid flavour What substance is reacting with the oil to cause these unwanted changes to take place (1)

23 A student writes the following statement It is incorrect Explain the mistake in the studentrsquos reasoning (1)

Alcohols are alkaline because of their OH groups

24 Carbon compounds take part in a wide variety of chemical reactions (a)

Name this type of chemical reaction (1)

(b)

Draw a structural formula for C3H6O (1)

25 Alkanols can be oxidised to alkanoic acids

32

(a) Why can Step 1 be described as an oxidation reaction (1)

(b) Acidified potassium dichromate solution can be used to oxidise propanal in Step 2 What colour change would be observed in this reaction (1)

26 Amines can be produced by reacting ammonia with an aldehyde or a ketone This reaction an example of reductive amination occurs in two stages

Stage 1 Amination

Stage 2 Reduction

(a) Give another name for the type of reaction taking place in Stage 2

(b) Draw the structural formula for the amine produced when butanal undergoes reductive amination with ammonia

27 Using a cobalt catalyst alkenes react with a mixture of hydrogen and carbon monoxideThe products are two isomeric aldehydes Propene reacts with the mixture as shown

(a) What name is given to a mixture of hydrogen and carbon monoxide (1)

(b) Draw a structural formula for compound B (1)

(c) (i) What would be observed if compound A was gently heated with Tollensrsquo reagent

(1)(ii) How would the reaction mixture be heated (1)

33

(d) Aldehydes can also be formed by the reaction of some alcohols with copper(II) oxideName the type of alcohol that would react with copper(II) oxide to form an aldehyde (1)

28 Aldehydes and ketones can take part in a reaction sometimes known as an aldol condensation The simplest aldol reaction involves two molecules of ethanal

In the reaction the carbon atom next to the carbonyl functional group of one molecule forms a bond with the carbonyl carbon atom of the second molecule

(a) Draw a structural formula for the product formed when propanone is used instead of ethanal in this type of reaction (1)

(b) Name an aldehyde that would not take part in an aldol condensation (1)

(c) Apart from the structure of the reactants suggest what is unusual about applying the term ldquocondensationrdquo to this particular type of reaction (1)

29 Primary secondary and tertiary alkanols can be prepared by the reaction of carbonyl compounds with Grignard reagents

Step 1The Grignard reagent reacts with the carbonyl compound

Step 2The reaction of the product of Step 1 with dilute acid produces the alkanol

(a) Describe the difference between a primary a secondary and a tertiary alkanol

You may wish to include labelled structures in your answer (1)34

(b) Suggest a name for the type of reaction that takes place in Step 1 (1)

(c) The same Grignard reagent can be used to produce the alkanol below

Name the carbonyl compound used in this reaction (1)

30 Hairspray is a mixture of chemicals(a) A primary alcohol 2-methylpropan-1-ol is added to hairspray to help it dry quickly on the hair

Draw a structural formula for a secondary alcohol that is an isomer of2-methylpropan-1-ol (1)

(b) Triethanol amine and triisopropyl amine are bases used to neutralise acidic compounds in the hairspray to prevent damage to the hair

In terms of the intermolecular bonding present explain clearly why triethanol amine has a much higher boiling point than triisopropyl amine (2)

35

36

31 Chocolate contains various compounds(a) Many of the flavour and aroma molecules found in chocolate are aldehydes and

ketones Two examples are shown below

Phenylethanal can be easily oxidised but 13-diphenylpropan-2-one cannot(i) Name a chemical that could be used to distinguish between these two

compounds (1)

(ii) Name the type of organic compound formed when phenylethanal is oxidised (1)

(b) Glycerol monostearate is an emulsifier used in chocolate

(i) Why is glycerol monostearate added to chocolate (1)

(ii) Draw a structural formula for glycerol (1)

(c) Theobromine a compound present in chocolate can cause illness in dogs and cats To decide if treatment is necessary vets must calculate the mass of theobromine consumed 1middot0 g of chocolate contains 1middot4 mg of theobromine Calculate the mass in mg of theobromine in a 17 g biscuit of which 28 is chocolate Show your working clearly (2)

(d) The flavour and texture of chocolate comes from a blend of compoundsUsing your knowledge of chemistry describe how you could show that there are ionic compounds and covalent compounds present in chocolate (3)

37

32 Ethanol has many uses

(a) Ethanol is found at relatively low concentrations in wine

(i) Name the chemical reaction that produces ethanol in wine (1)

(ii) Standard ethanol solutions were used to produce a graph of density against

concentration of ethanol given as a percentage of alcohol by volume ( abv)

What is the concentration of ethanol in units of abv in a solution of density 0middot9818 g cmminus3 (1)

(b) Whisky contains a higher concentration of ethanol

(i) Before 1980 the concentration of alcohol in drinks was measured in terms of degrees proof The concentration of alcohol in two drinks is shown in the table below both as abv and degrees proof

38

A cask strength whisky has an alcohol concentration of 65 abv Calculate the alcohol concentration of this whisky in degrees proof (1)

(ii) A barrel containing 195 litres of cask strength whisky costs pound1300 The cask strength whisky is diluted with water to reduce the concentration of alcohol from 65 abv to 46 abv before it is bottled Calculate the cost of the cask strength whisky needed to produce a 0middot70 litre bottle Show your working clearly (2)

(iii) 5-Butyl-4-methyltetrahydrofuran-2-ol is a flavour compound found in whisky

stored in oak barrels

Write the systematic name for the compound shown below (1) 13 11

33 (a) One test for glucose involves Fehlingrsquos solutionCircle the part of the glucose molecule that reacts with Fehlingrsquos solution (1)

(b) In solution sugar molecules exist in an equilibrium in straight-chain and ring forms

To change from the straight-chain form to the ring form the oxygen of the hydroxyl on carbon number 5 joins to the carbonyl carbon This is shown below for glucose

39

Draw the structure of a ring form for fructose (1)

34 (a) During the free radical chain reaction small molecules join to form large chain molecules

One example of a small molecule used is

Name the functional group circled above (1)

(b)Alcohol wipes are used to finish the varnishing treatment Alcohol wipes contain the alcohol propan-2-olState why propan-2-ol can be described as a secondary alcohol (1)

35 A student was carrying out an investigation into alcohols aldehydes and ketones

(a)The student was given three alcohols labelled as A B and C These alcohols were all isomers with the formula C4H9OH

(i) Draw a structural formula for the secondary alcohol with the formula C4H9OH(1)

(ii) The student set up the following experiment

A Suggest why a water bath is an appropriate method of heating the reaction mixture (1)

B Describe the colour change that would have been observed with alcohols A and C (1)

40

C Alcohol B is not oxidised State the type of alcohol which cannot be oxidised by acidified dichromate solution (1)

(iii) The student set up a second experiment with alcohol A

Hot copper(II) oxide is an oxidising agentA When alcohol A (C4H9OH) is oxidised the product turns the pH paper

redSuggest a name for the product (1)

B Complete the ion-electron equation for the oxidation reaction

C4H9OH rarr C4H8O2 (1)

(b)The student found the following information about the boiling points of some aldehydes

41

(i) Name the aldehyde that has a boiling point of 119 degC (1)(ii) Predict the boiling point in degC of the following molecule (1)

(iii) Using information from the table describe one way in which differences in structure affect the boiling point of isomeric aldehydes (1)

(iv) State what would be observed when an aldehyde is gently heated with Tollensrsquo reagent (1)

(c) Ketones contain a carbonyl groupName the type of intermolecular interaction between ketone molecules (1)

42

25 Soaps Detergents and Emulsions

1 Soaps are produced by the following reaction

This reaction is an example ofA condensationB esterificationC hydrolysisD oxidation

2 Which of the following is the salt of a long-chain fatty acid

A FatB OilC SoapD Glycerol

3 Emulsifiers for use in food are commonly made by reacting edible oils with

A estersB glycerolC fatty acidsD amino acids

4 A fatty acid is a long chain carboxylic acid Examples of fatty acids are shown in the table below

43

(a) What is the systematic name for linolenic acid (1)(b) Stearic acid reacts with sodium hydroxide solution to form sodium stearate

(i) Name the type of reaction taking place when stearic acid reacts with sodium hydroxide (1)

(ii) Explain fully how sodium stearate acts to keep grease and non-polar substances suspended in water during cleaning (3)

5 Small children can find it difficult to swallow tablets or pills so ibuprofen is supplied as an ldquoinfant formulardquo emulsion(a) The emulsifier used is polysorbate 80 Its structure is shown below

Explain why this molecule acts as an emulsifier (2)

(b) The emulsion contains 2 g of ibuprofen in every 100 cm3 of emulsion The recommended dose for treating a 6 month old baby is 0middot050 g Calculate the volume in cm3 of ldquoinfant formulardquo needed to treat a 6 month old baby (1)

6 Occasionally seabirds can become contaminated with hydrocarbons from oil spills This causes problems for birds because their feathers lose their waterproofing making the birds susceptible to temperature changes and

44

affecting their buoyancy If the birds attempt to clean themselves to remove the oil they may swallow the hydrocarbons causing damage to their internal organsContaminated seabirds can be cleaned by rubbing vegetable oil into their feathers and feet before the birds are rinsed with diluted washing-up liquidUsing your knowledge of chemistry comment on the problems created for seabirds by oil spills and the actions taken to treat affected birds (3)

7 Dishwasher tablets contain chemicals which remove dirt from dishesDishwasher tablets include detergents These molecules act like soaps to allow mixing of fat-soluble dirt and water(a)During the cleaning process the detergent molecules combine with fat-

soluble dirtA simplified diagram of a detergent molecule is shown

Complete the diagram below to show how detergent molecules combine with fat-soluble dirt (1)

(b)State the term used to describe the non-polar hydrocarbon tail of a detergent molecule (1)

45

26 Fragrances1 Myrcene is a simple terpene

Terpenes contain at least one isoprene unit Which of the following shows a correctly highlighted isoprene unit

2 Limonene is one of the terpene molecules responsible for the flavour of lemons

How many isoprene units are used in the production of one limonene moleculeA 1B 2C 3D 4

46

3 The structure of caryophyllene which can be extracted from clove oil is

Which of the following would be the best solvent for extracting caryophylleneA HexaneB HexanalC HexanolD Hexanone

4 The structure of isoprene is

Limonene is a terpene molecule present in lemons

How many isoprene units are joined together in a limonene molecule

A 1B 2

47

C 3D 4

5 Essential oils are

A non-water soluble non-volatile compoundsB non-water soluble volatile compoundsC water soluble non-volatile compoundsD water soluble volatile compounds

6 Two typical compounds that are present in many perfumes are shown

(a) Why does geraniol evaporate more slowly than limonene (1)

(b) The structure of one of the first synthetic scents used in perfume is shown below

(i) Name the family of carbonyl compounds to which this synthetic scent belongs (1)

(ii) Complete the structure below to show the product formed when this scent is

oxidised (1)

(c) Traces of a liquid were discovered in a bottle believed to contain perfume belonging to Queen Hatshepsut ruler of Egypt over 3500 years ago

Perfumes were made by dissolving plant extracts containing pleasant smelling terpenes and esters in an edible oil A little ethanol and water may also have been addedUsing your knowledge of chemistry comment on the possible smell(s) when such a bottle is opened after being stored for thousands of years (3)

48

49

7 A team of chemists are developing a fragrance for use in a shower gel for men(a) To give the gel a fruity smell the chemists are considering adding an ester

They synthesise six isomeric esters Volunteers smell each ester and give it a rating out of one hundred depending on how fruity the smell is

(i) Name the ester with the fruit-smell rating of 92 (1)

(ii) Shown below are the structures of three more isomers

Arrange these esters in order of decreasing fruit-smell rating (1)

50

(b) To create a fragrance for men the compound civetone is added

Draw a structural formula for the alcohol that can be oxidised to form civetone (1)

(c) To make the shower gel produce a cold tingling sensation when applied to the skin menthol is added

Like terpenes menthol is formed from isoprene (2-methylbuta-13-diene)Circle an isoprene unit on the menthol structure above (1)

8 Many of the compounds in perfumes are molecules consisting of joined isoprene units

(a) State the name that is given to molecules consisting of joined isoprene units (1)

(b)Geraniol is one of the compounds found in perfume It has the following structural formula and systematic name

Linalool can also be present Its structural formula is shown

51

(i) State the systematic name for linalool (1)(ii) Explain why linalool can be classified as a tertiary alcohol (1)

9 The component molecules found in lavender oils are terpenes or terpenoids(a)A chiral carbon is a carbon atom attached to four different atoms or groups of

atomsAn example is shown below

A molecule of the terpenoid linalool has a chiral carbon Linalool has the following structure

Circle the chiral carbon atom in the linalool structure (1)

(b)Farnesene is a terpene consisting of three isoprene units (2-methylbuta-13-diene) joined togetherWrite the molecular formula of farnesene (1)

52

27 Skin Care

1 Which of the following is not a step in a free radical chain reaction

A ActivationB InitiationC PropagationD Termination

2 Fluorine reacts with methane via a free radical chain reaction Some steps in the chain reaction are shown in the table below

Complete the table by(a) inserting the missing name for the first step (1)

(b) showing another possible termination reaction in the final row of the table (1)

3 Suncreams contain antioxidantsThe antioxidant compound A can prevent damage to skin by reacting with free

radicalssuch as NO2bull

53

Why can compound A be described as a free radical scavenger in the reaction shown above

4 Hydrogen and chlorine gases are used in an experiment to demonstrate a free radical reaction A plastic bottle is wrapped with black tape leaving a ldquowindowrdquo on one sideThe bottle is filled with a mixture of hydrogen and chlorine When bright light shines on the bottle there is an explosion

A free radical chain reaction is initiated when light energy causes chlorine radicals to form as shown below

(a) Complete the equations below showing possible propagation and termination steps

(2)

54

(b) Why is the plastic bottle used in the experiment wrapped in black tape (1)

5 Chloramines can be removed from water using ultraviolet light treatment

One step in the process is the formation of free radicals

(a)State what is meant by the term free radical (1)

(b)Another step in the process is shown below

State the name for this type of step in a free radical reaction (1)

6 Modern shellac nail varnishes are more durable and so last longer than traditional nail polish

The shellac nail varnish is applied in thin layers to the nails and then the fingers are placed under a UV lamp

(a) The Skin Care Foundation has recommended that a sun-block is applied to the fingers and hand before using the lampSuggest why the Skin Care Foundation makes this recommendation (1)

(b) A free radical chain reaction takes place and the varnish hardens (i) State what is meant by the term free radical (1)

(ii) The shellac nail varnish contains a mixture of ingredients that take part in the free radical chain reactionOne of the steps in the free radical chain reaction is

55

State the term used to describe this type of step in a free radical chain reaction(1)

7 Skin care products contain a mixture of polar covalent non-polar covalent and ionic compounds The compounds need to stay mixed within the product Skin care products also need to spread easily and remain on the skin for a period of time as well as provide physical and chemical protection from the sun In order to do this skin care products contain a range of chemicals including water fats and oils antioxidants minerals and sun blockUsing your knowledge of chemistry explain the role of different chemicals in skin care products (3)

General Questions

1 A mixture of carbon monoxide and hydrogen can be converted into water and a mixture of hydrocarbons

nCO + (2n + 1)H2 rarr nH2O + hydrocarbons

What is the general formula for the hydrocarbons producedA CnH2nndash2B CnH2nC CnH2n+1D CnH2n+2

2 Butadiene is the first member of a homologous series of hydrocarbons called dienesWhat is the general formula for this seriesA CnHn+2B CnHn+3C CnH2nD CnH2nndash2

3 Which of the following statements about methanol is falseA It can be made from synthesis gasB It can be dehydrated to form an alkeneC It can be oxidised to give a carboxylic acidD It reacts with acidified potassium dichromate solution

56

4

Which line in the table correctly describes reactions X and Y

5

Which line in the table correctly describes reactions X and Y

6 Which of the following fuels when burned would make no contribution to globalwarming

57

A HydrogenB Natural gasC PetrolD Coal

7 Which of the following hydrocarbons always gives the same product when one of itshydrogen atoms is replaced by a chlorine atomA HexaneB Hex-1-eneC CyclohexaneD Cyclohexene

8 Which of the following compounds does not have isomeric structuresA C2HCl3B C2H4Cl2C PropeneD Propan-1-ol

9 What organic compound is produced by the dehydration of ethanol A EthaneB EtheneC EthanalD Ethanoic acid

10

The above equation representsA hydrationB hydrogenationC condensationD hydrolysis

11

Which of the following compounds is an isomer of the structure shown aboveA ButanalB ButanoneC Butan-1-olD Butanoic acid

58

12 A compound with molecular formula C6H12O2 could beA hexanalB hexan-2-olC hexan-2-oneD hexanoic acid

13 Propan-2-ol can be prepared from propane as follows

Which line in the table correctly describes the types of reaction taking place at Steps 1 and 2

14 Which of the following compounds would be the most water soluble

15 Cyanohydrin compounds can be made from carbonyl compounds by reacting the carbonyl compound with hydrogen cyanide (HCN)

59

Which carbonyl compound would react with hydrogen cyanide (HCN) to form the following compound

16 Ethyne is the first member of the homologous series called the alkynes

Ethyne can undergo addition reactions as shown in the flow diagram

(a) Compound 2 is an isomer of 12-dichloroethaneDraw a structural formula for compound 2 (1)

(b) Reagents A B and C are three different diatomic gasesUsing information in the flow diagram identify reagents A B and C (1)

60

Reagent Gas

A

B

C

17 In 1865 the German chemist Kekuleacute proposed a ring structure for benzene This structure was based on alternating single and double bonds

(a) (i) Describe a chemical test that would indicate that the above chemical structure for benzene is incorrect (1)

(ii) Briefly describe the correct structure for benzene (1)

(b) Benzene can be formed from cyclohexaneC6H12 rarr C6H6 + 3H2

What name is given to this type of reaction (1)18 Infra-red spectroscopy is a technique that can be used to identify the bonds that

arepresent in a molecule Different bonds absorb infra-red radiation of different wavenumbers This is due to differences in the bond lsquostretchrsquo These absorptions are recorded in a spectrumA spectrum for propan-1-ol is shown

61

The correlation table on page 13 of the data booklet shows the wavenumber ranges for the absorptions due to different bonds

(a) Use the correlation table to identify the bonds responsible for the two absorptions x and y that are circled in the propan-1-ol spectrum (1)

(b) Propan-1-ol reacts with ethanoic acid(i) What name is given to this type of reaction (1)(ii) Draw a spectrum that could be obtained for the organic product of this

reaction (1)

19 Paracetamol is a widely used painkiller

(a) Write the molecular formula for paracetamol (1)

(b) One antidote for paracetamol overdose is methionine

62

To what family of organic compounds does methionine belong (1)

(c) The concentration of paracetamol in a solution can be determined by measuring how much UV radiation it absorbs

The graph shows how the absorbance of a sample containing 0middot040 g l ndash1 paracetamol varies with wavelength

The quantity of UV radiation of wavelength 245 nm absorbed is directly proportional to the concentration of paracetamolThe absorbance of a second sample of paracetamol solution measured at 245 nm was 0middot90 What is the concentration in g l ndash1 of this second paracetamol solution (1)

20 Many carbon compounds containing oxygen are very flammableThe table shows information about two families of isomersThe lowest temperature at which a compound will ignite is called its flash point

(a) A compound with the molecular formula C6H14O has a boiling point of 158 degC63

Draw a structural formula for this compound (1)

(b) For a family of isomers in the table write a general statement linking the flash points of the compounds to their structures (1)

21 Hydrogels are used in disposable nappies They are fine powders that can absorb up to 500 times their own weight in waterA hydrogel is a very long molecule with carboxyl groups at regular intervals along its length A short section of a hydrogel molecule is shown below

Hydrogels are extremely good at soaking up water because the water molecules are strongly attracted to them

Using your knowledge of chemistry comment on how suitable hydrogels would be for absorbing liquids or solutions spilled in a chemistry lab (1)

64

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

2 Erythrose can be used in the production of a chewing gum that helps prevent tooth decay

Which of the following compounds will be the best solvent for erythrose

3 The following molecules give flavour to food Which of the following flavour molecules would be most likely to be retained in the food when the food is cooked in water

24

4 Cooking involves many chemical reactions Proteins fats oils and esters are some examples of compounds found in food A chemist suggested that cooking food could change compounds from being fat-soluble to water-soluble Use your knowledge of chemistry to comment on the accuracy of this statement(3)

25

24 The Oxidation of Food

1 Apples and bananas turn brown when cut or bruised The first step of the reaction causing

the browning is shown below

Which of the following terms correctly describes this reactionA ReductionB OxidationC DehydrationD Condensation

2 Which of the following reactions can be classified as reductionA CH3CH2OH rarr CH3COOHB CH3 CH(OH)CH3 rarr CH3COCH3C CH3CH2COCH3 rarr CH3CH2CH(OH)CH3D CH3CH2CHO rarr CH3CH2COOH

3 The dehydration of butan-2-ol can produce two isomeric alkenes but-1-ene andbut-2-ene Which of the following alkanols can similarly produce on dehydration a pair of isomeric alkenesA Propan-2-olB Pentan-3-olC Hexan-3-olD Heptan-4-ol

4 Which of the following compounds is an alkanone

26

5 Which of the following is an aldehyde

6 Which of the following compounds would react with sodium hydroxide solution to forma saltA CH3CHOB CH3COOHC CH3COCH3D CH3CH2OH

7 Which line in the table shows the correct functional group for each homologous series

8 Which of the following organic compounds is an isomer of hexanalA 2-MethylbutanalB 3-Methylpentan-2-oneC 22-Dimethylbutan-1-olD 3-Ethylpentanal

27

9 The name of this compound is

A methanolB methanalC methanoic acidD methanone

10 Which alcohol could be oxidised to a carboxylic acid

11 Which of the following structural formulae represents a tertiary alcohol

12 Compound X reacted with hot copper(II) oxide and the organic product did not give acolour change when heated with Fehlingrsquos solution Compound X could beA butan-1-olB butan-2-olC butanoneD butanoic acid

28

13 Which two isomers would each produce an acid when warmed with acidified potassiumdichromate solution

A 1 and 2B 2 and 3C 1 and 4D 3 and 4

14 After heating for several minutes as shown in the diagram the pH indicator solution turned red

Liquid Q could beA propanoneB paraffinC propan-1-olD propan-2-ol

29

15 Enzymes are involved in the browning of cut fruitOne reaction taking place is

Which of the following correctly describes the above reaction

A OxidationB ReductionC HydrolysisD Condensation

16 Which of the following statements is correct for ketones

A They are formed by oxidation of tertiary alcohols

B They contain the group

C They contain a carboxyl groupD They will not react with Fehlingrsquos solution

17 Carvone is a natural product that can be extracted from orange peel

Which line in the table correctly describes the reaction of carvone with bromine solution and with acidified potassium dichromate solution

30

18 Which of the following is an isomer of 22-dimethylpentan-1-ol

A CH3CH2CH2CH(CH3)CH2OHB (CH3)3CCH(CH3)CH2OHC CH3CH2CH2CH2CH2CH2CH2CH2OHD (CH3)2CHC(CH3)2CH2CH2OH

19 The equation for the reduction reaction taking place when ethanal reacts with Tollensrsquo reagent is

A Cu2+(aq) + eminus rarr Cu+(aq)

B Ag+(aq) + eminus rarr Ag(s)

C Cr2O72minus(aq) + 14H+(aq) + 6eminus rarr 2Cr3+(aq) + 7H2O(ℓ)

D MnO4minus(aq) + 8H+(aq) + 5eminus rarr Mn2+(aq) + 4H2O(ℓ)

20 The name of the compound with structure

isA 23-dimethylpentan-4-oneB 23-dimethylpentan-2-alC 34-dimethylpentan-2-oneD 34-dimethylpentan-2-al

21 What is the systematic name for the compound below

A 222-trimethylethanolB 22-dimethylpropan-1-olC 22-dimethylpropan-3-olD 22-dimethylpentan-1-ol

31

22 The structure of a molecule found in olive oil can be represented as shown

(a) Olive oil can be hydrolysed using sodium hydroxide solution to produce sodium salts of fatty acids Name the other product of this reaction (1)

(b) In what way does the structure of a fat molecule differ from that of an oil molecule (1)

(c) Over time open containers of olive oil develop a rancid flavour What substance is reacting with the oil to cause these unwanted changes to take place (1)

23 A student writes the following statement It is incorrect Explain the mistake in the studentrsquos reasoning (1)

Alcohols are alkaline because of their OH groups

24 Carbon compounds take part in a wide variety of chemical reactions (a)

Name this type of chemical reaction (1)

(b)

Draw a structural formula for C3H6O (1)

25 Alkanols can be oxidised to alkanoic acids

32

(a) Why can Step 1 be described as an oxidation reaction (1)

(b) Acidified potassium dichromate solution can be used to oxidise propanal in Step 2 What colour change would be observed in this reaction (1)

26 Amines can be produced by reacting ammonia with an aldehyde or a ketone This reaction an example of reductive amination occurs in two stages

Stage 1 Amination

Stage 2 Reduction

(a) Give another name for the type of reaction taking place in Stage 2

(b) Draw the structural formula for the amine produced when butanal undergoes reductive amination with ammonia

27 Using a cobalt catalyst alkenes react with a mixture of hydrogen and carbon monoxideThe products are two isomeric aldehydes Propene reacts with the mixture as shown

(a) What name is given to a mixture of hydrogen and carbon monoxide (1)

(b) Draw a structural formula for compound B (1)

(c) (i) What would be observed if compound A was gently heated with Tollensrsquo reagent

(1)(ii) How would the reaction mixture be heated (1)

33

(d) Aldehydes can also be formed by the reaction of some alcohols with copper(II) oxideName the type of alcohol that would react with copper(II) oxide to form an aldehyde (1)

28 Aldehydes and ketones can take part in a reaction sometimes known as an aldol condensation The simplest aldol reaction involves two molecules of ethanal

In the reaction the carbon atom next to the carbonyl functional group of one molecule forms a bond with the carbonyl carbon atom of the second molecule

(a) Draw a structural formula for the product formed when propanone is used instead of ethanal in this type of reaction (1)

(b) Name an aldehyde that would not take part in an aldol condensation (1)

(c) Apart from the structure of the reactants suggest what is unusual about applying the term ldquocondensationrdquo to this particular type of reaction (1)

29 Primary secondary and tertiary alkanols can be prepared by the reaction of carbonyl compounds with Grignard reagents

Step 1The Grignard reagent reacts with the carbonyl compound

Step 2The reaction of the product of Step 1 with dilute acid produces the alkanol

(a) Describe the difference between a primary a secondary and a tertiary alkanol

You may wish to include labelled structures in your answer (1)34

(b) Suggest a name for the type of reaction that takes place in Step 1 (1)

(c) The same Grignard reagent can be used to produce the alkanol below

Name the carbonyl compound used in this reaction (1)

30 Hairspray is a mixture of chemicals(a) A primary alcohol 2-methylpropan-1-ol is added to hairspray to help it dry quickly on the hair

Draw a structural formula for a secondary alcohol that is an isomer of2-methylpropan-1-ol (1)

(b) Triethanol amine and triisopropyl amine are bases used to neutralise acidic compounds in the hairspray to prevent damage to the hair

In terms of the intermolecular bonding present explain clearly why triethanol amine has a much higher boiling point than triisopropyl amine (2)

35

36

31 Chocolate contains various compounds(a) Many of the flavour and aroma molecules found in chocolate are aldehydes and

ketones Two examples are shown below

Phenylethanal can be easily oxidised but 13-diphenylpropan-2-one cannot(i) Name a chemical that could be used to distinguish between these two

compounds (1)

(ii) Name the type of organic compound formed when phenylethanal is oxidised (1)

(b) Glycerol monostearate is an emulsifier used in chocolate

(i) Why is glycerol monostearate added to chocolate (1)

(ii) Draw a structural formula for glycerol (1)

(c) Theobromine a compound present in chocolate can cause illness in dogs and cats To decide if treatment is necessary vets must calculate the mass of theobromine consumed 1middot0 g of chocolate contains 1middot4 mg of theobromine Calculate the mass in mg of theobromine in a 17 g biscuit of which 28 is chocolate Show your working clearly (2)

(d) The flavour and texture of chocolate comes from a blend of compoundsUsing your knowledge of chemistry describe how you could show that there are ionic compounds and covalent compounds present in chocolate (3)

37

32 Ethanol has many uses

(a) Ethanol is found at relatively low concentrations in wine

(i) Name the chemical reaction that produces ethanol in wine (1)

(ii) Standard ethanol solutions were used to produce a graph of density against

concentration of ethanol given as a percentage of alcohol by volume ( abv)

What is the concentration of ethanol in units of abv in a solution of density 0middot9818 g cmminus3 (1)

(b) Whisky contains a higher concentration of ethanol

(i) Before 1980 the concentration of alcohol in drinks was measured in terms of degrees proof The concentration of alcohol in two drinks is shown in the table below both as abv and degrees proof

38

A cask strength whisky has an alcohol concentration of 65 abv Calculate the alcohol concentration of this whisky in degrees proof (1)

(ii) A barrel containing 195 litres of cask strength whisky costs pound1300 The cask strength whisky is diluted with water to reduce the concentration of alcohol from 65 abv to 46 abv before it is bottled Calculate the cost of the cask strength whisky needed to produce a 0middot70 litre bottle Show your working clearly (2)

(iii) 5-Butyl-4-methyltetrahydrofuran-2-ol is a flavour compound found in whisky

stored in oak barrels

Write the systematic name for the compound shown below (1) 13 11

33 (a) One test for glucose involves Fehlingrsquos solutionCircle the part of the glucose molecule that reacts with Fehlingrsquos solution (1)

(b) In solution sugar molecules exist in an equilibrium in straight-chain and ring forms

To change from the straight-chain form to the ring form the oxygen of the hydroxyl on carbon number 5 joins to the carbonyl carbon This is shown below for glucose

39

Draw the structure of a ring form for fructose (1)

34 (a) During the free radical chain reaction small molecules join to form large chain molecules

One example of a small molecule used is

Name the functional group circled above (1)

(b)Alcohol wipes are used to finish the varnishing treatment Alcohol wipes contain the alcohol propan-2-olState why propan-2-ol can be described as a secondary alcohol (1)

35 A student was carrying out an investigation into alcohols aldehydes and ketones

(a)The student was given three alcohols labelled as A B and C These alcohols were all isomers with the formula C4H9OH

(i) Draw a structural formula for the secondary alcohol with the formula C4H9OH(1)

(ii) The student set up the following experiment

A Suggest why a water bath is an appropriate method of heating the reaction mixture (1)

B Describe the colour change that would have been observed with alcohols A and C (1)

40

C Alcohol B is not oxidised State the type of alcohol which cannot be oxidised by acidified dichromate solution (1)

(iii) The student set up a second experiment with alcohol A

Hot copper(II) oxide is an oxidising agentA When alcohol A (C4H9OH) is oxidised the product turns the pH paper

redSuggest a name for the product (1)

B Complete the ion-electron equation for the oxidation reaction

C4H9OH rarr C4H8O2 (1)

(b)The student found the following information about the boiling points of some aldehydes

41

(i) Name the aldehyde that has a boiling point of 119 degC (1)(ii) Predict the boiling point in degC of the following molecule (1)

(iii) Using information from the table describe one way in which differences in structure affect the boiling point of isomeric aldehydes (1)

(iv) State what would be observed when an aldehyde is gently heated with Tollensrsquo reagent (1)

(c) Ketones contain a carbonyl groupName the type of intermolecular interaction between ketone molecules (1)

42

25 Soaps Detergents and Emulsions

1 Soaps are produced by the following reaction

This reaction is an example ofA condensationB esterificationC hydrolysisD oxidation

2 Which of the following is the salt of a long-chain fatty acid

A FatB OilC SoapD Glycerol

3 Emulsifiers for use in food are commonly made by reacting edible oils with

A estersB glycerolC fatty acidsD amino acids

4 A fatty acid is a long chain carboxylic acid Examples of fatty acids are shown in the table below

43

(a) What is the systematic name for linolenic acid (1)(b) Stearic acid reacts with sodium hydroxide solution to form sodium stearate

(i) Name the type of reaction taking place when stearic acid reacts with sodium hydroxide (1)

(ii) Explain fully how sodium stearate acts to keep grease and non-polar substances suspended in water during cleaning (3)

5 Small children can find it difficult to swallow tablets or pills so ibuprofen is supplied as an ldquoinfant formulardquo emulsion(a) The emulsifier used is polysorbate 80 Its structure is shown below

Explain why this molecule acts as an emulsifier (2)

(b) The emulsion contains 2 g of ibuprofen in every 100 cm3 of emulsion The recommended dose for treating a 6 month old baby is 0middot050 g Calculate the volume in cm3 of ldquoinfant formulardquo needed to treat a 6 month old baby (1)

6 Occasionally seabirds can become contaminated with hydrocarbons from oil spills This causes problems for birds because their feathers lose their waterproofing making the birds susceptible to temperature changes and

44

affecting their buoyancy If the birds attempt to clean themselves to remove the oil they may swallow the hydrocarbons causing damage to their internal organsContaminated seabirds can be cleaned by rubbing vegetable oil into their feathers and feet before the birds are rinsed with diluted washing-up liquidUsing your knowledge of chemistry comment on the problems created for seabirds by oil spills and the actions taken to treat affected birds (3)

7 Dishwasher tablets contain chemicals which remove dirt from dishesDishwasher tablets include detergents These molecules act like soaps to allow mixing of fat-soluble dirt and water(a)During the cleaning process the detergent molecules combine with fat-

soluble dirtA simplified diagram of a detergent molecule is shown

Complete the diagram below to show how detergent molecules combine with fat-soluble dirt (1)

(b)State the term used to describe the non-polar hydrocarbon tail of a detergent molecule (1)

45

26 Fragrances1 Myrcene is a simple terpene

Terpenes contain at least one isoprene unit Which of the following shows a correctly highlighted isoprene unit

2 Limonene is one of the terpene molecules responsible for the flavour of lemons

How many isoprene units are used in the production of one limonene moleculeA 1B 2C 3D 4

46

3 The structure of caryophyllene which can be extracted from clove oil is

Which of the following would be the best solvent for extracting caryophylleneA HexaneB HexanalC HexanolD Hexanone

4 The structure of isoprene is

Limonene is a terpene molecule present in lemons

How many isoprene units are joined together in a limonene molecule

A 1B 2

47

C 3D 4

5 Essential oils are

A non-water soluble non-volatile compoundsB non-water soluble volatile compoundsC water soluble non-volatile compoundsD water soluble volatile compounds

6 Two typical compounds that are present in many perfumes are shown

(a) Why does geraniol evaporate more slowly than limonene (1)

(b) The structure of one of the first synthetic scents used in perfume is shown below

(i) Name the family of carbonyl compounds to which this synthetic scent belongs (1)

(ii) Complete the structure below to show the product formed when this scent is

oxidised (1)

(c) Traces of a liquid were discovered in a bottle believed to contain perfume belonging to Queen Hatshepsut ruler of Egypt over 3500 years ago

Perfumes were made by dissolving plant extracts containing pleasant smelling terpenes and esters in an edible oil A little ethanol and water may also have been addedUsing your knowledge of chemistry comment on the possible smell(s) when such a bottle is opened after being stored for thousands of years (3)

48

49

7 A team of chemists are developing a fragrance for use in a shower gel for men(a) To give the gel a fruity smell the chemists are considering adding an ester

They synthesise six isomeric esters Volunteers smell each ester and give it a rating out of one hundred depending on how fruity the smell is

(i) Name the ester with the fruit-smell rating of 92 (1)

(ii) Shown below are the structures of three more isomers

Arrange these esters in order of decreasing fruit-smell rating (1)

50

(b) To create a fragrance for men the compound civetone is added

Draw a structural formula for the alcohol that can be oxidised to form civetone (1)

(c) To make the shower gel produce a cold tingling sensation when applied to the skin menthol is added

Like terpenes menthol is formed from isoprene (2-methylbuta-13-diene)Circle an isoprene unit on the menthol structure above (1)

8 Many of the compounds in perfumes are molecules consisting of joined isoprene units

(a) State the name that is given to molecules consisting of joined isoprene units (1)

(b)Geraniol is one of the compounds found in perfume It has the following structural formula and systematic name

Linalool can also be present Its structural formula is shown

51

(i) State the systematic name for linalool (1)(ii) Explain why linalool can be classified as a tertiary alcohol (1)

9 The component molecules found in lavender oils are terpenes or terpenoids(a)A chiral carbon is a carbon atom attached to four different atoms or groups of

atomsAn example is shown below

A molecule of the terpenoid linalool has a chiral carbon Linalool has the following structure

Circle the chiral carbon atom in the linalool structure (1)

(b)Farnesene is a terpene consisting of three isoprene units (2-methylbuta-13-diene) joined togetherWrite the molecular formula of farnesene (1)

52

27 Skin Care

1 Which of the following is not a step in a free radical chain reaction

A ActivationB InitiationC PropagationD Termination

2 Fluorine reacts with methane via a free radical chain reaction Some steps in the chain reaction are shown in the table below

Complete the table by(a) inserting the missing name for the first step (1)

(b) showing another possible termination reaction in the final row of the table (1)

3 Suncreams contain antioxidantsThe antioxidant compound A can prevent damage to skin by reacting with free

radicalssuch as NO2bull

53

Why can compound A be described as a free radical scavenger in the reaction shown above

4 Hydrogen and chlorine gases are used in an experiment to demonstrate a free radical reaction A plastic bottle is wrapped with black tape leaving a ldquowindowrdquo on one sideThe bottle is filled with a mixture of hydrogen and chlorine When bright light shines on the bottle there is an explosion

A free radical chain reaction is initiated when light energy causes chlorine radicals to form as shown below

(a) Complete the equations below showing possible propagation and termination steps

(2)

54

(b) Why is the plastic bottle used in the experiment wrapped in black tape (1)

5 Chloramines can be removed from water using ultraviolet light treatment

One step in the process is the formation of free radicals

(a)State what is meant by the term free radical (1)

(b)Another step in the process is shown below

State the name for this type of step in a free radical reaction (1)

6 Modern shellac nail varnishes are more durable and so last longer than traditional nail polish

The shellac nail varnish is applied in thin layers to the nails and then the fingers are placed under a UV lamp

(a) The Skin Care Foundation has recommended that a sun-block is applied to the fingers and hand before using the lampSuggest why the Skin Care Foundation makes this recommendation (1)

(b) A free radical chain reaction takes place and the varnish hardens (i) State what is meant by the term free radical (1)

(ii) The shellac nail varnish contains a mixture of ingredients that take part in the free radical chain reactionOne of the steps in the free radical chain reaction is

55

State the term used to describe this type of step in a free radical chain reaction(1)

7 Skin care products contain a mixture of polar covalent non-polar covalent and ionic compounds The compounds need to stay mixed within the product Skin care products also need to spread easily and remain on the skin for a period of time as well as provide physical and chemical protection from the sun In order to do this skin care products contain a range of chemicals including water fats and oils antioxidants minerals and sun blockUsing your knowledge of chemistry explain the role of different chemicals in skin care products (3)

General Questions

1 A mixture of carbon monoxide and hydrogen can be converted into water and a mixture of hydrocarbons

nCO + (2n + 1)H2 rarr nH2O + hydrocarbons

What is the general formula for the hydrocarbons producedA CnH2nndash2B CnH2nC CnH2n+1D CnH2n+2

2 Butadiene is the first member of a homologous series of hydrocarbons called dienesWhat is the general formula for this seriesA CnHn+2B CnHn+3C CnH2nD CnH2nndash2

3 Which of the following statements about methanol is falseA It can be made from synthesis gasB It can be dehydrated to form an alkeneC It can be oxidised to give a carboxylic acidD It reacts with acidified potassium dichromate solution

56

4

Which line in the table correctly describes reactions X and Y

5

Which line in the table correctly describes reactions X and Y

6 Which of the following fuels when burned would make no contribution to globalwarming

57

A HydrogenB Natural gasC PetrolD Coal

7 Which of the following hydrocarbons always gives the same product when one of itshydrogen atoms is replaced by a chlorine atomA HexaneB Hex-1-eneC CyclohexaneD Cyclohexene

8 Which of the following compounds does not have isomeric structuresA C2HCl3B C2H4Cl2C PropeneD Propan-1-ol

9 What organic compound is produced by the dehydration of ethanol A EthaneB EtheneC EthanalD Ethanoic acid

10

The above equation representsA hydrationB hydrogenationC condensationD hydrolysis

11

Which of the following compounds is an isomer of the structure shown aboveA ButanalB ButanoneC Butan-1-olD Butanoic acid

58

12 A compound with molecular formula C6H12O2 could beA hexanalB hexan-2-olC hexan-2-oneD hexanoic acid

13 Propan-2-ol can be prepared from propane as follows

Which line in the table correctly describes the types of reaction taking place at Steps 1 and 2

14 Which of the following compounds would be the most water soluble

15 Cyanohydrin compounds can be made from carbonyl compounds by reacting the carbonyl compound with hydrogen cyanide (HCN)

59

Which carbonyl compound would react with hydrogen cyanide (HCN) to form the following compound

16 Ethyne is the first member of the homologous series called the alkynes

Ethyne can undergo addition reactions as shown in the flow diagram

(a) Compound 2 is an isomer of 12-dichloroethaneDraw a structural formula for compound 2 (1)

(b) Reagents A B and C are three different diatomic gasesUsing information in the flow diagram identify reagents A B and C (1)

60

Reagent Gas

A

B

C

17 In 1865 the German chemist Kekuleacute proposed a ring structure for benzene This structure was based on alternating single and double bonds

(a) (i) Describe a chemical test that would indicate that the above chemical structure for benzene is incorrect (1)

(ii) Briefly describe the correct structure for benzene (1)

(b) Benzene can be formed from cyclohexaneC6H12 rarr C6H6 + 3H2

What name is given to this type of reaction (1)18 Infra-red spectroscopy is a technique that can be used to identify the bonds that

arepresent in a molecule Different bonds absorb infra-red radiation of different wavenumbers This is due to differences in the bond lsquostretchrsquo These absorptions are recorded in a spectrumA spectrum for propan-1-ol is shown

61

The correlation table on page 13 of the data booklet shows the wavenumber ranges for the absorptions due to different bonds

(a) Use the correlation table to identify the bonds responsible for the two absorptions x and y that are circled in the propan-1-ol spectrum (1)

(b) Propan-1-ol reacts with ethanoic acid(i) What name is given to this type of reaction (1)(ii) Draw a spectrum that could be obtained for the organic product of this

reaction (1)

19 Paracetamol is a widely used painkiller

(a) Write the molecular formula for paracetamol (1)

(b) One antidote for paracetamol overdose is methionine

62

To what family of organic compounds does methionine belong (1)

(c) The concentration of paracetamol in a solution can be determined by measuring how much UV radiation it absorbs

The graph shows how the absorbance of a sample containing 0middot040 g l ndash1 paracetamol varies with wavelength

The quantity of UV radiation of wavelength 245 nm absorbed is directly proportional to the concentration of paracetamolThe absorbance of a second sample of paracetamol solution measured at 245 nm was 0middot90 What is the concentration in g l ndash1 of this second paracetamol solution (1)

20 Many carbon compounds containing oxygen are very flammableThe table shows information about two families of isomersThe lowest temperature at which a compound will ignite is called its flash point

(a) A compound with the molecular formula C6H14O has a boiling point of 158 degC63

Draw a structural formula for this compound (1)

(b) For a family of isomers in the table write a general statement linking the flash points of the compounds to their structures (1)

21 Hydrogels are used in disposable nappies They are fine powders that can absorb up to 500 times their own weight in waterA hydrogel is a very long molecule with carboxyl groups at regular intervals along its length A short section of a hydrogel molecule is shown below

Hydrogels are extremely good at soaking up water because the water molecules are strongly attracted to them

Using your knowledge of chemistry comment on how suitable hydrogels would be for absorbing liquids or solutions spilled in a chemistry lab (1)

64

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

4 Cooking involves many chemical reactions Proteins fats oils and esters are some examples of compounds found in food A chemist suggested that cooking food could change compounds from being fat-soluble to water-soluble Use your knowledge of chemistry to comment on the accuracy of this statement(3)

25

24 The Oxidation of Food

1 Apples and bananas turn brown when cut or bruised The first step of the reaction causing

the browning is shown below

Which of the following terms correctly describes this reactionA ReductionB OxidationC DehydrationD Condensation

2 Which of the following reactions can be classified as reductionA CH3CH2OH rarr CH3COOHB CH3 CH(OH)CH3 rarr CH3COCH3C CH3CH2COCH3 rarr CH3CH2CH(OH)CH3D CH3CH2CHO rarr CH3CH2COOH

3 The dehydration of butan-2-ol can produce two isomeric alkenes but-1-ene andbut-2-ene Which of the following alkanols can similarly produce on dehydration a pair of isomeric alkenesA Propan-2-olB Pentan-3-olC Hexan-3-olD Heptan-4-ol

4 Which of the following compounds is an alkanone

26

5 Which of the following is an aldehyde

6 Which of the following compounds would react with sodium hydroxide solution to forma saltA CH3CHOB CH3COOHC CH3COCH3D CH3CH2OH

7 Which line in the table shows the correct functional group for each homologous series

8 Which of the following organic compounds is an isomer of hexanalA 2-MethylbutanalB 3-Methylpentan-2-oneC 22-Dimethylbutan-1-olD 3-Ethylpentanal

27

9 The name of this compound is

A methanolB methanalC methanoic acidD methanone

10 Which alcohol could be oxidised to a carboxylic acid

11 Which of the following structural formulae represents a tertiary alcohol

12 Compound X reacted with hot copper(II) oxide and the organic product did not give acolour change when heated with Fehlingrsquos solution Compound X could beA butan-1-olB butan-2-olC butanoneD butanoic acid

28

13 Which two isomers would each produce an acid when warmed with acidified potassiumdichromate solution

A 1 and 2B 2 and 3C 1 and 4D 3 and 4

14 After heating for several minutes as shown in the diagram the pH indicator solution turned red

Liquid Q could beA propanoneB paraffinC propan-1-olD propan-2-ol

29

15 Enzymes are involved in the browning of cut fruitOne reaction taking place is

Which of the following correctly describes the above reaction

A OxidationB ReductionC HydrolysisD Condensation

16 Which of the following statements is correct for ketones

A They are formed by oxidation of tertiary alcohols

B They contain the group

C They contain a carboxyl groupD They will not react with Fehlingrsquos solution

17 Carvone is a natural product that can be extracted from orange peel

Which line in the table correctly describes the reaction of carvone with bromine solution and with acidified potassium dichromate solution

30

18 Which of the following is an isomer of 22-dimethylpentan-1-ol

A CH3CH2CH2CH(CH3)CH2OHB (CH3)3CCH(CH3)CH2OHC CH3CH2CH2CH2CH2CH2CH2CH2OHD (CH3)2CHC(CH3)2CH2CH2OH

19 The equation for the reduction reaction taking place when ethanal reacts with Tollensrsquo reagent is

A Cu2+(aq) + eminus rarr Cu+(aq)

B Ag+(aq) + eminus rarr Ag(s)

C Cr2O72minus(aq) + 14H+(aq) + 6eminus rarr 2Cr3+(aq) + 7H2O(ℓ)

D MnO4minus(aq) + 8H+(aq) + 5eminus rarr Mn2+(aq) + 4H2O(ℓ)

20 The name of the compound with structure

isA 23-dimethylpentan-4-oneB 23-dimethylpentan-2-alC 34-dimethylpentan-2-oneD 34-dimethylpentan-2-al

21 What is the systematic name for the compound below

A 222-trimethylethanolB 22-dimethylpropan-1-olC 22-dimethylpropan-3-olD 22-dimethylpentan-1-ol

31

22 The structure of a molecule found in olive oil can be represented as shown

(a) Olive oil can be hydrolysed using sodium hydroxide solution to produce sodium salts of fatty acids Name the other product of this reaction (1)

(b) In what way does the structure of a fat molecule differ from that of an oil molecule (1)

(c) Over time open containers of olive oil develop a rancid flavour What substance is reacting with the oil to cause these unwanted changes to take place (1)

23 A student writes the following statement It is incorrect Explain the mistake in the studentrsquos reasoning (1)

Alcohols are alkaline because of their OH groups

24 Carbon compounds take part in a wide variety of chemical reactions (a)

Name this type of chemical reaction (1)

(b)

Draw a structural formula for C3H6O (1)

25 Alkanols can be oxidised to alkanoic acids

32

(a) Why can Step 1 be described as an oxidation reaction (1)

(b) Acidified potassium dichromate solution can be used to oxidise propanal in Step 2 What colour change would be observed in this reaction (1)

26 Amines can be produced by reacting ammonia with an aldehyde or a ketone This reaction an example of reductive amination occurs in two stages

Stage 1 Amination

Stage 2 Reduction

(a) Give another name for the type of reaction taking place in Stage 2

(b) Draw the structural formula for the amine produced when butanal undergoes reductive amination with ammonia

27 Using a cobalt catalyst alkenes react with a mixture of hydrogen and carbon monoxideThe products are two isomeric aldehydes Propene reacts with the mixture as shown

(a) What name is given to a mixture of hydrogen and carbon monoxide (1)

(b) Draw a structural formula for compound B (1)

(c) (i) What would be observed if compound A was gently heated with Tollensrsquo reagent

(1)(ii) How would the reaction mixture be heated (1)

33

(d) Aldehydes can also be formed by the reaction of some alcohols with copper(II) oxideName the type of alcohol that would react with copper(II) oxide to form an aldehyde (1)

28 Aldehydes and ketones can take part in a reaction sometimes known as an aldol condensation The simplest aldol reaction involves two molecules of ethanal

In the reaction the carbon atom next to the carbonyl functional group of one molecule forms a bond with the carbonyl carbon atom of the second molecule

(a) Draw a structural formula for the product formed when propanone is used instead of ethanal in this type of reaction (1)

(b) Name an aldehyde that would not take part in an aldol condensation (1)

(c) Apart from the structure of the reactants suggest what is unusual about applying the term ldquocondensationrdquo to this particular type of reaction (1)

29 Primary secondary and tertiary alkanols can be prepared by the reaction of carbonyl compounds with Grignard reagents

Step 1The Grignard reagent reacts with the carbonyl compound

Step 2The reaction of the product of Step 1 with dilute acid produces the alkanol

(a) Describe the difference between a primary a secondary and a tertiary alkanol

You may wish to include labelled structures in your answer (1)34

(b) Suggest a name for the type of reaction that takes place in Step 1 (1)

(c) The same Grignard reagent can be used to produce the alkanol below

Name the carbonyl compound used in this reaction (1)

30 Hairspray is a mixture of chemicals(a) A primary alcohol 2-methylpropan-1-ol is added to hairspray to help it dry quickly on the hair

Draw a structural formula for a secondary alcohol that is an isomer of2-methylpropan-1-ol (1)

(b) Triethanol amine and triisopropyl amine are bases used to neutralise acidic compounds in the hairspray to prevent damage to the hair

In terms of the intermolecular bonding present explain clearly why triethanol amine has a much higher boiling point than triisopropyl amine (2)

35

36

31 Chocolate contains various compounds(a) Many of the flavour and aroma molecules found in chocolate are aldehydes and

ketones Two examples are shown below

Phenylethanal can be easily oxidised but 13-diphenylpropan-2-one cannot(i) Name a chemical that could be used to distinguish between these two

compounds (1)

(ii) Name the type of organic compound formed when phenylethanal is oxidised (1)

(b) Glycerol monostearate is an emulsifier used in chocolate

(i) Why is glycerol monostearate added to chocolate (1)

(ii) Draw a structural formula for glycerol (1)

(c) Theobromine a compound present in chocolate can cause illness in dogs and cats To decide if treatment is necessary vets must calculate the mass of theobromine consumed 1middot0 g of chocolate contains 1middot4 mg of theobromine Calculate the mass in mg of theobromine in a 17 g biscuit of which 28 is chocolate Show your working clearly (2)

(d) The flavour and texture of chocolate comes from a blend of compoundsUsing your knowledge of chemistry describe how you could show that there are ionic compounds and covalent compounds present in chocolate (3)

37

32 Ethanol has many uses

(a) Ethanol is found at relatively low concentrations in wine

(i) Name the chemical reaction that produces ethanol in wine (1)

(ii) Standard ethanol solutions were used to produce a graph of density against

concentration of ethanol given as a percentage of alcohol by volume ( abv)

What is the concentration of ethanol in units of abv in a solution of density 0middot9818 g cmminus3 (1)

(b) Whisky contains a higher concentration of ethanol

(i) Before 1980 the concentration of alcohol in drinks was measured in terms of degrees proof The concentration of alcohol in two drinks is shown in the table below both as abv and degrees proof

38

A cask strength whisky has an alcohol concentration of 65 abv Calculate the alcohol concentration of this whisky in degrees proof (1)

(ii) A barrel containing 195 litres of cask strength whisky costs pound1300 The cask strength whisky is diluted with water to reduce the concentration of alcohol from 65 abv to 46 abv before it is bottled Calculate the cost of the cask strength whisky needed to produce a 0middot70 litre bottle Show your working clearly (2)

(iii) 5-Butyl-4-methyltetrahydrofuran-2-ol is a flavour compound found in whisky

stored in oak barrels

Write the systematic name for the compound shown below (1) 13 11

33 (a) One test for glucose involves Fehlingrsquos solutionCircle the part of the glucose molecule that reacts with Fehlingrsquos solution (1)

(b) In solution sugar molecules exist in an equilibrium in straight-chain and ring forms

To change from the straight-chain form to the ring form the oxygen of the hydroxyl on carbon number 5 joins to the carbonyl carbon This is shown below for glucose

39

Draw the structure of a ring form for fructose (1)

34 (a) During the free radical chain reaction small molecules join to form large chain molecules

One example of a small molecule used is

Name the functional group circled above (1)

(b)Alcohol wipes are used to finish the varnishing treatment Alcohol wipes contain the alcohol propan-2-olState why propan-2-ol can be described as a secondary alcohol (1)

35 A student was carrying out an investigation into alcohols aldehydes and ketones

(a)The student was given three alcohols labelled as A B and C These alcohols were all isomers with the formula C4H9OH

(i) Draw a structural formula for the secondary alcohol with the formula C4H9OH(1)

(ii) The student set up the following experiment

A Suggest why a water bath is an appropriate method of heating the reaction mixture (1)

B Describe the colour change that would have been observed with alcohols A and C (1)

40

C Alcohol B is not oxidised State the type of alcohol which cannot be oxidised by acidified dichromate solution (1)

(iii) The student set up a second experiment with alcohol A

Hot copper(II) oxide is an oxidising agentA When alcohol A (C4H9OH) is oxidised the product turns the pH paper

redSuggest a name for the product (1)

B Complete the ion-electron equation for the oxidation reaction

C4H9OH rarr C4H8O2 (1)

(b)The student found the following information about the boiling points of some aldehydes

41

(i) Name the aldehyde that has a boiling point of 119 degC (1)(ii) Predict the boiling point in degC of the following molecule (1)

(iii) Using information from the table describe one way in which differences in structure affect the boiling point of isomeric aldehydes (1)

(iv) State what would be observed when an aldehyde is gently heated with Tollensrsquo reagent (1)

(c) Ketones contain a carbonyl groupName the type of intermolecular interaction between ketone molecules (1)

42

25 Soaps Detergents and Emulsions

1 Soaps are produced by the following reaction

This reaction is an example ofA condensationB esterificationC hydrolysisD oxidation

2 Which of the following is the salt of a long-chain fatty acid

A FatB OilC SoapD Glycerol

3 Emulsifiers for use in food are commonly made by reacting edible oils with

A estersB glycerolC fatty acidsD amino acids

4 A fatty acid is a long chain carboxylic acid Examples of fatty acids are shown in the table below

43

(a) What is the systematic name for linolenic acid (1)(b) Stearic acid reacts with sodium hydroxide solution to form sodium stearate

(i) Name the type of reaction taking place when stearic acid reacts with sodium hydroxide (1)

(ii) Explain fully how sodium stearate acts to keep grease and non-polar substances suspended in water during cleaning (3)

5 Small children can find it difficult to swallow tablets or pills so ibuprofen is supplied as an ldquoinfant formulardquo emulsion(a) The emulsifier used is polysorbate 80 Its structure is shown below

Explain why this molecule acts as an emulsifier (2)

(b) The emulsion contains 2 g of ibuprofen in every 100 cm3 of emulsion The recommended dose for treating a 6 month old baby is 0middot050 g Calculate the volume in cm3 of ldquoinfant formulardquo needed to treat a 6 month old baby (1)

6 Occasionally seabirds can become contaminated with hydrocarbons from oil spills This causes problems for birds because their feathers lose their waterproofing making the birds susceptible to temperature changes and

44

affecting their buoyancy If the birds attempt to clean themselves to remove the oil they may swallow the hydrocarbons causing damage to their internal organsContaminated seabirds can be cleaned by rubbing vegetable oil into their feathers and feet before the birds are rinsed with diluted washing-up liquidUsing your knowledge of chemistry comment on the problems created for seabirds by oil spills and the actions taken to treat affected birds (3)

7 Dishwasher tablets contain chemicals which remove dirt from dishesDishwasher tablets include detergents These molecules act like soaps to allow mixing of fat-soluble dirt and water(a)During the cleaning process the detergent molecules combine with fat-

soluble dirtA simplified diagram of a detergent molecule is shown

Complete the diagram below to show how detergent molecules combine with fat-soluble dirt (1)

(b)State the term used to describe the non-polar hydrocarbon tail of a detergent molecule (1)

45

26 Fragrances1 Myrcene is a simple terpene

Terpenes contain at least one isoprene unit Which of the following shows a correctly highlighted isoprene unit

2 Limonene is one of the terpene molecules responsible for the flavour of lemons

How many isoprene units are used in the production of one limonene moleculeA 1B 2C 3D 4

46

3 The structure of caryophyllene which can be extracted from clove oil is

Which of the following would be the best solvent for extracting caryophylleneA HexaneB HexanalC HexanolD Hexanone

4 The structure of isoprene is

Limonene is a terpene molecule present in lemons

How many isoprene units are joined together in a limonene molecule

A 1B 2

47

C 3D 4

5 Essential oils are

A non-water soluble non-volatile compoundsB non-water soluble volatile compoundsC water soluble non-volatile compoundsD water soluble volatile compounds

6 Two typical compounds that are present in many perfumes are shown

(a) Why does geraniol evaporate more slowly than limonene (1)

(b) The structure of one of the first synthetic scents used in perfume is shown below

(i) Name the family of carbonyl compounds to which this synthetic scent belongs (1)

(ii) Complete the structure below to show the product formed when this scent is

oxidised (1)

(c) Traces of a liquid were discovered in a bottle believed to contain perfume belonging to Queen Hatshepsut ruler of Egypt over 3500 years ago

Perfumes were made by dissolving plant extracts containing pleasant smelling terpenes and esters in an edible oil A little ethanol and water may also have been addedUsing your knowledge of chemistry comment on the possible smell(s) when such a bottle is opened after being stored for thousands of years (3)

48

49

7 A team of chemists are developing a fragrance for use in a shower gel for men(a) To give the gel a fruity smell the chemists are considering adding an ester

They synthesise six isomeric esters Volunteers smell each ester and give it a rating out of one hundred depending on how fruity the smell is

(i) Name the ester with the fruit-smell rating of 92 (1)

(ii) Shown below are the structures of three more isomers

Arrange these esters in order of decreasing fruit-smell rating (1)

50

(b) To create a fragrance for men the compound civetone is added

Draw a structural formula for the alcohol that can be oxidised to form civetone (1)

(c) To make the shower gel produce a cold tingling sensation when applied to the skin menthol is added

Like terpenes menthol is formed from isoprene (2-methylbuta-13-diene)Circle an isoprene unit on the menthol structure above (1)

8 Many of the compounds in perfumes are molecules consisting of joined isoprene units

(a) State the name that is given to molecules consisting of joined isoprene units (1)

(b)Geraniol is one of the compounds found in perfume It has the following structural formula and systematic name

Linalool can also be present Its structural formula is shown

51

(i) State the systematic name for linalool (1)(ii) Explain why linalool can be classified as a tertiary alcohol (1)

9 The component molecules found in lavender oils are terpenes or terpenoids(a)A chiral carbon is a carbon atom attached to four different atoms or groups of

atomsAn example is shown below

A molecule of the terpenoid linalool has a chiral carbon Linalool has the following structure

Circle the chiral carbon atom in the linalool structure (1)

(b)Farnesene is a terpene consisting of three isoprene units (2-methylbuta-13-diene) joined togetherWrite the molecular formula of farnesene (1)

52

27 Skin Care

1 Which of the following is not a step in a free radical chain reaction

A ActivationB InitiationC PropagationD Termination

2 Fluorine reacts with methane via a free radical chain reaction Some steps in the chain reaction are shown in the table below

Complete the table by(a) inserting the missing name for the first step (1)

(b) showing another possible termination reaction in the final row of the table (1)

3 Suncreams contain antioxidantsThe antioxidant compound A can prevent damage to skin by reacting with free

radicalssuch as NO2bull

53

Why can compound A be described as a free radical scavenger in the reaction shown above

4 Hydrogen and chlorine gases are used in an experiment to demonstrate a free radical reaction A plastic bottle is wrapped with black tape leaving a ldquowindowrdquo on one sideThe bottle is filled with a mixture of hydrogen and chlorine When bright light shines on the bottle there is an explosion

A free radical chain reaction is initiated when light energy causes chlorine radicals to form as shown below

(a) Complete the equations below showing possible propagation and termination steps

(2)

54

(b) Why is the plastic bottle used in the experiment wrapped in black tape (1)

5 Chloramines can be removed from water using ultraviolet light treatment

One step in the process is the formation of free radicals

(a)State what is meant by the term free radical (1)

(b)Another step in the process is shown below

State the name for this type of step in a free radical reaction (1)

6 Modern shellac nail varnishes are more durable and so last longer than traditional nail polish

The shellac nail varnish is applied in thin layers to the nails and then the fingers are placed under a UV lamp

(a) The Skin Care Foundation has recommended that a sun-block is applied to the fingers and hand before using the lampSuggest why the Skin Care Foundation makes this recommendation (1)

(b) A free radical chain reaction takes place and the varnish hardens (i) State what is meant by the term free radical (1)

(ii) The shellac nail varnish contains a mixture of ingredients that take part in the free radical chain reactionOne of the steps in the free radical chain reaction is

55

State the term used to describe this type of step in a free radical chain reaction(1)

7 Skin care products contain a mixture of polar covalent non-polar covalent and ionic compounds The compounds need to stay mixed within the product Skin care products also need to spread easily and remain on the skin for a period of time as well as provide physical and chemical protection from the sun In order to do this skin care products contain a range of chemicals including water fats and oils antioxidants minerals and sun blockUsing your knowledge of chemistry explain the role of different chemicals in skin care products (3)

General Questions

1 A mixture of carbon monoxide and hydrogen can be converted into water and a mixture of hydrocarbons

nCO + (2n + 1)H2 rarr nH2O + hydrocarbons

What is the general formula for the hydrocarbons producedA CnH2nndash2B CnH2nC CnH2n+1D CnH2n+2

2 Butadiene is the first member of a homologous series of hydrocarbons called dienesWhat is the general formula for this seriesA CnHn+2B CnHn+3C CnH2nD CnH2nndash2

3 Which of the following statements about methanol is falseA It can be made from synthesis gasB It can be dehydrated to form an alkeneC It can be oxidised to give a carboxylic acidD It reacts with acidified potassium dichromate solution

56

4

Which line in the table correctly describes reactions X and Y

5

Which line in the table correctly describes reactions X and Y

6 Which of the following fuels when burned would make no contribution to globalwarming

57

A HydrogenB Natural gasC PetrolD Coal

7 Which of the following hydrocarbons always gives the same product when one of itshydrogen atoms is replaced by a chlorine atomA HexaneB Hex-1-eneC CyclohexaneD Cyclohexene

8 Which of the following compounds does not have isomeric structuresA C2HCl3B C2H4Cl2C PropeneD Propan-1-ol

9 What organic compound is produced by the dehydration of ethanol A EthaneB EtheneC EthanalD Ethanoic acid

10

The above equation representsA hydrationB hydrogenationC condensationD hydrolysis

11

Which of the following compounds is an isomer of the structure shown aboveA ButanalB ButanoneC Butan-1-olD Butanoic acid

58

12 A compound with molecular formula C6H12O2 could beA hexanalB hexan-2-olC hexan-2-oneD hexanoic acid

13 Propan-2-ol can be prepared from propane as follows

Which line in the table correctly describes the types of reaction taking place at Steps 1 and 2

14 Which of the following compounds would be the most water soluble

15 Cyanohydrin compounds can be made from carbonyl compounds by reacting the carbonyl compound with hydrogen cyanide (HCN)

59

Which carbonyl compound would react with hydrogen cyanide (HCN) to form the following compound

16 Ethyne is the first member of the homologous series called the alkynes

Ethyne can undergo addition reactions as shown in the flow diagram

(a) Compound 2 is an isomer of 12-dichloroethaneDraw a structural formula for compound 2 (1)

(b) Reagents A B and C are three different diatomic gasesUsing information in the flow diagram identify reagents A B and C (1)

60

Reagent Gas

A

B

C

17 In 1865 the German chemist Kekuleacute proposed a ring structure for benzene This structure was based on alternating single and double bonds

(a) (i) Describe a chemical test that would indicate that the above chemical structure for benzene is incorrect (1)

(ii) Briefly describe the correct structure for benzene (1)

(b) Benzene can be formed from cyclohexaneC6H12 rarr C6H6 + 3H2

What name is given to this type of reaction (1)18 Infra-red spectroscopy is a technique that can be used to identify the bonds that

arepresent in a molecule Different bonds absorb infra-red radiation of different wavenumbers This is due to differences in the bond lsquostretchrsquo These absorptions are recorded in a spectrumA spectrum for propan-1-ol is shown

61

The correlation table on page 13 of the data booklet shows the wavenumber ranges for the absorptions due to different bonds

(a) Use the correlation table to identify the bonds responsible for the two absorptions x and y that are circled in the propan-1-ol spectrum (1)

(b) Propan-1-ol reacts with ethanoic acid(i) What name is given to this type of reaction (1)(ii) Draw a spectrum that could be obtained for the organic product of this

reaction (1)

19 Paracetamol is a widely used painkiller

(a) Write the molecular formula for paracetamol (1)

(b) One antidote for paracetamol overdose is methionine

62

To what family of organic compounds does methionine belong (1)

(c) The concentration of paracetamol in a solution can be determined by measuring how much UV radiation it absorbs

The graph shows how the absorbance of a sample containing 0middot040 g l ndash1 paracetamol varies with wavelength

The quantity of UV radiation of wavelength 245 nm absorbed is directly proportional to the concentration of paracetamolThe absorbance of a second sample of paracetamol solution measured at 245 nm was 0middot90 What is the concentration in g l ndash1 of this second paracetamol solution (1)

20 Many carbon compounds containing oxygen are very flammableThe table shows information about two families of isomersThe lowest temperature at which a compound will ignite is called its flash point

(a) A compound with the molecular formula C6H14O has a boiling point of 158 degC63

Draw a structural formula for this compound (1)

(b) For a family of isomers in the table write a general statement linking the flash points of the compounds to their structures (1)

21 Hydrogels are used in disposable nappies They are fine powders that can absorb up to 500 times their own weight in waterA hydrogel is a very long molecule with carboxyl groups at regular intervals along its length A short section of a hydrogel molecule is shown below

Hydrogels are extremely good at soaking up water because the water molecules are strongly attracted to them

Using your knowledge of chemistry comment on how suitable hydrogels would be for absorbing liquids or solutions spilled in a chemistry lab (1)

64

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

24 The Oxidation of Food

1 Apples and bananas turn brown when cut or bruised The first step of the reaction causing

the browning is shown below

Which of the following terms correctly describes this reactionA ReductionB OxidationC DehydrationD Condensation

2 Which of the following reactions can be classified as reductionA CH3CH2OH rarr CH3COOHB CH3 CH(OH)CH3 rarr CH3COCH3C CH3CH2COCH3 rarr CH3CH2CH(OH)CH3D CH3CH2CHO rarr CH3CH2COOH

3 The dehydration of butan-2-ol can produce two isomeric alkenes but-1-ene andbut-2-ene Which of the following alkanols can similarly produce on dehydration a pair of isomeric alkenesA Propan-2-olB Pentan-3-olC Hexan-3-olD Heptan-4-ol

4 Which of the following compounds is an alkanone

26

5 Which of the following is an aldehyde

6 Which of the following compounds would react with sodium hydroxide solution to forma saltA CH3CHOB CH3COOHC CH3COCH3D CH3CH2OH

7 Which line in the table shows the correct functional group for each homologous series

8 Which of the following organic compounds is an isomer of hexanalA 2-MethylbutanalB 3-Methylpentan-2-oneC 22-Dimethylbutan-1-olD 3-Ethylpentanal

27

9 The name of this compound is

A methanolB methanalC methanoic acidD methanone

10 Which alcohol could be oxidised to a carboxylic acid

11 Which of the following structural formulae represents a tertiary alcohol

12 Compound X reacted with hot copper(II) oxide and the organic product did not give acolour change when heated with Fehlingrsquos solution Compound X could beA butan-1-olB butan-2-olC butanoneD butanoic acid

28

13 Which two isomers would each produce an acid when warmed with acidified potassiumdichromate solution

A 1 and 2B 2 and 3C 1 and 4D 3 and 4

14 After heating for several minutes as shown in the diagram the pH indicator solution turned red

Liquid Q could beA propanoneB paraffinC propan-1-olD propan-2-ol

29

15 Enzymes are involved in the browning of cut fruitOne reaction taking place is

Which of the following correctly describes the above reaction

A OxidationB ReductionC HydrolysisD Condensation

16 Which of the following statements is correct for ketones

A They are formed by oxidation of tertiary alcohols

B They contain the group

C They contain a carboxyl groupD They will not react with Fehlingrsquos solution

17 Carvone is a natural product that can be extracted from orange peel

Which line in the table correctly describes the reaction of carvone with bromine solution and with acidified potassium dichromate solution

30

18 Which of the following is an isomer of 22-dimethylpentan-1-ol

A CH3CH2CH2CH(CH3)CH2OHB (CH3)3CCH(CH3)CH2OHC CH3CH2CH2CH2CH2CH2CH2CH2OHD (CH3)2CHC(CH3)2CH2CH2OH

19 The equation for the reduction reaction taking place when ethanal reacts with Tollensrsquo reagent is

A Cu2+(aq) + eminus rarr Cu+(aq)

B Ag+(aq) + eminus rarr Ag(s)

C Cr2O72minus(aq) + 14H+(aq) + 6eminus rarr 2Cr3+(aq) + 7H2O(ℓ)

D MnO4minus(aq) + 8H+(aq) + 5eminus rarr Mn2+(aq) + 4H2O(ℓ)

20 The name of the compound with structure

isA 23-dimethylpentan-4-oneB 23-dimethylpentan-2-alC 34-dimethylpentan-2-oneD 34-dimethylpentan-2-al

21 What is the systematic name for the compound below

A 222-trimethylethanolB 22-dimethylpropan-1-olC 22-dimethylpropan-3-olD 22-dimethylpentan-1-ol

31

22 The structure of a molecule found in olive oil can be represented as shown

(a) Olive oil can be hydrolysed using sodium hydroxide solution to produce sodium salts of fatty acids Name the other product of this reaction (1)

(b) In what way does the structure of a fat molecule differ from that of an oil molecule (1)

(c) Over time open containers of olive oil develop a rancid flavour What substance is reacting with the oil to cause these unwanted changes to take place (1)

23 A student writes the following statement It is incorrect Explain the mistake in the studentrsquos reasoning (1)

Alcohols are alkaline because of their OH groups

24 Carbon compounds take part in a wide variety of chemical reactions (a)

Name this type of chemical reaction (1)

(b)

Draw a structural formula for C3H6O (1)

25 Alkanols can be oxidised to alkanoic acids

32

(a) Why can Step 1 be described as an oxidation reaction (1)

(b) Acidified potassium dichromate solution can be used to oxidise propanal in Step 2 What colour change would be observed in this reaction (1)

26 Amines can be produced by reacting ammonia with an aldehyde or a ketone This reaction an example of reductive amination occurs in two stages

Stage 1 Amination

Stage 2 Reduction

(a) Give another name for the type of reaction taking place in Stage 2

(b) Draw the structural formula for the amine produced when butanal undergoes reductive amination with ammonia

27 Using a cobalt catalyst alkenes react with a mixture of hydrogen and carbon monoxideThe products are two isomeric aldehydes Propene reacts with the mixture as shown

(a) What name is given to a mixture of hydrogen and carbon monoxide (1)

(b) Draw a structural formula for compound B (1)

(c) (i) What would be observed if compound A was gently heated with Tollensrsquo reagent

(1)(ii) How would the reaction mixture be heated (1)

33

(d) Aldehydes can also be formed by the reaction of some alcohols with copper(II) oxideName the type of alcohol that would react with copper(II) oxide to form an aldehyde (1)

28 Aldehydes and ketones can take part in a reaction sometimes known as an aldol condensation The simplest aldol reaction involves two molecules of ethanal

In the reaction the carbon atom next to the carbonyl functional group of one molecule forms a bond with the carbonyl carbon atom of the second molecule

(a) Draw a structural formula for the product formed when propanone is used instead of ethanal in this type of reaction (1)

(b) Name an aldehyde that would not take part in an aldol condensation (1)

(c) Apart from the structure of the reactants suggest what is unusual about applying the term ldquocondensationrdquo to this particular type of reaction (1)

29 Primary secondary and tertiary alkanols can be prepared by the reaction of carbonyl compounds with Grignard reagents

Step 1The Grignard reagent reacts with the carbonyl compound

Step 2The reaction of the product of Step 1 with dilute acid produces the alkanol

(a) Describe the difference between a primary a secondary and a tertiary alkanol

You may wish to include labelled structures in your answer (1)34

(b) Suggest a name for the type of reaction that takes place in Step 1 (1)

(c) The same Grignard reagent can be used to produce the alkanol below

Name the carbonyl compound used in this reaction (1)

30 Hairspray is a mixture of chemicals(a) A primary alcohol 2-methylpropan-1-ol is added to hairspray to help it dry quickly on the hair

Draw a structural formula for a secondary alcohol that is an isomer of2-methylpropan-1-ol (1)

(b) Triethanol amine and triisopropyl amine are bases used to neutralise acidic compounds in the hairspray to prevent damage to the hair

In terms of the intermolecular bonding present explain clearly why triethanol amine has a much higher boiling point than triisopropyl amine (2)

35

36

31 Chocolate contains various compounds(a) Many of the flavour and aroma molecules found in chocolate are aldehydes and

ketones Two examples are shown below

Phenylethanal can be easily oxidised but 13-diphenylpropan-2-one cannot(i) Name a chemical that could be used to distinguish between these two

compounds (1)

(ii) Name the type of organic compound formed when phenylethanal is oxidised (1)

(b) Glycerol monostearate is an emulsifier used in chocolate

(i) Why is glycerol monostearate added to chocolate (1)

(ii) Draw a structural formula for glycerol (1)

(c) Theobromine a compound present in chocolate can cause illness in dogs and cats To decide if treatment is necessary vets must calculate the mass of theobromine consumed 1middot0 g of chocolate contains 1middot4 mg of theobromine Calculate the mass in mg of theobromine in a 17 g biscuit of which 28 is chocolate Show your working clearly (2)

(d) The flavour and texture of chocolate comes from a blend of compoundsUsing your knowledge of chemistry describe how you could show that there are ionic compounds and covalent compounds present in chocolate (3)

37

32 Ethanol has many uses

(a) Ethanol is found at relatively low concentrations in wine

(i) Name the chemical reaction that produces ethanol in wine (1)

(ii) Standard ethanol solutions were used to produce a graph of density against

concentration of ethanol given as a percentage of alcohol by volume ( abv)

What is the concentration of ethanol in units of abv in a solution of density 0middot9818 g cmminus3 (1)

(b) Whisky contains a higher concentration of ethanol

(i) Before 1980 the concentration of alcohol in drinks was measured in terms of degrees proof The concentration of alcohol in two drinks is shown in the table below both as abv and degrees proof

38

A cask strength whisky has an alcohol concentration of 65 abv Calculate the alcohol concentration of this whisky in degrees proof (1)

(ii) A barrel containing 195 litres of cask strength whisky costs pound1300 The cask strength whisky is diluted with water to reduce the concentration of alcohol from 65 abv to 46 abv before it is bottled Calculate the cost of the cask strength whisky needed to produce a 0middot70 litre bottle Show your working clearly (2)

(iii) 5-Butyl-4-methyltetrahydrofuran-2-ol is a flavour compound found in whisky

stored in oak barrels

Write the systematic name for the compound shown below (1) 13 11

33 (a) One test for glucose involves Fehlingrsquos solutionCircle the part of the glucose molecule that reacts with Fehlingrsquos solution (1)

(b) In solution sugar molecules exist in an equilibrium in straight-chain and ring forms

To change from the straight-chain form to the ring form the oxygen of the hydroxyl on carbon number 5 joins to the carbonyl carbon This is shown below for glucose

39

Draw the structure of a ring form for fructose (1)

34 (a) During the free radical chain reaction small molecules join to form large chain molecules

One example of a small molecule used is

Name the functional group circled above (1)

(b)Alcohol wipes are used to finish the varnishing treatment Alcohol wipes contain the alcohol propan-2-olState why propan-2-ol can be described as a secondary alcohol (1)

35 A student was carrying out an investigation into alcohols aldehydes and ketones

(a)The student was given three alcohols labelled as A B and C These alcohols were all isomers with the formula C4H9OH

(i) Draw a structural formula for the secondary alcohol with the formula C4H9OH(1)

(ii) The student set up the following experiment

A Suggest why a water bath is an appropriate method of heating the reaction mixture (1)

B Describe the colour change that would have been observed with alcohols A and C (1)

40

C Alcohol B is not oxidised State the type of alcohol which cannot be oxidised by acidified dichromate solution (1)

(iii) The student set up a second experiment with alcohol A

Hot copper(II) oxide is an oxidising agentA When alcohol A (C4H9OH) is oxidised the product turns the pH paper

redSuggest a name for the product (1)

B Complete the ion-electron equation for the oxidation reaction

C4H9OH rarr C4H8O2 (1)

(b)The student found the following information about the boiling points of some aldehydes

41

(i) Name the aldehyde that has a boiling point of 119 degC (1)(ii) Predict the boiling point in degC of the following molecule (1)

(iii) Using information from the table describe one way in which differences in structure affect the boiling point of isomeric aldehydes (1)

(iv) State what would be observed when an aldehyde is gently heated with Tollensrsquo reagent (1)

(c) Ketones contain a carbonyl groupName the type of intermolecular interaction between ketone molecules (1)

42

25 Soaps Detergents and Emulsions

1 Soaps are produced by the following reaction

This reaction is an example ofA condensationB esterificationC hydrolysisD oxidation

2 Which of the following is the salt of a long-chain fatty acid

A FatB OilC SoapD Glycerol

3 Emulsifiers for use in food are commonly made by reacting edible oils with

A estersB glycerolC fatty acidsD amino acids

4 A fatty acid is a long chain carboxylic acid Examples of fatty acids are shown in the table below

43

(a) What is the systematic name for linolenic acid (1)(b) Stearic acid reacts with sodium hydroxide solution to form sodium stearate

(i) Name the type of reaction taking place when stearic acid reacts with sodium hydroxide (1)

(ii) Explain fully how sodium stearate acts to keep grease and non-polar substances suspended in water during cleaning (3)

5 Small children can find it difficult to swallow tablets or pills so ibuprofen is supplied as an ldquoinfant formulardquo emulsion(a) The emulsifier used is polysorbate 80 Its structure is shown below

Explain why this molecule acts as an emulsifier (2)

(b) The emulsion contains 2 g of ibuprofen in every 100 cm3 of emulsion The recommended dose for treating a 6 month old baby is 0middot050 g Calculate the volume in cm3 of ldquoinfant formulardquo needed to treat a 6 month old baby (1)

6 Occasionally seabirds can become contaminated with hydrocarbons from oil spills This causes problems for birds because their feathers lose their waterproofing making the birds susceptible to temperature changes and

44

affecting their buoyancy If the birds attempt to clean themselves to remove the oil they may swallow the hydrocarbons causing damage to their internal organsContaminated seabirds can be cleaned by rubbing vegetable oil into their feathers and feet before the birds are rinsed with diluted washing-up liquidUsing your knowledge of chemistry comment on the problems created for seabirds by oil spills and the actions taken to treat affected birds (3)

7 Dishwasher tablets contain chemicals which remove dirt from dishesDishwasher tablets include detergents These molecules act like soaps to allow mixing of fat-soluble dirt and water(a)During the cleaning process the detergent molecules combine with fat-

soluble dirtA simplified diagram of a detergent molecule is shown

Complete the diagram below to show how detergent molecules combine with fat-soluble dirt (1)

(b)State the term used to describe the non-polar hydrocarbon tail of a detergent molecule (1)

45

26 Fragrances1 Myrcene is a simple terpene

Terpenes contain at least one isoprene unit Which of the following shows a correctly highlighted isoprene unit

2 Limonene is one of the terpene molecules responsible for the flavour of lemons

How many isoprene units are used in the production of one limonene moleculeA 1B 2C 3D 4

46

3 The structure of caryophyllene which can be extracted from clove oil is

Which of the following would be the best solvent for extracting caryophylleneA HexaneB HexanalC HexanolD Hexanone

4 The structure of isoprene is

Limonene is a terpene molecule present in lemons

How many isoprene units are joined together in a limonene molecule

A 1B 2

47

C 3D 4

5 Essential oils are

A non-water soluble non-volatile compoundsB non-water soluble volatile compoundsC water soluble non-volatile compoundsD water soluble volatile compounds

6 Two typical compounds that are present in many perfumes are shown

(a) Why does geraniol evaporate more slowly than limonene (1)

(b) The structure of one of the first synthetic scents used in perfume is shown below

(i) Name the family of carbonyl compounds to which this synthetic scent belongs (1)

(ii) Complete the structure below to show the product formed when this scent is

oxidised (1)

(c) Traces of a liquid were discovered in a bottle believed to contain perfume belonging to Queen Hatshepsut ruler of Egypt over 3500 years ago

Perfumes were made by dissolving plant extracts containing pleasant smelling terpenes and esters in an edible oil A little ethanol and water may also have been addedUsing your knowledge of chemistry comment on the possible smell(s) when such a bottle is opened after being stored for thousands of years (3)

48

49

7 A team of chemists are developing a fragrance for use in a shower gel for men(a) To give the gel a fruity smell the chemists are considering adding an ester

They synthesise six isomeric esters Volunteers smell each ester and give it a rating out of one hundred depending on how fruity the smell is

(i) Name the ester with the fruit-smell rating of 92 (1)

(ii) Shown below are the structures of three more isomers

Arrange these esters in order of decreasing fruit-smell rating (1)

50

(b) To create a fragrance for men the compound civetone is added

Draw a structural formula for the alcohol that can be oxidised to form civetone (1)

(c) To make the shower gel produce a cold tingling sensation when applied to the skin menthol is added

Like terpenes menthol is formed from isoprene (2-methylbuta-13-diene)Circle an isoprene unit on the menthol structure above (1)

8 Many of the compounds in perfumes are molecules consisting of joined isoprene units

(a) State the name that is given to molecules consisting of joined isoprene units (1)

(b)Geraniol is one of the compounds found in perfume It has the following structural formula and systematic name

Linalool can also be present Its structural formula is shown

51

(i) State the systematic name for linalool (1)(ii) Explain why linalool can be classified as a tertiary alcohol (1)

9 The component molecules found in lavender oils are terpenes or terpenoids(a)A chiral carbon is a carbon atom attached to four different atoms or groups of

atomsAn example is shown below

A molecule of the terpenoid linalool has a chiral carbon Linalool has the following structure

Circle the chiral carbon atom in the linalool structure (1)

(b)Farnesene is a terpene consisting of three isoprene units (2-methylbuta-13-diene) joined togetherWrite the molecular formula of farnesene (1)

52

27 Skin Care

1 Which of the following is not a step in a free radical chain reaction

A ActivationB InitiationC PropagationD Termination

2 Fluorine reacts with methane via a free radical chain reaction Some steps in the chain reaction are shown in the table below

Complete the table by(a) inserting the missing name for the first step (1)

(b) showing another possible termination reaction in the final row of the table (1)

3 Suncreams contain antioxidantsThe antioxidant compound A can prevent damage to skin by reacting with free

radicalssuch as NO2bull

53

Why can compound A be described as a free radical scavenger in the reaction shown above

4 Hydrogen and chlorine gases are used in an experiment to demonstrate a free radical reaction A plastic bottle is wrapped with black tape leaving a ldquowindowrdquo on one sideThe bottle is filled with a mixture of hydrogen and chlorine When bright light shines on the bottle there is an explosion

A free radical chain reaction is initiated when light energy causes chlorine radicals to form as shown below

(a) Complete the equations below showing possible propagation and termination steps

(2)

54

(b) Why is the plastic bottle used in the experiment wrapped in black tape (1)

5 Chloramines can be removed from water using ultraviolet light treatment

One step in the process is the formation of free radicals

(a)State what is meant by the term free radical (1)

(b)Another step in the process is shown below

State the name for this type of step in a free radical reaction (1)

6 Modern shellac nail varnishes are more durable and so last longer than traditional nail polish

The shellac nail varnish is applied in thin layers to the nails and then the fingers are placed under a UV lamp

(a) The Skin Care Foundation has recommended that a sun-block is applied to the fingers and hand before using the lampSuggest why the Skin Care Foundation makes this recommendation (1)

(b) A free radical chain reaction takes place and the varnish hardens (i) State what is meant by the term free radical (1)

(ii) The shellac nail varnish contains a mixture of ingredients that take part in the free radical chain reactionOne of the steps in the free radical chain reaction is

55

State the term used to describe this type of step in a free radical chain reaction(1)

7 Skin care products contain a mixture of polar covalent non-polar covalent and ionic compounds The compounds need to stay mixed within the product Skin care products also need to spread easily and remain on the skin for a period of time as well as provide physical and chemical protection from the sun In order to do this skin care products contain a range of chemicals including water fats and oils antioxidants minerals and sun blockUsing your knowledge of chemistry explain the role of different chemicals in skin care products (3)

General Questions

1 A mixture of carbon monoxide and hydrogen can be converted into water and a mixture of hydrocarbons

nCO + (2n + 1)H2 rarr nH2O + hydrocarbons

What is the general formula for the hydrocarbons producedA CnH2nndash2B CnH2nC CnH2n+1D CnH2n+2

2 Butadiene is the first member of a homologous series of hydrocarbons called dienesWhat is the general formula for this seriesA CnHn+2B CnHn+3C CnH2nD CnH2nndash2

3 Which of the following statements about methanol is falseA It can be made from synthesis gasB It can be dehydrated to form an alkeneC It can be oxidised to give a carboxylic acidD It reacts with acidified potassium dichromate solution

56

4

Which line in the table correctly describes reactions X and Y

5

Which line in the table correctly describes reactions X and Y

6 Which of the following fuels when burned would make no contribution to globalwarming

57

A HydrogenB Natural gasC PetrolD Coal

7 Which of the following hydrocarbons always gives the same product when one of itshydrogen atoms is replaced by a chlorine atomA HexaneB Hex-1-eneC CyclohexaneD Cyclohexene

8 Which of the following compounds does not have isomeric structuresA C2HCl3B C2H4Cl2C PropeneD Propan-1-ol

9 What organic compound is produced by the dehydration of ethanol A EthaneB EtheneC EthanalD Ethanoic acid

10

The above equation representsA hydrationB hydrogenationC condensationD hydrolysis

11

Which of the following compounds is an isomer of the structure shown aboveA ButanalB ButanoneC Butan-1-olD Butanoic acid

58

12 A compound with molecular formula C6H12O2 could beA hexanalB hexan-2-olC hexan-2-oneD hexanoic acid

13 Propan-2-ol can be prepared from propane as follows

Which line in the table correctly describes the types of reaction taking place at Steps 1 and 2

14 Which of the following compounds would be the most water soluble

15 Cyanohydrin compounds can be made from carbonyl compounds by reacting the carbonyl compound with hydrogen cyanide (HCN)

59

Which carbonyl compound would react with hydrogen cyanide (HCN) to form the following compound

16 Ethyne is the first member of the homologous series called the alkynes

Ethyne can undergo addition reactions as shown in the flow diagram

(a) Compound 2 is an isomer of 12-dichloroethaneDraw a structural formula for compound 2 (1)

(b) Reagents A B and C are three different diatomic gasesUsing information in the flow diagram identify reagents A B and C (1)

60

Reagent Gas

A

B

C

17 In 1865 the German chemist Kekuleacute proposed a ring structure for benzene This structure was based on alternating single and double bonds

(a) (i) Describe a chemical test that would indicate that the above chemical structure for benzene is incorrect (1)

(ii) Briefly describe the correct structure for benzene (1)

(b) Benzene can be formed from cyclohexaneC6H12 rarr C6H6 + 3H2

What name is given to this type of reaction (1)18 Infra-red spectroscopy is a technique that can be used to identify the bonds that

arepresent in a molecule Different bonds absorb infra-red radiation of different wavenumbers This is due to differences in the bond lsquostretchrsquo These absorptions are recorded in a spectrumA spectrum for propan-1-ol is shown

61

The correlation table on page 13 of the data booklet shows the wavenumber ranges for the absorptions due to different bonds

(a) Use the correlation table to identify the bonds responsible for the two absorptions x and y that are circled in the propan-1-ol spectrum (1)

(b) Propan-1-ol reacts with ethanoic acid(i) What name is given to this type of reaction (1)(ii) Draw a spectrum that could be obtained for the organic product of this

reaction (1)

19 Paracetamol is a widely used painkiller

(a) Write the molecular formula for paracetamol (1)

(b) One antidote for paracetamol overdose is methionine

62

To what family of organic compounds does methionine belong (1)

(c) The concentration of paracetamol in a solution can be determined by measuring how much UV radiation it absorbs

The graph shows how the absorbance of a sample containing 0middot040 g l ndash1 paracetamol varies with wavelength

The quantity of UV radiation of wavelength 245 nm absorbed is directly proportional to the concentration of paracetamolThe absorbance of a second sample of paracetamol solution measured at 245 nm was 0middot90 What is the concentration in g l ndash1 of this second paracetamol solution (1)

20 Many carbon compounds containing oxygen are very flammableThe table shows information about two families of isomersThe lowest temperature at which a compound will ignite is called its flash point

(a) A compound with the molecular formula C6H14O has a boiling point of 158 degC63

Draw a structural formula for this compound (1)

(b) For a family of isomers in the table write a general statement linking the flash points of the compounds to their structures (1)

21 Hydrogels are used in disposable nappies They are fine powders that can absorb up to 500 times their own weight in waterA hydrogel is a very long molecule with carboxyl groups at regular intervals along its length A short section of a hydrogel molecule is shown below

Hydrogels are extremely good at soaking up water because the water molecules are strongly attracted to them

Using your knowledge of chemistry comment on how suitable hydrogels would be for absorbing liquids or solutions spilled in a chemistry lab (1)

64

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

5 Which of the following is an aldehyde

6 Which of the following compounds would react with sodium hydroxide solution to forma saltA CH3CHOB CH3COOHC CH3COCH3D CH3CH2OH

7 Which line in the table shows the correct functional group for each homologous series

8 Which of the following organic compounds is an isomer of hexanalA 2-MethylbutanalB 3-Methylpentan-2-oneC 22-Dimethylbutan-1-olD 3-Ethylpentanal

27

9 The name of this compound is

A methanolB methanalC methanoic acidD methanone

10 Which alcohol could be oxidised to a carboxylic acid

11 Which of the following structural formulae represents a tertiary alcohol

12 Compound X reacted with hot copper(II) oxide and the organic product did not give acolour change when heated with Fehlingrsquos solution Compound X could beA butan-1-olB butan-2-olC butanoneD butanoic acid

28

13 Which two isomers would each produce an acid when warmed with acidified potassiumdichromate solution

A 1 and 2B 2 and 3C 1 and 4D 3 and 4

14 After heating for several minutes as shown in the diagram the pH indicator solution turned red

Liquid Q could beA propanoneB paraffinC propan-1-olD propan-2-ol

29

15 Enzymes are involved in the browning of cut fruitOne reaction taking place is

Which of the following correctly describes the above reaction

A OxidationB ReductionC HydrolysisD Condensation

16 Which of the following statements is correct for ketones

A They are formed by oxidation of tertiary alcohols

B They contain the group

C They contain a carboxyl groupD They will not react with Fehlingrsquos solution

17 Carvone is a natural product that can be extracted from orange peel

Which line in the table correctly describes the reaction of carvone with bromine solution and with acidified potassium dichromate solution

30

18 Which of the following is an isomer of 22-dimethylpentan-1-ol

A CH3CH2CH2CH(CH3)CH2OHB (CH3)3CCH(CH3)CH2OHC CH3CH2CH2CH2CH2CH2CH2CH2OHD (CH3)2CHC(CH3)2CH2CH2OH

19 The equation for the reduction reaction taking place when ethanal reacts with Tollensrsquo reagent is

A Cu2+(aq) + eminus rarr Cu+(aq)

B Ag+(aq) + eminus rarr Ag(s)

C Cr2O72minus(aq) + 14H+(aq) + 6eminus rarr 2Cr3+(aq) + 7H2O(ℓ)

D MnO4minus(aq) + 8H+(aq) + 5eminus rarr Mn2+(aq) + 4H2O(ℓ)

20 The name of the compound with structure

isA 23-dimethylpentan-4-oneB 23-dimethylpentan-2-alC 34-dimethylpentan-2-oneD 34-dimethylpentan-2-al

21 What is the systematic name for the compound below

A 222-trimethylethanolB 22-dimethylpropan-1-olC 22-dimethylpropan-3-olD 22-dimethylpentan-1-ol

31

22 The structure of a molecule found in olive oil can be represented as shown

(a) Olive oil can be hydrolysed using sodium hydroxide solution to produce sodium salts of fatty acids Name the other product of this reaction (1)

(b) In what way does the structure of a fat molecule differ from that of an oil molecule (1)

(c) Over time open containers of olive oil develop a rancid flavour What substance is reacting with the oil to cause these unwanted changes to take place (1)

23 A student writes the following statement It is incorrect Explain the mistake in the studentrsquos reasoning (1)

Alcohols are alkaline because of their OH groups

24 Carbon compounds take part in a wide variety of chemical reactions (a)

Name this type of chemical reaction (1)

(b)

Draw a structural formula for C3H6O (1)

25 Alkanols can be oxidised to alkanoic acids

32

(a) Why can Step 1 be described as an oxidation reaction (1)

(b) Acidified potassium dichromate solution can be used to oxidise propanal in Step 2 What colour change would be observed in this reaction (1)

26 Amines can be produced by reacting ammonia with an aldehyde or a ketone This reaction an example of reductive amination occurs in two stages

Stage 1 Amination

Stage 2 Reduction

(a) Give another name for the type of reaction taking place in Stage 2

(b) Draw the structural formula for the amine produced when butanal undergoes reductive amination with ammonia

27 Using a cobalt catalyst alkenes react with a mixture of hydrogen and carbon monoxideThe products are two isomeric aldehydes Propene reacts with the mixture as shown

(a) What name is given to a mixture of hydrogen and carbon monoxide (1)

(b) Draw a structural formula for compound B (1)

(c) (i) What would be observed if compound A was gently heated with Tollensrsquo reagent

(1)(ii) How would the reaction mixture be heated (1)

33

(d) Aldehydes can also be formed by the reaction of some alcohols with copper(II) oxideName the type of alcohol that would react with copper(II) oxide to form an aldehyde (1)

28 Aldehydes and ketones can take part in a reaction sometimes known as an aldol condensation The simplest aldol reaction involves two molecules of ethanal

In the reaction the carbon atom next to the carbonyl functional group of one molecule forms a bond with the carbonyl carbon atom of the second molecule

(a) Draw a structural formula for the product formed when propanone is used instead of ethanal in this type of reaction (1)

(b) Name an aldehyde that would not take part in an aldol condensation (1)

(c) Apart from the structure of the reactants suggest what is unusual about applying the term ldquocondensationrdquo to this particular type of reaction (1)

29 Primary secondary and tertiary alkanols can be prepared by the reaction of carbonyl compounds with Grignard reagents

Step 1The Grignard reagent reacts with the carbonyl compound

Step 2The reaction of the product of Step 1 with dilute acid produces the alkanol

(a) Describe the difference between a primary a secondary and a tertiary alkanol

You may wish to include labelled structures in your answer (1)34

(b) Suggest a name for the type of reaction that takes place in Step 1 (1)

(c) The same Grignard reagent can be used to produce the alkanol below

Name the carbonyl compound used in this reaction (1)

30 Hairspray is a mixture of chemicals(a) A primary alcohol 2-methylpropan-1-ol is added to hairspray to help it dry quickly on the hair

Draw a structural formula for a secondary alcohol that is an isomer of2-methylpropan-1-ol (1)

(b) Triethanol amine and triisopropyl amine are bases used to neutralise acidic compounds in the hairspray to prevent damage to the hair

In terms of the intermolecular bonding present explain clearly why triethanol amine has a much higher boiling point than triisopropyl amine (2)

35

36

31 Chocolate contains various compounds(a) Many of the flavour and aroma molecules found in chocolate are aldehydes and

ketones Two examples are shown below

Phenylethanal can be easily oxidised but 13-diphenylpropan-2-one cannot(i) Name a chemical that could be used to distinguish between these two

compounds (1)

(ii) Name the type of organic compound formed when phenylethanal is oxidised (1)

(b) Glycerol monostearate is an emulsifier used in chocolate

(i) Why is glycerol monostearate added to chocolate (1)

(ii) Draw a structural formula for glycerol (1)

(c) Theobromine a compound present in chocolate can cause illness in dogs and cats To decide if treatment is necessary vets must calculate the mass of theobromine consumed 1middot0 g of chocolate contains 1middot4 mg of theobromine Calculate the mass in mg of theobromine in a 17 g biscuit of which 28 is chocolate Show your working clearly (2)

(d) The flavour and texture of chocolate comes from a blend of compoundsUsing your knowledge of chemistry describe how you could show that there are ionic compounds and covalent compounds present in chocolate (3)

37

32 Ethanol has many uses

(a) Ethanol is found at relatively low concentrations in wine

(i) Name the chemical reaction that produces ethanol in wine (1)

(ii) Standard ethanol solutions were used to produce a graph of density against

concentration of ethanol given as a percentage of alcohol by volume ( abv)

What is the concentration of ethanol in units of abv in a solution of density 0middot9818 g cmminus3 (1)

(b) Whisky contains a higher concentration of ethanol

(i) Before 1980 the concentration of alcohol in drinks was measured in terms of degrees proof The concentration of alcohol in two drinks is shown in the table below both as abv and degrees proof

38

A cask strength whisky has an alcohol concentration of 65 abv Calculate the alcohol concentration of this whisky in degrees proof (1)

(ii) A barrel containing 195 litres of cask strength whisky costs pound1300 The cask strength whisky is diluted with water to reduce the concentration of alcohol from 65 abv to 46 abv before it is bottled Calculate the cost of the cask strength whisky needed to produce a 0middot70 litre bottle Show your working clearly (2)

(iii) 5-Butyl-4-methyltetrahydrofuran-2-ol is a flavour compound found in whisky

stored in oak barrels

Write the systematic name for the compound shown below (1) 13 11

33 (a) One test for glucose involves Fehlingrsquos solutionCircle the part of the glucose molecule that reacts with Fehlingrsquos solution (1)

(b) In solution sugar molecules exist in an equilibrium in straight-chain and ring forms

To change from the straight-chain form to the ring form the oxygen of the hydroxyl on carbon number 5 joins to the carbonyl carbon This is shown below for glucose

39

Draw the structure of a ring form for fructose (1)

34 (a) During the free radical chain reaction small molecules join to form large chain molecules

One example of a small molecule used is

Name the functional group circled above (1)

(b)Alcohol wipes are used to finish the varnishing treatment Alcohol wipes contain the alcohol propan-2-olState why propan-2-ol can be described as a secondary alcohol (1)

35 A student was carrying out an investigation into alcohols aldehydes and ketones

(a)The student was given three alcohols labelled as A B and C These alcohols were all isomers with the formula C4H9OH

(i) Draw a structural formula for the secondary alcohol with the formula C4H9OH(1)

(ii) The student set up the following experiment

A Suggest why a water bath is an appropriate method of heating the reaction mixture (1)

B Describe the colour change that would have been observed with alcohols A and C (1)

40

C Alcohol B is not oxidised State the type of alcohol which cannot be oxidised by acidified dichromate solution (1)

(iii) The student set up a second experiment with alcohol A

Hot copper(II) oxide is an oxidising agentA When alcohol A (C4H9OH) is oxidised the product turns the pH paper

redSuggest a name for the product (1)

B Complete the ion-electron equation for the oxidation reaction

C4H9OH rarr C4H8O2 (1)

(b)The student found the following information about the boiling points of some aldehydes

41

(i) Name the aldehyde that has a boiling point of 119 degC (1)(ii) Predict the boiling point in degC of the following molecule (1)

(iii) Using information from the table describe one way in which differences in structure affect the boiling point of isomeric aldehydes (1)

(iv) State what would be observed when an aldehyde is gently heated with Tollensrsquo reagent (1)

(c) Ketones contain a carbonyl groupName the type of intermolecular interaction between ketone molecules (1)

42

25 Soaps Detergents and Emulsions

1 Soaps are produced by the following reaction

This reaction is an example ofA condensationB esterificationC hydrolysisD oxidation

2 Which of the following is the salt of a long-chain fatty acid

A FatB OilC SoapD Glycerol

3 Emulsifiers for use in food are commonly made by reacting edible oils with

A estersB glycerolC fatty acidsD amino acids

4 A fatty acid is a long chain carboxylic acid Examples of fatty acids are shown in the table below

43

(a) What is the systematic name for linolenic acid (1)(b) Stearic acid reacts with sodium hydroxide solution to form sodium stearate

(i) Name the type of reaction taking place when stearic acid reacts with sodium hydroxide (1)

(ii) Explain fully how sodium stearate acts to keep grease and non-polar substances suspended in water during cleaning (3)

5 Small children can find it difficult to swallow tablets or pills so ibuprofen is supplied as an ldquoinfant formulardquo emulsion(a) The emulsifier used is polysorbate 80 Its structure is shown below

Explain why this molecule acts as an emulsifier (2)

(b) The emulsion contains 2 g of ibuprofen in every 100 cm3 of emulsion The recommended dose for treating a 6 month old baby is 0middot050 g Calculate the volume in cm3 of ldquoinfant formulardquo needed to treat a 6 month old baby (1)

6 Occasionally seabirds can become contaminated with hydrocarbons from oil spills This causes problems for birds because their feathers lose their waterproofing making the birds susceptible to temperature changes and

44

affecting their buoyancy If the birds attempt to clean themselves to remove the oil they may swallow the hydrocarbons causing damage to their internal organsContaminated seabirds can be cleaned by rubbing vegetable oil into their feathers and feet before the birds are rinsed with diluted washing-up liquidUsing your knowledge of chemistry comment on the problems created for seabirds by oil spills and the actions taken to treat affected birds (3)

7 Dishwasher tablets contain chemicals which remove dirt from dishesDishwasher tablets include detergents These molecules act like soaps to allow mixing of fat-soluble dirt and water(a)During the cleaning process the detergent molecules combine with fat-

soluble dirtA simplified diagram of a detergent molecule is shown

Complete the diagram below to show how detergent molecules combine with fat-soluble dirt (1)

(b)State the term used to describe the non-polar hydrocarbon tail of a detergent molecule (1)

45

26 Fragrances1 Myrcene is a simple terpene

Terpenes contain at least one isoprene unit Which of the following shows a correctly highlighted isoprene unit

2 Limonene is one of the terpene molecules responsible for the flavour of lemons

How many isoprene units are used in the production of one limonene moleculeA 1B 2C 3D 4

46

3 The structure of caryophyllene which can be extracted from clove oil is

Which of the following would be the best solvent for extracting caryophylleneA HexaneB HexanalC HexanolD Hexanone

4 The structure of isoprene is

Limonene is a terpene molecule present in lemons

How many isoprene units are joined together in a limonene molecule

A 1B 2

47

C 3D 4

5 Essential oils are

A non-water soluble non-volatile compoundsB non-water soluble volatile compoundsC water soluble non-volatile compoundsD water soluble volatile compounds

6 Two typical compounds that are present in many perfumes are shown

(a) Why does geraniol evaporate more slowly than limonene (1)

(b) The structure of one of the first synthetic scents used in perfume is shown below

(i) Name the family of carbonyl compounds to which this synthetic scent belongs (1)

(ii) Complete the structure below to show the product formed when this scent is

oxidised (1)

(c) Traces of a liquid were discovered in a bottle believed to contain perfume belonging to Queen Hatshepsut ruler of Egypt over 3500 years ago

Perfumes were made by dissolving plant extracts containing pleasant smelling terpenes and esters in an edible oil A little ethanol and water may also have been addedUsing your knowledge of chemistry comment on the possible smell(s) when such a bottle is opened after being stored for thousands of years (3)

48

49

7 A team of chemists are developing a fragrance for use in a shower gel for men(a) To give the gel a fruity smell the chemists are considering adding an ester

They synthesise six isomeric esters Volunteers smell each ester and give it a rating out of one hundred depending on how fruity the smell is

(i) Name the ester with the fruit-smell rating of 92 (1)

(ii) Shown below are the structures of three more isomers

Arrange these esters in order of decreasing fruit-smell rating (1)

50

(b) To create a fragrance for men the compound civetone is added

Draw a structural formula for the alcohol that can be oxidised to form civetone (1)

(c) To make the shower gel produce a cold tingling sensation when applied to the skin menthol is added

Like terpenes menthol is formed from isoprene (2-methylbuta-13-diene)Circle an isoprene unit on the menthol structure above (1)

8 Many of the compounds in perfumes are molecules consisting of joined isoprene units

(a) State the name that is given to molecules consisting of joined isoprene units (1)

(b)Geraniol is one of the compounds found in perfume It has the following structural formula and systematic name

Linalool can also be present Its structural formula is shown

51

(i) State the systematic name for linalool (1)(ii) Explain why linalool can be classified as a tertiary alcohol (1)

9 The component molecules found in lavender oils are terpenes or terpenoids(a)A chiral carbon is a carbon atom attached to four different atoms or groups of

atomsAn example is shown below

A molecule of the terpenoid linalool has a chiral carbon Linalool has the following structure

Circle the chiral carbon atom in the linalool structure (1)

(b)Farnesene is a terpene consisting of three isoprene units (2-methylbuta-13-diene) joined togetherWrite the molecular formula of farnesene (1)

52

27 Skin Care

1 Which of the following is not a step in a free radical chain reaction

A ActivationB InitiationC PropagationD Termination

2 Fluorine reacts with methane via a free radical chain reaction Some steps in the chain reaction are shown in the table below

Complete the table by(a) inserting the missing name for the first step (1)

(b) showing another possible termination reaction in the final row of the table (1)

3 Suncreams contain antioxidantsThe antioxidant compound A can prevent damage to skin by reacting with free

radicalssuch as NO2bull

53

Why can compound A be described as a free radical scavenger in the reaction shown above

4 Hydrogen and chlorine gases are used in an experiment to demonstrate a free radical reaction A plastic bottle is wrapped with black tape leaving a ldquowindowrdquo on one sideThe bottle is filled with a mixture of hydrogen and chlorine When bright light shines on the bottle there is an explosion

A free radical chain reaction is initiated when light energy causes chlorine radicals to form as shown below

(a) Complete the equations below showing possible propagation and termination steps

(2)

54

(b) Why is the plastic bottle used in the experiment wrapped in black tape (1)

5 Chloramines can be removed from water using ultraviolet light treatment

One step in the process is the formation of free radicals

(a)State what is meant by the term free radical (1)

(b)Another step in the process is shown below

State the name for this type of step in a free radical reaction (1)

6 Modern shellac nail varnishes are more durable and so last longer than traditional nail polish

The shellac nail varnish is applied in thin layers to the nails and then the fingers are placed under a UV lamp

(a) The Skin Care Foundation has recommended that a sun-block is applied to the fingers and hand before using the lampSuggest why the Skin Care Foundation makes this recommendation (1)

(b) A free radical chain reaction takes place and the varnish hardens (i) State what is meant by the term free radical (1)

(ii) The shellac nail varnish contains a mixture of ingredients that take part in the free radical chain reactionOne of the steps in the free radical chain reaction is

55

State the term used to describe this type of step in a free radical chain reaction(1)

7 Skin care products contain a mixture of polar covalent non-polar covalent and ionic compounds The compounds need to stay mixed within the product Skin care products also need to spread easily and remain on the skin for a period of time as well as provide physical and chemical protection from the sun In order to do this skin care products contain a range of chemicals including water fats and oils antioxidants minerals and sun blockUsing your knowledge of chemistry explain the role of different chemicals in skin care products (3)

General Questions

1 A mixture of carbon monoxide and hydrogen can be converted into water and a mixture of hydrocarbons

nCO + (2n + 1)H2 rarr nH2O + hydrocarbons

What is the general formula for the hydrocarbons producedA CnH2nndash2B CnH2nC CnH2n+1D CnH2n+2

2 Butadiene is the first member of a homologous series of hydrocarbons called dienesWhat is the general formula for this seriesA CnHn+2B CnHn+3C CnH2nD CnH2nndash2

3 Which of the following statements about methanol is falseA It can be made from synthesis gasB It can be dehydrated to form an alkeneC It can be oxidised to give a carboxylic acidD It reacts with acidified potassium dichromate solution

56

4

Which line in the table correctly describes reactions X and Y

5

Which line in the table correctly describes reactions X and Y

6 Which of the following fuels when burned would make no contribution to globalwarming

57

A HydrogenB Natural gasC PetrolD Coal

7 Which of the following hydrocarbons always gives the same product when one of itshydrogen atoms is replaced by a chlorine atomA HexaneB Hex-1-eneC CyclohexaneD Cyclohexene

8 Which of the following compounds does not have isomeric structuresA C2HCl3B C2H4Cl2C PropeneD Propan-1-ol

9 What organic compound is produced by the dehydration of ethanol A EthaneB EtheneC EthanalD Ethanoic acid

10

The above equation representsA hydrationB hydrogenationC condensationD hydrolysis

11

Which of the following compounds is an isomer of the structure shown aboveA ButanalB ButanoneC Butan-1-olD Butanoic acid

58

12 A compound with molecular formula C6H12O2 could beA hexanalB hexan-2-olC hexan-2-oneD hexanoic acid

13 Propan-2-ol can be prepared from propane as follows

Which line in the table correctly describes the types of reaction taking place at Steps 1 and 2

14 Which of the following compounds would be the most water soluble

15 Cyanohydrin compounds can be made from carbonyl compounds by reacting the carbonyl compound with hydrogen cyanide (HCN)

59

Which carbonyl compound would react with hydrogen cyanide (HCN) to form the following compound

16 Ethyne is the first member of the homologous series called the alkynes

Ethyne can undergo addition reactions as shown in the flow diagram

(a) Compound 2 is an isomer of 12-dichloroethaneDraw a structural formula for compound 2 (1)

(b) Reagents A B and C are three different diatomic gasesUsing information in the flow diagram identify reagents A B and C (1)

60

Reagent Gas

A

B

C

17 In 1865 the German chemist Kekuleacute proposed a ring structure for benzene This structure was based on alternating single and double bonds

(a) (i) Describe a chemical test that would indicate that the above chemical structure for benzene is incorrect (1)

(ii) Briefly describe the correct structure for benzene (1)

(b) Benzene can be formed from cyclohexaneC6H12 rarr C6H6 + 3H2

What name is given to this type of reaction (1)18 Infra-red spectroscopy is a technique that can be used to identify the bonds that

arepresent in a molecule Different bonds absorb infra-red radiation of different wavenumbers This is due to differences in the bond lsquostretchrsquo These absorptions are recorded in a spectrumA spectrum for propan-1-ol is shown

61

The correlation table on page 13 of the data booklet shows the wavenumber ranges for the absorptions due to different bonds

(a) Use the correlation table to identify the bonds responsible for the two absorptions x and y that are circled in the propan-1-ol spectrum (1)

(b) Propan-1-ol reacts with ethanoic acid(i) What name is given to this type of reaction (1)(ii) Draw a spectrum that could be obtained for the organic product of this

reaction (1)

19 Paracetamol is a widely used painkiller

(a) Write the molecular formula for paracetamol (1)

(b) One antidote for paracetamol overdose is methionine

62

To what family of organic compounds does methionine belong (1)

(c) The concentration of paracetamol in a solution can be determined by measuring how much UV radiation it absorbs

The graph shows how the absorbance of a sample containing 0middot040 g l ndash1 paracetamol varies with wavelength

The quantity of UV radiation of wavelength 245 nm absorbed is directly proportional to the concentration of paracetamolThe absorbance of a second sample of paracetamol solution measured at 245 nm was 0middot90 What is the concentration in g l ndash1 of this second paracetamol solution (1)

20 Many carbon compounds containing oxygen are very flammableThe table shows information about two families of isomersThe lowest temperature at which a compound will ignite is called its flash point

(a) A compound with the molecular formula C6H14O has a boiling point of 158 degC63

Draw a structural formula for this compound (1)

(b) For a family of isomers in the table write a general statement linking the flash points of the compounds to their structures (1)

21 Hydrogels are used in disposable nappies They are fine powders that can absorb up to 500 times their own weight in waterA hydrogel is a very long molecule with carboxyl groups at regular intervals along its length A short section of a hydrogel molecule is shown below

Hydrogels are extremely good at soaking up water because the water molecules are strongly attracted to them

Using your knowledge of chemistry comment on how suitable hydrogels would be for absorbing liquids or solutions spilled in a chemistry lab (1)

64

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

9 The name of this compound is

A methanolB methanalC methanoic acidD methanone

10 Which alcohol could be oxidised to a carboxylic acid

11 Which of the following structural formulae represents a tertiary alcohol

12 Compound X reacted with hot copper(II) oxide and the organic product did not give acolour change when heated with Fehlingrsquos solution Compound X could beA butan-1-olB butan-2-olC butanoneD butanoic acid

28

13 Which two isomers would each produce an acid when warmed with acidified potassiumdichromate solution

A 1 and 2B 2 and 3C 1 and 4D 3 and 4

14 After heating for several minutes as shown in the diagram the pH indicator solution turned red

Liquid Q could beA propanoneB paraffinC propan-1-olD propan-2-ol

29

15 Enzymes are involved in the browning of cut fruitOne reaction taking place is

Which of the following correctly describes the above reaction

A OxidationB ReductionC HydrolysisD Condensation

16 Which of the following statements is correct for ketones

A They are formed by oxidation of tertiary alcohols

B They contain the group

C They contain a carboxyl groupD They will not react with Fehlingrsquos solution

17 Carvone is a natural product that can be extracted from orange peel

Which line in the table correctly describes the reaction of carvone with bromine solution and with acidified potassium dichromate solution

30

18 Which of the following is an isomer of 22-dimethylpentan-1-ol

A CH3CH2CH2CH(CH3)CH2OHB (CH3)3CCH(CH3)CH2OHC CH3CH2CH2CH2CH2CH2CH2CH2OHD (CH3)2CHC(CH3)2CH2CH2OH

19 The equation for the reduction reaction taking place when ethanal reacts with Tollensrsquo reagent is

A Cu2+(aq) + eminus rarr Cu+(aq)

B Ag+(aq) + eminus rarr Ag(s)

C Cr2O72minus(aq) + 14H+(aq) + 6eminus rarr 2Cr3+(aq) + 7H2O(ℓ)

D MnO4minus(aq) + 8H+(aq) + 5eminus rarr Mn2+(aq) + 4H2O(ℓ)

20 The name of the compound with structure

isA 23-dimethylpentan-4-oneB 23-dimethylpentan-2-alC 34-dimethylpentan-2-oneD 34-dimethylpentan-2-al

21 What is the systematic name for the compound below

A 222-trimethylethanolB 22-dimethylpropan-1-olC 22-dimethylpropan-3-olD 22-dimethylpentan-1-ol

31

22 The structure of a molecule found in olive oil can be represented as shown

(a) Olive oil can be hydrolysed using sodium hydroxide solution to produce sodium salts of fatty acids Name the other product of this reaction (1)

(b) In what way does the structure of a fat molecule differ from that of an oil molecule (1)

(c) Over time open containers of olive oil develop a rancid flavour What substance is reacting with the oil to cause these unwanted changes to take place (1)

23 A student writes the following statement It is incorrect Explain the mistake in the studentrsquos reasoning (1)

Alcohols are alkaline because of their OH groups

24 Carbon compounds take part in a wide variety of chemical reactions (a)

Name this type of chemical reaction (1)

(b)

Draw a structural formula for C3H6O (1)

25 Alkanols can be oxidised to alkanoic acids

32

(a) Why can Step 1 be described as an oxidation reaction (1)

(b) Acidified potassium dichromate solution can be used to oxidise propanal in Step 2 What colour change would be observed in this reaction (1)

26 Amines can be produced by reacting ammonia with an aldehyde or a ketone This reaction an example of reductive amination occurs in two stages

Stage 1 Amination

Stage 2 Reduction

(a) Give another name for the type of reaction taking place in Stage 2

(b) Draw the structural formula for the amine produced when butanal undergoes reductive amination with ammonia

27 Using a cobalt catalyst alkenes react with a mixture of hydrogen and carbon monoxideThe products are two isomeric aldehydes Propene reacts with the mixture as shown

(a) What name is given to a mixture of hydrogen and carbon monoxide (1)

(b) Draw a structural formula for compound B (1)

(c) (i) What would be observed if compound A was gently heated with Tollensrsquo reagent

(1)(ii) How would the reaction mixture be heated (1)

33

(d) Aldehydes can also be formed by the reaction of some alcohols with copper(II) oxideName the type of alcohol that would react with copper(II) oxide to form an aldehyde (1)

28 Aldehydes and ketones can take part in a reaction sometimes known as an aldol condensation The simplest aldol reaction involves two molecules of ethanal

In the reaction the carbon atom next to the carbonyl functional group of one molecule forms a bond with the carbonyl carbon atom of the second molecule

(a) Draw a structural formula for the product formed when propanone is used instead of ethanal in this type of reaction (1)

(b) Name an aldehyde that would not take part in an aldol condensation (1)

(c) Apart from the structure of the reactants suggest what is unusual about applying the term ldquocondensationrdquo to this particular type of reaction (1)

29 Primary secondary and tertiary alkanols can be prepared by the reaction of carbonyl compounds with Grignard reagents

Step 1The Grignard reagent reacts with the carbonyl compound

Step 2The reaction of the product of Step 1 with dilute acid produces the alkanol

(a) Describe the difference between a primary a secondary and a tertiary alkanol

You may wish to include labelled structures in your answer (1)34

(b) Suggest a name for the type of reaction that takes place in Step 1 (1)

(c) The same Grignard reagent can be used to produce the alkanol below

Name the carbonyl compound used in this reaction (1)

30 Hairspray is a mixture of chemicals(a) A primary alcohol 2-methylpropan-1-ol is added to hairspray to help it dry quickly on the hair

Draw a structural formula for a secondary alcohol that is an isomer of2-methylpropan-1-ol (1)

(b) Triethanol amine and triisopropyl amine are bases used to neutralise acidic compounds in the hairspray to prevent damage to the hair

In terms of the intermolecular bonding present explain clearly why triethanol amine has a much higher boiling point than triisopropyl amine (2)

35

36

31 Chocolate contains various compounds(a) Many of the flavour and aroma molecules found in chocolate are aldehydes and

ketones Two examples are shown below

Phenylethanal can be easily oxidised but 13-diphenylpropan-2-one cannot(i) Name a chemical that could be used to distinguish between these two

compounds (1)

(ii) Name the type of organic compound formed when phenylethanal is oxidised (1)

(b) Glycerol monostearate is an emulsifier used in chocolate

(i) Why is glycerol monostearate added to chocolate (1)

(ii) Draw a structural formula for glycerol (1)

(c) Theobromine a compound present in chocolate can cause illness in dogs and cats To decide if treatment is necessary vets must calculate the mass of theobromine consumed 1middot0 g of chocolate contains 1middot4 mg of theobromine Calculate the mass in mg of theobromine in a 17 g biscuit of which 28 is chocolate Show your working clearly (2)

(d) The flavour and texture of chocolate comes from a blend of compoundsUsing your knowledge of chemistry describe how you could show that there are ionic compounds and covalent compounds present in chocolate (3)

37

32 Ethanol has many uses

(a) Ethanol is found at relatively low concentrations in wine

(i) Name the chemical reaction that produces ethanol in wine (1)

(ii) Standard ethanol solutions were used to produce a graph of density against

concentration of ethanol given as a percentage of alcohol by volume ( abv)

What is the concentration of ethanol in units of abv in a solution of density 0middot9818 g cmminus3 (1)

(b) Whisky contains a higher concentration of ethanol

(i) Before 1980 the concentration of alcohol in drinks was measured in terms of degrees proof The concentration of alcohol in two drinks is shown in the table below both as abv and degrees proof

38

A cask strength whisky has an alcohol concentration of 65 abv Calculate the alcohol concentration of this whisky in degrees proof (1)

(ii) A barrel containing 195 litres of cask strength whisky costs pound1300 The cask strength whisky is diluted with water to reduce the concentration of alcohol from 65 abv to 46 abv before it is bottled Calculate the cost of the cask strength whisky needed to produce a 0middot70 litre bottle Show your working clearly (2)

(iii) 5-Butyl-4-methyltetrahydrofuran-2-ol is a flavour compound found in whisky

stored in oak barrels

Write the systematic name for the compound shown below (1) 13 11

33 (a) One test for glucose involves Fehlingrsquos solutionCircle the part of the glucose molecule that reacts with Fehlingrsquos solution (1)

(b) In solution sugar molecules exist in an equilibrium in straight-chain and ring forms

To change from the straight-chain form to the ring form the oxygen of the hydroxyl on carbon number 5 joins to the carbonyl carbon This is shown below for glucose

39

Draw the structure of a ring form for fructose (1)

34 (a) During the free radical chain reaction small molecules join to form large chain molecules

One example of a small molecule used is

Name the functional group circled above (1)

(b)Alcohol wipes are used to finish the varnishing treatment Alcohol wipes contain the alcohol propan-2-olState why propan-2-ol can be described as a secondary alcohol (1)

35 A student was carrying out an investigation into alcohols aldehydes and ketones

(a)The student was given three alcohols labelled as A B and C These alcohols were all isomers with the formula C4H9OH

(i) Draw a structural formula for the secondary alcohol with the formula C4H9OH(1)

(ii) The student set up the following experiment

A Suggest why a water bath is an appropriate method of heating the reaction mixture (1)

B Describe the colour change that would have been observed with alcohols A and C (1)

40

C Alcohol B is not oxidised State the type of alcohol which cannot be oxidised by acidified dichromate solution (1)

(iii) The student set up a second experiment with alcohol A

Hot copper(II) oxide is an oxidising agentA When alcohol A (C4H9OH) is oxidised the product turns the pH paper

redSuggest a name for the product (1)

B Complete the ion-electron equation for the oxidation reaction

C4H9OH rarr C4H8O2 (1)

(b)The student found the following information about the boiling points of some aldehydes

41

(i) Name the aldehyde that has a boiling point of 119 degC (1)(ii) Predict the boiling point in degC of the following molecule (1)

(iii) Using information from the table describe one way in which differences in structure affect the boiling point of isomeric aldehydes (1)

(iv) State what would be observed when an aldehyde is gently heated with Tollensrsquo reagent (1)

(c) Ketones contain a carbonyl groupName the type of intermolecular interaction between ketone molecules (1)

42

25 Soaps Detergents and Emulsions

1 Soaps are produced by the following reaction

This reaction is an example ofA condensationB esterificationC hydrolysisD oxidation

2 Which of the following is the salt of a long-chain fatty acid

A FatB OilC SoapD Glycerol

3 Emulsifiers for use in food are commonly made by reacting edible oils with

A estersB glycerolC fatty acidsD amino acids

4 A fatty acid is a long chain carboxylic acid Examples of fatty acids are shown in the table below

43

(a) What is the systematic name for linolenic acid (1)(b) Stearic acid reacts with sodium hydroxide solution to form sodium stearate

(i) Name the type of reaction taking place when stearic acid reacts with sodium hydroxide (1)

(ii) Explain fully how sodium stearate acts to keep grease and non-polar substances suspended in water during cleaning (3)

5 Small children can find it difficult to swallow tablets or pills so ibuprofen is supplied as an ldquoinfant formulardquo emulsion(a) The emulsifier used is polysorbate 80 Its structure is shown below

Explain why this molecule acts as an emulsifier (2)

(b) The emulsion contains 2 g of ibuprofen in every 100 cm3 of emulsion The recommended dose for treating a 6 month old baby is 0middot050 g Calculate the volume in cm3 of ldquoinfant formulardquo needed to treat a 6 month old baby (1)

6 Occasionally seabirds can become contaminated with hydrocarbons from oil spills This causes problems for birds because their feathers lose their waterproofing making the birds susceptible to temperature changes and

44

affecting their buoyancy If the birds attempt to clean themselves to remove the oil they may swallow the hydrocarbons causing damage to their internal organsContaminated seabirds can be cleaned by rubbing vegetable oil into their feathers and feet before the birds are rinsed with diluted washing-up liquidUsing your knowledge of chemistry comment on the problems created for seabirds by oil spills and the actions taken to treat affected birds (3)

7 Dishwasher tablets contain chemicals which remove dirt from dishesDishwasher tablets include detergents These molecules act like soaps to allow mixing of fat-soluble dirt and water(a)During the cleaning process the detergent molecules combine with fat-

soluble dirtA simplified diagram of a detergent molecule is shown

Complete the diagram below to show how detergent molecules combine with fat-soluble dirt (1)

(b)State the term used to describe the non-polar hydrocarbon tail of a detergent molecule (1)

45

26 Fragrances1 Myrcene is a simple terpene

Terpenes contain at least one isoprene unit Which of the following shows a correctly highlighted isoprene unit

2 Limonene is one of the terpene molecules responsible for the flavour of lemons

How many isoprene units are used in the production of one limonene moleculeA 1B 2C 3D 4

46

3 The structure of caryophyllene which can be extracted from clove oil is

Which of the following would be the best solvent for extracting caryophylleneA HexaneB HexanalC HexanolD Hexanone

4 The structure of isoprene is

Limonene is a terpene molecule present in lemons

How many isoprene units are joined together in a limonene molecule

A 1B 2

47

C 3D 4

5 Essential oils are

A non-water soluble non-volatile compoundsB non-water soluble volatile compoundsC water soluble non-volatile compoundsD water soluble volatile compounds

6 Two typical compounds that are present in many perfumes are shown

(a) Why does geraniol evaporate more slowly than limonene (1)

(b) The structure of one of the first synthetic scents used in perfume is shown below

(i) Name the family of carbonyl compounds to which this synthetic scent belongs (1)

(ii) Complete the structure below to show the product formed when this scent is

oxidised (1)

(c) Traces of a liquid were discovered in a bottle believed to contain perfume belonging to Queen Hatshepsut ruler of Egypt over 3500 years ago

Perfumes were made by dissolving plant extracts containing pleasant smelling terpenes and esters in an edible oil A little ethanol and water may also have been addedUsing your knowledge of chemistry comment on the possible smell(s) when such a bottle is opened after being stored for thousands of years (3)

48

49

7 A team of chemists are developing a fragrance for use in a shower gel for men(a) To give the gel a fruity smell the chemists are considering adding an ester

They synthesise six isomeric esters Volunteers smell each ester and give it a rating out of one hundred depending on how fruity the smell is

(i) Name the ester with the fruit-smell rating of 92 (1)

(ii) Shown below are the structures of three more isomers

Arrange these esters in order of decreasing fruit-smell rating (1)

50

(b) To create a fragrance for men the compound civetone is added

Draw a structural formula for the alcohol that can be oxidised to form civetone (1)

(c) To make the shower gel produce a cold tingling sensation when applied to the skin menthol is added

Like terpenes menthol is formed from isoprene (2-methylbuta-13-diene)Circle an isoprene unit on the menthol structure above (1)

8 Many of the compounds in perfumes are molecules consisting of joined isoprene units

(a) State the name that is given to molecules consisting of joined isoprene units (1)

(b)Geraniol is one of the compounds found in perfume It has the following structural formula and systematic name

Linalool can also be present Its structural formula is shown

51

(i) State the systematic name for linalool (1)(ii) Explain why linalool can be classified as a tertiary alcohol (1)

9 The component molecules found in lavender oils are terpenes or terpenoids(a)A chiral carbon is a carbon atom attached to four different atoms or groups of

atomsAn example is shown below

A molecule of the terpenoid linalool has a chiral carbon Linalool has the following structure

Circle the chiral carbon atom in the linalool structure (1)

(b)Farnesene is a terpene consisting of three isoprene units (2-methylbuta-13-diene) joined togetherWrite the molecular formula of farnesene (1)

52

27 Skin Care

1 Which of the following is not a step in a free radical chain reaction

A ActivationB InitiationC PropagationD Termination

2 Fluorine reacts with methane via a free radical chain reaction Some steps in the chain reaction are shown in the table below

Complete the table by(a) inserting the missing name for the first step (1)

(b) showing another possible termination reaction in the final row of the table (1)

3 Suncreams contain antioxidantsThe antioxidant compound A can prevent damage to skin by reacting with free

radicalssuch as NO2bull

53

Why can compound A be described as a free radical scavenger in the reaction shown above

4 Hydrogen and chlorine gases are used in an experiment to demonstrate a free radical reaction A plastic bottle is wrapped with black tape leaving a ldquowindowrdquo on one sideThe bottle is filled with a mixture of hydrogen and chlorine When bright light shines on the bottle there is an explosion

A free radical chain reaction is initiated when light energy causes chlorine radicals to form as shown below

(a) Complete the equations below showing possible propagation and termination steps

(2)

54

(b) Why is the plastic bottle used in the experiment wrapped in black tape (1)

5 Chloramines can be removed from water using ultraviolet light treatment

One step in the process is the formation of free radicals

(a)State what is meant by the term free radical (1)

(b)Another step in the process is shown below

State the name for this type of step in a free radical reaction (1)

6 Modern shellac nail varnishes are more durable and so last longer than traditional nail polish

The shellac nail varnish is applied in thin layers to the nails and then the fingers are placed under a UV lamp

(a) The Skin Care Foundation has recommended that a sun-block is applied to the fingers and hand before using the lampSuggest why the Skin Care Foundation makes this recommendation (1)

(b) A free radical chain reaction takes place and the varnish hardens (i) State what is meant by the term free radical (1)

(ii) The shellac nail varnish contains a mixture of ingredients that take part in the free radical chain reactionOne of the steps in the free radical chain reaction is

55

State the term used to describe this type of step in a free radical chain reaction(1)

7 Skin care products contain a mixture of polar covalent non-polar covalent and ionic compounds The compounds need to stay mixed within the product Skin care products also need to spread easily and remain on the skin for a period of time as well as provide physical and chemical protection from the sun In order to do this skin care products contain a range of chemicals including water fats and oils antioxidants minerals and sun blockUsing your knowledge of chemistry explain the role of different chemicals in skin care products (3)

General Questions

1 A mixture of carbon monoxide and hydrogen can be converted into water and a mixture of hydrocarbons

nCO + (2n + 1)H2 rarr nH2O + hydrocarbons

What is the general formula for the hydrocarbons producedA CnH2nndash2B CnH2nC CnH2n+1D CnH2n+2

2 Butadiene is the first member of a homologous series of hydrocarbons called dienesWhat is the general formula for this seriesA CnHn+2B CnHn+3C CnH2nD CnH2nndash2

3 Which of the following statements about methanol is falseA It can be made from synthesis gasB It can be dehydrated to form an alkeneC It can be oxidised to give a carboxylic acidD It reacts with acidified potassium dichromate solution

56

4

Which line in the table correctly describes reactions X and Y

5

Which line in the table correctly describes reactions X and Y

6 Which of the following fuels when burned would make no contribution to globalwarming

57

A HydrogenB Natural gasC PetrolD Coal

7 Which of the following hydrocarbons always gives the same product when one of itshydrogen atoms is replaced by a chlorine atomA HexaneB Hex-1-eneC CyclohexaneD Cyclohexene

8 Which of the following compounds does not have isomeric structuresA C2HCl3B C2H4Cl2C PropeneD Propan-1-ol

9 What organic compound is produced by the dehydration of ethanol A EthaneB EtheneC EthanalD Ethanoic acid

10

The above equation representsA hydrationB hydrogenationC condensationD hydrolysis

11

Which of the following compounds is an isomer of the structure shown aboveA ButanalB ButanoneC Butan-1-olD Butanoic acid

58

12 A compound with molecular formula C6H12O2 could beA hexanalB hexan-2-olC hexan-2-oneD hexanoic acid

13 Propan-2-ol can be prepared from propane as follows

Which line in the table correctly describes the types of reaction taking place at Steps 1 and 2

14 Which of the following compounds would be the most water soluble

15 Cyanohydrin compounds can be made from carbonyl compounds by reacting the carbonyl compound with hydrogen cyanide (HCN)

59

Which carbonyl compound would react with hydrogen cyanide (HCN) to form the following compound

16 Ethyne is the first member of the homologous series called the alkynes

Ethyne can undergo addition reactions as shown in the flow diagram

(a) Compound 2 is an isomer of 12-dichloroethaneDraw a structural formula for compound 2 (1)

(b) Reagents A B and C are three different diatomic gasesUsing information in the flow diagram identify reagents A B and C (1)

60

Reagent Gas

A

B

C

17 In 1865 the German chemist Kekuleacute proposed a ring structure for benzene This structure was based on alternating single and double bonds

(a) (i) Describe a chemical test that would indicate that the above chemical structure for benzene is incorrect (1)

(ii) Briefly describe the correct structure for benzene (1)

(b) Benzene can be formed from cyclohexaneC6H12 rarr C6H6 + 3H2

What name is given to this type of reaction (1)18 Infra-red spectroscopy is a technique that can be used to identify the bonds that

arepresent in a molecule Different bonds absorb infra-red radiation of different wavenumbers This is due to differences in the bond lsquostretchrsquo These absorptions are recorded in a spectrumA spectrum for propan-1-ol is shown

61

The correlation table on page 13 of the data booklet shows the wavenumber ranges for the absorptions due to different bonds

(a) Use the correlation table to identify the bonds responsible for the two absorptions x and y that are circled in the propan-1-ol spectrum (1)

(b) Propan-1-ol reacts with ethanoic acid(i) What name is given to this type of reaction (1)(ii) Draw a spectrum that could be obtained for the organic product of this

reaction (1)

19 Paracetamol is a widely used painkiller

(a) Write the molecular formula for paracetamol (1)

(b) One antidote for paracetamol overdose is methionine

62

To what family of organic compounds does methionine belong (1)

(c) The concentration of paracetamol in a solution can be determined by measuring how much UV radiation it absorbs

The graph shows how the absorbance of a sample containing 0middot040 g l ndash1 paracetamol varies with wavelength

The quantity of UV radiation of wavelength 245 nm absorbed is directly proportional to the concentration of paracetamolThe absorbance of a second sample of paracetamol solution measured at 245 nm was 0middot90 What is the concentration in g l ndash1 of this second paracetamol solution (1)

20 Many carbon compounds containing oxygen are very flammableThe table shows information about two families of isomersThe lowest temperature at which a compound will ignite is called its flash point

(a) A compound with the molecular formula C6H14O has a boiling point of 158 degC63

Draw a structural formula for this compound (1)

(b) For a family of isomers in the table write a general statement linking the flash points of the compounds to their structures (1)

21 Hydrogels are used in disposable nappies They are fine powders that can absorb up to 500 times their own weight in waterA hydrogel is a very long molecule with carboxyl groups at regular intervals along its length A short section of a hydrogel molecule is shown below

Hydrogels are extremely good at soaking up water because the water molecules are strongly attracted to them

Using your knowledge of chemistry comment on how suitable hydrogels would be for absorbing liquids or solutions spilled in a chemistry lab (1)

64

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

13 Which two isomers would each produce an acid when warmed with acidified potassiumdichromate solution

A 1 and 2B 2 and 3C 1 and 4D 3 and 4

14 After heating for several minutes as shown in the diagram the pH indicator solution turned red

Liquid Q could beA propanoneB paraffinC propan-1-olD propan-2-ol

29

15 Enzymes are involved in the browning of cut fruitOne reaction taking place is

Which of the following correctly describes the above reaction

A OxidationB ReductionC HydrolysisD Condensation

16 Which of the following statements is correct for ketones

A They are formed by oxidation of tertiary alcohols

B They contain the group

C They contain a carboxyl groupD They will not react with Fehlingrsquos solution

17 Carvone is a natural product that can be extracted from orange peel

Which line in the table correctly describes the reaction of carvone with bromine solution and with acidified potassium dichromate solution

30

18 Which of the following is an isomer of 22-dimethylpentan-1-ol

A CH3CH2CH2CH(CH3)CH2OHB (CH3)3CCH(CH3)CH2OHC CH3CH2CH2CH2CH2CH2CH2CH2OHD (CH3)2CHC(CH3)2CH2CH2OH

19 The equation for the reduction reaction taking place when ethanal reacts with Tollensrsquo reagent is

A Cu2+(aq) + eminus rarr Cu+(aq)

B Ag+(aq) + eminus rarr Ag(s)

C Cr2O72minus(aq) + 14H+(aq) + 6eminus rarr 2Cr3+(aq) + 7H2O(ℓ)

D MnO4minus(aq) + 8H+(aq) + 5eminus rarr Mn2+(aq) + 4H2O(ℓ)

20 The name of the compound with structure

isA 23-dimethylpentan-4-oneB 23-dimethylpentan-2-alC 34-dimethylpentan-2-oneD 34-dimethylpentan-2-al

21 What is the systematic name for the compound below

A 222-trimethylethanolB 22-dimethylpropan-1-olC 22-dimethylpropan-3-olD 22-dimethylpentan-1-ol

31

22 The structure of a molecule found in olive oil can be represented as shown

(a) Olive oil can be hydrolysed using sodium hydroxide solution to produce sodium salts of fatty acids Name the other product of this reaction (1)

(b) In what way does the structure of a fat molecule differ from that of an oil molecule (1)

(c) Over time open containers of olive oil develop a rancid flavour What substance is reacting with the oil to cause these unwanted changes to take place (1)

23 A student writes the following statement It is incorrect Explain the mistake in the studentrsquos reasoning (1)

Alcohols are alkaline because of their OH groups

24 Carbon compounds take part in a wide variety of chemical reactions (a)

Name this type of chemical reaction (1)

(b)

Draw a structural formula for C3H6O (1)

25 Alkanols can be oxidised to alkanoic acids

32

(a) Why can Step 1 be described as an oxidation reaction (1)

(b) Acidified potassium dichromate solution can be used to oxidise propanal in Step 2 What colour change would be observed in this reaction (1)

26 Amines can be produced by reacting ammonia with an aldehyde or a ketone This reaction an example of reductive amination occurs in two stages

Stage 1 Amination

Stage 2 Reduction

(a) Give another name for the type of reaction taking place in Stage 2

(b) Draw the structural formula for the amine produced when butanal undergoes reductive amination with ammonia

27 Using a cobalt catalyst alkenes react with a mixture of hydrogen and carbon monoxideThe products are two isomeric aldehydes Propene reacts with the mixture as shown

(a) What name is given to a mixture of hydrogen and carbon monoxide (1)

(b) Draw a structural formula for compound B (1)

(c) (i) What would be observed if compound A was gently heated with Tollensrsquo reagent

(1)(ii) How would the reaction mixture be heated (1)

33

(d) Aldehydes can also be formed by the reaction of some alcohols with copper(II) oxideName the type of alcohol that would react with copper(II) oxide to form an aldehyde (1)

28 Aldehydes and ketones can take part in a reaction sometimes known as an aldol condensation The simplest aldol reaction involves two molecules of ethanal

In the reaction the carbon atom next to the carbonyl functional group of one molecule forms a bond with the carbonyl carbon atom of the second molecule

(a) Draw a structural formula for the product formed when propanone is used instead of ethanal in this type of reaction (1)

(b) Name an aldehyde that would not take part in an aldol condensation (1)

(c) Apart from the structure of the reactants suggest what is unusual about applying the term ldquocondensationrdquo to this particular type of reaction (1)

29 Primary secondary and tertiary alkanols can be prepared by the reaction of carbonyl compounds with Grignard reagents

Step 1The Grignard reagent reacts with the carbonyl compound

Step 2The reaction of the product of Step 1 with dilute acid produces the alkanol

(a) Describe the difference between a primary a secondary and a tertiary alkanol

You may wish to include labelled structures in your answer (1)34

(b) Suggest a name for the type of reaction that takes place in Step 1 (1)

(c) The same Grignard reagent can be used to produce the alkanol below

Name the carbonyl compound used in this reaction (1)

30 Hairspray is a mixture of chemicals(a) A primary alcohol 2-methylpropan-1-ol is added to hairspray to help it dry quickly on the hair

Draw a structural formula for a secondary alcohol that is an isomer of2-methylpropan-1-ol (1)

(b) Triethanol amine and triisopropyl amine are bases used to neutralise acidic compounds in the hairspray to prevent damage to the hair

In terms of the intermolecular bonding present explain clearly why triethanol amine has a much higher boiling point than triisopropyl amine (2)

35

36

31 Chocolate contains various compounds(a) Many of the flavour and aroma molecules found in chocolate are aldehydes and

ketones Two examples are shown below

Phenylethanal can be easily oxidised but 13-diphenylpropan-2-one cannot(i) Name a chemical that could be used to distinguish between these two

compounds (1)

(ii) Name the type of organic compound formed when phenylethanal is oxidised (1)

(b) Glycerol monostearate is an emulsifier used in chocolate

(i) Why is glycerol monostearate added to chocolate (1)

(ii) Draw a structural formula for glycerol (1)

(c) Theobromine a compound present in chocolate can cause illness in dogs and cats To decide if treatment is necessary vets must calculate the mass of theobromine consumed 1middot0 g of chocolate contains 1middot4 mg of theobromine Calculate the mass in mg of theobromine in a 17 g biscuit of which 28 is chocolate Show your working clearly (2)

(d) The flavour and texture of chocolate comes from a blend of compoundsUsing your knowledge of chemistry describe how you could show that there are ionic compounds and covalent compounds present in chocolate (3)

37

32 Ethanol has many uses

(a) Ethanol is found at relatively low concentrations in wine

(i) Name the chemical reaction that produces ethanol in wine (1)

(ii) Standard ethanol solutions were used to produce a graph of density against

concentration of ethanol given as a percentage of alcohol by volume ( abv)

What is the concentration of ethanol in units of abv in a solution of density 0middot9818 g cmminus3 (1)

(b) Whisky contains a higher concentration of ethanol

(i) Before 1980 the concentration of alcohol in drinks was measured in terms of degrees proof The concentration of alcohol in two drinks is shown in the table below both as abv and degrees proof

38

A cask strength whisky has an alcohol concentration of 65 abv Calculate the alcohol concentration of this whisky in degrees proof (1)

(ii) A barrel containing 195 litres of cask strength whisky costs pound1300 The cask strength whisky is diluted with water to reduce the concentration of alcohol from 65 abv to 46 abv before it is bottled Calculate the cost of the cask strength whisky needed to produce a 0middot70 litre bottle Show your working clearly (2)

(iii) 5-Butyl-4-methyltetrahydrofuran-2-ol is a flavour compound found in whisky

stored in oak barrels

Write the systematic name for the compound shown below (1) 13 11

33 (a) One test for glucose involves Fehlingrsquos solutionCircle the part of the glucose molecule that reacts with Fehlingrsquos solution (1)

(b) In solution sugar molecules exist in an equilibrium in straight-chain and ring forms

To change from the straight-chain form to the ring form the oxygen of the hydroxyl on carbon number 5 joins to the carbonyl carbon This is shown below for glucose

39

Draw the structure of a ring form for fructose (1)

34 (a) During the free radical chain reaction small molecules join to form large chain molecules

One example of a small molecule used is

Name the functional group circled above (1)

(b)Alcohol wipes are used to finish the varnishing treatment Alcohol wipes contain the alcohol propan-2-olState why propan-2-ol can be described as a secondary alcohol (1)

35 A student was carrying out an investigation into alcohols aldehydes and ketones

(a)The student was given three alcohols labelled as A B and C These alcohols were all isomers with the formula C4H9OH

(i) Draw a structural formula for the secondary alcohol with the formula C4H9OH(1)

(ii) The student set up the following experiment

A Suggest why a water bath is an appropriate method of heating the reaction mixture (1)

B Describe the colour change that would have been observed with alcohols A and C (1)

40

C Alcohol B is not oxidised State the type of alcohol which cannot be oxidised by acidified dichromate solution (1)

(iii) The student set up a second experiment with alcohol A

Hot copper(II) oxide is an oxidising agentA When alcohol A (C4H9OH) is oxidised the product turns the pH paper

redSuggest a name for the product (1)

B Complete the ion-electron equation for the oxidation reaction

C4H9OH rarr C4H8O2 (1)

(b)The student found the following information about the boiling points of some aldehydes

41

(i) Name the aldehyde that has a boiling point of 119 degC (1)(ii) Predict the boiling point in degC of the following molecule (1)

(iii) Using information from the table describe one way in which differences in structure affect the boiling point of isomeric aldehydes (1)

(iv) State what would be observed when an aldehyde is gently heated with Tollensrsquo reagent (1)

(c) Ketones contain a carbonyl groupName the type of intermolecular interaction between ketone molecules (1)

42

25 Soaps Detergents and Emulsions

1 Soaps are produced by the following reaction

This reaction is an example ofA condensationB esterificationC hydrolysisD oxidation

2 Which of the following is the salt of a long-chain fatty acid

A FatB OilC SoapD Glycerol

3 Emulsifiers for use in food are commonly made by reacting edible oils with

A estersB glycerolC fatty acidsD amino acids

4 A fatty acid is a long chain carboxylic acid Examples of fatty acids are shown in the table below

43

(a) What is the systematic name for linolenic acid (1)(b) Stearic acid reacts with sodium hydroxide solution to form sodium stearate

(i) Name the type of reaction taking place when stearic acid reacts with sodium hydroxide (1)

(ii) Explain fully how sodium stearate acts to keep grease and non-polar substances suspended in water during cleaning (3)

5 Small children can find it difficult to swallow tablets or pills so ibuprofen is supplied as an ldquoinfant formulardquo emulsion(a) The emulsifier used is polysorbate 80 Its structure is shown below

Explain why this molecule acts as an emulsifier (2)

(b) The emulsion contains 2 g of ibuprofen in every 100 cm3 of emulsion The recommended dose for treating a 6 month old baby is 0middot050 g Calculate the volume in cm3 of ldquoinfant formulardquo needed to treat a 6 month old baby (1)

6 Occasionally seabirds can become contaminated with hydrocarbons from oil spills This causes problems for birds because their feathers lose their waterproofing making the birds susceptible to temperature changes and

44

affecting their buoyancy If the birds attempt to clean themselves to remove the oil they may swallow the hydrocarbons causing damage to their internal organsContaminated seabirds can be cleaned by rubbing vegetable oil into their feathers and feet before the birds are rinsed with diluted washing-up liquidUsing your knowledge of chemistry comment on the problems created for seabirds by oil spills and the actions taken to treat affected birds (3)

7 Dishwasher tablets contain chemicals which remove dirt from dishesDishwasher tablets include detergents These molecules act like soaps to allow mixing of fat-soluble dirt and water(a)During the cleaning process the detergent molecules combine with fat-

soluble dirtA simplified diagram of a detergent molecule is shown

Complete the diagram below to show how detergent molecules combine with fat-soluble dirt (1)

(b)State the term used to describe the non-polar hydrocarbon tail of a detergent molecule (1)

45

26 Fragrances1 Myrcene is a simple terpene

Terpenes contain at least one isoprene unit Which of the following shows a correctly highlighted isoprene unit

2 Limonene is one of the terpene molecules responsible for the flavour of lemons

How many isoprene units are used in the production of one limonene moleculeA 1B 2C 3D 4

46

3 The structure of caryophyllene which can be extracted from clove oil is

Which of the following would be the best solvent for extracting caryophylleneA HexaneB HexanalC HexanolD Hexanone

4 The structure of isoprene is

Limonene is a terpene molecule present in lemons

How many isoprene units are joined together in a limonene molecule

A 1B 2

47

C 3D 4

5 Essential oils are

A non-water soluble non-volatile compoundsB non-water soluble volatile compoundsC water soluble non-volatile compoundsD water soluble volatile compounds

6 Two typical compounds that are present in many perfumes are shown

(a) Why does geraniol evaporate more slowly than limonene (1)

(b) The structure of one of the first synthetic scents used in perfume is shown below

(i) Name the family of carbonyl compounds to which this synthetic scent belongs (1)

(ii) Complete the structure below to show the product formed when this scent is

oxidised (1)

(c) Traces of a liquid were discovered in a bottle believed to contain perfume belonging to Queen Hatshepsut ruler of Egypt over 3500 years ago

Perfumes were made by dissolving plant extracts containing pleasant smelling terpenes and esters in an edible oil A little ethanol and water may also have been addedUsing your knowledge of chemistry comment on the possible smell(s) when such a bottle is opened after being stored for thousands of years (3)

48

49

7 A team of chemists are developing a fragrance for use in a shower gel for men(a) To give the gel a fruity smell the chemists are considering adding an ester

They synthesise six isomeric esters Volunteers smell each ester and give it a rating out of one hundred depending on how fruity the smell is

(i) Name the ester with the fruit-smell rating of 92 (1)

(ii) Shown below are the structures of three more isomers

Arrange these esters in order of decreasing fruit-smell rating (1)

50

(b) To create a fragrance for men the compound civetone is added

Draw a structural formula for the alcohol that can be oxidised to form civetone (1)

(c) To make the shower gel produce a cold tingling sensation when applied to the skin menthol is added

Like terpenes menthol is formed from isoprene (2-methylbuta-13-diene)Circle an isoprene unit on the menthol structure above (1)

8 Many of the compounds in perfumes are molecules consisting of joined isoprene units

(a) State the name that is given to molecules consisting of joined isoprene units (1)

(b)Geraniol is one of the compounds found in perfume It has the following structural formula and systematic name

Linalool can also be present Its structural formula is shown

51

(i) State the systematic name for linalool (1)(ii) Explain why linalool can be classified as a tertiary alcohol (1)

9 The component molecules found in lavender oils are terpenes or terpenoids(a)A chiral carbon is a carbon atom attached to four different atoms or groups of

atomsAn example is shown below

A molecule of the terpenoid linalool has a chiral carbon Linalool has the following structure

Circle the chiral carbon atom in the linalool structure (1)

(b)Farnesene is a terpene consisting of three isoprene units (2-methylbuta-13-diene) joined togetherWrite the molecular formula of farnesene (1)

52

27 Skin Care

1 Which of the following is not a step in a free radical chain reaction

A ActivationB InitiationC PropagationD Termination

2 Fluorine reacts with methane via a free radical chain reaction Some steps in the chain reaction are shown in the table below

Complete the table by(a) inserting the missing name for the first step (1)

(b) showing another possible termination reaction in the final row of the table (1)

3 Suncreams contain antioxidantsThe antioxidant compound A can prevent damage to skin by reacting with free

radicalssuch as NO2bull

53

Why can compound A be described as a free radical scavenger in the reaction shown above

4 Hydrogen and chlorine gases are used in an experiment to demonstrate a free radical reaction A plastic bottle is wrapped with black tape leaving a ldquowindowrdquo on one sideThe bottle is filled with a mixture of hydrogen and chlorine When bright light shines on the bottle there is an explosion

A free radical chain reaction is initiated when light energy causes chlorine radicals to form as shown below

(a) Complete the equations below showing possible propagation and termination steps

(2)

54

(b) Why is the plastic bottle used in the experiment wrapped in black tape (1)

5 Chloramines can be removed from water using ultraviolet light treatment

One step in the process is the formation of free radicals

(a)State what is meant by the term free radical (1)

(b)Another step in the process is shown below

State the name for this type of step in a free radical reaction (1)

6 Modern shellac nail varnishes are more durable and so last longer than traditional nail polish

The shellac nail varnish is applied in thin layers to the nails and then the fingers are placed under a UV lamp

(a) The Skin Care Foundation has recommended that a sun-block is applied to the fingers and hand before using the lampSuggest why the Skin Care Foundation makes this recommendation (1)

(b) A free radical chain reaction takes place and the varnish hardens (i) State what is meant by the term free radical (1)

(ii) The shellac nail varnish contains a mixture of ingredients that take part in the free radical chain reactionOne of the steps in the free radical chain reaction is

55

State the term used to describe this type of step in a free radical chain reaction(1)

7 Skin care products contain a mixture of polar covalent non-polar covalent and ionic compounds The compounds need to stay mixed within the product Skin care products also need to spread easily and remain on the skin for a period of time as well as provide physical and chemical protection from the sun In order to do this skin care products contain a range of chemicals including water fats and oils antioxidants minerals and sun blockUsing your knowledge of chemistry explain the role of different chemicals in skin care products (3)

General Questions

1 A mixture of carbon monoxide and hydrogen can be converted into water and a mixture of hydrocarbons

nCO + (2n + 1)H2 rarr nH2O + hydrocarbons

What is the general formula for the hydrocarbons producedA CnH2nndash2B CnH2nC CnH2n+1D CnH2n+2

2 Butadiene is the first member of a homologous series of hydrocarbons called dienesWhat is the general formula for this seriesA CnHn+2B CnHn+3C CnH2nD CnH2nndash2

3 Which of the following statements about methanol is falseA It can be made from synthesis gasB It can be dehydrated to form an alkeneC It can be oxidised to give a carboxylic acidD It reacts with acidified potassium dichromate solution

56

4

Which line in the table correctly describes reactions X and Y

5

Which line in the table correctly describes reactions X and Y

6 Which of the following fuels when burned would make no contribution to globalwarming

57

A HydrogenB Natural gasC PetrolD Coal

7 Which of the following hydrocarbons always gives the same product when one of itshydrogen atoms is replaced by a chlorine atomA HexaneB Hex-1-eneC CyclohexaneD Cyclohexene

8 Which of the following compounds does not have isomeric structuresA C2HCl3B C2H4Cl2C PropeneD Propan-1-ol

9 What organic compound is produced by the dehydration of ethanol A EthaneB EtheneC EthanalD Ethanoic acid

10

The above equation representsA hydrationB hydrogenationC condensationD hydrolysis

11

Which of the following compounds is an isomer of the structure shown aboveA ButanalB ButanoneC Butan-1-olD Butanoic acid

58

12 A compound with molecular formula C6H12O2 could beA hexanalB hexan-2-olC hexan-2-oneD hexanoic acid

13 Propan-2-ol can be prepared from propane as follows

Which line in the table correctly describes the types of reaction taking place at Steps 1 and 2

14 Which of the following compounds would be the most water soluble

15 Cyanohydrin compounds can be made from carbonyl compounds by reacting the carbonyl compound with hydrogen cyanide (HCN)

59

Which carbonyl compound would react with hydrogen cyanide (HCN) to form the following compound

16 Ethyne is the first member of the homologous series called the alkynes

Ethyne can undergo addition reactions as shown in the flow diagram

(a) Compound 2 is an isomer of 12-dichloroethaneDraw a structural formula for compound 2 (1)

(b) Reagents A B and C are three different diatomic gasesUsing information in the flow diagram identify reagents A B and C (1)

60

Reagent Gas

A

B

C

17 In 1865 the German chemist Kekuleacute proposed a ring structure for benzene This structure was based on alternating single and double bonds

(a) (i) Describe a chemical test that would indicate that the above chemical structure for benzene is incorrect (1)

(ii) Briefly describe the correct structure for benzene (1)

(b) Benzene can be formed from cyclohexaneC6H12 rarr C6H6 + 3H2

What name is given to this type of reaction (1)18 Infra-red spectroscopy is a technique that can be used to identify the bonds that

arepresent in a molecule Different bonds absorb infra-red radiation of different wavenumbers This is due to differences in the bond lsquostretchrsquo These absorptions are recorded in a spectrumA spectrum for propan-1-ol is shown

61

The correlation table on page 13 of the data booklet shows the wavenumber ranges for the absorptions due to different bonds

(a) Use the correlation table to identify the bonds responsible for the two absorptions x and y that are circled in the propan-1-ol spectrum (1)

(b) Propan-1-ol reacts with ethanoic acid(i) What name is given to this type of reaction (1)(ii) Draw a spectrum that could be obtained for the organic product of this

reaction (1)

19 Paracetamol is a widely used painkiller

(a) Write the molecular formula for paracetamol (1)

(b) One antidote for paracetamol overdose is methionine

62

To what family of organic compounds does methionine belong (1)

(c) The concentration of paracetamol in a solution can be determined by measuring how much UV radiation it absorbs

The graph shows how the absorbance of a sample containing 0middot040 g l ndash1 paracetamol varies with wavelength

The quantity of UV radiation of wavelength 245 nm absorbed is directly proportional to the concentration of paracetamolThe absorbance of a second sample of paracetamol solution measured at 245 nm was 0middot90 What is the concentration in g l ndash1 of this second paracetamol solution (1)

20 Many carbon compounds containing oxygen are very flammableThe table shows information about two families of isomersThe lowest temperature at which a compound will ignite is called its flash point

(a) A compound with the molecular formula C6H14O has a boiling point of 158 degC63

Draw a structural formula for this compound (1)

(b) For a family of isomers in the table write a general statement linking the flash points of the compounds to their structures (1)

21 Hydrogels are used in disposable nappies They are fine powders that can absorb up to 500 times their own weight in waterA hydrogel is a very long molecule with carboxyl groups at regular intervals along its length A short section of a hydrogel molecule is shown below

Hydrogels are extremely good at soaking up water because the water molecules are strongly attracted to them

Using your knowledge of chemistry comment on how suitable hydrogels would be for absorbing liquids or solutions spilled in a chemistry lab (1)

64

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

15 Enzymes are involved in the browning of cut fruitOne reaction taking place is

Which of the following correctly describes the above reaction

A OxidationB ReductionC HydrolysisD Condensation

16 Which of the following statements is correct for ketones

A They are formed by oxidation of tertiary alcohols

B They contain the group

C They contain a carboxyl groupD They will not react with Fehlingrsquos solution

17 Carvone is a natural product that can be extracted from orange peel

Which line in the table correctly describes the reaction of carvone with bromine solution and with acidified potassium dichromate solution

30

18 Which of the following is an isomer of 22-dimethylpentan-1-ol

A CH3CH2CH2CH(CH3)CH2OHB (CH3)3CCH(CH3)CH2OHC CH3CH2CH2CH2CH2CH2CH2CH2OHD (CH3)2CHC(CH3)2CH2CH2OH

19 The equation for the reduction reaction taking place when ethanal reacts with Tollensrsquo reagent is

A Cu2+(aq) + eminus rarr Cu+(aq)

B Ag+(aq) + eminus rarr Ag(s)

C Cr2O72minus(aq) + 14H+(aq) + 6eminus rarr 2Cr3+(aq) + 7H2O(ℓ)

D MnO4minus(aq) + 8H+(aq) + 5eminus rarr Mn2+(aq) + 4H2O(ℓ)

20 The name of the compound with structure

isA 23-dimethylpentan-4-oneB 23-dimethylpentan-2-alC 34-dimethylpentan-2-oneD 34-dimethylpentan-2-al

21 What is the systematic name for the compound below

A 222-trimethylethanolB 22-dimethylpropan-1-olC 22-dimethylpropan-3-olD 22-dimethylpentan-1-ol

31

22 The structure of a molecule found in olive oil can be represented as shown

(a) Olive oil can be hydrolysed using sodium hydroxide solution to produce sodium salts of fatty acids Name the other product of this reaction (1)

(b) In what way does the structure of a fat molecule differ from that of an oil molecule (1)

(c) Over time open containers of olive oil develop a rancid flavour What substance is reacting with the oil to cause these unwanted changes to take place (1)

23 A student writes the following statement It is incorrect Explain the mistake in the studentrsquos reasoning (1)

Alcohols are alkaline because of their OH groups

24 Carbon compounds take part in a wide variety of chemical reactions (a)

Name this type of chemical reaction (1)

(b)

Draw a structural formula for C3H6O (1)

25 Alkanols can be oxidised to alkanoic acids

32

(a) Why can Step 1 be described as an oxidation reaction (1)

(b) Acidified potassium dichromate solution can be used to oxidise propanal in Step 2 What colour change would be observed in this reaction (1)

26 Amines can be produced by reacting ammonia with an aldehyde or a ketone This reaction an example of reductive amination occurs in two stages

Stage 1 Amination

Stage 2 Reduction

(a) Give another name for the type of reaction taking place in Stage 2

(b) Draw the structural formula for the amine produced when butanal undergoes reductive amination with ammonia

27 Using a cobalt catalyst alkenes react with a mixture of hydrogen and carbon monoxideThe products are two isomeric aldehydes Propene reacts with the mixture as shown

(a) What name is given to a mixture of hydrogen and carbon monoxide (1)

(b) Draw a structural formula for compound B (1)

(c) (i) What would be observed if compound A was gently heated with Tollensrsquo reagent

(1)(ii) How would the reaction mixture be heated (1)

33

(d) Aldehydes can also be formed by the reaction of some alcohols with copper(II) oxideName the type of alcohol that would react with copper(II) oxide to form an aldehyde (1)

28 Aldehydes and ketones can take part in a reaction sometimes known as an aldol condensation The simplest aldol reaction involves two molecules of ethanal

In the reaction the carbon atom next to the carbonyl functional group of one molecule forms a bond with the carbonyl carbon atom of the second molecule

(a) Draw a structural formula for the product formed when propanone is used instead of ethanal in this type of reaction (1)

(b) Name an aldehyde that would not take part in an aldol condensation (1)

(c) Apart from the structure of the reactants suggest what is unusual about applying the term ldquocondensationrdquo to this particular type of reaction (1)

29 Primary secondary and tertiary alkanols can be prepared by the reaction of carbonyl compounds with Grignard reagents

Step 1The Grignard reagent reacts with the carbonyl compound

Step 2The reaction of the product of Step 1 with dilute acid produces the alkanol

(a) Describe the difference between a primary a secondary and a tertiary alkanol

You may wish to include labelled structures in your answer (1)34

(b) Suggest a name for the type of reaction that takes place in Step 1 (1)

(c) The same Grignard reagent can be used to produce the alkanol below

Name the carbonyl compound used in this reaction (1)

30 Hairspray is a mixture of chemicals(a) A primary alcohol 2-methylpropan-1-ol is added to hairspray to help it dry quickly on the hair

Draw a structural formula for a secondary alcohol that is an isomer of2-methylpropan-1-ol (1)

(b) Triethanol amine and triisopropyl amine are bases used to neutralise acidic compounds in the hairspray to prevent damage to the hair

In terms of the intermolecular bonding present explain clearly why triethanol amine has a much higher boiling point than triisopropyl amine (2)

35

36

31 Chocolate contains various compounds(a) Many of the flavour and aroma molecules found in chocolate are aldehydes and

ketones Two examples are shown below

Phenylethanal can be easily oxidised but 13-diphenylpropan-2-one cannot(i) Name a chemical that could be used to distinguish between these two

compounds (1)

(ii) Name the type of organic compound formed when phenylethanal is oxidised (1)

(b) Glycerol monostearate is an emulsifier used in chocolate

(i) Why is glycerol monostearate added to chocolate (1)

(ii) Draw a structural formula for glycerol (1)

(c) Theobromine a compound present in chocolate can cause illness in dogs and cats To decide if treatment is necessary vets must calculate the mass of theobromine consumed 1middot0 g of chocolate contains 1middot4 mg of theobromine Calculate the mass in mg of theobromine in a 17 g biscuit of which 28 is chocolate Show your working clearly (2)

(d) The flavour and texture of chocolate comes from a blend of compoundsUsing your knowledge of chemistry describe how you could show that there are ionic compounds and covalent compounds present in chocolate (3)

37

32 Ethanol has many uses

(a) Ethanol is found at relatively low concentrations in wine

(i) Name the chemical reaction that produces ethanol in wine (1)

(ii) Standard ethanol solutions were used to produce a graph of density against

concentration of ethanol given as a percentage of alcohol by volume ( abv)

What is the concentration of ethanol in units of abv in a solution of density 0middot9818 g cmminus3 (1)

(b) Whisky contains a higher concentration of ethanol

(i) Before 1980 the concentration of alcohol in drinks was measured in terms of degrees proof The concentration of alcohol in two drinks is shown in the table below both as abv and degrees proof

38

A cask strength whisky has an alcohol concentration of 65 abv Calculate the alcohol concentration of this whisky in degrees proof (1)

(ii) A barrel containing 195 litres of cask strength whisky costs pound1300 The cask strength whisky is diluted with water to reduce the concentration of alcohol from 65 abv to 46 abv before it is bottled Calculate the cost of the cask strength whisky needed to produce a 0middot70 litre bottle Show your working clearly (2)

(iii) 5-Butyl-4-methyltetrahydrofuran-2-ol is a flavour compound found in whisky

stored in oak barrels

Write the systematic name for the compound shown below (1) 13 11

33 (a) One test for glucose involves Fehlingrsquos solutionCircle the part of the glucose molecule that reacts with Fehlingrsquos solution (1)

(b) In solution sugar molecules exist in an equilibrium in straight-chain and ring forms

To change from the straight-chain form to the ring form the oxygen of the hydroxyl on carbon number 5 joins to the carbonyl carbon This is shown below for glucose

39

Draw the structure of a ring form for fructose (1)

34 (a) During the free radical chain reaction small molecules join to form large chain molecules

One example of a small molecule used is

Name the functional group circled above (1)

(b)Alcohol wipes are used to finish the varnishing treatment Alcohol wipes contain the alcohol propan-2-olState why propan-2-ol can be described as a secondary alcohol (1)

35 A student was carrying out an investigation into alcohols aldehydes and ketones

(a)The student was given three alcohols labelled as A B and C These alcohols were all isomers with the formula C4H9OH

(i) Draw a structural formula for the secondary alcohol with the formula C4H9OH(1)

(ii) The student set up the following experiment

A Suggest why a water bath is an appropriate method of heating the reaction mixture (1)

B Describe the colour change that would have been observed with alcohols A and C (1)

40

C Alcohol B is not oxidised State the type of alcohol which cannot be oxidised by acidified dichromate solution (1)

(iii) The student set up a second experiment with alcohol A

Hot copper(II) oxide is an oxidising agentA When alcohol A (C4H9OH) is oxidised the product turns the pH paper

redSuggest a name for the product (1)

B Complete the ion-electron equation for the oxidation reaction

C4H9OH rarr C4H8O2 (1)

(b)The student found the following information about the boiling points of some aldehydes

41

(i) Name the aldehyde that has a boiling point of 119 degC (1)(ii) Predict the boiling point in degC of the following molecule (1)

(iii) Using information from the table describe one way in which differences in structure affect the boiling point of isomeric aldehydes (1)

(iv) State what would be observed when an aldehyde is gently heated with Tollensrsquo reagent (1)

(c) Ketones contain a carbonyl groupName the type of intermolecular interaction between ketone molecules (1)

42

25 Soaps Detergents and Emulsions

1 Soaps are produced by the following reaction

This reaction is an example ofA condensationB esterificationC hydrolysisD oxidation

2 Which of the following is the salt of a long-chain fatty acid

A FatB OilC SoapD Glycerol

3 Emulsifiers for use in food are commonly made by reacting edible oils with

A estersB glycerolC fatty acidsD amino acids

4 A fatty acid is a long chain carboxylic acid Examples of fatty acids are shown in the table below

43

(a) What is the systematic name for linolenic acid (1)(b) Stearic acid reacts with sodium hydroxide solution to form sodium stearate

(i) Name the type of reaction taking place when stearic acid reacts with sodium hydroxide (1)

(ii) Explain fully how sodium stearate acts to keep grease and non-polar substances suspended in water during cleaning (3)

5 Small children can find it difficult to swallow tablets or pills so ibuprofen is supplied as an ldquoinfant formulardquo emulsion(a) The emulsifier used is polysorbate 80 Its structure is shown below

Explain why this molecule acts as an emulsifier (2)

(b) The emulsion contains 2 g of ibuprofen in every 100 cm3 of emulsion The recommended dose for treating a 6 month old baby is 0middot050 g Calculate the volume in cm3 of ldquoinfant formulardquo needed to treat a 6 month old baby (1)

6 Occasionally seabirds can become contaminated with hydrocarbons from oil spills This causes problems for birds because their feathers lose their waterproofing making the birds susceptible to temperature changes and

44

affecting their buoyancy If the birds attempt to clean themselves to remove the oil they may swallow the hydrocarbons causing damage to their internal organsContaminated seabirds can be cleaned by rubbing vegetable oil into their feathers and feet before the birds are rinsed with diluted washing-up liquidUsing your knowledge of chemistry comment on the problems created for seabirds by oil spills and the actions taken to treat affected birds (3)

7 Dishwasher tablets contain chemicals which remove dirt from dishesDishwasher tablets include detergents These molecules act like soaps to allow mixing of fat-soluble dirt and water(a)During the cleaning process the detergent molecules combine with fat-

soluble dirtA simplified diagram of a detergent molecule is shown

Complete the diagram below to show how detergent molecules combine with fat-soluble dirt (1)

(b)State the term used to describe the non-polar hydrocarbon tail of a detergent molecule (1)

45

26 Fragrances1 Myrcene is a simple terpene

Terpenes contain at least one isoprene unit Which of the following shows a correctly highlighted isoprene unit

2 Limonene is one of the terpene molecules responsible for the flavour of lemons

How many isoprene units are used in the production of one limonene moleculeA 1B 2C 3D 4

46

3 The structure of caryophyllene which can be extracted from clove oil is

Which of the following would be the best solvent for extracting caryophylleneA HexaneB HexanalC HexanolD Hexanone

4 The structure of isoprene is

Limonene is a terpene molecule present in lemons

How many isoprene units are joined together in a limonene molecule

A 1B 2

47

C 3D 4

5 Essential oils are

A non-water soluble non-volatile compoundsB non-water soluble volatile compoundsC water soluble non-volatile compoundsD water soluble volatile compounds

6 Two typical compounds that are present in many perfumes are shown

(a) Why does geraniol evaporate more slowly than limonene (1)

(b) The structure of one of the first synthetic scents used in perfume is shown below

(i) Name the family of carbonyl compounds to which this synthetic scent belongs (1)

(ii) Complete the structure below to show the product formed when this scent is

oxidised (1)

(c) Traces of a liquid were discovered in a bottle believed to contain perfume belonging to Queen Hatshepsut ruler of Egypt over 3500 years ago

Perfumes were made by dissolving plant extracts containing pleasant smelling terpenes and esters in an edible oil A little ethanol and water may also have been addedUsing your knowledge of chemistry comment on the possible smell(s) when such a bottle is opened after being stored for thousands of years (3)

48

49

7 A team of chemists are developing a fragrance for use in a shower gel for men(a) To give the gel a fruity smell the chemists are considering adding an ester

They synthesise six isomeric esters Volunteers smell each ester and give it a rating out of one hundred depending on how fruity the smell is

(i) Name the ester with the fruit-smell rating of 92 (1)

(ii) Shown below are the structures of three more isomers

Arrange these esters in order of decreasing fruit-smell rating (1)

50

(b) To create a fragrance for men the compound civetone is added

Draw a structural formula for the alcohol that can be oxidised to form civetone (1)

(c) To make the shower gel produce a cold tingling sensation when applied to the skin menthol is added

Like terpenes menthol is formed from isoprene (2-methylbuta-13-diene)Circle an isoprene unit on the menthol structure above (1)

8 Many of the compounds in perfumes are molecules consisting of joined isoprene units

(a) State the name that is given to molecules consisting of joined isoprene units (1)

(b)Geraniol is one of the compounds found in perfume It has the following structural formula and systematic name

Linalool can also be present Its structural formula is shown

51

(i) State the systematic name for linalool (1)(ii) Explain why linalool can be classified as a tertiary alcohol (1)

9 The component molecules found in lavender oils are terpenes or terpenoids(a)A chiral carbon is a carbon atom attached to four different atoms or groups of

atomsAn example is shown below

A molecule of the terpenoid linalool has a chiral carbon Linalool has the following structure

Circle the chiral carbon atom in the linalool structure (1)

(b)Farnesene is a terpene consisting of three isoprene units (2-methylbuta-13-diene) joined togetherWrite the molecular formula of farnesene (1)

52

27 Skin Care

1 Which of the following is not a step in a free radical chain reaction

A ActivationB InitiationC PropagationD Termination

2 Fluorine reacts with methane via a free radical chain reaction Some steps in the chain reaction are shown in the table below

Complete the table by(a) inserting the missing name for the first step (1)

(b) showing another possible termination reaction in the final row of the table (1)

3 Suncreams contain antioxidantsThe antioxidant compound A can prevent damage to skin by reacting with free

radicalssuch as NO2bull

53

Why can compound A be described as a free radical scavenger in the reaction shown above

4 Hydrogen and chlorine gases are used in an experiment to demonstrate a free radical reaction A plastic bottle is wrapped with black tape leaving a ldquowindowrdquo on one sideThe bottle is filled with a mixture of hydrogen and chlorine When bright light shines on the bottle there is an explosion

A free radical chain reaction is initiated when light energy causes chlorine radicals to form as shown below

(a) Complete the equations below showing possible propagation and termination steps

(2)

54

(b) Why is the plastic bottle used in the experiment wrapped in black tape (1)

5 Chloramines can be removed from water using ultraviolet light treatment

One step in the process is the formation of free radicals

(a)State what is meant by the term free radical (1)

(b)Another step in the process is shown below

State the name for this type of step in a free radical reaction (1)

6 Modern shellac nail varnishes are more durable and so last longer than traditional nail polish

The shellac nail varnish is applied in thin layers to the nails and then the fingers are placed under a UV lamp

(a) The Skin Care Foundation has recommended that a sun-block is applied to the fingers and hand before using the lampSuggest why the Skin Care Foundation makes this recommendation (1)

(b) A free radical chain reaction takes place and the varnish hardens (i) State what is meant by the term free radical (1)

(ii) The shellac nail varnish contains a mixture of ingredients that take part in the free radical chain reactionOne of the steps in the free radical chain reaction is

55

State the term used to describe this type of step in a free radical chain reaction(1)

7 Skin care products contain a mixture of polar covalent non-polar covalent and ionic compounds The compounds need to stay mixed within the product Skin care products also need to spread easily and remain on the skin for a period of time as well as provide physical and chemical protection from the sun In order to do this skin care products contain a range of chemicals including water fats and oils antioxidants minerals and sun blockUsing your knowledge of chemistry explain the role of different chemicals in skin care products (3)

General Questions

1 A mixture of carbon monoxide and hydrogen can be converted into water and a mixture of hydrocarbons

nCO + (2n + 1)H2 rarr nH2O + hydrocarbons

What is the general formula for the hydrocarbons producedA CnH2nndash2B CnH2nC CnH2n+1D CnH2n+2

2 Butadiene is the first member of a homologous series of hydrocarbons called dienesWhat is the general formula for this seriesA CnHn+2B CnHn+3C CnH2nD CnH2nndash2

3 Which of the following statements about methanol is falseA It can be made from synthesis gasB It can be dehydrated to form an alkeneC It can be oxidised to give a carboxylic acidD It reacts with acidified potassium dichromate solution

56

4

Which line in the table correctly describes reactions X and Y

5

Which line in the table correctly describes reactions X and Y

6 Which of the following fuels when burned would make no contribution to globalwarming

57

A HydrogenB Natural gasC PetrolD Coal

7 Which of the following hydrocarbons always gives the same product when one of itshydrogen atoms is replaced by a chlorine atomA HexaneB Hex-1-eneC CyclohexaneD Cyclohexene

8 Which of the following compounds does not have isomeric structuresA C2HCl3B C2H4Cl2C PropeneD Propan-1-ol

9 What organic compound is produced by the dehydration of ethanol A EthaneB EtheneC EthanalD Ethanoic acid

10

The above equation representsA hydrationB hydrogenationC condensationD hydrolysis

11

Which of the following compounds is an isomer of the structure shown aboveA ButanalB ButanoneC Butan-1-olD Butanoic acid

58

12 A compound with molecular formula C6H12O2 could beA hexanalB hexan-2-olC hexan-2-oneD hexanoic acid

13 Propan-2-ol can be prepared from propane as follows

Which line in the table correctly describes the types of reaction taking place at Steps 1 and 2

14 Which of the following compounds would be the most water soluble

15 Cyanohydrin compounds can be made from carbonyl compounds by reacting the carbonyl compound with hydrogen cyanide (HCN)

59

Which carbonyl compound would react with hydrogen cyanide (HCN) to form the following compound

16 Ethyne is the first member of the homologous series called the alkynes

Ethyne can undergo addition reactions as shown in the flow diagram

(a) Compound 2 is an isomer of 12-dichloroethaneDraw a structural formula for compound 2 (1)

(b) Reagents A B and C are three different diatomic gasesUsing information in the flow diagram identify reagents A B and C (1)

60

Reagent Gas

A

B

C

17 In 1865 the German chemist Kekuleacute proposed a ring structure for benzene This structure was based on alternating single and double bonds

(a) (i) Describe a chemical test that would indicate that the above chemical structure for benzene is incorrect (1)

(ii) Briefly describe the correct structure for benzene (1)

(b) Benzene can be formed from cyclohexaneC6H12 rarr C6H6 + 3H2

What name is given to this type of reaction (1)18 Infra-red spectroscopy is a technique that can be used to identify the bonds that

arepresent in a molecule Different bonds absorb infra-red radiation of different wavenumbers This is due to differences in the bond lsquostretchrsquo These absorptions are recorded in a spectrumA spectrum for propan-1-ol is shown

61

The correlation table on page 13 of the data booklet shows the wavenumber ranges for the absorptions due to different bonds

(a) Use the correlation table to identify the bonds responsible for the two absorptions x and y that are circled in the propan-1-ol spectrum (1)

(b) Propan-1-ol reacts with ethanoic acid(i) What name is given to this type of reaction (1)(ii) Draw a spectrum that could be obtained for the organic product of this

reaction (1)

19 Paracetamol is a widely used painkiller

(a) Write the molecular formula for paracetamol (1)

(b) One antidote for paracetamol overdose is methionine

62

To what family of organic compounds does methionine belong (1)

(c) The concentration of paracetamol in a solution can be determined by measuring how much UV radiation it absorbs

The graph shows how the absorbance of a sample containing 0middot040 g l ndash1 paracetamol varies with wavelength

The quantity of UV radiation of wavelength 245 nm absorbed is directly proportional to the concentration of paracetamolThe absorbance of a second sample of paracetamol solution measured at 245 nm was 0middot90 What is the concentration in g l ndash1 of this second paracetamol solution (1)

20 Many carbon compounds containing oxygen are very flammableThe table shows information about two families of isomersThe lowest temperature at which a compound will ignite is called its flash point

(a) A compound with the molecular formula C6H14O has a boiling point of 158 degC63

Draw a structural formula for this compound (1)

(b) For a family of isomers in the table write a general statement linking the flash points of the compounds to their structures (1)

21 Hydrogels are used in disposable nappies They are fine powders that can absorb up to 500 times their own weight in waterA hydrogel is a very long molecule with carboxyl groups at regular intervals along its length A short section of a hydrogel molecule is shown below

Hydrogels are extremely good at soaking up water because the water molecules are strongly attracted to them

Using your knowledge of chemistry comment on how suitable hydrogels would be for absorbing liquids or solutions spilled in a chemistry lab (1)

64

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

18 Which of the following is an isomer of 22-dimethylpentan-1-ol

A CH3CH2CH2CH(CH3)CH2OHB (CH3)3CCH(CH3)CH2OHC CH3CH2CH2CH2CH2CH2CH2CH2OHD (CH3)2CHC(CH3)2CH2CH2OH

19 The equation for the reduction reaction taking place when ethanal reacts with Tollensrsquo reagent is

A Cu2+(aq) + eminus rarr Cu+(aq)

B Ag+(aq) + eminus rarr Ag(s)

C Cr2O72minus(aq) + 14H+(aq) + 6eminus rarr 2Cr3+(aq) + 7H2O(ℓ)

D MnO4minus(aq) + 8H+(aq) + 5eminus rarr Mn2+(aq) + 4H2O(ℓ)

20 The name of the compound with structure

isA 23-dimethylpentan-4-oneB 23-dimethylpentan-2-alC 34-dimethylpentan-2-oneD 34-dimethylpentan-2-al

21 What is the systematic name for the compound below

A 222-trimethylethanolB 22-dimethylpropan-1-olC 22-dimethylpropan-3-olD 22-dimethylpentan-1-ol

31

22 The structure of a molecule found in olive oil can be represented as shown

(a) Olive oil can be hydrolysed using sodium hydroxide solution to produce sodium salts of fatty acids Name the other product of this reaction (1)

(b) In what way does the structure of a fat molecule differ from that of an oil molecule (1)

(c) Over time open containers of olive oil develop a rancid flavour What substance is reacting with the oil to cause these unwanted changes to take place (1)

23 A student writes the following statement It is incorrect Explain the mistake in the studentrsquos reasoning (1)

Alcohols are alkaline because of their OH groups

24 Carbon compounds take part in a wide variety of chemical reactions (a)

Name this type of chemical reaction (1)

(b)

Draw a structural formula for C3H6O (1)

25 Alkanols can be oxidised to alkanoic acids

32

(a) Why can Step 1 be described as an oxidation reaction (1)

(b) Acidified potassium dichromate solution can be used to oxidise propanal in Step 2 What colour change would be observed in this reaction (1)

26 Amines can be produced by reacting ammonia with an aldehyde or a ketone This reaction an example of reductive amination occurs in two stages

Stage 1 Amination

Stage 2 Reduction

(a) Give another name for the type of reaction taking place in Stage 2

(b) Draw the structural formula for the amine produced when butanal undergoes reductive amination with ammonia

27 Using a cobalt catalyst alkenes react with a mixture of hydrogen and carbon monoxideThe products are two isomeric aldehydes Propene reacts with the mixture as shown

(a) What name is given to a mixture of hydrogen and carbon monoxide (1)

(b) Draw a structural formula for compound B (1)

(c) (i) What would be observed if compound A was gently heated with Tollensrsquo reagent

(1)(ii) How would the reaction mixture be heated (1)

33

(d) Aldehydes can also be formed by the reaction of some alcohols with copper(II) oxideName the type of alcohol that would react with copper(II) oxide to form an aldehyde (1)

28 Aldehydes and ketones can take part in a reaction sometimes known as an aldol condensation The simplest aldol reaction involves two molecules of ethanal

In the reaction the carbon atom next to the carbonyl functional group of one molecule forms a bond with the carbonyl carbon atom of the second molecule

(a) Draw a structural formula for the product formed when propanone is used instead of ethanal in this type of reaction (1)

(b) Name an aldehyde that would not take part in an aldol condensation (1)

(c) Apart from the structure of the reactants suggest what is unusual about applying the term ldquocondensationrdquo to this particular type of reaction (1)

29 Primary secondary and tertiary alkanols can be prepared by the reaction of carbonyl compounds with Grignard reagents

Step 1The Grignard reagent reacts with the carbonyl compound

Step 2The reaction of the product of Step 1 with dilute acid produces the alkanol

(a) Describe the difference between a primary a secondary and a tertiary alkanol

You may wish to include labelled structures in your answer (1)34

(b) Suggest a name for the type of reaction that takes place in Step 1 (1)

(c) The same Grignard reagent can be used to produce the alkanol below

Name the carbonyl compound used in this reaction (1)

30 Hairspray is a mixture of chemicals(a) A primary alcohol 2-methylpropan-1-ol is added to hairspray to help it dry quickly on the hair

Draw a structural formula for a secondary alcohol that is an isomer of2-methylpropan-1-ol (1)

(b) Triethanol amine and triisopropyl amine are bases used to neutralise acidic compounds in the hairspray to prevent damage to the hair

In terms of the intermolecular bonding present explain clearly why triethanol amine has a much higher boiling point than triisopropyl amine (2)

35

36

31 Chocolate contains various compounds(a) Many of the flavour and aroma molecules found in chocolate are aldehydes and

ketones Two examples are shown below

Phenylethanal can be easily oxidised but 13-diphenylpropan-2-one cannot(i) Name a chemical that could be used to distinguish between these two

compounds (1)

(ii) Name the type of organic compound formed when phenylethanal is oxidised (1)

(b) Glycerol monostearate is an emulsifier used in chocolate

(i) Why is glycerol monostearate added to chocolate (1)

(ii) Draw a structural formula for glycerol (1)

(c) Theobromine a compound present in chocolate can cause illness in dogs and cats To decide if treatment is necessary vets must calculate the mass of theobromine consumed 1middot0 g of chocolate contains 1middot4 mg of theobromine Calculate the mass in mg of theobromine in a 17 g biscuit of which 28 is chocolate Show your working clearly (2)

(d) The flavour and texture of chocolate comes from a blend of compoundsUsing your knowledge of chemistry describe how you could show that there are ionic compounds and covalent compounds present in chocolate (3)

37

32 Ethanol has many uses

(a) Ethanol is found at relatively low concentrations in wine

(i) Name the chemical reaction that produces ethanol in wine (1)

(ii) Standard ethanol solutions were used to produce a graph of density against

concentration of ethanol given as a percentage of alcohol by volume ( abv)

What is the concentration of ethanol in units of abv in a solution of density 0middot9818 g cmminus3 (1)

(b) Whisky contains a higher concentration of ethanol

(i) Before 1980 the concentration of alcohol in drinks was measured in terms of degrees proof The concentration of alcohol in two drinks is shown in the table below both as abv and degrees proof

38

A cask strength whisky has an alcohol concentration of 65 abv Calculate the alcohol concentration of this whisky in degrees proof (1)

(ii) A barrel containing 195 litres of cask strength whisky costs pound1300 The cask strength whisky is diluted with water to reduce the concentration of alcohol from 65 abv to 46 abv before it is bottled Calculate the cost of the cask strength whisky needed to produce a 0middot70 litre bottle Show your working clearly (2)

(iii) 5-Butyl-4-methyltetrahydrofuran-2-ol is a flavour compound found in whisky

stored in oak barrels

Write the systematic name for the compound shown below (1) 13 11

33 (a) One test for glucose involves Fehlingrsquos solutionCircle the part of the glucose molecule that reacts with Fehlingrsquos solution (1)

(b) In solution sugar molecules exist in an equilibrium in straight-chain and ring forms

To change from the straight-chain form to the ring form the oxygen of the hydroxyl on carbon number 5 joins to the carbonyl carbon This is shown below for glucose

39

Draw the structure of a ring form for fructose (1)

34 (a) During the free radical chain reaction small molecules join to form large chain molecules

One example of a small molecule used is

Name the functional group circled above (1)

(b)Alcohol wipes are used to finish the varnishing treatment Alcohol wipes contain the alcohol propan-2-olState why propan-2-ol can be described as a secondary alcohol (1)

35 A student was carrying out an investigation into alcohols aldehydes and ketones

(a)The student was given three alcohols labelled as A B and C These alcohols were all isomers with the formula C4H9OH

(i) Draw a structural formula for the secondary alcohol with the formula C4H9OH(1)

(ii) The student set up the following experiment

A Suggest why a water bath is an appropriate method of heating the reaction mixture (1)

B Describe the colour change that would have been observed with alcohols A and C (1)

40

C Alcohol B is not oxidised State the type of alcohol which cannot be oxidised by acidified dichromate solution (1)

(iii) The student set up a second experiment with alcohol A

Hot copper(II) oxide is an oxidising agentA When alcohol A (C4H9OH) is oxidised the product turns the pH paper

redSuggest a name for the product (1)

B Complete the ion-electron equation for the oxidation reaction

C4H9OH rarr C4H8O2 (1)

(b)The student found the following information about the boiling points of some aldehydes

41

(i) Name the aldehyde that has a boiling point of 119 degC (1)(ii) Predict the boiling point in degC of the following molecule (1)

(iii) Using information from the table describe one way in which differences in structure affect the boiling point of isomeric aldehydes (1)

(iv) State what would be observed when an aldehyde is gently heated with Tollensrsquo reagent (1)

(c) Ketones contain a carbonyl groupName the type of intermolecular interaction between ketone molecules (1)

42

25 Soaps Detergents and Emulsions

1 Soaps are produced by the following reaction

This reaction is an example ofA condensationB esterificationC hydrolysisD oxidation

2 Which of the following is the salt of a long-chain fatty acid

A FatB OilC SoapD Glycerol

3 Emulsifiers for use in food are commonly made by reacting edible oils with

A estersB glycerolC fatty acidsD amino acids

4 A fatty acid is a long chain carboxylic acid Examples of fatty acids are shown in the table below

43

(a) What is the systematic name for linolenic acid (1)(b) Stearic acid reacts with sodium hydroxide solution to form sodium stearate

(i) Name the type of reaction taking place when stearic acid reacts with sodium hydroxide (1)

(ii) Explain fully how sodium stearate acts to keep grease and non-polar substances suspended in water during cleaning (3)

5 Small children can find it difficult to swallow tablets or pills so ibuprofen is supplied as an ldquoinfant formulardquo emulsion(a) The emulsifier used is polysorbate 80 Its structure is shown below

Explain why this molecule acts as an emulsifier (2)

(b) The emulsion contains 2 g of ibuprofen in every 100 cm3 of emulsion The recommended dose for treating a 6 month old baby is 0middot050 g Calculate the volume in cm3 of ldquoinfant formulardquo needed to treat a 6 month old baby (1)

6 Occasionally seabirds can become contaminated with hydrocarbons from oil spills This causes problems for birds because their feathers lose their waterproofing making the birds susceptible to temperature changes and

44

affecting their buoyancy If the birds attempt to clean themselves to remove the oil they may swallow the hydrocarbons causing damage to their internal organsContaminated seabirds can be cleaned by rubbing vegetable oil into their feathers and feet before the birds are rinsed with diluted washing-up liquidUsing your knowledge of chemistry comment on the problems created for seabirds by oil spills and the actions taken to treat affected birds (3)

7 Dishwasher tablets contain chemicals which remove dirt from dishesDishwasher tablets include detergents These molecules act like soaps to allow mixing of fat-soluble dirt and water(a)During the cleaning process the detergent molecules combine with fat-

soluble dirtA simplified diagram of a detergent molecule is shown

Complete the diagram below to show how detergent molecules combine with fat-soluble dirt (1)

(b)State the term used to describe the non-polar hydrocarbon tail of a detergent molecule (1)

45

26 Fragrances1 Myrcene is a simple terpene

Terpenes contain at least one isoprene unit Which of the following shows a correctly highlighted isoprene unit

2 Limonene is one of the terpene molecules responsible for the flavour of lemons

How many isoprene units are used in the production of one limonene moleculeA 1B 2C 3D 4

46

3 The structure of caryophyllene which can be extracted from clove oil is

Which of the following would be the best solvent for extracting caryophylleneA HexaneB HexanalC HexanolD Hexanone

4 The structure of isoprene is

Limonene is a terpene molecule present in lemons

How many isoprene units are joined together in a limonene molecule

A 1B 2

47

C 3D 4

5 Essential oils are

A non-water soluble non-volatile compoundsB non-water soluble volatile compoundsC water soluble non-volatile compoundsD water soluble volatile compounds

6 Two typical compounds that are present in many perfumes are shown

(a) Why does geraniol evaporate more slowly than limonene (1)

(b) The structure of one of the first synthetic scents used in perfume is shown below

(i) Name the family of carbonyl compounds to which this synthetic scent belongs (1)

(ii) Complete the structure below to show the product formed when this scent is

oxidised (1)

(c) Traces of a liquid were discovered in a bottle believed to contain perfume belonging to Queen Hatshepsut ruler of Egypt over 3500 years ago

Perfumes were made by dissolving plant extracts containing pleasant smelling terpenes and esters in an edible oil A little ethanol and water may also have been addedUsing your knowledge of chemistry comment on the possible smell(s) when such a bottle is opened after being stored for thousands of years (3)

48

49

7 A team of chemists are developing a fragrance for use in a shower gel for men(a) To give the gel a fruity smell the chemists are considering adding an ester

They synthesise six isomeric esters Volunteers smell each ester and give it a rating out of one hundred depending on how fruity the smell is

(i) Name the ester with the fruit-smell rating of 92 (1)

(ii) Shown below are the structures of three more isomers

Arrange these esters in order of decreasing fruit-smell rating (1)

50

(b) To create a fragrance for men the compound civetone is added

Draw a structural formula for the alcohol that can be oxidised to form civetone (1)

(c) To make the shower gel produce a cold tingling sensation when applied to the skin menthol is added

Like terpenes menthol is formed from isoprene (2-methylbuta-13-diene)Circle an isoprene unit on the menthol structure above (1)

8 Many of the compounds in perfumes are molecules consisting of joined isoprene units

(a) State the name that is given to molecules consisting of joined isoprene units (1)

(b)Geraniol is one of the compounds found in perfume It has the following structural formula and systematic name

Linalool can also be present Its structural formula is shown

51

(i) State the systematic name for linalool (1)(ii) Explain why linalool can be classified as a tertiary alcohol (1)

9 The component molecules found in lavender oils are terpenes or terpenoids(a)A chiral carbon is a carbon atom attached to four different atoms or groups of

atomsAn example is shown below

A molecule of the terpenoid linalool has a chiral carbon Linalool has the following structure

Circle the chiral carbon atom in the linalool structure (1)

(b)Farnesene is a terpene consisting of three isoprene units (2-methylbuta-13-diene) joined togetherWrite the molecular formula of farnesene (1)

52

27 Skin Care

1 Which of the following is not a step in a free radical chain reaction

A ActivationB InitiationC PropagationD Termination

2 Fluorine reacts with methane via a free radical chain reaction Some steps in the chain reaction are shown in the table below

Complete the table by(a) inserting the missing name for the first step (1)

(b) showing another possible termination reaction in the final row of the table (1)

3 Suncreams contain antioxidantsThe antioxidant compound A can prevent damage to skin by reacting with free

radicalssuch as NO2bull

53

Why can compound A be described as a free radical scavenger in the reaction shown above

4 Hydrogen and chlorine gases are used in an experiment to demonstrate a free radical reaction A plastic bottle is wrapped with black tape leaving a ldquowindowrdquo on one sideThe bottle is filled with a mixture of hydrogen and chlorine When bright light shines on the bottle there is an explosion

A free radical chain reaction is initiated when light energy causes chlorine radicals to form as shown below

(a) Complete the equations below showing possible propagation and termination steps

(2)

54

(b) Why is the plastic bottle used in the experiment wrapped in black tape (1)

5 Chloramines can be removed from water using ultraviolet light treatment

One step in the process is the formation of free radicals

(a)State what is meant by the term free radical (1)

(b)Another step in the process is shown below

State the name for this type of step in a free radical reaction (1)

6 Modern shellac nail varnishes are more durable and so last longer than traditional nail polish

The shellac nail varnish is applied in thin layers to the nails and then the fingers are placed under a UV lamp

(a) The Skin Care Foundation has recommended that a sun-block is applied to the fingers and hand before using the lampSuggest why the Skin Care Foundation makes this recommendation (1)

(b) A free radical chain reaction takes place and the varnish hardens (i) State what is meant by the term free radical (1)

(ii) The shellac nail varnish contains a mixture of ingredients that take part in the free radical chain reactionOne of the steps in the free radical chain reaction is

55

State the term used to describe this type of step in a free radical chain reaction(1)

7 Skin care products contain a mixture of polar covalent non-polar covalent and ionic compounds The compounds need to stay mixed within the product Skin care products also need to spread easily and remain on the skin for a period of time as well as provide physical and chemical protection from the sun In order to do this skin care products contain a range of chemicals including water fats and oils antioxidants minerals and sun blockUsing your knowledge of chemistry explain the role of different chemicals in skin care products (3)

General Questions

1 A mixture of carbon monoxide and hydrogen can be converted into water and a mixture of hydrocarbons

nCO + (2n + 1)H2 rarr nH2O + hydrocarbons

What is the general formula for the hydrocarbons producedA CnH2nndash2B CnH2nC CnH2n+1D CnH2n+2

2 Butadiene is the first member of a homologous series of hydrocarbons called dienesWhat is the general formula for this seriesA CnHn+2B CnHn+3C CnH2nD CnH2nndash2

3 Which of the following statements about methanol is falseA It can be made from synthesis gasB It can be dehydrated to form an alkeneC It can be oxidised to give a carboxylic acidD It reacts with acidified potassium dichromate solution

56

4

Which line in the table correctly describes reactions X and Y

5

Which line in the table correctly describes reactions X and Y

6 Which of the following fuels when burned would make no contribution to globalwarming

57

A HydrogenB Natural gasC PetrolD Coal

7 Which of the following hydrocarbons always gives the same product when one of itshydrogen atoms is replaced by a chlorine atomA HexaneB Hex-1-eneC CyclohexaneD Cyclohexene

8 Which of the following compounds does not have isomeric structuresA C2HCl3B C2H4Cl2C PropeneD Propan-1-ol

9 What organic compound is produced by the dehydration of ethanol A EthaneB EtheneC EthanalD Ethanoic acid

10

The above equation representsA hydrationB hydrogenationC condensationD hydrolysis

11

Which of the following compounds is an isomer of the structure shown aboveA ButanalB ButanoneC Butan-1-olD Butanoic acid

58

12 A compound with molecular formula C6H12O2 could beA hexanalB hexan-2-olC hexan-2-oneD hexanoic acid

13 Propan-2-ol can be prepared from propane as follows

Which line in the table correctly describes the types of reaction taking place at Steps 1 and 2

14 Which of the following compounds would be the most water soluble

15 Cyanohydrin compounds can be made from carbonyl compounds by reacting the carbonyl compound with hydrogen cyanide (HCN)

59

Which carbonyl compound would react with hydrogen cyanide (HCN) to form the following compound

16 Ethyne is the first member of the homologous series called the alkynes

Ethyne can undergo addition reactions as shown in the flow diagram

(a) Compound 2 is an isomer of 12-dichloroethaneDraw a structural formula for compound 2 (1)

(b) Reagents A B and C are three different diatomic gasesUsing information in the flow diagram identify reagents A B and C (1)

60

Reagent Gas

A

B

C

17 In 1865 the German chemist Kekuleacute proposed a ring structure for benzene This structure was based on alternating single and double bonds

(a) (i) Describe a chemical test that would indicate that the above chemical structure for benzene is incorrect (1)

(ii) Briefly describe the correct structure for benzene (1)

(b) Benzene can be formed from cyclohexaneC6H12 rarr C6H6 + 3H2

What name is given to this type of reaction (1)18 Infra-red spectroscopy is a technique that can be used to identify the bonds that

arepresent in a molecule Different bonds absorb infra-red radiation of different wavenumbers This is due to differences in the bond lsquostretchrsquo These absorptions are recorded in a spectrumA spectrum for propan-1-ol is shown

61

The correlation table on page 13 of the data booklet shows the wavenumber ranges for the absorptions due to different bonds

(a) Use the correlation table to identify the bonds responsible for the two absorptions x and y that are circled in the propan-1-ol spectrum (1)

(b) Propan-1-ol reacts with ethanoic acid(i) What name is given to this type of reaction (1)(ii) Draw a spectrum that could be obtained for the organic product of this

reaction (1)

19 Paracetamol is a widely used painkiller

(a) Write the molecular formula for paracetamol (1)

(b) One antidote for paracetamol overdose is methionine

62

To what family of organic compounds does methionine belong (1)

(c) The concentration of paracetamol in a solution can be determined by measuring how much UV radiation it absorbs

The graph shows how the absorbance of a sample containing 0middot040 g l ndash1 paracetamol varies with wavelength

The quantity of UV radiation of wavelength 245 nm absorbed is directly proportional to the concentration of paracetamolThe absorbance of a second sample of paracetamol solution measured at 245 nm was 0middot90 What is the concentration in g l ndash1 of this second paracetamol solution (1)

20 Many carbon compounds containing oxygen are very flammableThe table shows information about two families of isomersThe lowest temperature at which a compound will ignite is called its flash point

(a) A compound with the molecular formula C6H14O has a boiling point of 158 degC63

Draw a structural formula for this compound (1)

(b) For a family of isomers in the table write a general statement linking the flash points of the compounds to their structures (1)

21 Hydrogels are used in disposable nappies They are fine powders that can absorb up to 500 times their own weight in waterA hydrogel is a very long molecule with carboxyl groups at regular intervals along its length A short section of a hydrogel molecule is shown below

Hydrogels are extremely good at soaking up water because the water molecules are strongly attracted to them

Using your knowledge of chemistry comment on how suitable hydrogels would be for absorbing liquids or solutions spilled in a chemistry lab (1)

64

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

22 The structure of a molecule found in olive oil can be represented as shown

(a) Olive oil can be hydrolysed using sodium hydroxide solution to produce sodium salts of fatty acids Name the other product of this reaction (1)

(b) In what way does the structure of a fat molecule differ from that of an oil molecule (1)

(c) Over time open containers of olive oil develop a rancid flavour What substance is reacting with the oil to cause these unwanted changes to take place (1)

23 A student writes the following statement It is incorrect Explain the mistake in the studentrsquos reasoning (1)

Alcohols are alkaline because of their OH groups

24 Carbon compounds take part in a wide variety of chemical reactions (a)

Name this type of chemical reaction (1)

(b)

Draw a structural formula for C3H6O (1)

25 Alkanols can be oxidised to alkanoic acids

32

(a) Why can Step 1 be described as an oxidation reaction (1)

(b) Acidified potassium dichromate solution can be used to oxidise propanal in Step 2 What colour change would be observed in this reaction (1)

26 Amines can be produced by reacting ammonia with an aldehyde or a ketone This reaction an example of reductive amination occurs in two stages

Stage 1 Amination

Stage 2 Reduction

(a) Give another name for the type of reaction taking place in Stage 2

(b) Draw the structural formula for the amine produced when butanal undergoes reductive amination with ammonia

27 Using a cobalt catalyst alkenes react with a mixture of hydrogen and carbon monoxideThe products are two isomeric aldehydes Propene reacts with the mixture as shown

(a) What name is given to a mixture of hydrogen and carbon monoxide (1)

(b) Draw a structural formula for compound B (1)

(c) (i) What would be observed if compound A was gently heated with Tollensrsquo reagent

(1)(ii) How would the reaction mixture be heated (1)

33

(d) Aldehydes can also be formed by the reaction of some alcohols with copper(II) oxideName the type of alcohol that would react with copper(II) oxide to form an aldehyde (1)

28 Aldehydes and ketones can take part in a reaction sometimes known as an aldol condensation The simplest aldol reaction involves two molecules of ethanal

In the reaction the carbon atom next to the carbonyl functional group of one molecule forms a bond with the carbonyl carbon atom of the second molecule

(a) Draw a structural formula for the product formed when propanone is used instead of ethanal in this type of reaction (1)

(b) Name an aldehyde that would not take part in an aldol condensation (1)

(c) Apart from the structure of the reactants suggest what is unusual about applying the term ldquocondensationrdquo to this particular type of reaction (1)

29 Primary secondary and tertiary alkanols can be prepared by the reaction of carbonyl compounds with Grignard reagents

Step 1The Grignard reagent reacts with the carbonyl compound

Step 2The reaction of the product of Step 1 with dilute acid produces the alkanol

(a) Describe the difference between a primary a secondary and a tertiary alkanol

You may wish to include labelled structures in your answer (1)34

(b) Suggest a name for the type of reaction that takes place in Step 1 (1)

(c) The same Grignard reagent can be used to produce the alkanol below

Name the carbonyl compound used in this reaction (1)

30 Hairspray is a mixture of chemicals(a) A primary alcohol 2-methylpropan-1-ol is added to hairspray to help it dry quickly on the hair

Draw a structural formula for a secondary alcohol that is an isomer of2-methylpropan-1-ol (1)

(b) Triethanol amine and triisopropyl amine are bases used to neutralise acidic compounds in the hairspray to prevent damage to the hair

In terms of the intermolecular bonding present explain clearly why triethanol amine has a much higher boiling point than triisopropyl amine (2)

35

36

31 Chocolate contains various compounds(a) Many of the flavour and aroma molecules found in chocolate are aldehydes and

ketones Two examples are shown below

Phenylethanal can be easily oxidised but 13-diphenylpropan-2-one cannot(i) Name a chemical that could be used to distinguish between these two

compounds (1)

(ii) Name the type of organic compound formed when phenylethanal is oxidised (1)

(b) Glycerol monostearate is an emulsifier used in chocolate

(i) Why is glycerol monostearate added to chocolate (1)

(ii) Draw a structural formula for glycerol (1)

(c) Theobromine a compound present in chocolate can cause illness in dogs and cats To decide if treatment is necessary vets must calculate the mass of theobromine consumed 1middot0 g of chocolate contains 1middot4 mg of theobromine Calculate the mass in mg of theobromine in a 17 g biscuit of which 28 is chocolate Show your working clearly (2)

(d) The flavour and texture of chocolate comes from a blend of compoundsUsing your knowledge of chemistry describe how you could show that there are ionic compounds and covalent compounds present in chocolate (3)

37

32 Ethanol has many uses

(a) Ethanol is found at relatively low concentrations in wine

(i) Name the chemical reaction that produces ethanol in wine (1)

(ii) Standard ethanol solutions were used to produce a graph of density against

concentration of ethanol given as a percentage of alcohol by volume ( abv)

What is the concentration of ethanol in units of abv in a solution of density 0middot9818 g cmminus3 (1)

(b) Whisky contains a higher concentration of ethanol

(i) Before 1980 the concentration of alcohol in drinks was measured in terms of degrees proof The concentration of alcohol in two drinks is shown in the table below both as abv and degrees proof

38

A cask strength whisky has an alcohol concentration of 65 abv Calculate the alcohol concentration of this whisky in degrees proof (1)

(ii) A barrel containing 195 litres of cask strength whisky costs pound1300 The cask strength whisky is diluted with water to reduce the concentration of alcohol from 65 abv to 46 abv before it is bottled Calculate the cost of the cask strength whisky needed to produce a 0middot70 litre bottle Show your working clearly (2)

(iii) 5-Butyl-4-methyltetrahydrofuran-2-ol is a flavour compound found in whisky

stored in oak barrels

Write the systematic name for the compound shown below (1) 13 11

33 (a) One test for glucose involves Fehlingrsquos solutionCircle the part of the glucose molecule that reacts with Fehlingrsquos solution (1)

(b) In solution sugar molecules exist in an equilibrium in straight-chain and ring forms

To change from the straight-chain form to the ring form the oxygen of the hydroxyl on carbon number 5 joins to the carbonyl carbon This is shown below for glucose

39

Draw the structure of a ring form for fructose (1)

34 (a) During the free radical chain reaction small molecules join to form large chain molecules

One example of a small molecule used is

Name the functional group circled above (1)

(b)Alcohol wipes are used to finish the varnishing treatment Alcohol wipes contain the alcohol propan-2-olState why propan-2-ol can be described as a secondary alcohol (1)

35 A student was carrying out an investigation into alcohols aldehydes and ketones

(a)The student was given three alcohols labelled as A B and C These alcohols were all isomers with the formula C4H9OH

(i) Draw a structural formula for the secondary alcohol with the formula C4H9OH(1)

(ii) The student set up the following experiment

A Suggest why a water bath is an appropriate method of heating the reaction mixture (1)

B Describe the colour change that would have been observed with alcohols A and C (1)

40

C Alcohol B is not oxidised State the type of alcohol which cannot be oxidised by acidified dichromate solution (1)

(iii) The student set up a second experiment with alcohol A

Hot copper(II) oxide is an oxidising agentA When alcohol A (C4H9OH) is oxidised the product turns the pH paper

redSuggest a name for the product (1)

B Complete the ion-electron equation for the oxidation reaction

C4H9OH rarr C4H8O2 (1)

(b)The student found the following information about the boiling points of some aldehydes

41

(i) Name the aldehyde that has a boiling point of 119 degC (1)(ii) Predict the boiling point in degC of the following molecule (1)

(iii) Using information from the table describe one way in which differences in structure affect the boiling point of isomeric aldehydes (1)

(iv) State what would be observed when an aldehyde is gently heated with Tollensrsquo reagent (1)

(c) Ketones contain a carbonyl groupName the type of intermolecular interaction between ketone molecules (1)

42

25 Soaps Detergents and Emulsions

1 Soaps are produced by the following reaction

This reaction is an example ofA condensationB esterificationC hydrolysisD oxidation

2 Which of the following is the salt of a long-chain fatty acid

A FatB OilC SoapD Glycerol

3 Emulsifiers for use in food are commonly made by reacting edible oils with

A estersB glycerolC fatty acidsD amino acids

4 A fatty acid is a long chain carboxylic acid Examples of fatty acids are shown in the table below

43

(a) What is the systematic name for linolenic acid (1)(b) Stearic acid reacts with sodium hydroxide solution to form sodium stearate

(i) Name the type of reaction taking place when stearic acid reacts with sodium hydroxide (1)

(ii) Explain fully how sodium stearate acts to keep grease and non-polar substances suspended in water during cleaning (3)

5 Small children can find it difficult to swallow tablets or pills so ibuprofen is supplied as an ldquoinfant formulardquo emulsion(a) The emulsifier used is polysorbate 80 Its structure is shown below

Explain why this molecule acts as an emulsifier (2)

(b) The emulsion contains 2 g of ibuprofen in every 100 cm3 of emulsion The recommended dose for treating a 6 month old baby is 0middot050 g Calculate the volume in cm3 of ldquoinfant formulardquo needed to treat a 6 month old baby (1)

6 Occasionally seabirds can become contaminated with hydrocarbons from oil spills This causes problems for birds because their feathers lose their waterproofing making the birds susceptible to temperature changes and

44

affecting their buoyancy If the birds attempt to clean themselves to remove the oil they may swallow the hydrocarbons causing damage to their internal organsContaminated seabirds can be cleaned by rubbing vegetable oil into their feathers and feet before the birds are rinsed with diluted washing-up liquidUsing your knowledge of chemistry comment on the problems created for seabirds by oil spills and the actions taken to treat affected birds (3)

7 Dishwasher tablets contain chemicals which remove dirt from dishesDishwasher tablets include detergents These molecules act like soaps to allow mixing of fat-soluble dirt and water(a)During the cleaning process the detergent molecules combine with fat-

soluble dirtA simplified diagram of a detergent molecule is shown

Complete the diagram below to show how detergent molecules combine with fat-soluble dirt (1)

(b)State the term used to describe the non-polar hydrocarbon tail of a detergent molecule (1)

45

26 Fragrances1 Myrcene is a simple terpene

Terpenes contain at least one isoprene unit Which of the following shows a correctly highlighted isoprene unit

2 Limonene is one of the terpene molecules responsible for the flavour of lemons

How many isoprene units are used in the production of one limonene moleculeA 1B 2C 3D 4

46

3 The structure of caryophyllene which can be extracted from clove oil is

Which of the following would be the best solvent for extracting caryophylleneA HexaneB HexanalC HexanolD Hexanone

4 The structure of isoprene is

Limonene is a terpene molecule present in lemons

How many isoprene units are joined together in a limonene molecule

A 1B 2

47

C 3D 4

5 Essential oils are

A non-water soluble non-volatile compoundsB non-water soluble volatile compoundsC water soluble non-volatile compoundsD water soluble volatile compounds

6 Two typical compounds that are present in many perfumes are shown

(a) Why does geraniol evaporate more slowly than limonene (1)

(b) The structure of one of the first synthetic scents used in perfume is shown below

(i) Name the family of carbonyl compounds to which this synthetic scent belongs (1)

(ii) Complete the structure below to show the product formed when this scent is

oxidised (1)

(c) Traces of a liquid were discovered in a bottle believed to contain perfume belonging to Queen Hatshepsut ruler of Egypt over 3500 years ago

Perfumes were made by dissolving plant extracts containing pleasant smelling terpenes and esters in an edible oil A little ethanol and water may also have been addedUsing your knowledge of chemistry comment on the possible smell(s) when such a bottle is opened after being stored for thousands of years (3)

48

49

7 A team of chemists are developing a fragrance for use in a shower gel for men(a) To give the gel a fruity smell the chemists are considering adding an ester

They synthesise six isomeric esters Volunteers smell each ester and give it a rating out of one hundred depending on how fruity the smell is

(i) Name the ester with the fruit-smell rating of 92 (1)

(ii) Shown below are the structures of three more isomers

Arrange these esters in order of decreasing fruit-smell rating (1)

50

(b) To create a fragrance for men the compound civetone is added

Draw a structural formula for the alcohol that can be oxidised to form civetone (1)

(c) To make the shower gel produce a cold tingling sensation when applied to the skin menthol is added

Like terpenes menthol is formed from isoprene (2-methylbuta-13-diene)Circle an isoprene unit on the menthol structure above (1)

8 Many of the compounds in perfumes are molecules consisting of joined isoprene units

(a) State the name that is given to molecules consisting of joined isoprene units (1)

(b)Geraniol is one of the compounds found in perfume It has the following structural formula and systematic name

Linalool can also be present Its structural formula is shown

51

(i) State the systematic name for linalool (1)(ii) Explain why linalool can be classified as a tertiary alcohol (1)

9 The component molecules found in lavender oils are terpenes or terpenoids(a)A chiral carbon is a carbon atom attached to four different atoms or groups of

atomsAn example is shown below

A molecule of the terpenoid linalool has a chiral carbon Linalool has the following structure

Circle the chiral carbon atom in the linalool structure (1)

(b)Farnesene is a terpene consisting of three isoprene units (2-methylbuta-13-diene) joined togetherWrite the molecular formula of farnesene (1)

52

27 Skin Care

1 Which of the following is not a step in a free radical chain reaction

A ActivationB InitiationC PropagationD Termination

2 Fluorine reacts with methane via a free radical chain reaction Some steps in the chain reaction are shown in the table below

Complete the table by(a) inserting the missing name for the first step (1)

(b) showing another possible termination reaction in the final row of the table (1)

3 Suncreams contain antioxidantsThe antioxidant compound A can prevent damage to skin by reacting with free

radicalssuch as NO2bull

53

Why can compound A be described as a free radical scavenger in the reaction shown above

4 Hydrogen and chlorine gases are used in an experiment to demonstrate a free radical reaction A plastic bottle is wrapped with black tape leaving a ldquowindowrdquo on one sideThe bottle is filled with a mixture of hydrogen and chlorine When bright light shines on the bottle there is an explosion

A free radical chain reaction is initiated when light energy causes chlorine radicals to form as shown below

(a) Complete the equations below showing possible propagation and termination steps

(2)

54

(b) Why is the plastic bottle used in the experiment wrapped in black tape (1)

5 Chloramines can be removed from water using ultraviolet light treatment

One step in the process is the formation of free radicals

(a)State what is meant by the term free radical (1)

(b)Another step in the process is shown below

State the name for this type of step in a free radical reaction (1)

6 Modern shellac nail varnishes are more durable and so last longer than traditional nail polish

The shellac nail varnish is applied in thin layers to the nails and then the fingers are placed under a UV lamp

(a) The Skin Care Foundation has recommended that a sun-block is applied to the fingers and hand before using the lampSuggest why the Skin Care Foundation makes this recommendation (1)

(b) A free radical chain reaction takes place and the varnish hardens (i) State what is meant by the term free radical (1)

(ii) The shellac nail varnish contains a mixture of ingredients that take part in the free radical chain reactionOne of the steps in the free radical chain reaction is

55

State the term used to describe this type of step in a free radical chain reaction(1)

7 Skin care products contain a mixture of polar covalent non-polar covalent and ionic compounds The compounds need to stay mixed within the product Skin care products also need to spread easily and remain on the skin for a period of time as well as provide physical and chemical protection from the sun In order to do this skin care products contain a range of chemicals including water fats and oils antioxidants minerals and sun blockUsing your knowledge of chemistry explain the role of different chemicals in skin care products (3)

General Questions

1 A mixture of carbon monoxide and hydrogen can be converted into water and a mixture of hydrocarbons

nCO + (2n + 1)H2 rarr nH2O + hydrocarbons

What is the general formula for the hydrocarbons producedA CnH2nndash2B CnH2nC CnH2n+1D CnH2n+2

2 Butadiene is the first member of a homologous series of hydrocarbons called dienesWhat is the general formula for this seriesA CnHn+2B CnHn+3C CnH2nD CnH2nndash2

3 Which of the following statements about methanol is falseA It can be made from synthesis gasB It can be dehydrated to form an alkeneC It can be oxidised to give a carboxylic acidD It reacts with acidified potassium dichromate solution

56

4

Which line in the table correctly describes reactions X and Y

5

Which line in the table correctly describes reactions X and Y

6 Which of the following fuels when burned would make no contribution to globalwarming

57

A HydrogenB Natural gasC PetrolD Coal

7 Which of the following hydrocarbons always gives the same product when one of itshydrogen atoms is replaced by a chlorine atomA HexaneB Hex-1-eneC CyclohexaneD Cyclohexene

8 Which of the following compounds does not have isomeric structuresA C2HCl3B C2H4Cl2C PropeneD Propan-1-ol

9 What organic compound is produced by the dehydration of ethanol A EthaneB EtheneC EthanalD Ethanoic acid

10

The above equation representsA hydrationB hydrogenationC condensationD hydrolysis

11

Which of the following compounds is an isomer of the structure shown aboveA ButanalB ButanoneC Butan-1-olD Butanoic acid

58

12 A compound with molecular formula C6H12O2 could beA hexanalB hexan-2-olC hexan-2-oneD hexanoic acid

13 Propan-2-ol can be prepared from propane as follows

Which line in the table correctly describes the types of reaction taking place at Steps 1 and 2

14 Which of the following compounds would be the most water soluble

15 Cyanohydrin compounds can be made from carbonyl compounds by reacting the carbonyl compound with hydrogen cyanide (HCN)

59

Which carbonyl compound would react with hydrogen cyanide (HCN) to form the following compound

16 Ethyne is the first member of the homologous series called the alkynes

Ethyne can undergo addition reactions as shown in the flow diagram

(a) Compound 2 is an isomer of 12-dichloroethaneDraw a structural formula for compound 2 (1)

(b) Reagents A B and C are three different diatomic gasesUsing information in the flow diagram identify reagents A B and C (1)

60

Reagent Gas

A

B

C

17 In 1865 the German chemist Kekuleacute proposed a ring structure for benzene This structure was based on alternating single and double bonds

(a) (i) Describe a chemical test that would indicate that the above chemical structure for benzene is incorrect (1)

(ii) Briefly describe the correct structure for benzene (1)

(b) Benzene can be formed from cyclohexaneC6H12 rarr C6H6 + 3H2

What name is given to this type of reaction (1)18 Infra-red spectroscopy is a technique that can be used to identify the bonds that

arepresent in a molecule Different bonds absorb infra-red radiation of different wavenumbers This is due to differences in the bond lsquostretchrsquo These absorptions are recorded in a spectrumA spectrum for propan-1-ol is shown

61

The correlation table on page 13 of the data booklet shows the wavenumber ranges for the absorptions due to different bonds

(a) Use the correlation table to identify the bonds responsible for the two absorptions x and y that are circled in the propan-1-ol spectrum (1)

(b) Propan-1-ol reacts with ethanoic acid(i) What name is given to this type of reaction (1)(ii) Draw a spectrum that could be obtained for the organic product of this

reaction (1)

19 Paracetamol is a widely used painkiller

(a) Write the molecular formula for paracetamol (1)

(b) One antidote for paracetamol overdose is methionine

62

To what family of organic compounds does methionine belong (1)

(c) The concentration of paracetamol in a solution can be determined by measuring how much UV radiation it absorbs

The graph shows how the absorbance of a sample containing 0middot040 g l ndash1 paracetamol varies with wavelength

The quantity of UV radiation of wavelength 245 nm absorbed is directly proportional to the concentration of paracetamolThe absorbance of a second sample of paracetamol solution measured at 245 nm was 0middot90 What is the concentration in g l ndash1 of this second paracetamol solution (1)

20 Many carbon compounds containing oxygen are very flammableThe table shows information about two families of isomersThe lowest temperature at which a compound will ignite is called its flash point

(a) A compound with the molecular formula C6H14O has a boiling point of 158 degC63

Draw a structural formula for this compound (1)

(b) For a family of isomers in the table write a general statement linking the flash points of the compounds to their structures (1)

21 Hydrogels are used in disposable nappies They are fine powders that can absorb up to 500 times their own weight in waterA hydrogel is a very long molecule with carboxyl groups at regular intervals along its length A short section of a hydrogel molecule is shown below

Hydrogels are extremely good at soaking up water because the water molecules are strongly attracted to them

Using your knowledge of chemistry comment on how suitable hydrogels would be for absorbing liquids or solutions spilled in a chemistry lab (1)

64

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

(a) Why can Step 1 be described as an oxidation reaction (1)

(b) Acidified potassium dichromate solution can be used to oxidise propanal in Step 2 What colour change would be observed in this reaction (1)

26 Amines can be produced by reacting ammonia with an aldehyde or a ketone This reaction an example of reductive amination occurs in two stages

Stage 1 Amination

Stage 2 Reduction

(a) Give another name for the type of reaction taking place in Stage 2

(b) Draw the structural formula for the amine produced when butanal undergoes reductive amination with ammonia

27 Using a cobalt catalyst alkenes react with a mixture of hydrogen and carbon monoxideThe products are two isomeric aldehydes Propene reacts with the mixture as shown

(a) What name is given to a mixture of hydrogen and carbon monoxide (1)

(b) Draw a structural formula for compound B (1)

(c) (i) What would be observed if compound A was gently heated with Tollensrsquo reagent

(1)(ii) How would the reaction mixture be heated (1)

33

(d) Aldehydes can also be formed by the reaction of some alcohols with copper(II) oxideName the type of alcohol that would react with copper(II) oxide to form an aldehyde (1)

28 Aldehydes and ketones can take part in a reaction sometimes known as an aldol condensation The simplest aldol reaction involves two molecules of ethanal

In the reaction the carbon atom next to the carbonyl functional group of one molecule forms a bond with the carbonyl carbon atom of the second molecule

(a) Draw a structural formula for the product formed when propanone is used instead of ethanal in this type of reaction (1)

(b) Name an aldehyde that would not take part in an aldol condensation (1)

(c) Apart from the structure of the reactants suggest what is unusual about applying the term ldquocondensationrdquo to this particular type of reaction (1)

29 Primary secondary and tertiary alkanols can be prepared by the reaction of carbonyl compounds with Grignard reagents

Step 1The Grignard reagent reacts with the carbonyl compound

Step 2The reaction of the product of Step 1 with dilute acid produces the alkanol

(a) Describe the difference between a primary a secondary and a tertiary alkanol

You may wish to include labelled structures in your answer (1)34

(b) Suggest a name for the type of reaction that takes place in Step 1 (1)

(c) The same Grignard reagent can be used to produce the alkanol below

Name the carbonyl compound used in this reaction (1)

30 Hairspray is a mixture of chemicals(a) A primary alcohol 2-methylpropan-1-ol is added to hairspray to help it dry quickly on the hair

Draw a structural formula for a secondary alcohol that is an isomer of2-methylpropan-1-ol (1)

(b) Triethanol amine and triisopropyl amine are bases used to neutralise acidic compounds in the hairspray to prevent damage to the hair

In terms of the intermolecular bonding present explain clearly why triethanol amine has a much higher boiling point than triisopropyl amine (2)

35

36

31 Chocolate contains various compounds(a) Many of the flavour and aroma molecules found in chocolate are aldehydes and

ketones Two examples are shown below

Phenylethanal can be easily oxidised but 13-diphenylpropan-2-one cannot(i) Name a chemical that could be used to distinguish between these two

compounds (1)

(ii) Name the type of organic compound formed when phenylethanal is oxidised (1)

(b) Glycerol monostearate is an emulsifier used in chocolate

(i) Why is glycerol monostearate added to chocolate (1)

(ii) Draw a structural formula for glycerol (1)

(c) Theobromine a compound present in chocolate can cause illness in dogs and cats To decide if treatment is necessary vets must calculate the mass of theobromine consumed 1middot0 g of chocolate contains 1middot4 mg of theobromine Calculate the mass in mg of theobromine in a 17 g biscuit of which 28 is chocolate Show your working clearly (2)

(d) The flavour and texture of chocolate comes from a blend of compoundsUsing your knowledge of chemistry describe how you could show that there are ionic compounds and covalent compounds present in chocolate (3)

37

32 Ethanol has many uses

(a) Ethanol is found at relatively low concentrations in wine

(i) Name the chemical reaction that produces ethanol in wine (1)

(ii) Standard ethanol solutions were used to produce a graph of density against

concentration of ethanol given as a percentage of alcohol by volume ( abv)

What is the concentration of ethanol in units of abv in a solution of density 0middot9818 g cmminus3 (1)

(b) Whisky contains a higher concentration of ethanol

(i) Before 1980 the concentration of alcohol in drinks was measured in terms of degrees proof The concentration of alcohol in two drinks is shown in the table below both as abv and degrees proof

38

A cask strength whisky has an alcohol concentration of 65 abv Calculate the alcohol concentration of this whisky in degrees proof (1)

(ii) A barrel containing 195 litres of cask strength whisky costs pound1300 The cask strength whisky is diluted with water to reduce the concentration of alcohol from 65 abv to 46 abv before it is bottled Calculate the cost of the cask strength whisky needed to produce a 0middot70 litre bottle Show your working clearly (2)

(iii) 5-Butyl-4-methyltetrahydrofuran-2-ol is a flavour compound found in whisky

stored in oak barrels

Write the systematic name for the compound shown below (1) 13 11

33 (a) One test for glucose involves Fehlingrsquos solutionCircle the part of the glucose molecule that reacts with Fehlingrsquos solution (1)

(b) In solution sugar molecules exist in an equilibrium in straight-chain and ring forms

To change from the straight-chain form to the ring form the oxygen of the hydroxyl on carbon number 5 joins to the carbonyl carbon This is shown below for glucose

39

Draw the structure of a ring form for fructose (1)

34 (a) During the free radical chain reaction small molecules join to form large chain molecules

One example of a small molecule used is

Name the functional group circled above (1)

(b)Alcohol wipes are used to finish the varnishing treatment Alcohol wipes contain the alcohol propan-2-olState why propan-2-ol can be described as a secondary alcohol (1)

35 A student was carrying out an investigation into alcohols aldehydes and ketones

(a)The student was given three alcohols labelled as A B and C These alcohols were all isomers with the formula C4H9OH

(i) Draw a structural formula for the secondary alcohol with the formula C4H9OH(1)

(ii) The student set up the following experiment

A Suggest why a water bath is an appropriate method of heating the reaction mixture (1)

B Describe the colour change that would have been observed with alcohols A and C (1)

40

C Alcohol B is not oxidised State the type of alcohol which cannot be oxidised by acidified dichromate solution (1)

(iii) The student set up a second experiment with alcohol A

Hot copper(II) oxide is an oxidising agentA When alcohol A (C4H9OH) is oxidised the product turns the pH paper

redSuggest a name for the product (1)

B Complete the ion-electron equation for the oxidation reaction

C4H9OH rarr C4H8O2 (1)

(b)The student found the following information about the boiling points of some aldehydes

41

(i) Name the aldehyde that has a boiling point of 119 degC (1)(ii) Predict the boiling point in degC of the following molecule (1)

(iii) Using information from the table describe one way in which differences in structure affect the boiling point of isomeric aldehydes (1)

(iv) State what would be observed when an aldehyde is gently heated with Tollensrsquo reagent (1)

(c) Ketones contain a carbonyl groupName the type of intermolecular interaction between ketone molecules (1)

42

25 Soaps Detergents and Emulsions

1 Soaps are produced by the following reaction

This reaction is an example ofA condensationB esterificationC hydrolysisD oxidation

2 Which of the following is the salt of a long-chain fatty acid

A FatB OilC SoapD Glycerol

3 Emulsifiers for use in food are commonly made by reacting edible oils with

A estersB glycerolC fatty acidsD amino acids

4 A fatty acid is a long chain carboxylic acid Examples of fatty acids are shown in the table below

43

(a) What is the systematic name for linolenic acid (1)(b) Stearic acid reacts with sodium hydroxide solution to form sodium stearate

(i) Name the type of reaction taking place when stearic acid reacts with sodium hydroxide (1)

(ii) Explain fully how sodium stearate acts to keep grease and non-polar substances suspended in water during cleaning (3)

5 Small children can find it difficult to swallow tablets or pills so ibuprofen is supplied as an ldquoinfant formulardquo emulsion(a) The emulsifier used is polysorbate 80 Its structure is shown below

Explain why this molecule acts as an emulsifier (2)

(b) The emulsion contains 2 g of ibuprofen in every 100 cm3 of emulsion The recommended dose for treating a 6 month old baby is 0middot050 g Calculate the volume in cm3 of ldquoinfant formulardquo needed to treat a 6 month old baby (1)

6 Occasionally seabirds can become contaminated with hydrocarbons from oil spills This causes problems for birds because their feathers lose their waterproofing making the birds susceptible to temperature changes and

44

affecting their buoyancy If the birds attempt to clean themselves to remove the oil they may swallow the hydrocarbons causing damage to their internal organsContaminated seabirds can be cleaned by rubbing vegetable oil into their feathers and feet before the birds are rinsed with diluted washing-up liquidUsing your knowledge of chemistry comment on the problems created for seabirds by oil spills and the actions taken to treat affected birds (3)

7 Dishwasher tablets contain chemicals which remove dirt from dishesDishwasher tablets include detergents These molecules act like soaps to allow mixing of fat-soluble dirt and water(a)During the cleaning process the detergent molecules combine with fat-

soluble dirtA simplified diagram of a detergent molecule is shown

Complete the diagram below to show how detergent molecules combine with fat-soluble dirt (1)

(b)State the term used to describe the non-polar hydrocarbon tail of a detergent molecule (1)

45

26 Fragrances1 Myrcene is a simple terpene

Terpenes contain at least one isoprene unit Which of the following shows a correctly highlighted isoprene unit

2 Limonene is one of the terpene molecules responsible for the flavour of lemons

How many isoprene units are used in the production of one limonene moleculeA 1B 2C 3D 4

46

3 The structure of caryophyllene which can be extracted from clove oil is

Which of the following would be the best solvent for extracting caryophylleneA HexaneB HexanalC HexanolD Hexanone

4 The structure of isoprene is

Limonene is a terpene molecule present in lemons

How many isoprene units are joined together in a limonene molecule

A 1B 2

47

C 3D 4

5 Essential oils are

A non-water soluble non-volatile compoundsB non-water soluble volatile compoundsC water soluble non-volatile compoundsD water soluble volatile compounds

6 Two typical compounds that are present in many perfumes are shown

(a) Why does geraniol evaporate more slowly than limonene (1)

(b) The structure of one of the first synthetic scents used in perfume is shown below

(i) Name the family of carbonyl compounds to which this synthetic scent belongs (1)

(ii) Complete the structure below to show the product formed when this scent is

oxidised (1)

(c) Traces of a liquid were discovered in a bottle believed to contain perfume belonging to Queen Hatshepsut ruler of Egypt over 3500 years ago

Perfumes were made by dissolving plant extracts containing pleasant smelling terpenes and esters in an edible oil A little ethanol and water may also have been addedUsing your knowledge of chemistry comment on the possible smell(s) when such a bottle is opened after being stored for thousands of years (3)

48

49

7 A team of chemists are developing a fragrance for use in a shower gel for men(a) To give the gel a fruity smell the chemists are considering adding an ester

They synthesise six isomeric esters Volunteers smell each ester and give it a rating out of one hundred depending on how fruity the smell is

(i) Name the ester with the fruit-smell rating of 92 (1)

(ii) Shown below are the structures of three more isomers

Arrange these esters in order of decreasing fruit-smell rating (1)

50

(b) To create a fragrance for men the compound civetone is added

Draw a structural formula for the alcohol that can be oxidised to form civetone (1)

(c) To make the shower gel produce a cold tingling sensation when applied to the skin menthol is added

Like terpenes menthol is formed from isoprene (2-methylbuta-13-diene)Circle an isoprene unit on the menthol structure above (1)

8 Many of the compounds in perfumes are molecules consisting of joined isoprene units

(a) State the name that is given to molecules consisting of joined isoprene units (1)

(b)Geraniol is one of the compounds found in perfume It has the following structural formula and systematic name

Linalool can also be present Its structural formula is shown

51

(i) State the systematic name for linalool (1)(ii) Explain why linalool can be classified as a tertiary alcohol (1)

9 The component molecules found in lavender oils are terpenes or terpenoids(a)A chiral carbon is a carbon atom attached to four different atoms or groups of

atomsAn example is shown below

A molecule of the terpenoid linalool has a chiral carbon Linalool has the following structure

Circle the chiral carbon atom in the linalool structure (1)

(b)Farnesene is a terpene consisting of three isoprene units (2-methylbuta-13-diene) joined togetherWrite the molecular formula of farnesene (1)

52

27 Skin Care

1 Which of the following is not a step in a free radical chain reaction

A ActivationB InitiationC PropagationD Termination

2 Fluorine reacts with methane via a free radical chain reaction Some steps in the chain reaction are shown in the table below

Complete the table by(a) inserting the missing name for the first step (1)

(b) showing another possible termination reaction in the final row of the table (1)

3 Suncreams contain antioxidantsThe antioxidant compound A can prevent damage to skin by reacting with free

radicalssuch as NO2bull

53

Why can compound A be described as a free radical scavenger in the reaction shown above

4 Hydrogen and chlorine gases are used in an experiment to demonstrate a free radical reaction A plastic bottle is wrapped with black tape leaving a ldquowindowrdquo on one sideThe bottle is filled with a mixture of hydrogen and chlorine When bright light shines on the bottle there is an explosion

A free radical chain reaction is initiated when light energy causes chlorine radicals to form as shown below

(a) Complete the equations below showing possible propagation and termination steps

(2)

54

(b) Why is the plastic bottle used in the experiment wrapped in black tape (1)

5 Chloramines can be removed from water using ultraviolet light treatment

One step in the process is the formation of free radicals

(a)State what is meant by the term free radical (1)

(b)Another step in the process is shown below

State the name for this type of step in a free radical reaction (1)

6 Modern shellac nail varnishes are more durable and so last longer than traditional nail polish

The shellac nail varnish is applied in thin layers to the nails and then the fingers are placed under a UV lamp

(a) The Skin Care Foundation has recommended that a sun-block is applied to the fingers and hand before using the lampSuggest why the Skin Care Foundation makes this recommendation (1)

(b) A free radical chain reaction takes place and the varnish hardens (i) State what is meant by the term free radical (1)

(ii) The shellac nail varnish contains a mixture of ingredients that take part in the free radical chain reactionOne of the steps in the free radical chain reaction is

55

State the term used to describe this type of step in a free radical chain reaction(1)

7 Skin care products contain a mixture of polar covalent non-polar covalent and ionic compounds The compounds need to stay mixed within the product Skin care products also need to spread easily and remain on the skin for a period of time as well as provide physical and chemical protection from the sun In order to do this skin care products contain a range of chemicals including water fats and oils antioxidants minerals and sun blockUsing your knowledge of chemistry explain the role of different chemicals in skin care products (3)

General Questions

1 A mixture of carbon monoxide and hydrogen can be converted into water and a mixture of hydrocarbons

nCO + (2n + 1)H2 rarr nH2O + hydrocarbons

What is the general formula for the hydrocarbons producedA CnH2nndash2B CnH2nC CnH2n+1D CnH2n+2

2 Butadiene is the first member of a homologous series of hydrocarbons called dienesWhat is the general formula for this seriesA CnHn+2B CnHn+3C CnH2nD CnH2nndash2

3 Which of the following statements about methanol is falseA It can be made from synthesis gasB It can be dehydrated to form an alkeneC It can be oxidised to give a carboxylic acidD It reacts with acidified potassium dichromate solution

56

4

Which line in the table correctly describes reactions X and Y

5

Which line in the table correctly describes reactions X and Y

6 Which of the following fuels when burned would make no contribution to globalwarming

57

A HydrogenB Natural gasC PetrolD Coal

7 Which of the following hydrocarbons always gives the same product when one of itshydrogen atoms is replaced by a chlorine atomA HexaneB Hex-1-eneC CyclohexaneD Cyclohexene

8 Which of the following compounds does not have isomeric structuresA C2HCl3B C2H4Cl2C PropeneD Propan-1-ol

9 What organic compound is produced by the dehydration of ethanol A EthaneB EtheneC EthanalD Ethanoic acid

10

The above equation representsA hydrationB hydrogenationC condensationD hydrolysis

11

Which of the following compounds is an isomer of the structure shown aboveA ButanalB ButanoneC Butan-1-olD Butanoic acid

58

12 A compound with molecular formula C6H12O2 could beA hexanalB hexan-2-olC hexan-2-oneD hexanoic acid

13 Propan-2-ol can be prepared from propane as follows

Which line in the table correctly describes the types of reaction taking place at Steps 1 and 2

14 Which of the following compounds would be the most water soluble

15 Cyanohydrin compounds can be made from carbonyl compounds by reacting the carbonyl compound with hydrogen cyanide (HCN)

59

Which carbonyl compound would react with hydrogen cyanide (HCN) to form the following compound

16 Ethyne is the first member of the homologous series called the alkynes

Ethyne can undergo addition reactions as shown in the flow diagram

(a) Compound 2 is an isomer of 12-dichloroethaneDraw a structural formula for compound 2 (1)

(b) Reagents A B and C are three different diatomic gasesUsing information in the flow diagram identify reagents A B and C (1)

60

Reagent Gas

A

B

C

17 In 1865 the German chemist Kekuleacute proposed a ring structure for benzene This structure was based on alternating single and double bonds

(a) (i) Describe a chemical test that would indicate that the above chemical structure for benzene is incorrect (1)

(ii) Briefly describe the correct structure for benzene (1)

(b) Benzene can be formed from cyclohexaneC6H12 rarr C6H6 + 3H2

What name is given to this type of reaction (1)18 Infra-red spectroscopy is a technique that can be used to identify the bonds that

arepresent in a molecule Different bonds absorb infra-red radiation of different wavenumbers This is due to differences in the bond lsquostretchrsquo These absorptions are recorded in a spectrumA spectrum for propan-1-ol is shown

61

The correlation table on page 13 of the data booklet shows the wavenumber ranges for the absorptions due to different bonds

(a) Use the correlation table to identify the bonds responsible for the two absorptions x and y that are circled in the propan-1-ol spectrum (1)

(b) Propan-1-ol reacts with ethanoic acid(i) What name is given to this type of reaction (1)(ii) Draw a spectrum that could be obtained for the organic product of this

reaction (1)

19 Paracetamol is a widely used painkiller

(a) Write the molecular formula for paracetamol (1)

(b) One antidote for paracetamol overdose is methionine

62

To what family of organic compounds does methionine belong (1)

(c) The concentration of paracetamol in a solution can be determined by measuring how much UV radiation it absorbs

The graph shows how the absorbance of a sample containing 0middot040 g l ndash1 paracetamol varies with wavelength

The quantity of UV radiation of wavelength 245 nm absorbed is directly proportional to the concentration of paracetamolThe absorbance of a second sample of paracetamol solution measured at 245 nm was 0middot90 What is the concentration in g l ndash1 of this second paracetamol solution (1)

20 Many carbon compounds containing oxygen are very flammableThe table shows information about two families of isomersThe lowest temperature at which a compound will ignite is called its flash point

(a) A compound with the molecular formula C6H14O has a boiling point of 158 degC63

Draw a structural formula for this compound (1)

(b) For a family of isomers in the table write a general statement linking the flash points of the compounds to their structures (1)

21 Hydrogels are used in disposable nappies They are fine powders that can absorb up to 500 times their own weight in waterA hydrogel is a very long molecule with carboxyl groups at regular intervals along its length A short section of a hydrogel molecule is shown below

Hydrogels are extremely good at soaking up water because the water molecules are strongly attracted to them

Using your knowledge of chemistry comment on how suitable hydrogels would be for absorbing liquids or solutions spilled in a chemistry lab (1)

64

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

(d) Aldehydes can also be formed by the reaction of some alcohols with copper(II) oxideName the type of alcohol that would react with copper(II) oxide to form an aldehyde (1)

28 Aldehydes and ketones can take part in a reaction sometimes known as an aldol condensation The simplest aldol reaction involves two molecules of ethanal

In the reaction the carbon atom next to the carbonyl functional group of one molecule forms a bond with the carbonyl carbon atom of the second molecule

(a) Draw a structural formula for the product formed when propanone is used instead of ethanal in this type of reaction (1)

(b) Name an aldehyde that would not take part in an aldol condensation (1)

(c) Apart from the structure of the reactants suggest what is unusual about applying the term ldquocondensationrdquo to this particular type of reaction (1)

29 Primary secondary and tertiary alkanols can be prepared by the reaction of carbonyl compounds with Grignard reagents

Step 1The Grignard reagent reacts with the carbonyl compound

Step 2The reaction of the product of Step 1 with dilute acid produces the alkanol

(a) Describe the difference between a primary a secondary and a tertiary alkanol

You may wish to include labelled structures in your answer (1)34

(b) Suggest a name for the type of reaction that takes place in Step 1 (1)

(c) The same Grignard reagent can be used to produce the alkanol below

Name the carbonyl compound used in this reaction (1)

30 Hairspray is a mixture of chemicals(a) A primary alcohol 2-methylpropan-1-ol is added to hairspray to help it dry quickly on the hair

Draw a structural formula for a secondary alcohol that is an isomer of2-methylpropan-1-ol (1)

(b) Triethanol amine and triisopropyl amine are bases used to neutralise acidic compounds in the hairspray to prevent damage to the hair

In terms of the intermolecular bonding present explain clearly why triethanol amine has a much higher boiling point than triisopropyl amine (2)

35

36

31 Chocolate contains various compounds(a) Many of the flavour and aroma molecules found in chocolate are aldehydes and

ketones Two examples are shown below

Phenylethanal can be easily oxidised but 13-diphenylpropan-2-one cannot(i) Name a chemical that could be used to distinguish between these two

compounds (1)

(ii) Name the type of organic compound formed when phenylethanal is oxidised (1)

(b) Glycerol monostearate is an emulsifier used in chocolate

(i) Why is glycerol monostearate added to chocolate (1)

(ii) Draw a structural formula for glycerol (1)

(c) Theobromine a compound present in chocolate can cause illness in dogs and cats To decide if treatment is necessary vets must calculate the mass of theobromine consumed 1middot0 g of chocolate contains 1middot4 mg of theobromine Calculate the mass in mg of theobromine in a 17 g biscuit of which 28 is chocolate Show your working clearly (2)

(d) The flavour and texture of chocolate comes from a blend of compoundsUsing your knowledge of chemistry describe how you could show that there are ionic compounds and covalent compounds present in chocolate (3)

37

32 Ethanol has many uses

(a) Ethanol is found at relatively low concentrations in wine

(i) Name the chemical reaction that produces ethanol in wine (1)

(ii) Standard ethanol solutions were used to produce a graph of density against

concentration of ethanol given as a percentage of alcohol by volume ( abv)

What is the concentration of ethanol in units of abv in a solution of density 0middot9818 g cmminus3 (1)

(b) Whisky contains a higher concentration of ethanol

(i) Before 1980 the concentration of alcohol in drinks was measured in terms of degrees proof The concentration of alcohol in two drinks is shown in the table below both as abv and degrees proof

38

A cask strength whisky has an alcohol concentration of 65 abv Calculate the alcohol concentration of this whisky in degrees proof (1)

(ii) A barrel containing 195 litres of cask strength whisky costs pound1300 The cask strength whisky is diluted with water to reduce the concentration of alcohol from 65 abv to 46 abv before it is bottled Calculate the cost of the cask strength whisky needed to produce a 0middot70 litre bottle Show your working clearly (2)

(iii) 5-Butyl-4-methyltetrahydrofuran-2-ol is a flavour compound found in whisky

stored in oak barrels

Write the systematic name for the compound shown below (1) 13 11

33 (a) One test for glucose involves Fehlingrsquos solutionCircle the part of the glucose molecule that reacts with Fehlingrsquos solution (1)

(b) In solution sugar molecules exist in an equilibrium in straight-chain and ring forms

To change from the straight-chain form to the ring form the oxygen of the hydroxyl on carbon number 5 joins to the carbonyl carbon This is shown below for glucose

39

Draw the structure of a ring form for fructose (1)

34 (a) During the free radical chain reaction small molecules join to form large chain molecules

One example of a small molecule used is

Name the functional group circled above (1)

(b)Alcohol wipes are used to finish the varnishing treatment Alcohol wipes contain the alcohol propan-2-olState why propan-2-ol can be described as a secondary alcohol (1)

35 A student was carrying out an investigation into alcohols aldehydes and ketones

(a)The student was given three alcohols labelled as A B and C These alcohols were all isomers with the formula C4H9OH

(i) Draw a structural formula for the secondary alcohol with the formula C4H9OH(1)

(ii) The student set up the following experiment

A Suggest why a water bath is an appropriate method of heating the reaction mixture (1)

B Describe the colour change that would have been observed with alcohols A and C (1)

40

C Alcohol B is not oxidised State the type of alcohol which cannot be oxidised by acidified dichromate solution (1)

(iii) The student set up a second experiment with alcohol A

Hot copper(II) oxide is an oxidising agentA When alcohol A (C4H9OH) is oxidised the product turns the pH paper

redSuggest a name for the product (1)

B Complete the ion-electron equation for the oxidation reaction

C4H9OH rarr C4H8O2 (1)

(b)The student found the following information about the boiling points of some aldehydes

41

(i) Name the aldehyde that has a boiling point of 119 degC (1)(ii) Predict the boiling point in degC of the following molecule (1)

(iii) Using information from the table describe one way in which differences in structure affect the boiling point of isomeric aldehydes (1)

(iv) State what would be observed when an aldehyde is gently heated with Tollensrsquo reagent (1)

(c) Ketones contain a carbonyl groupName the type of intermolecular interaction between ketone molecules (1)

42

25 Soaps Detergents and Emulsions

1 Soaps are produced by the following reaction

This reaction is an example ofA condensationB esterificationC hydrolysisD oxidation

2 Which of the following is the salt of a long-chain fatty acid

A FatB OilC SoapD Glycerol

3 Emulsifiers for use in food are commonly made by reacting edible oils with

A estersB glycerolC fatty acidsD amino acids

4 A fatty acid is a long chain carboxylic acid Examples of fatty acids are shown in the table below

43

(a) What is the systematic name for linolenic acid (1)(b) Stearic acid reacts with sodium hydroxide solution to form sodium stearate

(i) Name the type of reaction taking place when stearic acid reacts with sodium hydroxide (1)

(ii) Explain fully how sodium stearate acts to keep grease and non-polar substances suspended in water during cleaning (3)

5 Small children can find it difficult to swallow tablets or pills so ibuprofen is supplied as an ldquoinfant formulardquo emulsion(a) The emulsifier used is polysorbate 80 Its structure is shown below

Explain why this molecule acts as an emulsifier (2)

(b) The emulsion contains 2 g of ibuprofen in every 100 cm3 of emulsion The recommended dose for treating a 6 month old baby is 0middot050 g Calculate the volume in cm3 of ldquoinfant formulardquo needed to treat a 6 month old baby (1)

6 Occasionally seabirds can become contaminated with hydrocarbons from oil spills This causes problems for birds because their feathers lose their waterproofing making the birds susceptible to temperature changes and

44

affecting their buoyancy If the birds attempt to clean themselves to remove the oil they may swallow the hydrocarbons causing damage to their internal organsContaminated seabirds can be cleaned by rubbing vegetable oil into their feathers and feet before the birds are rinsed with diluted washing-up liquidUsing your knowledge of chemistry comment on the problems created for seabirds by oil spills and the actions taken to treat affected birds (3)

7 Dishwasher tablets contain chemicals which remove dirt from dishesDishwasher tablets include detergents These molecules act like soaps to allow mixing of fat-soluble dirt and water(a)During the cleaning process the detergent molecules combine with fat-

soluble dirtA simplified diagram of a detergent molecule is shown

Complete the diagram below to show how detergent molecules combine with fat-soluble dirt (1)

(b)State the term used to describe the non-polar hydrocarbon tail of a detergent molecule (1)

45

26 Fragrances1 Myrcene is a simple terpene

Terpenes contain at least one isoprene unit Which of the following shows a correctly highlighted isoprene unit

2 Limonene is one of the terpene molecules responsible for the flavour of lemons

How many isoprene units are used in the production of one limonene moleculeA 1B 2C 3D 4

46

3 The structure of caryophyllene which can be extracted from clove oil is

Which of the following would be the best solvent for extracting caryophylleneA HexaneB HexanalC HexanolD Hexanone

4 The structure of isoprene is

Limonene is a terpene molecule present in lemons

How many isoprene units are joined together in a limonene molecule

A 1B 2

47

C 3D 4

5 Essential oils are

A non-water soluble non-volatile compoundsB non-water soluble volatile compoundsC water soluble non-volatile compoundsD water soluble volatile compounds

6 Two typical compounds that are present in many perfumes are shown

(a) Why does geraniol evaporate more slowly than limonene (1)

(b) The structure of one of the first synthetic scents used in perfume is shown below

(i) Name the family of carbonyl compounds to which this synthetic scent belongs (1)

(ii) Complete the structure below to show the product formed when this scent is

oxidised (1)

(c) Traces of a liquid were discovered in a bottle believed to contain perfume belonging to Queen Hatshepsut ruler of Egypt over 3500 years ago

Perfumes were made by dissolving plant extracts containing pleasant smelling terpenes and esters in an edible oil A little ethanol and water may also have been addedUsing your knowledge of chemistry comment on the possible smell(s) when such a bottle is opened after being stored for thousands of years (3)

48

49

7 A team of chemists are developing a fragrance for use in a shower gel for men(a) To give the gel a fruity smell the chemists are considering adding an ester

They synthesise six isomeric esters Volunteers smell each ester and give it a rating out of one hundred depending on how fruity the smell is

(i) Name the ester with the fruit-smell rating of 92 (1)

(ii) Shown below are the structures of three more isomers

Arrange these esters in order of decreasing fruit-smell rating (1)

50

(b) To create a fragrance for men the compound civetone is added

Draw a structural formula for the alcohol that can be oxidised to form civetone (1)

(c) To make the shower gel produce a cold tingling sensation when applied to the skin menthol is added

Like terpenes menthol is formed from isoprene (2-methylbuta-13-diene)Circle an isoprene unit on the menthol structure above (1)

8 Many of the compounds in perfumes are molecules consisting of joined isoprene units

(a) State the name that is given to molecules consisting of joined isoprene units (1)

(b)Geraniol is one of the compounds found in perfume It has the following structural formula and systematic name

Linalool can also be present Its structural formula is shown

51

(i) State the systematic name for linalool (1)(ii) Explain why linalool can be classified as a tertiary alcohol (1)

9 The component molecules found in lavender oils are terpenes or terpenoids(a)A chiral carbon is a carbon atom attached to four different atoms or groups of

atomsAn example is shown below

A molecule of the terpenoid linalool has a chiral carbon Linalool has the following structure

Circle the chiral carbon atom in the linalool structure (1)

(b)Farnesene is a terpene consisting of three isoprene units (2-methylbuta-13-diene) joined togetherWrite the molecular formula of farnesene (1)

52

27 Skin Care

1 Which of the following is not a step in a free radical chain reaction

A ActivationB InitiationC PropagationD Termination

2 Fluorine reacts with methane via a free radical chain reaction Some steps in the chain reaction are shown in the table below

Complete the table by(a) inserting the missing name for the first step (1)

(b) showing another possible termination reaction in the final row of the table (1)

3 Suncreams contain antioxidantsThe antioxidant compound A can prevent damage to skin by reacting with free

radicalssuch as NO2bull

53

Why can compound A be described as a free radical scavenger in the reaction shown above

4 Hydrogen and chlorine gases are used in an experiment to demonstrate a free radical reaction A plastic bottle is wrapped with black tape leaving a ldquowindowrdquo on one sideThe bottle is filled with a mixture of hydrogen and chlorine When bright light shines on the bottle there is an explosion

A free radical chain reaction is initiated when light energy causes chlorine radicals to form as shown below

(a) Complete the equations below showing possible propagation and termination steps

(2)

54

(b) Why is the plastic bottle used in the experiment wrapped in black tape (1)

5 Chloramines can be removed from water using ultraviolet light treatment

One step in the process is the formation of free radicals

(a)State what is meant by the term free radical (1)

(b)Another step in the process is shown below

State the name for this type of step in a free radical reaction (1)

6 Modern shellac nail varnishes are more durable and so last longer than traditional nail polish

The shellac nail varnish is applied in thin layers to the nails and then the fingers are placed under a UV lamp

(a) The Skin Care Foundation has recommended that a sun-block is applied to the fingers and hand before using the lampSuggest why the Skin Care Foundation makes this recommendation (1)

(b) A free radical chain reaction takes place and the varnish hardens (i) State what is meant by the term free radical (1)

(ii) The shellac nail varnish contains a mixture of ingredients that take part in the free radical chain reactionOne of the steps in the free radical chain reaction is

55

State the term used to describe this type of step in a free radical chain reaction(1)

7 Skin care products contain a mixture of polar covalent non-polar covalent and ionic compounds The compounds need to stay mixed within the product Skin care products also need to spread easily and remain on the skin for a period of time as well as provide physical and chemical protection from the sun In order to do this skin care products contain a range of chemicals including water fats and oils antioxidants minerals and sun blockUsing your knowledge of chemistry explain the role of different chemicals in skin care products (3)

General Questions

1 A mixture of carbon monoxide and hydrogen can be converted into water and a mixture of hydrocarbons

nCO + (2n + 1)H2 rarr nH2O + hydrocarbons

What is the general formula for the hydrocarbons producedA CnH2nndash2B CnH2nC CnH2n+1D CnH2n+2

2 Butadiene is the first member of a homologous series of hydrocarbons called dienesWhat is the general formula for this seriesA CnHn+2B CnHn+3C CnH2nD CnH2nndash2

3 Which of the following statements about methanol is falseA It can be made from synthesis gasB It can be dehydrated to form an alkeneC It can be oxidised to give a carboxylic acidD It reacts with acidified potassium dichromate solution

56

4

Which line in the table correctly describes reactions X and Y

5

Which line in the table correctly describes reactions X and Y

6 Which of the following fuels when burned would make no contribution to globalwarming

57

A HydrogenB Natural gasC PetrolD Coal

7 Which of the following hydrocarbons always gives the same product when one of itshydrogen atoms is replaced by a chlorine atomA HexaneB Hex-1-eneC CyclohexaneD Cyclohexene

8 Which of the following compounds does not have isomeric structuresA C2HCl3B C2H4Cl2C PropeneD Propan-1-ol

9 What organic compound is produced by the dehydration of ethanol A EthaneB EtheneC EthanalD Ethanoic acid

10

The above equation representsA hydrationB hydrogenationC condensationD hydrolysis

11

Which of the following compounds is an isomer of the structure shown aboveA ButanalB ButanoneC Butan-1-olD Butanoic acid

58

12 A compound with molecular formula C6H12O2 could beA hexanalB hexan-2-olC hexan-2-oneD hexanoic acid

13 Propan-2-ol can be prepared from propane as follows

Which line in the table correctly describes the types of reaction taking place at Steps 1 and 2

14 Which of the following compounds would be the most water soluble

15 Cyanohydrin compounds can be made from carbonyl compounds by reacting the carbonyl compound with hydrogen cyanide (HCN)

59

Which carbonyl compound would react with hydrogen cyanide (HCN) to form the following compound

16 Ethyne is the first member of the homologous series called the alkynes

Ethyne can undergo addition reactions as shown in the flow diagram

(a) Compound 2 is an isomer of 12-dichloroethaneDraw a structural formula for compound 2 (1)

(b) Reagents A B and C are three different diatomic gasesUsing information in the flow diagram identify reagents A B and C (1)

60

Reagent Gas

A

B

C

17 In 1865 the German chemist Kekuleacute proposed a ring structure for benzene This structure was based on alternating single and double bonds

(a) (i) Describe a chemical test that would indicate that the above chemical structure for benzene is incorrect (1)

(ii) Briefly describe the correct structure for benzene (1)

(b) Benzene can be formed from cyclohexaneC6H12 rarr C6H6 + 3H2

What name is given to this type of reaction (1)18 Infra-red spectroscopy is a technique that can be used to identify the bonds that

arepresent in a molecule Different bonds absorb infra-red radiation of different wavenumbers This is due to differences in the bond lsquostretchrsquo These absorptions are recorded in a spectrumA spectrum for propan-1-ol is shown

61

The correlation table on page 13 of the data booklet shows the wavenumber ranges for the absorptions due to different bonds

(a) Use the correlation table to identify the bonds responsible for the two absorptions x and y that are circled in the propan-1-ol spectrum (1)

(b) Propan-1-ol reacts with ethanoic acid(i) What name is given to this type of reaction (1)(ii) Draw a spectrum that could be obtained for the organic product of this

reaction (1)

19 Paracetamol is a widely used painkiller

(a) Write the molecular formula for paracetamol (1)

(b) One antidote for paracetamol overdose is methionine

62

To what family of organic compounds does methionine belong (1)

(c) The concentration of paracetamol in a solution can be determined by measuring how much UV radiation it absorbs

The graph shows how the absorbance of a sample containing 0middot040 g l ndash1 paracetamol varies with wavelength

The quantity of UV radiation of wavelength 245 nm absorbed is directly proportional to the concentration of paracetamolThe absorbance of a second sample of paracetamol solution measured at 245 nm was 0middot90 What is the concentration in g l ndash1 of this second paracetamol solution (1)

20 Many carbon compounds containing oxygen are very flammableThe table shows information about two families of isomersThe lowest temperature at which a compound will ignite is called its flash point

(a) A compound with the molecular formula C6H14O has a boiling point of 158 degC63

Draw a structural formula for this compound (1)

(b) For a family of isomers in the table write a general statement linking the flash points of the compounds to their structures (1)

21 Hydrogels are used in disposable nappies They are fine powders that can absorb up to 500 times their own weight in waterA hydrogel is a very long molecule with carboxyl groups at regular intervals along its length A short section of a hydrogel molecule is shown below

Hydrogels are extremely good at soaking up water because the water molecules are strongly attracted to them

Using your knowledge of chemistry comment on how suitable hydrogels would be for absorbing liquids or solutions spilled in a chemistry lab (1)

64

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

(b) Suggest a name for the type of reaction that takes place in Step 1 (1)

(c) The same Grignard reagent can be used to produce the alkanol below

Name the carbonyl compound used in this reaction (1)

30 Hairspray is a mixture of chemicals(a) A primary alcohol 2-methylpropan-1-ol is added to hairspray to help it dry quickly on the hair

Draw a structural formula for a secondary alcohol that is an isomer of2-methylpropan-1-ol (1)

(b) Triethanol amine and triisopropyl amine are bases used to neutralise acidic compounds in the hairspray to prevent damage to the hair

In terms of the intermolecular bonding present explain clearly why triethanol amine has a much higher boiling point than triisopropyl amine (2)

35

36

31 Chocolate contains various compounds(a) Many of the flavour and aroma molecules found in chocolate are aldehydes and

ketones Two examples are shown below

Phenylethanal can be easily oxidised but 13-diphenylpropan-2-one cannot(i) Name a chemical that could be used to distinguish between these two

compounds (1)

(ii) Name the type of organic compound formed when phenylethanal is oxidised (1)

(b) Glycerol monostearate is an emulsifier used in chocolate

(i) Why is glycerol monostearate added to chocolate (1)

(ii) Draw a structural formula for glycerol (1)

(c) Theobromine a compound present in chocolate can cause illness in dogs and cats To decide if treatment is necessary vets must calculate the mass of theobromine consumed 1middot0 g of chocolate contains 1middot4 mg of theobromine Calculate the mass in mg of theobromine in a 17 g biscuit of which 28 is chocolate Show your working clearly (2)

(d) The flavour and texture of chocolate comes from a blend of compoundsUsing your knowledge of chemistry describe how you could show that there are ionic compounds and covalent compounds present in chocolate (3)

37

32 Ethanol has many uses

(a) Ethanol is found at relatively low concentrations in wine

(i) Name the chemical reaction that produces ethanol in wine (1)

(ii) Standard ethanol solutions were used to produce a graph of density against

concentration of ethanol given as a percentage of alcohol by volume ( abv)

What is the concentration of ethanol in units of abv in a solution of density 0middot9818 g cmminus3 (1)

(b) Whisky contains a higher concentration of ethanol

(i) Before 1980 the concentration of alcohol in drinks was measured in terms of degrees proof The concentration of alcohol in two drinks is shown in the table below both as abv and degrees proof

38

A cask strength whisky has an alcohol concentration of 65 abv Calculate the alcohol concentration of this whisky in degrees proof (1)

(ii) A barrel containing 195 litres of cask strength whisky costs pound1300 The cask strength whisky is diluted with water to reduce the concentration of alcohol from 65 abv to 46 abv before it is bottled Calculate the cost of the cask strength whisky needed to produce a 0middot70 litre bottle Show your working clearly (2)

(iii) 5-Butyl-4-methyltetrahydrofuran-2-ol is a flavour compound found in whisky

stored in oak barrels

Write the systematic name for the compound shown below (1) 13 11

33 (a) One test for glucose involves Fehlingrsquos solutionCircle the part of the glucose molecule that reacts with Fehlingrsquos solution (1)

(b) In solution sugar molecules exist in an equilibrium in straight-chain and ring forms

To change from the straight-chain form to the ring form the oxygen of the hydroxyl on carbon number 5 joins to the carbonyl carbon This is shown below for glucose

39

Draw the structure of a ring form for fructose (1)

34 (a) During the free radical chain reaction small molecules join to form large chain molecules

One example of a small molecule used is

Name the functional group circled above (1)

(b)Alcohol wipes are used to finish the varnishing treatment Alcohol wipes contain the alcohol propan-2-olState why propan-2-ol can be described as a secondary alcohol (1)

35 A student was carrying out an investigation into alcohols aldehydes and ketones

(a)The student was given three alcohols labelled as A B and C These alcohols were all isomers with the formula C4H9OH

(i) Draw a structural formula for the secondary alcohol with the formula C4H9OH(1)

(ii) The student set up the following experiment

A Suggest why a water bath is an appropriate method of heating the reaction mixture (1)

B Describe the colour change that would have been observed with alcohols A and C (1)

40

C Alcohol B is not oxidised State the type of alcohol which cannot be oxidised by acidified dichromate solution (1)

(iii) The student set up a second experiment with alcohol A

Hot copper(II) oxide is an oxidising agentA When alcohol A (C4H9OH) is oxidised the product turns the pH paper

redSuggest a name for the product (1)

B Complete the ion-electron equation for the oxidation reaction

C4H9OH rarr C4H8O2 (1)

(b)The student found the following information about the boiling points of some aldehydes

41

(i) Name the aldehyde that has a boiling point of 119 degC (1)(ii) Predict the boiling point in degC of the following molecule (1)

(iii) Using information from the table describe one way in which differences in structure affect the boiling point of isomeric aldehydes (1)

(iv) State what would be observed when an aldehyde is gently heated with Tollensrsquo reagent (1)

(c) Ketones contain a carbonyl groupName the type of intermolecular interaction between ketone molecules (1)

42

25 Soaps Detergents and Emulsions

1 Soaps are produced by the following reaction

This reaction is an example ofA condensationB esterificationC hydrolysisD oxidation

2 Which of the following is the salt of a long-chain fatty acid

A FatB OilC SoapD Glycerol

3 Emulsifiers for use in food are commonly made by reacting edible oils with

A estersB glycerolC fatty acidsD amino acids

4 A fatty acid is a long chain carboxylic acid Examples of fatty acids are shown in the table below

43

(a) What is the systematic name for linolenic acid (1)(b) Stearic acid reacts with sodium hydroxide solution to form sodium stearate

(i) Name the type of reaction taking place when stearic acid reacts with sodium hydroxide (1)

(ii) Explain fully how sodium stearate acts to keep grease and non-polar substances suspended in water during cleaning (3)

5 Small children can find it difficult to swallow tablets or pills so ibuprofen is supplied as an ldquoinfant formulardquo emulsion(a) The emulsifier used is polysorbate 80 Its structure is shown below

Explain why this molecule acts as an emulsifier (2)

(b) The emulsion contains 2 g of ibuprofen in every 100 cm3 of emulsion The recommended dose for treating a 6 month old baby is 0middot050 g Calculate the volume in cm3 of ldquoinfant formulardquo needed to treat a 6 month old baby (1)

6 Occasionally seabirds can become contaminated with hydrocarbons from oil spills This causes problems for birds because their feathers lose their waterproofing making the birds susceptible to temperature changes and

44

affecting their buoyancy If the birds attempt to clean themselves to remove the oil they may swallow the hydrocarbons causing damage to their internal organsContaminated seabirds can be cleaned by rubbing vegetable oil into their feathers and feet before the birds are rinsed with diluted washing-up liquidUsing your knowledge of chemistry comment on the problems created for seabirds by oil spills and the actions taken to treat affected birds (3)

7 Dishwasher tablets contain chemicals which remove dirt from dishesDishwasher tablets include detergents These molecules act like soaps to allow mixing of fat-soluble dirt and water(a)During the cleaning process the detergent molecules combine with fat-

soluble dirtA simplified diagram of a detergent molecule is shown

Complete the diagram below to show how detergent molecules combine with fat-soluble dirt (1)

(b)State the term used to describe the non-polar hydrocarbon tail of a detergent molecule (1)

45

26 Fragrances1 Myrcene is a simple terpene

Terpenes contain at least one isoprene unit Which of the following shows a correctly highlighted isoprene unit

2 Limonene is one of the terpene molecules responsible for the flavour of lemons

How many isoprene units are used in the production of one limonene moleculeA 1B 2C 3D 4

46

3 The structure of caryophyllene which can be extracted from clove oil is

Which of the following would be the best solvent for extracting caryophylleneA HexaneB HexanalC HexanolD Hexanone

4 The structure of isoprene is

Limonene is a terpene molecule present in lemons

How many isoprene units are joined together in a limonene molecule

A 1B 2

47

C 3D 4

5 Essential oils are

A non-water soluble non-volatile compoundsB non-water soluble volatile compoundsC water soluble non-volatile compoundsD water soluble volatile compounds

6 Two typical compounds that are present in many perfumes are shown

(a) Why does geraniol evaporate more slowly than limonene (1)

(b) The structure of one of the first synthetic scents used in perfume is shown below

(i) Name the family of carbonyl compounds to which this synthetic scent belongs (1)

(ii) Complete the structure below to show the product formed when this scent is

oxidised (1)

(c) Traces of a liquid were discovered in a bottle believed to contain perfume belonging to Queen Hatshepsut ruler of Egypt over 3500 years ago

Perfumes were made by dissolving plant extracts containing pleasant smelling terpenes and esters in an edible oil A little ethanol and water may also have been addedUsing your knowledge of chemistry comment on the possible smell(s) when such a bottle is opened after being stored for thousands of years (3)

48

49

7 A team of chemists are developing a fragrance for use in a shower gel for men(a) To give the gel a fruity smell the chemists are considering adding an ester

They synthesise six isomeric esters Volunteers smell each ester and give it a rating out of one hundred depending on how fruity the smell is

(i) Name the ester with the fruit-smell rating of 92 (1)

(ii) Shown below are the structures of three more isomers

Arrange these esters in order of decreasing fruit-smell rating (1)

50

(b) To create a fragrance for men the compound civetone is added

Draw a structural formula for the alcohol that can be oxidised to form civetone (1)

(c) To make the shower gel produce a cold tingling sensation when applied to the skin menthol is added

Like terpenes menthol is formed from isoprene (2-methylbuta-13-diene)Circle an isoprene unit on the menthol structure above (1)

8 Many of the compounds in perfumes are molecules consisting of joined isoprene units

(a) State the name that is given to molecules consisting of joined isoprene units (1)

(b)Geraniol is one of the compounds found in perfume It has the following structural formula and systematic name

Linalool can also be present Its structural formula is shown

51

(i) State the systematic name for linalool (1)(ii) Explain why linalool can be classified as a tertiary alcohol (1)

9 The component molecules found in lavender oils are terpenes or terpenoids(a)A chiral carbon is a carbon atom attached to four different atoms or groups of

atomsAn example is shown below

A molecule of the terpenoid linalool has a chiral carbon Linalool has the following structure

Circle the chiral carbon atom in the linalool structure (1)

(b)Farnesene is a terpene consisting of three isoprene units (2-methylbuta-13-diene) joined togetherWrite the molecular formula of farnesene (1)

52

27 Skin Care

1 Which of the following is not a step in a free radical chain reaction

A ActivationB InitiationC PropagationD Termination

2 Fluorine reacts with methane via a free radical chain reaction Some steps in the chain reaction are shown in the table below

Complete the table by(a) inserting the missing name for the first step (1)

(b) showing another possible termination reaction in the final row of the table (1)

3 Suncreams contain antioxidantsThe antioxidant compound A can prevent damage to skin by reacting with free

radicalssuch as NO2bull

53

Why can compound A be described as a free radical scavenger in the reaction shown above

4 Hydrogen and chlorine gases are used in an experiment to demonstrate a free radical reaction A plastic bottle is wrapped with black tape leaving a ldquowindowrdquo on one sideThe bottle is filled with a mixture of hydrogen and chlorine When bright light shines on the bottle there is an explosion

A free radical chain reaction is initiated when light energy causes chlorine radicals to form as shown below

(a) Complete the equations below showing possible propagation and termination steps

(2)

54

(b) Why is the plastic bottle used in the experiment wrapped in black tape (1)

5 Chloramines can be removed from water using ultraviolet light treatment

One step in the process is the formation of free radicals

(a)State what is meant by the term free radical (1)

(b)Another step in the process is shown below

State the name for this type of step in a free radical reaction (1)

6 Modern shellac nail varnishes are more durable and so last longer than traditional nail polish

The shellac nail varnish is applied in thin layers to the nails and then the fingers are placed under a UV lamp

(a) The Skin Care Foundation has recommended that a sun-block is applied to the fingers and hand before using the lampSuggest why the Skin Care Foundation makes this recommendation (1)

(b) A free radical chain reaction takes place and the varnish hardens (i) State what is meant by the term free radical (1)

(ii) The shellac nail varnish contains a mixture of ingredients that take part in the free radical chain reactionOne of the steps in the free radical chain reaction is

55

State the term used to describe this type of step in a free radical chain reaction(1)

7 Skin care products contain a mixture of polar covalent non-polar covalent and ionic compounds The compounds need to stay mixed within the product Skin care products also need to spread easily and remain on the skin for a period of time as well as provide physical and chemical protection from the sun In order to do this skin care products contain a range of chemicals including water fats and oils antioxidants minerals and sun blockUsing your knowledge of chemistry explain the role of different chemicals in skin care products (3)

General Questions

1 A mixture of carbon monoxide and hydrogen can be converted into water and a mixture of hydrocarbons

nCO + (2n + 1)H2 rarr nH2O + hydrocarbons

What is the general formula for the hydrocarbons producedA CnH2nndash2B CnH2nC CnH2n+1D CnH2n+2

2 Butadiene is the first member of a homologous series of hydrocarbons called dienesWhat is the general formula for this seriesA CnHn+2B CnHn+3C CnH2nD CnH2nndash2

3 Which of the following statements about methanol is falseA It can be made from synthesis gasB It can be dehydrated to form an alkeneC It can be oxidised to give a carboxylic acidD It reacts with acidified potassium dichromate solution

56

4

Which line in the table correctly describes reactions X and Y

5

Which line in the table correctly describes reactions X and Y

6 Which of the following fuels when burned would make no contribution to globalwarming

57

A HydrogenB Natural gasC PetrolD Coal

7 Which of the following hydrocarbons always gives the same product when one of itshydrogen atoms is replaced by a chlorine atomA HexaneB Hex-1-eneC CyclohexaneD Cyclohexene

8 Which of the following compounds does not have isomeric structuresA C2HCl3B C2H4Cl2C PropeneD Propan-1-ol

9 What organic compound is produced by the dehydration of ethanol A EthaneB EtheneC EthanalD Ethanoic acid

10

The above equation representsA hydrationB hydrogenationC condensationD hydrolysis

11

Which of the following compounds is an isomer of the structure shown aboveA ButanalB ButanoneC Butan-1-olD Butanoic acid

58

12 A compound with molecular formula C6H12O2 could beA hexanalB hexan-2-olC hexan-2-oneD hexanoic acid

13 Propan-2-ol can be prepared from propane as follows

Which line in the table correctly describes the types of reaction taking place at Steps 1 and 2

14 Which of the following compounds would be the most water soluble

15 Cyanohydrin compounds can be made from carbonyl compounds by reacting the carbonyl compound with hydrogen cyanide (HCN)

59

Which carbonyl compound would react with hydrogen cyanide (HCN) to form the following compound

16 Ethyne is the first member of the homologous series called the alkynes

Ethyne can undergo addition reactions as shown in the flow diagram

(a) Compound 2 is an isomer of 12-dichloroethaneDraw a structural formula for compound 2 (1)

(b) Reagents A B and C are three different diatomic gasesUsing information in the flow diagram identify reagents A B and C (1)

60

Reagent Gas

A

B

C

17 In 1865 the German chemist Kekuleacute proposed a ring structure for benzene This structure was based on alternating single and double bonds

(a) (i) Describe a chemical test that would indicate that the above chemical structure for benzene is incorrect (1)

(ii) Briefly describe the correct structure for benzene (1)

(b) Benzene can be formed from cyclohexaneC6H12 rarr C6H6 + 3H2

What name is given to this type of reaction (1)18 Infra-red spectroscopy is a technique that can be used to identify the bonds that

arepresent in a molecule Different bonds absorb infra-red radiation of different wavenumbers This is due to differences in the bond lsquostretchrsquo These absorptions are recorded in a spectrumA spectrum for propan-1-ol is shown

61

The correlation table on page 13 of the data booklet shows the wavenumber ranges for the absorptions due to different bonds

(a) Use the correlation table to identify the bonds responsible for the two absorptions x and y that are circled in the propan-1-ol spectrum (1)

(b) Propan-1-ol reacts with ethanoic acid(i) What name is given to this type of reaction (1)(ii) Draw a spectrum that could be obtained for the organic product of this

reaction (1)

19 Paracetamol is a widely used painkiller

(a) Write the molecular formula for paracetamol (1)

(b) One antidote for paracetamol overdose is methionine

62

To what family of organic compounds does methionine belong (1)

(c) The concentration of paracetamol in a solution can be determined by measuring how much UV radiation it absorbs

The graph shows how the absorbance of a sample containing 0middot040 g l ndash1 paracetamol varies with wavelength

The quantity of UV radiation of wavelength 245 nm absorbed is directly proportional to the concentration of paracetamolThe absorbance of a second sample of paracetamol solution measured at 245 nm was 0middot90 What is the concentration in g l ndash1 of this second paracetamol solution (1)

20 Many carbon compounds containing oxygen are very flammableThe table shows information about two families of isomersThe lowest temperature at which a compound will ignite is called its flash point

(a) A compound with the molecular formula C6H14O has a boiling point of 158 degC63

Draw a structural formula for this compound (1)

(b) For a family of isomers in the table write a general statement linking the flash points of the compounds to their structures (1)

21 Hydrogels are used in disposable nappies They are fine powders that can absorb up to 500 times their own weight in waterA hydrogel is a very long molecule with carboxyl groups at regular intervals along its length A short section of a hydrogel molecule is shown below

Hydrogels are extremely good at soaking up water because the water molecules are strongly attracted to them

Using your knowledge of chemistry comment on how suitable hydrogels would be for absorbing liquids or solutions spilled in a chemistry lab (1)

64

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

36

31 Chocolate contains various compounds(a) Many of the flavour and aroma molecules found in chocolate are aldehydes and

ketones Two examples are shown below

Phenylethanal can be easily oxidised but 13-diphenylpropan-2-one cannot(i) Name a chemical that could be used to distinguish between these two

compounds (1)

(ii) Name the type of organic compound formed when phenylethanal is oxidised (1)

(b) Glycerol monostearate is an emulsifier used in chocolate

(i) Why is glycerol monostearate added to chocolate (1)

(ii) Draw a structural formula for glycerol (1)

(c) Theobromine a compound present in chocolate can cause illness in dogs and cats To decide if treatment is necessary vets must calculate the mass of theobromine consumed 1middot0 g of chocolate contains 1middot4 mg of theobromine Calculate the mass in mg of theobromine in a 17 g biscuit of which 28 is chocolate Show your working clearly (2)

(d) The flavour and texture of chocolate comes from a blend of compoundsUsing your knowledge of chemistry describe how you could show that there are ionic compounds and covalent compounds present in chocolate (3)

37

32 Ethanol has many uses

(a) Ethanol is found at relatively low concentrations in wine

(i) Name the chemical reaction that produces ethanol in wine (1)

(ii) Standard ethanol solutions were used to produce a graph of density against

concentration of ethanol given as a percentage of alcohol by volume ( abv)

What is the concentration of ethanol in units of abv in a solution of density 0middot9818 g cmminus3 (1)

(b) Whisky contains a higher concentration of ethanol

(i) Before 1980 the concentration of alcohol in drinks was measured in terms of degrees proof The concentration of alcohol in two drinks is shown in the table below both as abv and degrees proof

38

A cask strength whisky has an alcohol concentration of 65 abv Calculate the alcohol concentration of this whisky in degrees proof (1)

(ii) A barrel containing 195 litres of cask strength whisky costs pound1300 The cask strength whisky is diluted with water to reduce the concentration of alcohol from 65 abv to 46 abv before it is bottled Calculate the cost of the cask strength whisky needed to produce a 0middot70 litre bottle Show your working clearly (2)

(iii) 5-Butyl-4-methyltetrahydrofuran-2-ol is a flavour compound found in whisky

stored in oak barrels

Write the systematic name for the compound shown below (1) 13 11

33 (a) One test for glucose involves Fehlingrsquos solutionCircle the part of the glucose molecule that reacts with Fehlingrsquos solution (1)

(b) In solution sugar molecules exist in an equilibrium in straight-chain and ring forms

To change from the straight-chain form to the ring form the oxygen of the hydroxyl on carbon number 5 joins to the carbonyl carbon This is shown below for glucose

39

Draw the structure of a ring form for fructose (1)

34 (a) During the free radical chain reaction small molecules join to form large chain molecules

One example of a small molecule used is

Name the functional group circled above (1)

(b)Alcohol wipes are used to finish the varnishing treatment Alcohol wipes contain the alcohol propan-2-olState why propan-2-ol can be described as a secondary alcohol (1)

35 A student was carrying out an investigation into alcohols aldehydes and ketones

(a)The student was given three alcohols labelled as A B and C These alcohols were all isomers with the formula C4H9OH

(i) Draw a structural formula for the secondary alcohol with the formula C4H9OH(1)

(ii) The student set up the following experiment

A Suggest why a water bath is an appropriate method of heating the reaction mixture (1)

B Describe the colour change that would have been observed with alcohols A and C (1)

40

C Alcohol B is not oxidised State the type of alcohol which cannot be oxidised by acidified dichromate solution (1)

(iii) The student set up a second experiment with alcohol A

Hot copper(II) oxide is an oxidising agentA When alcohol A (C4H9OH) is oxidised the product turns the pH paper

redSuggest a name for the product (1)

B Complete the ion-electron equation for the oxidation reaction

C4H9OH rarr C4H8O2 (1)

(b)The student found the following information about the boiling points of some aldehydes

41

(i) Name the aldehyde that has a boiling point of 119 degC (1)(ii) Predict the boiling point in degC of the following molecule (1)

(iii) Using information from the table describe one way in which differences in structure affect the boiling point of isomeric aldehydes (1)

(iv) State what would be observed when an aldehyde is gently heated with Tollensrsquo reagent (1)

(c) Ketones contain a carbonyl groupName the type of intermolecular interaction between ketone molecules (1)

42

25 Soaps Detergents and Emulsions

1 Soaps are produced by the following reaction

This reaction is an example ofA condensationB esterificationC hydrolysisD oxidation

2 Which of the following is the salt of a long-chain fatty acid

A FatB OilC SoapD Glycerol

3 Emulsifiers for use in food are commonly made by reacting edible oils with

A estersB glycerolC fatty acidsD amino acids

4 A fatty acid is a long chain carboxylic acid Examples of fatty acids are shown in the table below

43

(a) What is the systematic name for linolenic acid (1)(b) Stearic acid reacts with sodium hydroxide solution to form sodium stearate

(i) Name the type of reaction taking place when stearic acid reacts with sodium hydroxide (1)

(ii) Explain fully how sodium stearate acts to keep grease and non-polar substances suspended in water during cleaning (3)

5 Small children can find it difficult to swallow tablets or pills so ibuprofen is supplied as an ldquoinfant formulardquo emulsion(a) The emulsifier used is polysorbate 80 Its structure is shown below

Explain why this molecule acts as an emulsifier (2)

(b) The emulsion contains 2 g of ibuprofen in every 100 cm3 of emulsion The recommended dose for treating a 6 month old baby is 0middot050 g Calculate the volume in cm3 of ldquoinfant formulardquo needed to treat a 6 month old baby (1)

6 Occasionally seabirds can become contaminated with hydrocarbons from oil spills This causes problems for birds because their feathers lose their waterproofing making the birds susceptible to temperature changes and

44

affecting their buoyancy If the birds attempt to clean themselves to remove the oil they may swallow the hydrocarbons causing damage to their internal organsContaminated seabirds can be cleaned by rubbing vegetable oil into their feathers and feet before the birds are rinsed with diluted washing-up liquidUsing your knowledge of chemistry comment on the problems created for seabirds by oil spills and the actions taken to treat affected birds (3)

7 Dishwasher tablets contain chemicals which remove dirt from dishesDishwasher tablets include detergents These molecules act like soaps to allow mixing of fat-soluble dirt and water(a)During the cleaning process the detergent molecules combine with fat-

soluble dirtA simplified diagram of a detergent molecule is shown

Complete the diagram below to show how detergent molecules combine with fat-soluble dirt (1)

(b)State the term used to describe the non-polar hydrocarbon tail of a detergent molecule (1)

45

26 Fragrances1 Myrcene is a simple terpene

Terpenes contain at least one isoprene unit Which of the following shows a correctly highlighted isoprene unit

2 Limonene is one of the terpene molecules responsible for the flavour of lemons

How many isoprene units are used in the production of one limonene moleculeA 1B 2C 3D 4

46

3 The structure of caryophyllene which can be extracted from clove oil is

Which of the following would be the best solvent for extracting caryophylleneA HexaneB HexanalC HexanolD Hexanone

4 The structure of isoprene is

Limonene is a terpene molecule present in lemons

How many isoprene units are joined together in a limonene molecule

A 1B 2

47

C 3D 4

5 Essential oils are

A non-water soluble non-volatile compoundsB non-water soluble volatile compoundsC water soluble non-volatile compoundsD water soluble volatile compounds

6 Two typical compounds that are present in many perfumes are shown

(a) Why does geraniol evaporate more slowly than limonene (1)

(b) The structure of one of the first synthetic scents used in perfume is shown below

(i) Name the family of carbonyl compounds to which this synthetic scent belongs (1)

(ii) Complete the structure below to show the product formed when this scent is

oxidised (1)

(c) Traces of a liquid were discovered in a bottle believed to contain perfume belonging to Queen Hatshepsut ruler of Egypt over 3500 years ago

Perfumes were made by dissolving plant extracts containing pleasant smelling terpenes and esters in an edible oil A little ethanol and water may also have been addedUsing your knowledge of chemistry comment on the possible smell(s) when such a bottle is opened after being stored for thousands of years (3)

48

49

7 A team of chemists are developing a fragrance for use in a shower gel for men(a) To give the gel a fruity smell the chemists are considering adding an ester

They synthesise six isomeric esters Volunteers smell each ester and give it a rating out of one hundred depending on how fruity the smell is

(i) Name the ester with the fruit-smell rating of 92 (1)

(ii) Shown below are the structures of three more isomers

Arrange these esters in order of decreasing fruit-smell rating (1)

50

(b) To create a fragrance for men the compound civetone is added

Draw a structural formula for the alcohol that can be oxidised to form civetone (1)

(c) To make the shower gel produce a cold tingling sensation when applied to the skin menthol is added

Like terpenes menthol is formed from isoprene (2-methylbuta-13-diene)Circle an isoprene unit on the menthol structure above (1)

8 Many of the compounds in perfumes are molecules consisting of joined isoprene units

(a) State the name that is given to molecules consisting of joined isoprene units (1)

(b)Geraniol is one of the compounds found in perfume It has the following structural formula and systematic name

Linalool can also be present Its structural formula is shown

51

(i) State the systematic name for linalool (1)(ii) Explain why linalool can be classified as a tertiary alcohol (1)

9 The component molecules found in lavender oils are terpenes or terpenoids(a)A chiral carbon is a carbon atom attached to four different atoms or groups of

atomsAn example is shown below

A molecule of the terpenoid linalool has a chiral carbon Linalool has the following structure

Circle the chiral carbon atom in the linalool structure (1)

(b)Farnesene is a terpene consisting of three isoprene units (2-methylbuta-13-diene) joined togetherWrite the molecular formula of farnesene (1)

52

27 Skin Care

1 Which of the following is not a step in a free radical chain reaction

A ActivationB InitiationC PropagationD Termination

2 Fluorine reacts with methane via a free radical chain reaction Some steps in the chain reaction are shown in the table below

Complete the table by(a) inserting the missing name for the first step (1)

(b) showing another possible termination reaction in the final row of the table (1)

3 Suncreams contain antioxidantsThe antioxidant compound A can prevent damage to skin by reacting with free

radicalssuch as NO2bull

53

Why can compound A be described as a free radical scavenger in the reaction shown above

4 Hydrogen and chlorine gases are used in an experiment to demonstrate a free radical reaction A plastic bottle is wrapped with black tape leaving a ldquowindowrdquo on one sideThe bottle is filled with a mixture of hydrogen and chlorine When bright light shines on the bottle there is an explosion

A free radical chain reaction is initiated when light energy causes chlorine radicals to form as shown below

(a) Complete the equations below showing possible propagation and termination steps

(2)

54

(b) Why is the plastic bottle used in the experiment wrapped in black tape (1)

5 Chloramines can be removed from water using ultraviolet light treatment

One step in the process is the formation of free radicals

(a)State what is meant by the term free radical (1)

(b)Another step in the process is shown below

State the name for this type of step in a free radical reaction (1)

6 Modern shellac nail varnishes are more durable and so last longer than traditional nail polish

The shellac nail varnish is applied in thin layers to the nails and then the fingers are placed under a UV lamp

(a) The Skin Care Foundation has recommended that a sun-block is applied to the fingers and hand before using the lampSuggest why the Skin Care Foundation makes this recommendation (1)

(b) A free radical chain reaction takes place and the varnish hardens (i) State what is meant by the term free radical (1)

(ii) The shellac nail varnish contains a mixture of ingredients that take part in the free radical chain reactionOne of the steps in the free radical chain reaction is

55

State the term used to describe this type of step in a free radical chain reaction(1)

7 Skin care products contain a mixture of polar covalent non-polar covalent and ionic compounds The compounds need to stay mixed within the product Skin care products also need to spread easily and remain on the skin for a period of time as well as provide physical and chemical protection from the sun In order to do this skin care products contain a range of chemicals including water fats and oils antioxidants minerals and sun blockUsing your knowledge of chemistry explain the role of different chemicals in skin care products (3)

General Questions

1 A mixture of carbon monoxide and hydrogen can be converted into water and a mixture of hydrocarbons

nCO + (2n + 1)H2 rarr nH2O + hydrocarbons

What is the general formula for the hydrocarbons producedA CnH2nndash2B CnH2nC CnH2n+1D CnH2n+2

2 Butadiene is the first member of a homologous series of hydrocarbons called dienesWhat is the general formula for this seriesA CnHn+2B CnHn+3C CnH2nD CnH2nndash2

3 Which of the following statements about methanol is falseA It can be made from synthesis gasB It can be dehydrated to form an alkeneC It can be oxidised to give a carboxylic acidD It reacts with acidified potassium dichromate solution

56

4

Which line in the table correctly describes reactions X and Y

5

Which line in the table correctly describes reactions X and Y

6 Which of the following fuels when burned would make no contribution to globalwarming

57

A HydrogenB Natural gasC PetrolD Coal

7 Which of the following hydrocarbons always gives the same product when one of itshydrogen atoms is replaced by a chlorine atomA HexaneB Hex-1-eneC CyclohexaneD Cyclohexene

8 Which of the following compounds does not have isomeric structuresA C2HCl3B C2H4Cl2C PropeneD Propan-1-ol

9 What organic compound is produced by the dehydration of ethanol A EthaneB EtheneC EthanalD Ethanoic acid

10

The above equation representsA hydrationB hydrogenationC condensationD hydrolysis

11

Which of the following compounds is an isomer of the structure shown aboveA ButanalB ButanoneC Butan-1-olD Butanoic acid

58

12 A compound with molecular formula C6H12O2 could beA hexanalB hexan-2-olC hexan-2-oneD hexanoic acid

13 Propan-2-ol can be prepared from propane as follows

Which line in the table correctly describes the types of reaction taking place at Steps 1 and 2

14 Which of the following compounds would be the most water soluble

15 Cyanohydrin compounds can be made from carbonyl compounds by reacting the carbonyl compound with hydrogen cyanide (HCN)

59

Which carbonyl compound would react with hydrogen cyanide (HCN) to form the following compound

16 Ethyne is the first member of the homologous series called the alkynes

Ethyne can undergo addition reactions as shown in the flow diagram

(a) Compound 2 is an isomer of 12-dichloroethaneDraw a structural formula for compound 2 (1)

(b) Reagents A B and C are three different diatomic gasesUsing information in the flow diagram identify reagents A B and C (1)

60

Reagent Gas

A

B

C

17 In 1865 the German chemist Kekuleacute proposed a ring structure for benzene This structure was based on alternating single and double bonds

(a) (i) Describe a chemical test that would indicate that the above chemical structure for benzene is incorrect (1)

(ii) Briefly describe the correct structure for benzene (1)

(b) Benzene can be formed from cyclohexaneC6H12 rarr C6H6 + 3H2

What name is given to this type of reaction (1)18 Infra-red spectroscopy is a technique that can be used to identify the bonds that

arepresent in a molecule Different bonds absorb infra-red radiation of different wavenumbers This is due to differences in the bond lsquostretchrsquo These absorptions are recorded in a spectrumA spectrum for propan-1-ol is shown

61

The correlation table on page 13 of the data booklet shows the wavenumber ranges for the absorptions due to different bonds

(a) Use the correlation table to identify the bonds responsible for the two absorptions x and y that are circled in the propan-1-ol spectrum (1)

(b) Propan-1-ol reacts with ethanoic acid(i) What name is given to this type of reaction (1)(ii) Draw a spectrum that could be obtained for the organic product of this

reaction (1)

19 Paracetamol is a widely used painkiller

(a) Write the molecular formula for paracetamol (1)

(b) One antidote for paracetamol overdose is methionine

62

To what family of organic compounds does methionine belong (1)

(c) The concentration of paracetamol in a solution can be determined by measuring how much UV radiation it absorbs

The graph shows how the absorbance of a sample containing 0middot040 g l ndash1 paracetamol varies with wavelength

The quantity of UV radiation of wavelength 245 nm absorbed is directly proportional to the concentration of paracetamolThe absorbance of a second sample of paracetamol solution measured at 245 nm was 0middot90 What is the concentration in g l ndash1 of this second paracetamol solution (1)

20 Many carbon compounds containing oxygen are very flammableThe table shows information about two families of isomersThe lowest temperature at which a compound will ignite is called its flash point

(a) A compound with the molecular formula C6H14O has a boiling point of 158 degC63

Draw a structural formula for this compound (1)

(b) For a family of isomers in the table write a general statement linking the flash points of the compounds to their structures (1)

21 Hydrogels are used in disposable nappies They are fine powders that can absorb up to 500 times their own weight in waterA hydrogel is a very long molecule with carboxyl groups at regular intervals along its length A short section of a hydrogel molecule is shown below

Hydrogels are extremely good at soaking up water because the water molecules are strongly attracted to them

Using your knowledge of chemistry comment on how suitable hydrogels would be for absorbing liquids or solutions spilled in a chemistry lab (1)

64

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

31 Chocolate contains various compounds(a) Many of the flavour and aroma molecules found in chocolate are aldehydes and

ketones Two examples are shown below

Phenylethanal can be easily oxidised but 13-diphenylpropan-2-one cannot(i) Name a chemical that could be used to distinguish between these two

compounds (1)

(ii) Name the type of organic compound formed when phenylethanal is oxidised (1)

(b) Glycerol monostearate is an emulsifier used in chocolate

(i) Why is glycerol monostearate added to chocolate (1)

(ii) Draw a structural formula for glycerol (1)

(c) Theobromine a compound present in chocolate can cause illness in dogs and cats To decide if treatment is necessary vets must calculate the mass of theobromine consumed 1middot0 g of chocolate contains 1middot4 mg of theobromine Calculate the mass in mg of theobromine in a 17 g biscuit of which 28 is chocolate Show your working clearly (2)

(d) The flavour and texture of chocolate comes from a blend of compoundsUsing your knowledge of chemistry describe how you could show that there are ionic compounds and covalent compounds present in chocolate (3)

37

32 Ethanol has many uses

(a) Ethanol is found at relatively low concentrations in wine

(i) Name the chemical reaction that produces ethanol in wine (1)

(ii) Standard ethanol solutions were used to produce a graph of density against

concentration of ethanol given as a percentage of alcohol by volume ( abv)

What is the concentration of ethanol in units of abv in a solution of density 0middot9818 g cmminus3 (1)

(b) Whisky contains a higher concentration of ethanol

(i) Before 1980 the concentration of alcohol in drinks was measured in terms of degrees proof The concentration of alcohol in two drinks is shown in the table below both as abv and degrees proof

38

A cask strength whisky has an alcohol concentration of 65 abv Calculate the alcohol concentration of this whisky in degrees proof (1)

(ii) A barrel containing 195 litres of cask strength whisky costs pound1300 The cask strength whisky is diluted with water to reduce the concentration of alcohol from 65 abv to 46 abv before it is bottled Calculate the cost of the cask strength whisky needed to produce a 0middot70 litre bottle Show your working clearly (2)

(iii) 5-Butyl-4-methyltetrahydrofuran-2-ol is a flavour compound found in whisky

stored in oak barrels

Write the systematic name for the compound shown below (1) 13 11

33 (a) One test for glucose involves Fehlingrsquos solutionCircle the part of the glucose molecule that reacts with Fehlingrsquos solution (1)

(b) In solution sugar molecules exist in an equilibrium in straight-chain and ring forms

To change from the straight-chain form to the ring form the oxygen of the hydroxyl on carbon number 5 joins to the carbonyl carbon This is shown below for glucose

39

Draw the structure of a ring form for fructose (1)

34 (a) During the free radical chain reaction small molecules join to form large chain molecules

One example of a small molecule used is

Name the functional group circled above (1)

(b)Alcohol wipes are used to finish the varnishing treatment Alcohol wipes contain the alcohol propan-2-olState why propan-2-ol can be described as a secondary alcohol (1)

35 A student was carrying out an investigation into alcohols aldehydes and ketones

(a)The student was given three alcohols labelled as A B and C These alcohols were all isomers with the formula C4H9OH

(i) Draw a structural formula for the secondary alcohol with the formula C4H9OH(1)

(ii) The student set up the following experiment

A Suggest why a water bath is an appropriate method of heating the reaction mixture (1)

B Describe the colour change that would have been observed with alcohols A and C (1)

40

C Alcohol B is not oxidised State the type of alcohol which cannot be oxidised by acidified dichromate solution (1)

(iii) The student set up a second experiment with alcohol A

Hot copper(II) oxide is an oxidising agentA When alcohol A (C4H9OH) is oxidised the product turns the pH paper

redSuggest a name for the product (1)

B Complete the ion-electron equation for the oxidation reaction

C4H9OH rarr C4H8O2 (1)

(b)The student found the following information about the boiling points of some aldehydes

41

(i) Name the aldehyde that has a boiling point of 119 degC (1)(ii) Predict the boiling point in degC of the following molecule (1)

(iii) Using information from the table describe one way in which differences in structure affect the boiling point of isomeric aldehydes (1)

(iv) State what would be observed when an aldehyde is gently heated with Tollensrsquo reagent (1)

(c) Ketones contain a carbonyl groupName the type of intermolecular interaction between ketone molecules (1)

42

25 Soaps Detergents and Emulsions

1 Soaps are produced by the following reaction

This reaction is an example ofA condensationB esterificationC hydrolysisD oxidation

2 Which of the following is the salt of a long-chain fatty acid

A FatB OilC SoapD Glycerol

3 Emulsifiers for use in food are commonly made by reacting edible oils with

A estersB glycerolC fatty acidsD amino acids

4 A fatty acid is a long chain carboxylic acid Examples of fatty acids are shown in the table below

43

(a) What is the systematic name for linolenic acid (1)(b) Stearic acid reacts with sodium hydroxide solution to form sodium stearate

(i) Name the type of reaction taking place when stearic acid reacts with sodium hydroxide (1)

(ii) Explain fully how sodium stearate acts to keep grease and non-polar substances suspended in water during cleaning (3)

5 Small children can find it difficult to swallow tablets or pills so ibuprofen is supplied as an ldquoinfant formulardquo emulsion(a) The emulsifier used is polysorbate 80 Its structure is shown below

Explain why this molecule acts as an emulsifier (2)

(b) The emulsion contains 2 g of ibuprofen in every 100 cm3 of emulsion The recommended dose for treating a 6 month old baby is 0middot050 g Calculate the volume in cm3 of ldquoinfant formulardquo needed to treat a 6 month old baby (1)

6 Occasionally seabirds can become contaminated with hydrocarbons from oil spills This causes problems for birds because their feathers lose their waterproofing making the birds susceptible to temperature changes and

44

affecting their buoyancy If the birds attempt to clean themselves to remove the oil they may swallow the hydrocarbons causing damage to their internal organsContaminated seabirds can be cleaned by rubbing vegetable oil into their feathers and feet before the birds are rinsed with diluted washing-up liquidUsing your knowledge of chemistry comment on the problems created for seabirds by oil spills and the actions taken to treat affected birds (3)

7 Dishwasher tablets contain chemicals which remove dirt from dishesDishwasher tablets include detergents These molecules act like soaps to allow mixing of fat-soluble dirt and water(a)During the cleaning process the detergent molecules combine with fat-

soluble dirtA simplified diagram of a detergent molecule is shown

Complete the diagram below to show how detergent molecules combine with fat-soluble dirt (1)

(b)State the term used to describe the non-polar hydrocarbon tail of a detergent molecule (1)

45

26 Fragrances1 Myrcene is a simple terpene

Terpenes contain at least one isoprene unit Which of the following shows a correctly highlighted isoprene unit

2 Limonene is one of the terpene molecules responsible for the flavour of lemons

How many isoprene units are used in the production of one limonene moleculeA 1B 2C 3D 4

46

3 The structure of caryophyllene which can be extracted from clove oil is

Which of the following would be the best solvent for extracting caryophylleneA HexaneB HexanalC HexanolD Hexanone

4 The structure of isoprene is

Limonene is a terpene molecule present in lemons

How many isoprene units are joined together in a limonene molecule

A 1B 2

47

C 3D 4

5 Essential oils are

A non-water soluble non-volatile compoundsB non-water soluble volatile compoundsC water soluble non-volatile compoundsD water soluble volatile compounds

6 Two typical compounds that are present in many perfumes are shown

(a) Why does geraniol evaporate more slowly than limonene (1)

(b) The structure of one of the first synthetic scents used in perfume is shown below

(i) Name the family of carbonyl compounds to which this synthetic scent belongs (1)

(ii) Complete the structure below to show the product formed when this scent is

oxidised (1)

(c) Traces of a liquid were discovered in a bottle believed to contain perfume belonging to Queen Hatshepsut ruler of Egypt over 3500 years ago

Perfumes were made by dissolving plant extracts containing pleasant smelling terpenes and esters in an edible oil A little ethanol and water may also have been addedUsing your knowledge of chemistry comment on the possible smell(s) when such a bottle is opened after being stored for thousands of years (3)

48

49

7 A team of chemists are developing a fragrance for use in a shower gel for men(a) To give the gel a fruity smell the chemists are considering adding an ester

They synthesise six isomeric esters Volunteers smell each ester and give it a rating out of one hundred depending on how fruity the smell is

(i) Name the ester with the fruit-smell rating of 92 (1)

(ii) Shown below are the structures of three more isomers

Arrange these esters in order of decreasing fruit-smell rating (1)

50

(b) To create a fragrance for men the compound civetone is added

Draw a structural formula for the alcohol that can be oxidised to form civetone (1)

(c) To make the shower gel produce a cold tingling sensation when applied to the skin menthol is added

Like terpenes menthol is formed from isoprene (2-methylbuta-13-diene)Circle an isoprene unit on the menthol structure above (1)

8 Many of the compounds in perfumes are molecules consisting of joined isoprene units

(a) State the name that is given to molecules consisting of joined isoprene units (1)

(b)Geraniol is one of the compounds found in perfume It has the following structural formula and systematic name

Linalool can also be present Its structural formula is shown

51

(i) State the systematic name for linalool (1)(ii) Explain why linalool can be classified as a tertiary alcohol (1)

9 The component molecules found in lavender oils are terpenes or terpenoids(a)A chiral carbon is a carbon atom attached to four different atoms or groups of

atomsAn example is shown below

A molecule of the terpenoid linalool has a chiral carbon Linalool has the following structure

Circle the chiral carbon atom in the linalool structure (1)

(b)Farnesene is a terpene consisting of three isoprene units (2-methylbuta-13-diene) joined togetherWrite the molecular formula of farnesene (1)

52

27 Skin Care

1 Which of the following is not a step in a free radical chain reaction

A ActivationB InitiationC PropagationD Termination

2 Fluorine reacts with methane via a free radical chain reaction Some steps in the chain reaction are shown in the table below

Complete the table by(a) inserting the missing name for the first step (1)

(b) showing another possible termination reaction in the final row of the table (1)

3 Suncreams contain antioxidantsThe antioxidant compound A can prevent damage to skin by reacting with free

radicalssuch as NO2bull

53

Why can compound A be described as a free radical scavenger in the reaction shown above

4 Hydrogen and chlorine gases are used in an experiment to demonstrate a free radical reaction A plastic bottle is wrapped with black tape leaving a ldquowindowrdquo on one sideThe bottle is filled with a mixture of hydrogen and chlorine When bright light shines on the bottle there is an explosion

A free radical chain reaction is initiated when light energy causes chlorine radicals to form as shown below

(a) Complete the equations below showing possible propagation and termination steps

(2)

54

(b) Why is the plastic bottle used in the experiment wrapped in black tape (1)

5 Chloramines can be removed from water using ultraviolet light treatment

One step in the process is the formation of free radicals

(a)State what is meant by the term free radical (1)

(b)Another step in the process is shown below

State the name for this type of step in a free radical reaction (1)

6 Modern shellac nail varnishes are more durable and so last longer than traditional nail polish

The shellac nail varnish is applied in thin layers to the nails and then the fingers are placed under a UV lamp

(a) The Skin Care Foundation has recommended that a sun-block is applied to the fingers and hand before using the lampSuggest why the Skin Care Foundation makes this recommendation (1)

(b) A free radical chain reaction takes place and the varnish hardens (i) State what is meant by the term free radical (1)

(ii) The shellac nail varnish contains a mixture of ingredients that take part in the free radical chain reactionOne of the steps in the free radical chain reaction is

55

State the term used to describe this type of step in a free radical chain reaction(1)

7 Skin care products contain a mixture of polar covalent non-polar covalent and ionic compounds The compounds need to stay mixed within the product Skin care products also need to spread easily and remain on the skin for a period of time as well as provide physical and chemical protection from the sun In order to do this skin care products contain a range of chemicals including water fats and oils antioxidants minerals and sun blockUsing your knowledge of chemistry explain the role of different chemicals in skin care products (3)

General Questions

1 A mixture of carbon monoxide and hydrogen can be converted into water and a mixture of hydrocarbons

nCO + (2n + 1)H2 rarr nH2O + hydrocarbons

What is the general formula for the hydrocarbons producedA CnH2nndash2B CnH2nC CnH2n+1D CnH2n+2

2 Butadiene is the first member of a homologous series of hydrocarbons called dienesWhat is the general formula for this seriesA CnHn+2B CnHn+3C CnH2nD CnH2nndash2

3 Which of the following statements about methanol is falseA It can be made from synthesis gasB It can be dehydrated to form an alkeneC It can be oxidised to give a carboxylic acidD It reacts with acidified potassium dichromate solution

56

4

Which line in the table correctly describes reactions X and Y

5

Which line in the table correctly describes reactions X and Y

6 Which of the following fuels when burned would make no contribution to globalwarming

57

A HydrogenB Natural gasC PetrolD Coal

7 Which of the following hydrocarbons always gives the same product when one of itshydrogen atoms is replaced by a chlorine atomA HexaneB Hex-1-eneC CyclohexaneD Cyclohexene

8 Which of the following compounds does not have isomeric structuresA C2HCl3B C2H4Cl2C PropeneD Propan-1-ol

9 What organic compound is produced by the dehydration of ethanol A EthaneB EtheneC EthanalD Ethanoic acid

10

The above equation representsA hydrationB hydrogenationC condensationD hydrolysis

11

Which of the following compounds is an isomer of the structure shown aboveA ButanalB ButanoneC Butan-1-olD Butanoic acid

58

12 A compound with molecular formula C6H12O2 could beA hexanalB hexan-2-olC hexan-2-oneD hexanoic acid

13 Propan-2-ol can be prepared from propane as follows

Which line in the table correctly describes the types of reaction taking place at Steps 1 and 2

14 Which of the following compounds would be the most water soluble

15 Cyanohydrin compounds can be made from carbonyl compounds by reacting the carbonyl compound with hydrogen cyanide (HCN)

59

Which carbonyl compound would react with hydrogen cyanide (HCN) to form the following compound

16 Ethyne is the first member of the homologous series called the alkynes

Ethyne can undergo addition reactions as shown in the flow diagram

(a) Compound 2 is an isomer of 12-dichloroethaneDraw a structural formula for compound 2 (1)

(b) Reagents A B and C are three different diatomic gasesUsing information in the flow diagram identify reagents A B and C (1)

60

Reagent Gas

A

B

C

17 In 1865 the German chemist Kekuleacute proposed a ring structure for benzene This structure was based on alternating single and double bonds

(a) (i) Describe a chemical test that would indicate that the above chemical structure for benzene is incorrect (1)

(ii) Briefly describe the correct structure for benzene (1)

(b) Benzene can be formed from cyclohexaneC6H12 rarr C6H6 + 3H2

What name is given to this type of reaction (1)18 Infra-red spectroscopy is a technique that can be used to identify the bonds that

arepresent in a molecule Different bonds absorb infra-red radiation of different wavenumbers This is due to differences in the bond lsquostretchrsquo These absorptions are recorded in a spectrumA spectrum for propan-1-ol is shown

61

The correlation table on page 13 of the data booklet shows the wavenumber ranges for the absorptions due to different bonds

(a) Use the correlation table to identify the bonds responsible for the two absorptions x and y that are circled in the propan-1-ol spectrum (1)

(b) Propan-1-ol reacts with ethanoic acid(i) What name is given to this type of reaction (1)(ii) Draw a spectrum that could be obtained for the organic product of this

reaction (1)

19 Paracetamol is a widely used painkiller

(a) Write the molecular formula for paracetamol (1)

(b) One antidote for paracetamol overdose is methionine

62

To what family of organic compounds does methionine belong (1)

(c) The concentration of paracetamol in a solution can be determined by measuring how much UV radiation it absorbs

The graph shows how the absorbance of a sample containing 0middot040 g l ndash1 paracetamol varies with wavelength

The quantity of UV radiation of wavelength 245 nm absorbed is directly proportional to the concentration of paracetamolThe absorbance of a second sample of paracetamol solution measured at 245 nm was 0middot90 What is the concentration in g l ndash1 of this second paracetamol solution (1)

20 Many carbon compounds containing oxygen are very flammableThe table shows information about two families of isomersThe lowest temperature at which a compound will ignite is called its flash point

(a) A compound with the molecular formula C6H14O has a boiling point of 158 degC63

Draw a structural formula for this compound (1)

(b) For a family of isomers in the table write a general statement linking the flash points of the compounds to their structures (1)

21 Hydrogels are used in disposable nappies They are fine powders that can absorb up to 500 times their own weight in waterA hydrogel is a very long molecule with carboxyl groups at regular intervals along its length A short section of a hydrogel molecule is shown below

Hydrogels are extremely good at soaking up water because the water molecules are strongly attracted to them

Using your knowledge of chemistry comment on how suitable hydrogels would be for absorbing liquids or solutions spilled in a chemistry lab (1)

64

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

32 Ethanol has many uses

(a) Ethanol is found at relatively low concentrations in wine

(i) Name the chemical reaction that produces ethanol in wine (1)

(ii) Standard ethanol solutions were used to produce a graph of density against

concentration of ethanol given as a percentage of alcohol by volume ( abv)

What is the concentration of ethanol in units of abv in a solution of density 0middot9818 g cmminus3 (1)

(b) Whisky contains a higher concentration of ethanol

(i) Before 1980 the concentration of alcohol in drinks was measured in terms of degrees proof The concentration of alcohol in two drinks is shown in the table below both as abv and degrees proof

38

A cask strength whisky has an alcohol concentration of 65 abv Calculate the alcohol concentration of this whisky in degrees proof (1)

(ii) A barrel containing 195 litres of cask strength whisky costs pound1300 The cask strength whisky is diluted with water to reduce the concentration of alcohol from 65 abv to 46 abv before it is bottled Calculate the cost of the cask strength whisky needed to produce a 0middot70 litre bottle Show your working clearly (2)

(iii) 5-Butyl-4-methyltetrahydrofuran-2-ol is a flavour compound found in whisky

stored in oak barrels

Write the systematic name for the compound shown below (1) 13 11

33 (a) One test for glucose involves Fehlingrsquos solutionCircle the part of the glucose molecule that reacts with Fehlingrsquos solution (1)

(b) In solution sugar molecules exist in an equilibrium in straight-chain and ring forms

To change from the straight-chain form to the ring form the oxygen of the hydroxyl on carbon number 5 joins to the carbonyl carbon This is shown below for glucose

39

Draw the structure of a ring form for fructose (1)

34 (a) During the free radical chain reaction small molecules join to form large chain molecules

One example of a small molecule used is

Name the functional group circled above (1)

(b)Alcohol wipes are used to finish the varnishing treatment Alcohol wipes contain the alcohol propan-2-olState why propan-2-ol can be described as a secondary alcohol (1)

35 A student was carrying out an investigation into alcohols aldehydes and ketones

(a)The student was given three alcohols labelled as A B and C These alcohols were all isomers with the formula C4H9OH

(i) Draw a structural formula for the secondary alcohol with the formula C4H9OH(1)

(ii) The student set up the following experiment

A Suggest why a water bath is an appropriate method of heating the reaction mixture (1)

B Describe the colour change that would have been observed with alcohols A and C (1)

40

C Alcohol B is not oxidised State the type of alcohol which cannot be oxidised by acidified dichromate solution (1)

(iii) The student set up a second experiment with alcohol A

Hot copper(II) oxide is an oxidising agentA When alcohol A (C4H9OH) is oxidised the product turns the pH paper

redSuggest a name for the product (1)

B Complete the ion-electron equation for the oxidation reaction

C4H9OH rarr C4H8O2 (1)

(b)The student found the following information about the boiling points of some aldehydes

41

(i) Name the aldehyde that has a boiling point of 119 degC (1)(ii) Predict the boiling point in degC of the following molecule (1)

(iii) Using information from the table describe one way in which differences in structure affect the boiling point of isomeric aldehydes (1)

(iv) State what would be observed when an aldehyde is gently heated with Tollensrsquo reagent (1)

(c) Ketones contain a carbonyl groupName the type of intermolecular interaction between ketone molecules (1)

42

25 Soaps Detergents and Emulsions

1 Soaps are produced by the following reaction

This reaction is an example ofA condensationB esterificationC hydrolysisD oxidation

2 Which of the following is the salt of a long-chain fatty acid

A FatB OilC SoapD Glycerol

3 Emulsifiers for use in food are commonly made by reacting edible oils with

A estersB glycerolC fatty acidsD amino acids

4 A fatty acid is a long chain carboxylic acid Examples of fatty acids are shown in the table below

43

(a) What is the systematic name for linolenic acid (1)(b) Stearic acid reacts with sodium hydroxide solution to form sodium stearate

(i) Name the type of reaction taking place when stearic acid reacts with sodium hydroxide (1)

(ii) Explain fully how sodium stearate acts to keep grease and non-polar substances suspended in water during cleaning (3)

5 Small children can find it difficult to swallow tablets or pills so ibuprofen is supplied as an ldquoinfant formulardquo emulsion(a) The emulsifier used is polysorbate 80 Its structure is shown below

Explain why this molecule acts as an emulsifier (2)

(b) The emulsion contains 2 g of ibuprofen in every 100 cm3 of emulsion The recommended dose for treating a 6 month old baby is 0middot050 g Calculate the volume in cm3 of ldquoinfant formulardquo needed to treat a 6 month old baby (1)

6 Occasionally seabirds can become contaminated with hydrocarbons from oil spills This causes problems for birds because their feathers lose their waterproofing making the birds susceptible to temperature changes and

44

affecting their buoyancy If the birds attempt to clean themselves to remove the oil they may swallow the hydrocarbons causing damage to their internal organsContaminated seabirds can be cleaned by rubbing vegetable oil into their feathers and feet before the birds are rinsed with diluted washing-up liquidUsing your knowledge of chemistry comment on the problems created for seabirds by oil spills and the actions taken to treat affected birds (3)

7 Dishwasher tablets contain chemicals which remove dirt from dishesDishwasher tablets include detergents These molecules act like soaps to allow mixing of fat-soluble dirt and water(a)During the cleaning process the detergent molecules combine with fat-

soluble dirtA simplified diagram of a detergent molecule is shown

Complete the diagram below to show how detergent molecules combine with fat-soluble dirt (1)

(b)State the term used to describe the non-polar hydrocarbon tail of a detergent molecule (1)

45

26 Fragrances1 Myrcene is a simple terpene

Terpenes contain at least one isoprene unit Which of the following shows a correctly highlighted isoprene unit

2 Limonene is one of the terpene molecules responsible for the flavour of lemons

How many isoprene units are used in the production of one limonene moleculeA 1B 2C 3D 4

46

3 The structure of caryophyllene which can be extracted from clove oil is

Which of the following would be the best solvent for extracting caryophylleneA HexaneB HexanalC HexanolD Hexanone

4 The structure of isoprene is

Limonene is a terpene molecule present in lemons

How many isoprene units are joined together in a limonene molecule

A 1B 2

47

C 3D 4

5 Essential oils are

A non-water soluble non-volatile compoundsB non-water soluble volatile compoundsC water soluble non-volatile compoundsD water soluble volatile compounds

6 Two typical compounds that are present in many perfumes are shown

(a) Why does geraniol evaporate more slowly than limonene (1)

(b) The structure of one of the first synthetic scents used in perfume is shown below

(i) Name the family of carbonyl compounds to which this synthetic scent belongs (1)

(ii) Complete the structure below to show the product formed when this scent is

oxidised (1)

(c) Traces of a liquid were discovered in a bottle believed to contain perfume belonging to Queen Hatshepsut ruler of Egypt over 3500 years ago

Perfumes were made by dissolving plant extracts containing pleasant smelling terpenes and esters in an edible oil A little ethanol and water may also have been addedUsing your knowledge of chemistry comment on the possible smell(s) when such a bottle is opened after being stored for thousands of years (3)

48

49

7 A team of chemists are developing a fragrance for use in a shower gel for men(a) To give the gel a fruity smell the chemists are considering adding an ester

They synthesise six isomeric esters Volunteers smell each ester and give it a rating out of one hundred depending on how fruity the smell is

(i) Name the ester with the fruit-smell rating of 92 (1)

(ii) Shown below are the structures of three more isomers

Arrange these esters in order of decreasing fruit-smell rating (1)

50

(b) To create a fragrance for men the compound civetone is added

Draw a structural formula for the alcohol that can be oxidised to form civetone (1)

(c) To make the shower gel produce a cold tingling sensation when applied to the skin menthol is added

Like terpenes menthol is formed from isoprene (2-methylbuta-13-diene)Circle an isoprene unit on the menthol structure above (1)

8 Many of the compounds in perfumes are molecules consisting of joined isoprene units

(a) State the name that is given to molecules consisting of joined isoprene units (1)

(b)Geraniol is one of the compounds found in perfume It has the following structural formula and systematic name

Linalool can also be present Its structural formula is shown

51

(i) State the systematic name for linalool (1)(ii) Explain why linalool can be classified as a tertiary alcohol (1)

9 The component molecules found in lavender oils are terpenes or terpenoids(a)A chiral carbon is a carbon atom attached to four different atoms or groups of

atomsAn example is shown below

A molecule of the terpenoid linalool has a chiral carbon Linalool has the following structure

Circle the chiral carbon atom in the linalool structure (1)

(b)Farnesene is a terpene consisting of three isoprene units (2-methylbuta-13-diene) joined togetherWrite the molecular formula of farnesene (1)

52

27 Skin Care

1 Which of the following is not a step in a free radical chain reaction

A ActivationB InitiationC PropagationD Termination

2 Fluorine reacts with methane via a free radical chain reaction Some steps in the chain reaction are shown in the table below

Complete the table by(a) inserting the missing name for the first step (1)

(b) showing another possible termination reaction in the final row of the table (1)

3 Suncreams contain antioxidantsThe antioxidant compound A can prevent damage to skin by reacting with free

radicalssuch as NO2bull

53

Why can compound A be described as a free radical scavenger in the reaction shown above

4 Hydrogen and chlorine gases are used in an experiment to demonstrate a free radical reaction A plastic bottle is wrapped with black tape leaving a ldquowindowrdquo on one sideThe bottle is filled with a mixture of hydrogen and chlorine When bright light shines on the bottle there is an explosion

A free radical chain reaction is initiated when light energy causes chlorine radicals to form as shown below

(a) Complete the equations below showing possible propagation and termination steps

(2)

54

(b) Why is the plastic bottle used in the experiment wrapped in black tape (1)

5 Chloramines can be removed from water using ultraviolet light treatment

One step in the process is the formation of free radicals

(a)State what is meant by the term free radical (1)

(b)Another step in the process is shown below

State the name for this type of step in a free radical reaction (1)

6 Modern shellac nail varnishes are more durable and so last longer than traditional nail polish

The shellac nail varnish is applied in thin layers to the nails and then the fingers are placed under a UV lamp

(a) The Skin Care Foundation has recommended that a sun-block is applied to the fingers and hand before using the lampSuggest why the Skin Care Foundation makes this recommendation (1)

(b) A free radical chain reaction takes place and the varnish hardens (i) State what is meant by the term free radical (1)

(ii) The shellac nail varnish contains a mixture of ingredients that take part in the free radical chain reactionOne of the steps in the free radical chain reaction is

55

State the term used to describe this type of step in a free radical chain reaction(1)

7 Skin care products contain a mixture of polar covalent non-polar covalent and ionic compounds The compounds need to stay mixed within the product Skin care products also need to spread easily and remain on the skin for a period of time as well as provide physical and chemical protection from the sun In order to do this skin care products contain a range of chemicals including water fats and oils antioxidants minerals and sun blockUsing your knowledge of chemistry explain the role of different chemicals in skin care products (3)

General Questions

1 A mixture of carbon monoxide and hydrogen can be converted into water and a mixture of hydrocarbons

nCO + (2n + 1)H2 rarr nH2O + hydrocarbons

What is the general formula for the hydrocarbons producedA CnH2nndash2B CnH2nC CnH2n+1D CnH2n+2

2 Butadiene is the first member of a homologous series of hydrocarbons called dienesWhat is the general formula for this seriesA CnHn+2B CnHn+3C CnH2nD CnH2nndash2

3 Which of the following statements about methanol is falseA It can be made from synthesis gasB It can be dehydrated to form an alkeneC It can be oxidised to give a carboxylic acidD It reacts with acidified potassium dichromate solution

56

4

Which line in the table correctly describes reactions X and Y

5

Which line in the table correctly describes reactions X and Y

6 Which of the following fuels when burned would make no contribution to globalwarming

57

A HydrogenB Natural gasC PetrolD Coal

7 Which of the following hydrocarbons always gives the same product when one of itshydrogen atoms is replaced by a chlorine atomA HexaneB Hex-1-eneC CyclohexaneD Cyclohexene

8 Which of the following compounds does not have isomeric structuresA C2HCl3B C2H4Cl2C PropeneD Propan-1-ol

9 What organic compound is produced by the dehydration of ethanol A EthaneB EtheneC EthanalD Ethanoic acid

10

The above equation representsA hydrationB hydrogenationC condensationD hydrolysis

11

Which of the following compounds is an isomer of the structure shown aboveA ButanalB ButanoneC Butan-1-olD Butanoic acid

58

12 A compound with molecular formula C6H12O2 could beA hexanalB hexan-2-olC hexan-2-oneD hexanoic acid

13 Propan-2-ol can be prepared from propane as follows

Which line in the table correctly describes the types of reaction taking place at Steps 1 and 2

14 Which of the following compounds would be the most water soluble

15 Cyanohydrin compounds can be made from carbonyl compounds by reacting the carbonyl compound with hydrogen cyanide (HCN)

59

Which carbonyl compound would react with hydrogen cyanide (HCN) to form the following compound

16 Ethyne is the first member of the homologous series called the alkynes

Ethyne can undergo addition reactions as shown in the flow diagram

(a) Compound 2 is an isomer of 12-dichloroethaneDraw a structural formula for compound 2 (1)

(b) Reagents A B and C are three different diatomic gasesUsing information in the flow diagram identify reagents A B and C (1)

60

Reagent Gas

A

B

C

17 In 1865 the German chemist Kekuleacute proposed a ring structure for benzene This structure was based on alternating single and double bonds

(a) (i) Describe a chemical test that would indicate that the above chemical structure for benzene is incorrect (1)

(ii) Briefly describe the correct structure for benzene (1)

(b) Benzene can be formed from cyclohexaneC6H12 rarr C6H6 + 3H2

What name is given to this type of reaction (1)18 Infra-red spectroscopy is a technique that can be used to identify the bonds that

arepresent in a molecule Different bonds absorb infra-red radiation of different wavenumbers This is due to differences in the bond lsquostretchrsquo These absorptions are recorded in a spectrumA spectrum for propan-1-ol is shown

61

The correlation table on page 13 of the data booklet shows the wavenumber ranges for the absorptions due to different bonds

(a) Use the correlation table to identify the bonds responsible for the two absorptions x and y that are circled in the propan-1-ol spectrum (1)

(b) Propan-1-ol reacts with ethanoic acid(i) What name is given to this type of reaction (1)(ii) Draw a spectrum that could be obtained for the organic product of this

reaction (1)

19 Paracetamol is a widely used painkiller

(a) Write the molecular formula for paracetamol (1)

(b) One antidote for paracetamol overdose is methionine

62

To what family of organic compounds does methionine belong (1)

(c) The concentration of paracetamol in a solution can be determined by measuring how much UV radiation it absorbs

The graph shows how the absorbance of a sample containing 0middot040 g l ndash1 paracetamol varies with wavelength

The quantity of UV radiation of wavelength 245 nm absorbed is directly proportional to the concentration of paracetamolThe absorbance of a second sample of paracetamol solution measured at 245 nm was 0middot90 What is the concentration in g l ndash1 of this second paracetamol solution (1)

20 Many carbon compounds containing oxygen are very flammableThe table shows information about two families of isomersThe lowest temperature at which a compound will ignite is called its flash point

(a) A compound with the molecular formula C6H14O has a boiling point of 158 degC63

Draw a structural formula for this compound (1)

(b) For a family of isomers in the table write a general statement linking the flash points of the compounds to their structures (1)

21 Hydrogels are used in disposable nappies They are fine powders that can absorb up to 500 times their own weight in waterA hydrogel is a very long molecule with carboxyl groups at regular intervals along its length A short section of a hydrogel molecule is shown below

Hydrogels are extremely good at soaking up water because the water molecules are strongly attracted to them

Using your knowledge of chemistry comment on how suitable hydrogels would be for absorbing liquids or solutions spilled in a chemistry lab (1)

64

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

A cask strength whisky has an alcohol concentration of 65 abv Calculate the alcohol concentration of this whisky in degrees proof (1)

(ii) A barrel containing 195 litres of cask strength whisky costs pound1300 The cask strength whisky is diluted with water to reduce the concentration of alcohol from 65 abv to 46 abv before it is bottled Calculate the cost of the cask strength whisky needed to produce a 0middot70 litre bottle Show your working clearly (2)

(iii) 5-Butyl-4-methyltetrahydrofuran-2-ol is a flavour compound found in whisky

stored in oak barrels

Write the systematic name for the compound shown below (1) 13 11

33 (a) One test for glucose involves Fehlingrsquos solutionCircle the part of the glucose molecule that reacts with Fehlingrsquos solution (1)

(b) In solution sugar molecules exist in an equilibrium in straight-chain and ring forms

To change from the straight-chain form to the ring form the oxygen of the hydroxyl on carbon number 5 joins to the carbonyl carbon This is shown below for glucose

39

Draw the structure of a ring form for fructose (1)

34 (a) During the free radical chain reaction small molecules join to form large chain molecules

One example of a small molecule used is

Name the functional group circled above (1)

(b)Alcohol wipes are used to finish the varnishing treatment Alcohol wipes contain the alcohol propan-2-olState why propan-2-ol can be described as a secondary alcohol (1)

35 A student was carrying out an investigation into alcohols aldehydes and ketones

(a)The student was given three alcohols labelled as A B and C These alcohols were all isomers with the formula C4H9OH

(i) Draw a structural formula for the secondary alcohol with the formula C4H9OH(1)

(ii) The student set up the following experiment

A Suggest why a water bath is an appropriate method of heating the reaction mixture (1)

B Describe the colour change that would have been observed with alcohols A and C (1)

40

C Alcohol B is not oxidised State the type of alcohol which cannot be oxidised by acidified dichromate solution (1)

(iii) The student set up a second experiment with alcohol A

Hot copper(II) oxide is an oxidising agentA When alcohol A (C4H9OH) is oxidised the product turns the pH paper

redSuggest a name for the product (1)

B Complete the ion-electron equation for the oxidation reaction

C4H9OH rarr C4H8O2 (1)

(b)The student found the following information about the boiling points of some aldehydes

41

(i) Name the aldehyde that has a boiling point of 119 degC (1)(ii) Predict the boiling point in degC of the following molecule (1)

(iii) Using information from the table describe one way in which differences in structure affect the boiling point of isomeric aldehydes (1)

(iv) State what would be observed when an aldehyde is gently heated with Tollensrsquo reagent (1)

(c) Ketones contain a carbonyl groupName the type of intermolecular interaction between ketone molecules (1)

42

25 Soaps Detergents and Emulsions

1 Soaps are produced by the following reaction

This reaction is an example ofA condensationB esterificationC hydrolysisD oxidation

2 Which of the following is the salt of a long-chain fatty acid

A FatB OilC SoapD Glycerol

3 Emulsifiers for use in food are commonly made by reacting edible oils with

A estersB glycerolC fatty acidsD amino acids

4 A fatty acid is a long chain carboxylic acid Examples of fatty acids are shown in the table below

43

(a) What is the systematic name for linolenic acid (1)(b) Stearic acid reacts with sodium hydroxide solution to form sodium stearate

(i) Name the type of reaction taking place when stearic acid reacts with sodium hydroxide (1)

(ii) Explain fully how sodium stearate acts to keep grease and non-polar substances suspended in water during cleaning (3)

5 Small children can find it difficult to swallow tablets or pills so ibuprofen is supplied as an ldquoinfant formulardquo emulsion(a) The emulsifier used is polysorbate 80 Its structure is shown below

Explain why this molecule acts as an emulsifier (2)

(b) The emulsion contains 2 g of ibuprofen in every 100 cm3 of emulsion The recommended dose for treating a 6 month old baby is 0middot050 g Calculate the volume in cm3 of ldquoinfant formulardquo needed to treat a 6 month old baby (1)

6 Occasionally seabirds can become contaminated with hydrocarbons from oil spills This causes problems for birds because their feathers lose their waterproofing making the birds susceptible to temperature changes and

44

affecting their buoyancy If the birds attempt to clean themselves to remove the oil they may swallow the hydrocarbons causing damage to their internal organsContaminated seabirds can be cleaned by rubbing vegetable oil into their feathers and feet before the birds are rinsed with diluted washing-up liquidUsing your knowledge of chemistry comment on the problems created for seabirds by oil spills and the actions taken to treat affected birds (3)

7 Dishwasher tablets contain chemicals which remove dirt from dishesDishwasher tablets include detergents These molecules act like soaps to allow mixing of fat-soluble dirt and water(a)During the cleaning process the detergent molecules combine with fat-

soluble dirtA simplified diagram of a detergent molecule is shown

Complete the diagram below to show how detergent molecules combine with fat-soluble dirt (1)

(b)State the term used to describe the non-polar hydrocarbon tail of a detergent molecule (1)

45

26 Fragrances1 Myrcene is a simple terpene

Terpenes contain at least one isoprene unit Which of the following shows a correctly highlighted isoprene unit

2 Limonene is one of the terpene molecules responsible for the flavour of lemons

How many isoprene units are used in the production of one limonene moleculeA 1B 2C 3D 4

46

3 The structure of caryophyllene which can be extracted from clove oil is

Which of the following would be the best solvent for extracting caryophylleneA HexaneB HexanalC HexanolD Hexanone

4 The structure of isoprene is

Limonene is a terpene molecule present in lemons

How many isoprene units are joined together in a limonene molecule

A 1B 2

47

C 3D 4

5 Essential oils are

A non-water soluble non-volatile compoundsB non-water soluble volatile compoundsC water soluble non-volatile compoundsD water soluble volatile compounds

6 Two typical compounds that are present in many perfumes are shown

(a) Why does geraniol evaporate more slowly than limonene (1)

(b) The structure of one of the first synthetic scents used in perfume is shown below

(i) Name the family of carbonyl compounds to which this synthetic scent belongs (1)

(ii) Complete the structure below to show the product formed when this scent is

oxidised (1)

(c) Traces of a liquid were discovered in a bottle believed to contain perfume belonging to Queen Hatshepsut ruler of Egypt over 3500 years ago

Perfumes were made by dissolving plant extracts containing pleasant smelling terpenes and esters in an edible oil A little ethanol and water may also have been addedUsing your knowledge of chemistry comment on the possible smell(s) when such a bottle is opened after being stored for thousands of years (3)

48

49

7 A team of chemists are developing a fragrance for use in a shower gel for men(a) To give the gel a fruity smell the chemists are considering adding an ester

They synthesise six isomeric esters Volunteers smell each ester and give it a rating out of one hundred depending on how fruity the smell is

(i) Name the ester with the fruit-smell rating of 92 (1)

(ii) Shown below are the structures of three more isomers

Arrange these esters in order of decreasing fruit-smell rating (1)

50

(b) To create a fragrance for men the compound civetone is added

Draw a structural formula for the alcohol that can be oxidised to form civetone (1)

(c) To make the shower gel produce a cold tingling sensation when applied to the skin menthol is added

Like terpenes menthol is formed from isoprene (2-methylbuta-13-diene)Circle an isoprene unit on the menthol structure above (1)

8 Many of the compounds in perfumes are molecules consisting of joined isoprene units

(a) State the name that is given to molecules consisting of joined isoprene units (1)

(b)Geraniol is one of the compounds found in perfume It has the following structural formula and systematic name

Linalool can also be present Its structural formula is shown

51

(i) State the systematic name for linalool (1)(ii) Explain why linalool can be classified as a tertiary alcohol (1)

9 The component molecules found in lavender oils are terpenes or terpenoids(a)A chiral carbon is a carbon atom attached to four different atoms or groups of

atomsAn example is shown below

A molecule of the terpenoid linalool has a chiral carbon Linalool has the following structure

Circle the chiral carbon atom in the linalool structure (1)

(b)Farnesene is a terpene consisting of three isoprene units (2-methylbuta-13-diene) joined togetherWrite the molecular formula of farnesene (1)

52

27 Skin Care

1 Which of the following is not a step in a free radical chain reaction

A ActivationB InitiationC PropagationD Termination

2 Fluorine reacts with methane via a free radical chain reaction Some steps in the chain reaction are shown in the table below

Complete the table by(a) inserting the missing name for the first step (1)

(b) showing another possible termination reaction in the final row of the table (1)

3 Suncreams contain antioxidantsThe antioxidant compound A can prevent damage to skin by reacting with free

radicalssuch as NO2bull

53

Why can compound A be described as a free radical scavenger in the reaction shown above

4 Hydrogen and chlorine gases are used in an experiment to demonstrate a free radical reaction A plastic bottle is wrapped with black tape leaving a ldquowindowrdquo on one sideThe bottle is filled with a mixture of hydrogen and chlorine When bright light shines on the bottle there is an explosion

A free radical chain reaction is initiated when light energy causes chlorine radicals to form as shown below

(a) Complete the equations below showing possible propagation and termination steps

(2)

54

(b) Why is the plastic bottle used in the experiment wrapped in black tape (1)

5 Chloramines can be removed from water using ultraviolet light treatment

One step in the process is the formation of free radicals

(a)State what is meant by the term free radical (1)

(b)Another step in the process is shown below

State the name for this type of step in a free radical reaction (1)

6 Modern shellac nail varnishes are more durable and so last longer than traditional nail polish

The shellac nail varnish is applied in thin layers to the nails and then the fingers are placed under a UV lamp

(a) The Skin Care Foundation has recommended that a sun-block is applied to the fingers and hand before using the lampSuggest why the Skin Care Foundation makes this recommendation (1)

(b) A free radical chain reaction takes place and the varnish hardens (i) State what is meant by the term free radical (1)

(ii) The shellac nail varnish contains a mixture of ingredients that take part in the free radical chain reactionOne of the steps in the free radical chain reaction is

55

State the term used to describe this type of step in a free radical chain reaction(1)

7 Skin care products contain a mixture of polar covalent non-polar covalent and ionic compounds The compounds need to stay mixed within the product Skin care products also need to spread easily and remain on the skin for a period of time as well as provide physical and chemical protection from the sun In order to do this skin care products contain a range of chemicals including water fats and oils antioxidants minerals and sun blockUsing your knowledge of chemistry explain the role of different chemicals in skin care products (3)

General Questions

1 A mixture of carbon monoxide and hydrogen can be converted into water and a mixture of hydrocarbons

nCO + (2n + 1)H2 rarr nH2O + hydrocarbons

What is the general formula for the hydrocarbons producedA CnH2nndash2B CnH2nC CnH2n+1D CnH2n+2

2 Butadiene is the first member of a homologous series of hydrocarbons called dienesWhat is the general formula for this seriesA CnHn+2B CnHn+3C CnH2nD CnH2nndash2

3 Which of the following statements about methanol is falseA It can be made from synthesis gasB It can be dehydrated to form an alkeneC It can be oxidised to give a carboxylic acidD It reacts with acidified potassium dichromate solution

56

4

Which line in the table correctly describes reactions X and Y

5

Which line in the table correctly describes reactions X and Y

6 Which of the following fuels when burned would make no contribution to globalwarming

57

A HydrogenB Natural gasC PetrolD Coal

7 Which of the following hydrocarbons always gives the same product when one of itshydrogen atoms is replaced by a chlorine atomA HexaneB Hex-1-eneC CyclohexaneD Cyclohexene

8 Which of the following compounds does not have isomeric structuresA C2HCl3B C2H4Cl2C PropeneD Propan-1-ol

9 What organic compound is produced by the dehydration of ethanol A EthaneB EtheneC EthanalD Ethanoic acid

10

The above equation representsA hydrationB hydrogenationC condensationD hydrolysis

11

Which of the following compounds is an isomer of the structure shown aboveA ButanalB ButanoneC Butan-1-olD Butanoic acid

58

12 A compound with molecular formula C6H12O2 could beA hexanalB hexan-2-olC hexan-2-oneD hexanoic acid

13 Propan-2-ol can be prepared from propane as follows

Which line in the table correctly describes the types of reaction taking place at Steps 1 and 2

14 Which of the following compounds would be the most water soluble

15 Cyanohydrin compounds can be made from carbonyl compounds by reacting the carbonyl compound with hydrogen cyanide (HCN)

59

Which carbonyl compound would react with hydrogen cyanide (HCN) to form the following compound

16 Ethyne is the first member of the homologous series called the alkynes

Ethyne can undergo addition reactions as shown in the flow diagram

(a) Compound 2 is an isomer of 12-dichloroethaneDraw a structural formula for compound 2 (1)

(b) Reagents A B and C are three different diatomic gasesUsing information in the flow diagram identify reagents A B and C (1)

60

Reagent Gas

A

B

C

17 In 1865 the German chemist Kekuleacute proposed a ring structure for benzene This structure was based on alternating single and double bonds

(a) (i) Describe a chemical test that would indicate that the above chemical structure for benzene is incorrect (1)

(ii) Briefly describe the correct structure for benzene (1)

(b) Benzene can be formed from cyclohexaneC6H12 rarr C6H6 + 3H2

What name is given to this type of reaction (1)18 Infra-red spectroscopy is a technique that can be used to identify the bonds that

arepresent in a molecule Different bonds absorb infra-red radiation of different wavenumbers This is due to differences in the bond lsquostretchrsquo These absorptions are recorded in a spectrumA spectrum for propan-1-ol is shown

61

The correlation table on page 13 of the data booklet shows the wavenumber ranges for the absorptions due to different bonds

(a) Use the correlation table to identify the bonds responsible for the two absorptions x and y that are circled in the propan-1-ol spectrum (1)

(b) Propan-1-ol reacts with ethanoic acid(i) What name is given to this type of reaction (1)(ii) Draw a spectrum that could be obtained for the organic product of this

reaction (1)

19 Paracetamol is a widely used painkiller

(a) Write the molecular formula for paracetamol (1)

(b) One antidote for paracetamol overdose is methionine

62

To what family of organic compounds does methionine belong (1)

(c) The concentration of paracetamol in a solution can be determined by measuring how much UV radiation it absorbs

The graph shows how the absorbance of a sample containing 0middot040 g l ndash1 paracetamol varies with wavelength

The quantity of UV radiation of wavelength 245 nm absorbed is directly proportional to the concentration of paracetamolThe absorbance of a second sample of paracetamol solution measured at 245 nm was 0middot90 What is the concentration in g l ndash1 of this second paracetamol solution (1)

20 Many carbon compounds containing oxygen are very flammableThe table shows information about two families of isomersThe lowest temperature at which a compound will ignite is called its flash point

(a) A compound with the molecular formula C6H14O has a boiling point of 158 degC63

Draw a structural formula for this compound (1)

(b) For a family of isomers in the table write a general statement linking the flash points of the compounds to their structures (1)

21 Hydrogels are used in disposable nappies They are fine powders that can absorb up to 500 times their own weight in waterA hydrogel is a very long molecule with carboxyl groups at regular intervals along its length A short section of a hydrogel molecule is shown below

Hydrogels are extremely good at soaking up water because the water molecules are strongly attracted to them

Using your knowledge of chemistry comment on how suitable hydrogels would be for absorbing liquids or solutions spilled in a chemistry lab (1)

64

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

Draw the structure of a ring form for fructose (1)

34 (a) During the free radical chain reaction small molecules join to form large chain molecules

One example of a small molecule used is

Name the functional group circled above (1)

(b)Alcohol wipes are used to finish the varnishing treatment Alcohol wipes contain the alcohol propan-2-olState why propan-2-ol can be described as a secondary alcohol (1)

35 A student was carrying out an investigation into alcohols aldehydes and ketones

(a)The student was given three alcohols labelled as A B and C These alcohols were all isomers with the formula C4H9OH

(i) Draw a structural formula for the secondary alcohol with the formula C4H9OH(1)

(ii) The student set up the following experiment

A Suggest why a water bath is an appropriate method of heating the reaction mixture (1)

B Describe the colour change that would have been observed with alcohols A and C (1)

40

C Alcohol B is not oxidised State the type of alcohol which cannot be oxidised by acidified dichromate solution (1)

(iii) The student set up a second experiment with alcohol A

Hot copper(II) oxide is an oxidising agentA When alcohol A (C4H9OH) is oxidised the product turns the pH paper

redSuggest a name for the product (1)

B Complete the ion-electron equation for the oxidation reaction

C4H9OH rarr C4H8O2 (1)

(b)The student found the following information about the boiling points of some aldehydes

41

(i) Name the aldehyde that has a boiling point of 119 degC (1)(ii) Predict the boiling point in degC of the following molecule (1)

(iii) Using information from the table describe one way in which differences in structure affect the boiling point of isomeric aldehydes (1)

(iv) State what would be observed when an aldehyde is gently heated with Tollensrsquo reagent (1)

(c) Ketones contain a carbonyl groupName the type of intermolecular interaction between ketone molecules (1)

42

25 Soaps Detergents and Emulsions

1 Soaps are produced by the following reaction

This reaction is an example ofA condensationB esterificationC hydrolysisD oxidation

2 Which of the following is the salt of a long-chain fatty acid

A FatB OilC SoapD Glycerol

3 Emulsifiers for use in food are commonly made by reacting edible oils with

A estersB glycerolC fatty acidsD amino acids

4 A fatty acid is a long chain carboxylic acid Examples of fatty acids are shown in the table below

43

(a) What is the systematic name for linolenic acid (1)(b) Stearic acid reacts with sodium hydroxide solution to form sodium stearate

(i) Name the type of reaction taking place when stearic acid reacts with sodium hydroxide (1)

(ii) Explain fully how sodium stearate acts to keep grease and non-polar substances suspended in water during cleaning (3)

5 Small children can find it difficult to swallow tablets or pills so ibuprofen is supplied as an ldquoinfant formulardquo emulsion(a) The emulsifier used is polysorbate 80 Its structure is shown below

Explain why this molecule acts as an emulsifier (2)

(b) The emulsion contains 2 g of ibuprofen in every 100 cm3 of emulsion The recommended dose for treating a 6 month old baby is 0middot050 g Calculate the volume in cm3 of ldquoinfant formulardquo needed to treat a 6 month old baby (1)

6 Occasionally seabirds can become contaminated with hydrocarbons from oil spills This causes problems for birds because their feathers lose their waterproofing making the birds susceptible to temperature changes and

44

affecting their buoyancy If the birds attempt to clean themselves to remove the oil they may swallow the hydrocarbons causing damage to their internal organsContaminated seabirds can be cleaned by rubbing vegetable oil into their feathers and feet before the birds are rinsed with diluted washing-up liquidUsing your knowledge of chemistry comment on the problems created for seabirds by oil spills and the actions taken to treat affected birds (3)

7 Dishwasher tablets contain chemicals which remove dirt from dishesDishwasher tablets include detergents These molecules act like soaps to allow mixing of fat-soluble dirt and water(a)During the cleaning process the detergent molecules combine with fat-

soluble dirtA simplified diagram of a detergent molecule is shown

Complete the diagram below to show how detergent molecules combine with fat-soluble dirt (1)

(b)State the term used to describe the non-polar hydrocarbon tail of a detergent molecule (1)

45

26 Fragrances1 Myrcene is a simple terpene

Terpenes contain at least one isoprene unit Which of the following shows a correctly highlighted isoprene unit

2 Limonene is one of the terpene molecules responsible for the flavour of lemons

How many isoprene units are used in the production of one limonene moleculeA 1B 2C 3D 4

46

3 The structure of caryophyllene which can be extracted from clove oil is

Which of the following would be the best solvent for extracting caryophylleneA HexaneB HexanalC HexanolD Hexanone

4 The structure of isoprene is

Limonene is a terpene molecule present in lemons

How many isoprene units are joined together in a limonene molecule

A 1B 2

47

C 3D 4

5 Essential oils are

A non-water soluble non-volatile compoundsB non-water soluble volatile compoundsC water soluble non-volatile compoundsD water soluble volatile compounds

6 Two typical compounds that are present in many perfumes are shown

(a) Why does geraniol evaporate more slowly than limonene (1)

(b) The structure of one of the first synthetic scents used in perfume is shown below

(i) Name the family of carbonyl compounds to which this synthetic scent belongs (1)

(ii) Complete the structure below to show the product formed when this scent is

oxidised (1)

(c) Traces of a liquid were discovered in a bottle believed to contain perfume belonging to Queen Hatshepsut ruler of Egypt over 3500 years ago

Perfumes were made by dissolving plant extracts containing pleasant smelling terpenes and esters in an edible oil A little ethanol and water may also have been addedUsing your knowledge of chemistry comment on the possible smell(s) when such a bottle is opened after being stored for thousands of years (3)

48

49

7 A team of chemists are developing a fragrance for use in a shower gel for men(a) To give the gel a fruity smell the chemists are considering adding an ester

They synthesise six isomeric esters Volunteers smell each ester and give it a rating out of one hundred depending on how fruity the smell is

(i) Name the ester with the fruit-smell rating of 92 (1)

(ii) Shown below are the structures of three more isomers

Arrange these esters in order of decreasing fruit-smell rating (1)

50

(b) To create a fragrance for men the compound civetone is added

Draw a structural formula for the alcohol that can be oxidised to form civetone (1)

(c) To make the shower gel produce a cold tingling sensation when applied to the skin menthol is added

Like terpenes menthol is formed from isoprene (2-methylbuta-13-diene)Circle an isoprene unit on the menthol structure above (1)

8 Many of the compounds in perfumes are molecules consisting of joined isoprene units

(a) State the name that is given to molecules consisting of joined isoprene units (1)

(b)Geraniol is one of the compounds found in perfume It has the following structural formula and systematic name

Linalool can also be present Its structural formula is shown

51

(i) State the systematic name for linalool (1)(ii) Explain why linalool can be classified as a tertiary alcohol (1)

9 The component molecules found in lavender oils are terpenes or terpenoids(a)A chiral carbon is a carbon atom attached to four different atoms or groups of

atomsAn example is shown below

A molecule of the terpenoid linalool has a chiral carbon Linalool has the following structure

Circle the chiral carbon atom in the linalool structure (1)

(b)Farnesene is a terpene consisting of three isoprene units (2-methylbuta-13-diene) joined togetherWrite the molecular formula of farnesene (1)

52

27 Skin Care

1 Which of the following is not a step in a free radical chain reaction

A ActivationB InitiationC PropagationD Termination

2 Fluorine reacts with methane via a free radical chain reaction Some steps in the chain reaction are shown in the table below

Complete the table by(a) inserting the missing name for the first step (1)

(b) showing another possible termination reaction in the final row of the table (1)

3 Suncreams contain antioxidantsThe antioxidant compound A can prevent damage to skin by reacting with free

radicalssuch as NO2bull

53

Why can compound A be described as a free radical scavenger in the reaction shown above

4 Hydrogen and chlorine gases are used in an experiment to demonstrate a free radical reaction A plastic bottle is wrapped with black tape leaving a ldquowindowrdquo on one sideThe bottle is filled with a mixture of hydrogen and chlorine When bright light shines on the bottle there is an explosion

A free radical chain reaction is initiated when light energy causes chlorine radicals to form as shown below

(a) Complete the equations below showing possible propagation and termination steps

(2)

54

(b) Why is the plastic bottle used in the experiment wrapped in black tape (1)

5 Chloramines can be removed from water using ultraviolet light treatment

One step in the process is the formation of free radicals

(a)State what is meant by the term free radical (1)

(b)Another step in the process is shown below

State the name for this type of step in a free radical reaction (1)

6 Modern shellac nail varnishes are more durable and so last longer than traditional nail polish

The shellac nail varnish is applied in thin layers to the nails and then the fingers are placed under a UV lamp

(a) The Skin Care Foundation has recommended that a sun-block is applied to the fingers and hand before using the lampSuggest why the Skin Care Foundation makes this recommendation (1)

(b) A free radical chain reaction takes place and the varnish hardens (i) State what is meant by the term free radical (1)

(ii) The shellac nail varnish contains a mixture of ingredients that take part in the free radical chain reactionOne of the steps in the free radical chain reaction is

55

State the term used to describe this type of step in a free radical chain reaction(1)

7 Skin care products contain a mixture of polar covalent non-polar covalent and ionic compounds The compounds need to stay mixed within the product Skin care products also need to spread easily and remain on the skin for a period of time as well as provide physical and chemical protection from the sun In order to do this skin care products contain a range of chemicals including water fats and oils antioxidants minerals and sun blockUsing your knowledge of chemistry explain the role of different chemicals in skin care products (3)

General Questions

1 A mixture of carbon monoxide and hydrogen can be converted into water and a mixture of hydrocarbons

nCO + (2n + 1)H2 rarr nH2O + hydrocarbons

What is the general formula for the hydrocarbons producedA CnH2nndash2B CnH2nC CnH2n+1D CnH2n+2

2 Butadiene is the first member of a homologous series of hydrocarbons called dienesWhat is the general formula for this seriesA CnHn+2B CnHn+3C CnH2nD CnH2nndash2

3 Which of the following statements about methanol is falseA It can be made from synthesis gasB It can be dehydrated to form an alkeneC It can be oxidised to give a carboxylic acidD It reacts with acidified potassium dichromate solution

56

4

Which line in the table correctly describes reactions X and Y

5

Which line in the table correctly describes reactions X and Y

6 Which of the following fuels when burned would make no contribution to globalwarming

57

A HydrogenB Natural gasC PetrolD Coal

7 Which of the following hydrocarbons always gives the same product when one of itshydrogen atoms is replaced by a chlorine atomA HexaneB Hex-1-eneC CyclohexaneD Cyclohexene

8 Which of the following compounds does not have isomeric structuresA C2HCl3B C2H4Cl2C PropeneD Propan-1-ol

9 What organic compound is produced by the dehydration of ethanol A EthaneB EtheneC EthanalD Ethanoic acid

10

The above equation representsA hydrationB hydrogenationC condensationD hydrolysis

11

Which of the following compounds is an isomer of the structure shown aboveA ButanalB ButanoneC Butan-1-olD Butanoic acid

58

12 A compound with molecular formula C6H12O2 could beA hexanalB hexan-2-olC hexan-2-oneD hexanoic acid

13 Propan-2-ol can be prepared from propane as follows

Which line in the table correctly describes the types of reaction taking place at Steps 1 and 2

14 Which of the following compounds would be the most water soluble

15 Cyanohydrin compounds can be made from carbonyl compounds by reacting the carbonyl compound with hydrogen cyanide (HCN)

59

Which carbonyl compound would react with hydrogen cyanide (HCN) to form the following compound

16 Ethyne is the first member of the homologous series called the alkynes

Ethyne can undergo addition reactions as shown in the flow diagram

(a) Compound 2 is an isomer of 12-dichloroethaneDraw a structural formula for compound 2 (1)

(b) Reagents A B and C are three different diatomic gasesUsing information in the flow diagram identify reagents A B and C (1)

60

Reagent Gas

A

B

C

17 In 1865 the German chemist Kekuleacute proposed a ring structure for benzene This structure was based on alternating single and double bonds

(a) (i) Describe a chemical test that would indicate that the above chemical structure for benzene is incorrect (1)

(ii) Briefly describe the correct structure for benzene (1)

(b) Benzene can be formed from cyclohexaneC6H12 rarr C6H6 + 3H2

What name is given to this type of reaction (1)18 Infra-red spectroscopy is a technique that can be used to identify the bonds that

arepresent in a molecule Different bonds absorb infra-red radiation of different wavenumbers This is due to differences in the bond lsquostretchrsquo These absorptions are recorded in a spectrumA spectrum for propan-1-ol is shown

61

The correlation table on page 13 of the data booklet shows the wavenumber ranges for the absorptions due to different bonds

(a) Use the correlation table to identify the bonds responsible for the two absorptions x and y that are circled in the propan-1-ol spectrum (1)

(b) Propan-1-ol reacts with ethanoic acid(i) What name is given to this type of reaction (1)(ii) Draw a spectrum that could be obtained for the organic product of this

reaction (1)

19 Paracetamol is a widely used painkiller

(a) Write the molecular formula for paracetamol (1)

(b) One antidote for paracetamol overdose is methionine

62

To what family of organic compounds does methionine belong (1)

(c) The concentration of paracetamol in a solution can be determined by measuring how much UV radiation it absorbs

The graph shows how the absorbance of a sample containing 0middot040 g l ndash1 paracetamol varies with wavelength

The quantity of UV radiation of wavelength 245 nm absorbed is directly proportional to the concentration of paracetamolThe absorbance of a second sample of paracetamol solution measured at 245 nm was 0middot90 What is the concentration in g l ndash1 of this second paracetamol solution (1)

20 Many carbon compounds containing oxygen are very flammableThe table shows information about two families of isomersThe lowest temperature at which a compound will ignite is called its flash point

(a) A compound with the molecular formula C6H14O has a boiling point of 158 degC63

Draw a structural formula for this compound (1)

(b) For a family of isomers in the table write a general statement linking the flash points of the compounds to their structures (1)

21 Hydrogels are used in disposable nappies They are fine powders that can absorb up to 500 times their own weight in waterA hydrogel is a very long molecule with carboxyl groups at regular intervals along its length A short section of a hydrogel molecule is shown below

Hydrogels are extremely good at soaking up water because the water molecules are strongly attracted to them

Using your knowledge of chemistry comment on how suitable hydrogels would be for absorbing liquids or solutions spilled in a chemistry lab (1)

64

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

C Alcohol B is not oxidised State the type of alcohol which cannot be oxidised by acidified dichromate solution (1)

(iii) The student set up a second experiment with alcohol A

Hot copper(II) oxide is an oxidising agentA When alcohol A (C4H9OH) is oxidised the product turns the pH paper

redSuggest a name for the product (1)

B Complete the ion-electron equation for the oxidation reaction

C4H9OH rarr C4H8O2 (1)

(b)The student found the following information about the boiling points of some aldehydes

41

(i) Name the aldehyde that has a boiling point of 119 degC (1)(ii) Predict the boiling point in degC of the following molecule (1)

(iii) Using information from the table describe one way in which differences in structure affect the boiling point of isomeric aldehydes (1)

(iv) State what would be observed when an aldehyde is gently heated with Tollensrsquo reagent (1)

(c) Ketones contain a carbonyl groupName the type of intermolecular interaction between ketone molecules (1)

42

25 Soaps Detergents and Emulsions

1 Soaps are produced by the following reaction

This reaction is an example ofA condensationB esterificationC hydrolysisD oxidation

2 Which of the following is the salt of a long-chain fatty acid

A FatB OilC SoapD Glycerol

3 Emulsifiers for use in food are commonly made by reacting edible oils with

A estersB glycerolC fatty acidsD amino acids

4 A fatty acid is a long chain carboxylic acid Examples of fatty acids are shown in the table below

43

(a) What is the systematic name for linolenic acid (1)(b) Stearic acid reacts with sodium hydroxide solution to form sodium stearate

(i) Name the type of reaction taking place when stearic acid reacts with sodium hydroxide (1)

(ii) Explain fully how sodium stearate acts to keep grease and non-polar substances suspended in water during cleaning (3)

5 Small children can find it difficult to swallow tablets or pills so ibuprofen is supplied as an ldquoinfant formulardquo emulsion(a) The emulsifier used is polysorbate 80 Its structure is shown below

Explain why this molecule acts as an emulsifier (2)

(b) The emulsion contains 2 g of ibuprofen in every 100 cm3 of emulsion The recommended dose for treating a 6 month old baby is 0middot050 g Calculate the volume in cm3 of ldquoinfant formulardquo needed to treat a 6 month old baby (1)

6 Occasionally seabirds can become contaminated with hydrocarbons from oil spills This causes problems for birds because their feathers lose their waterproofing making the birds susceptible to temperature changes and

44

affecting their buoyancy If the birds attempt to clean themselves to remove the oil they may swallow the hydrocarbons causing damage to their internal organsContaminated seabirds can be cleaned by rubbing vegetable oil into their feathers and feet before the birds are rinsed with diluted washing-up liquidUsing your knowledge of chemistry comment on the problems created for seabirds by oil spills and the actions taken to treat affected birds (3)

7 Dishwasher tablets contain chemicals which remove dirt from dishesDishwasher tablets include detergents These molecules act like soaps to allow mixing of fat-soluble dirt and water(a)During the cleaning process the detergent molecules combine with fat-

soluble dirtA simplified diagram of a detergent molecule is shown

Complete the diagram below to show how detergent molecules combine with fat-soluble dirt (1)

(b)State the term used to describe the non-polar hydrocarbon tail of a detergent molecule (1)

45

26 Fragrances1 Myrcene is a simple terpene

Terpenes contain at least one isoprene unit Which of the following shows a correctly highlighted isoprene unit

2 Limonene is one of the terpene molecules responsible for the flavour of lemons

How many isoprene units are used in the production of one limonene moleculeA 1B 2C 3D 4

46

3 The structure of caryophyllene which can be extracted from clove oil is

Which of the following would be the best solvent for extracting caryophylleneA HexaneB HexanalC HexanolD Hexanone

4 The structure of isoprene is

Limonene is a terpene molecule present in lemons

How many isoprene units are joined together in a limonene molecule

A 1B 2

47

C 3D 4

5 Essential oils are

A non-water soluble non-volatile compoundsB non-water soluble volatile compoundsC water soluble non-volatile compoundsD water soluble volatile compounds

6 Two typical compounds that are present in many perfumes are shown

(a) Why does geraniol evaporate more slowly than limonene (1)

(b) The structure of one of the first synthetic scents used in perfume is shown below

(i) Name the family of carbonyl compounds to which this synthetic scent belongs (1)

(ii) Complete the structure below to show the product formed when this scent is

oxidised (1)

(c) Traces of a liquid were discovered in a bottle believed to contain perfume belonging to Queen Hatshepsut ruler of Egypt over 3500 years ago

Perfumes were made by dissolving plant extracts containing pleasant smelling terpenes and esters in an edible oil A little ethanol and water may also have been addedUsing your knowledge of chemistry comment on the possible smell(s) when such a bottle is opened after being stored for thousands of years (3)

48

49

7 A team of chemists are developing a fragrance for use in a shower gel for men(a) To give the gel a fruity smell the chemists are considering adding an ester

They synthesise six isomeric esters Volunteers smell each ester and give it a rating out of one hundred depending on how fruity the smell is

(i) Name the ester with the fruit-smell rating of 92 (1)

(ii) Shown below are the structures of three more isomers

Arrange these esters in order of decreasing fruit-smell rating (1)

50

(b) To create a fragrance for men the compound civetone is added

Draw a structural formula for the alcohol that can be oxidised to form civetone (1)

(c) To make the shower gel produce a cold tingling sensation when applied to the skin menthol is added

Like terpenes menthol is formed from isoprene (2-methylbuta-13-diene)Circle an isoprene unit on the menthol structure above (1)

8 Many of the compounds in perfumes are molecules consisting of joined isoprene units

(a) State the name that is given to molecules consisting of joined isoprene units (1)

(b)Geraniol is one of the compounds found in perfume It has the following structural formula and systematic name

Linalool can also be present Its structural formula is shown

51

(i) State the systematic name for linalool (1)(ii) Explain why linalool can be classified as a tertiary alcohol (1)

9 The component molecules found in lavender oils are terpenes or terpenoids(a)A chiral carbon is a carbon atom attached to four different atoms or groups of

atomsAn example is shown below

A molecule of the terpenoid linalool has a chiral carbon Linalool has the following structure

Circle the chiral carbon atom in the linalool structure (1)

(b)Farnesene is a terpene consisting of three isoprene units (2-methylbuta-13-diene) joined togetherWrite the molecular formula of farnesene (1)

52

27 Skin Care

1 Which of the following is not a step in a free radical chain reaction

A ActivationB InitiationC PropagationD Termination

2 Fluorine reacts with methane via a free radical chain reaction Some steps in the chain reaction are shown in the table below

Complete the table by(a) inserting the missing name for the first step (1)

(b) showing another possible termination reaction in the final row of the table (1)

3 Suncreams contain antioxidantsThe antioxidant compound A can prevent damage to skin by reacting with free

radicalssuch as NO2bull

53

Why can compound A be described as a free radical scavenger in the reaction shown above

4 Hydrogen and chlorine gases are used in an experiment to demonstrate a free radical reaction A plastic bottle is wrapped with black tape leaving a ldquowindowrdquo on one sideThe bottle is filled with a mixture of hydrogen and chlorine When bright light shines on the bottle there is an explosion

A free radical chain reaction is initiated when light energy causes chlorine radicals to form as shown below

(a) Complete the equations below showing possible propagation and termination steps

(2)

54

(b) Why is the plastic bottle used in the experiment wrapped in black tape (1)

5 Chloramines can be removed from water using ultraviolet light treatment

One step in the process is the formation of free radicals

(a)State what is meant by the term free radical (1)

(b)Another step in the process is shown below

State the name for this type of step in a free radical reaction (1)

6 Modern shellac nail varnishes are more durable and so last longer than traditional nail polish

The shellac nail varnish is applied in thin layers to the nails and then the fingers are placed under a UV lamp

(a) The Skin Care Foundation has recommended that a sun-block is applied to the fingers and hand before using the lampSuggest why the Skin Care Foundation makes this recommendation (1)

(b) A free radical chain reaction takes place and the varnish hardens (i) State what is meant by the term free radical (1)

(ii) The shellac nail varnish contains a mixture of ingredients that take part in the free radical chain reactionOne of the steps in the free radical chain reaction is

55

State the term used to describe this type of step in a free radical chain reaction(1)

7 Skin care products contain a mixture of polar covalent non-polar covalent and ionic compounds The compounds need to stay mixed within the product Skin care products also need to spread easily and remain on the skin for a period of time as well as provide physical and chemical protection from the sun In order to do this skin care products contain a range of chemicals including water fats and oils antioxidants minerals and sun blockUsing your knowledge of chemistry explain the role of different chemicals in skin care products (3)

General Questions

1 A mixture of carbon monoxide and hydrogen can be converted into water and a mixture of hydrocarbons

nCO + (2n + 1)H2 rarr nH2O + hydrocarbons

What is the general formula for the hydrocarbons producedA CnH2nndash2B CnH2nC CnH2n+1D CnH2n+2

2 Butadiene is the first member of a homologous series of hydrocarbons called dienesWhat is the general formula for this seriesA CnHn+2B CnHn+3C CnH2nD CnH2nndash2

3 Which of the following statements about methanol is falseA It can be made from synthesis gasB It can be dehydrated to form an alkeneC It can be oxidised to give a carboxylic acidD It reacts with acidified potassium dichromate solution

56

4

Which line in the table correctly describes reactions X and Y

5

Which line in the table correctly describes reactions X and Y

6 Which of the following fuels when burned would make no contribution to globalwarming

57

A HydrogenB Natural gasC PetrolD Coal

7 Which of the following hydrocarbons always gives the same product when one of itshydrogen atoms is replaced by a chlorine atomA HexaneB Hex-1-eneC CyclohexaneD Cyclohexene

8 Which of the following compounds does not have isomeric structuresA C2HCl3B C2H4Cl2C PropeneD Propan-1-ol

9 What organic compound is produced by the dehydration of ethanol A EthaneB EtheneC EthanalD Ethanoic acid

10

The above equation representsA hydrationB hydrogenationC condensationD hydrolysis

11

Which of the following compounds is an isomer of the structure shown aboveA ButanalB ButanoneC Butan-1-olD Butanoic acid

58

12 A compound with molecular formula C6H12O2 could beA hexanalB hexan-2-olC hexan-2-oneD hexanoic acid

13 Propan-2-ol can be prepared from propane as follows

Which line in the table correctly describes the types of reaction taking place at Steps 1 and 2

14 Which of the following compounds would be the most water soluble

15 Cyanohydrin compounds can be made from carbonyl compounds by reacting the carbonyl compound with hydrogen cyanide (HCN)

59

Which carbonyl compound would react with hydrogen cyanide (HCN) to form the following compound

16 Ethyne is the first member of the homologous series called the alkynes

Ethyne can undergo addition reactions as shown in the flow diagram

(a) Compound 2 is an isomer of 12-dichloroethaneDraw a structural formula for compound 2 (1)

(b) Reagents A B and C are three different diatomic gasesUsing information in the flow diagram identify reagents A B and C (1)

60

Reagent Gas

A

B

C

17 In 1865 the German chemist Kekuleacute proposed a ring structure for benzene This structure was based on alternating single and double bonds

(a) (i) Describe a chemical test that would indicate that the above chemical structure for benzene is incorrect (1)

(ii) Briefly describe the correct structure for benzene (1)

(b) Benzene can be formed from cyclohexaneC6H12 rarr C6H6 + 3H2

What name is given to this type of reaction (1)18 Infra-red spectroscopy is a technique that can be used to identify the bonds that

arepresent in a molecule Different bonds absorb infra-red radiation of different wavenumbers This is due to differences in the bond lsquostretchrsquo These absorptions are recorded in a spectrumA spectrum for propan-1-ol is shown

61

The correlation table on page 13 of the data booklet shows the wavenumber ranges for the absorptions due to different bonds

(a) Use the correlation table to identify the bonds responsible for the two absorptions x and y that are circled in the propan-1-ol spectrum (1)

(b) Propan-1-ol reacts with ethanoic acid(i) What name is given to this type of reaction (1)(ii) Draw a spectrum that could be obtained for the organic product of this

reaction (1)

19 Paracetamol is a widely used painkiller

(a) Write the molecular formula for paracetamol (1)

(b) One antidote for paracetamol overdose is methionine

62

To what family of organic compounds does methionine belong (1)

(c) The concentration of paracetamol in a solution can be determined by measuring how much UV radiation it absorbs

The graph shows how the absorbance of a sample containing 0middot040 g l ndash1 paracetamol varies with wavelength

The quantity of UV radiation of wavelength 245 nm absorbed is directly proportional to the concentration of paracetamolThe absorbance of a second sample of paracetamol solution measured at 245 nm was 0middot90 What is the concentration in g l ndash1 of this second paracetamol solution (1)

20 Many carbon compounds containing oxygen are very flammableThe table shows information about two families of isomersThe lowest temperature at which a compound will ignite is called its flash point

(a) A compound with the molecular formula C6H14O has a boiling point of 158 degC63

Draw a structural formula for this compound (1)

(b) For a family of isomers in the table write a general statement linking the flash points of the compounds to their structures (1)

21 Hydrogels are used in disposable nappies They are fine powders that can absorb up to 500 times their own weight in waterA hydrogel is a very long molecule with carboxyl groups at regular intervals along its length A short section of a hydrogel molecule is shown below

Hydrogels are extremely good at soaking up water because the water molecules are strongly attracted to them

Using your knowledge of chemistry comment on how suitable hydrogels would be for absorbing liquids or solutions spilled in a chemistry lab (1)

64

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

(i) Name the aldehyde that has a boiling point of 119 degC (1)(ii) Predict the boiling point in degC of the following molecule (1)

(iii) Using information from the table describe one way in which differences in structure affect the boiling point of isomeric aldehydes (1)

(iv) State what would be observed when an aldehyde is gently heated with Tollensrsquo reagent (1)

(c) Ketones contain a carbonyl groupName the type of intermolecular interaction between ketone molecules (1)

42

25 Soaps Detergents and Emulsions

1 Soaps are produced by the following reaction

This reaction is an example ofA condensationB esterificationC hydrolysisD oxidation

2 Which of the following is the salt of a long-chain fatty acid

A FatB OilC SoapD Glycerol

3 Emulsifiers for use in food are commonly made by reacting edible oils with

A estersB glycerolC fatty acidsD amino acids

4 A fatty acid is a long chain carboxylic acid Examples of fatty acids are shown in the table below

43

(a) What is the systematic name for linolenic acid (1)(b) Stearic acid reacts with sodium hydroxide solution to form sodium stearate

(i) Name the type of reaction taking place when stearic acid reacts with sodium hydroxide (1)

(ii) Explain fully how sodium stearate acts to keep grease and non-polar substances suspended in water during cleaning (3)

5 Small children can find it difficult to swallow tablets or pills so ibuprofen is supplied as an ldquoinfant formulardquo emulsion(a) The emulsifier used is polysorbate 80 Its structure is shown below

Explain why this molecule acts as an emulsifier (2)

(b) The emulsion contains 2 g of ibuprofen in every 100 cm3 of emulsion The recommended dose for treating a 6 month old baby is 0middot050 g Calculate the volume in cm3 of ldquoinfant formulardquo needed to treat a 6 month old baby (1)

6 Occasionally seabirds can become contaminated with hydrocarbons from oil spills This causes problems for birds because their feathers lose their waterproofing making the birds susceptible to temperature changes and

44

affecting their buoyancy If the birds attempt to clean themselves to remove the oil they may swallow the hydrocarbons causing damage to their internal organsContaminated seabirds can be cleaned by rubbing vegetable oil into their feathers and feet before the birds are rinsed with diluted washing-up liquidUsing your knowledge of chemistry comment on the problems created for seabirds by oil spills and the actions taken to treat affected birds (3)

7 Dishwasher tablets contain chemicals which remove dirt from dishesDishwasher tablets include detergents These molecules act like soaps to allow mixing of fat-soluble dirt and water(a)During the cleaning process the detergent molecules combine with fat-

soluble dirtA simplified diagram of a detergent molecule is shown

Complete the diagram below to show how detergent molecules combine with fat-soluble dirt (1)

(b)State the term used to describe the non-polar hydrocarbon tail of a detergent molecule (1)

45

26 Fragrances1 Myrcene is a simple terpene

Terpenes contain at least one isoprene unit Which of the following shows a correctly highlighted isoprene unit

2 Limonene is one of the terpene molecules responsible for the flavour of lemons

How many isoprene units are used in the production of one limonene moleculeA 1B 2C 3D 4

46

3 The structure of caryophyllene which can be extracted from clove oil is

Which of the following would be the best solvent for extracting caryophylleneA HexaneB HexanalC HexanolD Hexanone

4 The structure of isoprene is

Limonene is a terpene molecule present in lemons

How many isoprene units are joined together in a limonene molecule

A 1B 2

47

C 3D 4

5 Essential oils are

A non-water soluble non-volatile compoundsB non-water soluble volatile compoundsC water soluble non-volatile compoundsD water soluble volatile compounds

6 Two typical compounds that are present in many perfumes are shown

(a) Why does geraniol evaporate more slowly than limonene (1)

(b) The structure of one of the first synthetic scents used in perfume is shown below

(i) Name the family of carbonyl compounds to which this synthetic scent belongs (1)

(ii) Complete the structure below to show the product formed when this scent is

oxidised (1)

(c) Traces of a liquid were discovered in a bottle believed to contain perfume belonging to Queen Hatshepsut ruler of Egypt over 3500 years ago

Perfumes were made by dissolving plant extracts containing pleasant smelling terpenes and esters in an edible oil A little ethanol and water may also have been addedUsing your knowledge of chemistry comment on the possible smell(s) when such a bottle is opened after being stored for thousands of years (3)

48

49

7 A team of chemists are developing a fragrance for use in a shower gel for men(a) To give the gel a fruity smell the chemists are considering adding an ester

They synthesise six isomeric esters Volunteers smell each ester and give it a rating out of one hundred depending on how fruity the smell is

(i) Name the ester with the fruit-smell rating of 92 (1)

(ii) Shown below are the structures of three more isomers

Arrange these esters in order of decreasing fruit-smell rating (1)

50

(b) To create a fragrance for men the compound civetone is added

Draw a structural formula for the alcohol that can be oxidised to form civetone (1)

(c) To make the shower gel produce a cold tingling sensation when applied to the skin menthol is added

Like terpenes menthol is formed from isoprene (2-methylbuta-13-diene)Circle an isoprene unit on the menthol structure above (1)

8 Many of the compounds in perfumes are molecules consisting of joined isoprene units

(a) State the name that is given to molecules consisting of joined isoprene units (1)

(b)Geraniol is one of the compounds found in perfume It has the following structural formula and systematic name

Linalool can also be present Its structural formula is shown

51

(i) State the systematic name for linalool (1)(ii) Explain why linalool can be classified as a tertiary alcohol (1)

9 The component molecules found in lavender oils are terpenes or terpenoids(a)A chiral carbon is a carbon atom attached to four different atoms or groups of

atomsAn example is shown below

A molecule of the terpenoid linalool has a chiral carbon Linalool has the following structure

Circle the chiral carbon atom in the linalool structure (1)

(b)Farnesene is a terpene consisting of three isoprene units (2-methylbuta-13-diene) joined togetherWrite the molecular formula of farnesene (1)

52

27 Skin Care

1 Which of the following is not a step in a free radical chain reaction

A ActivationB InitiationC PropagationD Termination

2 Fluorine reacts with methane via a free radical chain reaction Some steps in the chain reaction are shown in the table below

Complete the table by(a) inserting the missing name for the first step (1)

(b) showing another possible termination reaction in the final row of the table (1)

3 Suncreams contain antioxidantsThe antioxidant compound A can prevent damage to skin by reacting with free

radicalssuch as NO2bull

53

Why can compound A be described as a free radical scavenger in the reaction shown above

4 Hydrogen and chlorine gases are used in an experiment to demonstrate a free radical reaction A plastic bottle is wrapped with black tape leaving a ldquowindowrdquo on one sideThe bottle is filled with a mixture of hydrogen and chlorine When bright light shines on the bottle there is an explosion

A free radical chain reaction is initiated when light energy causes chlorine radicals to form as shown below

(a) Complete the equations below showing possible propagation and termination steps

(2)

54

(b) Why is the plastic bottle used in the experiment wrapped in black tape (1)

5 Chloramines can be removed from water using ultraviolet light treatment

One step in the process is the formation of free radicals

(a)State what is meant by the term free radical (1)

(b)Another step in the process is shown below

State the name for this type of step in a free radical reaction (1)

6 Modern shellac nail varnishes are more durable and so last longer than traditional nail polish

The shellac nail varnish is applied in thin layers to the nails and then the fingers are placed under a UV lamp

(a) The Skin Care Foundation has recommended that a sun-block is applied to the fingers and hand before using the lampSuggest why the Skin Care Foundation makes this recommendation (1)

(b) A free radical chain reaction takes place and the varnish hardens (i) State what is meant by the term free radical (1)

(ii) The shellac nail varnish contains a mixture of ingredients that take part in the free radical chain reactionOne of the steps in the free radical chain reaction is

55

State the term used to describe this type of step in a free radical chain reaction(1)

7 Skin care products contain a mixture of polar covalent non-polar covalent and ionic compounds The compounds need to stay mixed within the product Skin care products also need to spread easily and remain on the skin for a period of time as well as provide physical and chemical protection from the sun In order to do this skin care products contain a range of chemicals including water fats and oils antioxidants minerals and sun blockUsing your knowledge of chemistry explain the role of different chemicals in skin care products (3)

General Questions

1 A mixture of carbon monoxide and hydrogen can be converted into water and a mixture of hydrocarbons

nCO + (2n + 1)H2 rarr nH2O + hydrocarbons

What is the general formula for the hydrocarbons producedA CnH2nndash2B CnH2nC CnH2n+1D CnH2n+2

2 Butadiene is the first member of a homologous series of hydrocarbons called dienesWhat is the general formula for this seriesA CnHn+2B CnHn+3C CnH2nD CnH2nndash2

3 Which of the following statements about methanol is falseA It can be made from synthesis gasB It can be dehydrated to form an alkeneC It can be oxidised to give a carboxylic acidD It reacts with acidified potassium dichromate solution

56

4

Which line in the table correctly describes reactions X and Y

5

Which line in the table correctly describes reactions X and Y

6 Which of the following fuels when burned would make no contribution to globalwarming

57

A HydrogenB Natural gasC PetrolD Coal

7 Which of the following hydrocarbons always gives the same product when one of itshydrogen atoms is replaced by a chlorine atomA HexaneB Hex-1-eneC CyclohexaneD Cyclohexene

8 Which of the following compounds does not have isomeric structuresA C2HCl3B C2H4Cl2C PropeneD Propan-1-ol

9 What organic compound is produced by the dehydration of ethanol A EthaneB EtheneC EthanalD Ethanoic acid

10

The above equation representsA hydrationB hydrogenationC condensationD hydrolysis

11

Which of the following compounds is an isomer of the structure shown aboveA ButanalB ButanoneC Butan-1-olD Butanoic acid

58

12 A compound with molecular formula C6H12O2 could beA hexanalB hexan-2-olC hexan-2-oneD hexanoic acid

13 Propan-2-ol can be prepared from propane as follows

Which line in the table correctly describes the types of reaction taking place at Steps 1 and 2

14 Which of the following compounds would be the most water soluble

15 Cyanohydrin compounds can be made from carbonyl compounds by reacting the carbonyl compound with hydrogen cyanide (HCN)

59

Which carbonyl compound would react with hydrogen cyanide (HCN) to form the following compound

16 Ethyne is the first member of the homologous series called the alkynes

Ethyne can undergo addition reactions as shown in the flow diagram

(a) Compound 2 is an isomer of 12-dichloroethaneDraw a structural formula for compound 2 (1)

(b) Reagents A B and C are three different diatomic gasesUsing information in the flow diagram identify reagents A B and C (1)

60

Reagent Gas

A

B

C

17 In 1865 the German chemist Kekuleacute proposed a ring structure for benzene This structure was based on alternating single and double bonds

(a) (i) Describe a chemical test that would indicate that the above chemical structure for benzene is incorrect (1)

(ii) Briefly describe the correct structure for benzene (1)

(b) Benzene can be formed from cyclohexaneC6H12 rarr C6H6 + 3H2

What name is given to this type of reaction (1)18 Infra-red spectroscopy is a technique that can be used to identify the bonds that

arepresent in a molecule Different bonds absorb infra-red radiation of different wavenumbers This is due to differences in the bond lsquostretchrsquo These absorptions are recorded in a spectrumA spectrum for propan-1-ol is shown

61

The correlation table on page 13 of the data booklet shows the wavenumber ranges for the absorptions due to different bonds

(a) Use the correlation table to identify the bonds responsible for the two absorptions x and y that are circled in the propan-1-ol spectrum (1)

(b) Propan-1-ol reacts with ethanoic acid(i) What name is given to this type of reaction (1)(ii) Draw a spectrum that could be obtained for the organic product of this

reaction (1)

19 Paracetamol is a widely used painkiller

(a) Write the molecular formula for paracetamol (1)

(b) One antidote for paracetamol overdose is methionine

62

To what family of organic compounds does methionine belong (1)

(c) The concentration of paracetamol in a solution can be determined by measuring how much UV radiation it absorbs

The graph shows how the absorbance of a sample containing 0middot040 g l ndash1 paracetamol varies with wavelength

The quantity of UV radiation of wavelength 245 nm absorbed is directly proportional to the concentration of paracetamolThe absorbance of a second sample of paracetamol solution measured at 245 nm was 0middot90 What is the concentration in g l ndash1 of this second paracetamol solution (1)

20 Many carbon compounds containing oxygen are very flammableThe table shows information about two families of isomersThe lowest temperature at which a compound will ignite is called its flash point

(a) A compound with the molecular formula C6H14O has a boiling point of 158 degC63

Draw a structural formula for this compound (1)

(b) For a family of isomers in the table write a general statement linking the flash points of the compounds to their structures (1)

21 Hydrogels are used in disposable nappies They are fine powders that can absorb up to 500 times their own weight in waterA hydrogel is a very long molecule with carboxyl groups at regular intervals along its length A short section of a hydrogel molecule is shown below

Hydrogels are extremely good at soaking up water because the water molecules are strongly attracted to them

Using your knowledge of chemistry comment on how suitable hydrogels would be for absorbing liquids or solutions spilled in a chemistry lab (1)

64

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

25 Soaps Detergents and Emulsions

1 Soaps are produced by the following reaction

This reaction is an example ofA condensationB esterificationC hydrolysisD oxidation

2 Which of the following is the salt of a long-chain fatty acid

A FatB OilC SoapD Glycerol

3 Emulsifiers for use in food are commonly made by reacting edible oils with

A estersB glycerolC fatty acidsD amino acids

4 A fatty acid is a long chain carboxylic acid Examples of fatty acids are shown in the table below

43

(a) What is the systematic name for linolenic acid (1)(b) Stearic acid reacts with sodium hydroxide solution to form sodium stearate

(i) Name the type of reaction taking place when stearic acid reacts with sodium hydroxide (1)

(ii) Explain fully how sodium stearate acts to keep grease and non-polar substances suspended in water during cleaning (3)

5 Small children can find it difficult to swallow tablets or pills so ibuprofen is supplied as an ldquoinfant formulardquo emulsion(a) The emulsifier used is polysorbate 80 Its structure is shown below

Explain why this molecule acts as an emulsifier (2)

(b) The emulsion contains 2 g of ibuprofen in every 100 cm3 of emulsion The recommended dose for treating a 6 month old baby is 0middot050 g Calculate the volume in cm3 of ldquoinfant formulardquo needed to treat a 6 month old baby (1)

6 Occasionally seabirds can become contaminated with hydrocarbons from oil spills This causes problems for birds because their feathers lose their waterproofing making the birds susceptible to temperature changes and

44

affecting their buoyancy If the birds attempt to clean themselves to remove the oil they may swallow the hydrocarbons causing damage to their internal organsContaminated seabirds can be cleaned by rubbing vegetable oil into their feathers and feet before the birds are rinsed with diluted washing-up liquidUsing your knowledge of chemistry comment on the problems created for seabirds by oil spills and the actions taken to treat affected birds (3)

7 Dishwasher tablets contain chemicals which remove dirt from dishesDishwasher tablets include detergents These molecules act like soaps to allow mixing of fat-soluble dirt and water(a)During the cleaning process the detergent molecules combine with fat-

soluble dirtA simplified diagram of a detergent molecule is shown

Complete the diagram below to show how detergent molecules combine with fat-soluble dirt (1)

(b)State the term used to describe the non-polar hydrocarbon tail of a detergent molecule (1)

45

26 Fragrances1 Myrcene is a simple terpene

Terpenes contain at least one isoprene unit Which of the following shows a correctly highlighted isoprene unit

2 Limonene is one of the terpene molecules responsible for the flavour of lemons

How many isoprene units are used in the production of one limonene moleculeA 1B 2C 3D 4

46

3 The structure of caryophyllene which can be extracted from clove oil is

Which of the following would be the best solvent for extracting caryophylleneA HexaneB HexanalC HexanolD Hexanone

4 The structure of isoprene is

Limonene is a terpene molecule present in lemons

How many isoprene units are joined together in a limonene molecule

A 1B 2

47

C 3D 4

5 Essential oils are

A non-water soluble non-volatile compoundsB non-water soluble volatile compoundsC water soluble non-volatile compoundsD water soluble volatile compounds

6 Two typical compounds that are present in many perfumes are shown

(a) Why does geraniol evaporate more slowly than limonene (1)

(b) The structure of one of the first synthetic scents used in perfume is shown below

(i) Name the family of carbonyl compounds to which this synthetic scent belongs (1)

(ii) Complete the structure below to show the product formed when this scent is

oxidised (1)

(c) Traces of a liquid were discovered in a bottle believed to contain perfume belonging to Queen Hatshepsut ruler of Egypt over 3500 years ago

Perfumes were made by dissolving plant extracts containing pleasant smelling terpenes and esters in an edible oil A little ethanol and water may also have been addedUsing your knowledge of chemistry comment on the possible smell(s) when such a bottle is opened after being stored for thousands of years (3)

48

49

7 A team of chemists are developing a fragrance for use in a shower gel for men(a) To give the gel a fruity smell the chemists are considering adding an ester

They synthesise six isomeric esters Volunteers smell each ester and give it a rating out of one hundred depending on how fruity the smell is

(i) Name the ester with the fruit-smell rating of 92 (1)

(ii) Shown below are the structures of three more isomers

Arrange these esters in order of decreasing fruit-smell rating (1)

50

(b) To create a fragrance for men the compound civetone is added

Draw a structural formula for the alcohol that can be oxidised to form civetone (1)

(c) To make the shower gel produce a cold tingling sensation when applied to the skin menthol is added

Like terpenes menthol is formed from isoprene (2-methylbuta-13-diene)Circle an isoprene unit on the menthol structure above (1)

8 Many of the compounds in perfumes are molecules consisting of joined isoprene units

(a) State the name that is given to molecules consisting of joined isoprene units (1)

(b)Geraniol is one of the compounds found in perfume It has the following structural formula and systematic name

Linalool can also be present Its structural formula is shown

51

(i) State the systematic name for linalool (1)(ii) Explain why linalool can be classified as a tertiary alcohol (1)

9 The component molecules found in lavender oils are terpenes or terpenoids(a)A chiral carbon is a carbon atom attached to four different atoms or groups of

atomsAn example is shown below

A molecule of the terpenoid linalool has a chiral carbon Linalool has the following structure

Circle the chiral carbon atom in the linalool structure (1)

(b)Farnesene is a terpene consisting of three isoprene units (2-methylbuta-13-diene) joined togetherWrite the molecular formula of farnesene (1)

52

27 Skin Care

1 Which of the following is not a step in a free radical chain reaction

A ActivationB InitiationC PropagationD Termination

2 Fluorine reacts with methane via a free radical chain reaction Some steps in the chain reaction are shown in the table below

Complete the table by(a) inserting the missing name for the first step (1)

(b) showing another possible termination reaction in the final row of the table (1)

3 Suncreams contain antioxidantsThe antioxidant compound A can prevent damage to skin by reacting with free

radicalssuch as NO2bull

53

Why can compound A be described as a free radical scavenger in the reaction shown above

4 Hydrogen and chlorine gases are used in an experiment to demonstrate a free radical reaction A plastic bottle is wrapped with black tape leaving a ldquowindowrdquo on one sideThe bottle is filled with a mixture of hydrogen and chlorine When bright light shines on the bottle there is an explosion

A free radical chain reaction is initiated when light energy causes chlorine radicals to form as shown below

(a) Complete the equations below showing possible propagation and termination steps

(2)

54

(b) Why is the plastic bottle used in the experiment wrapped in black tape (1)

5 Chloramines can be removed from water using ultraviolet light treatment

One step in the process is the formation of free radicals

(a)State what is meant by the term free radical (1)

(b)Another step in the process is shown below

State the name for this type of step in a free radical reaction (1)

6 Modern shellac nail varnishes are more durable and so last longer than traditional nail polish

The shellac nail varnish is applied in thin layers to the nails and then the fingers are placed under a UV lamp

(a) The Skin Care Foundation has recommended that a sun-block is applied to the fingers and hand before using the lampSuggest why the Skin Care Foundation makes this recommendation (1)

(b) A free radical chain reaction takes place and the varnish hardens (i) State what is meant by the term free radical (1)

(ii) The shellac nail varnish contains a mixture of ingredients that take part in the free radical chain reactionOne of the steps in the free radical chain reaction is

55

State the term used to describe this type of step in a free radical chain reaction(1)

7 Skin care products contain a mixture of polar covalent non-polar covalent and ionic compounds The compounds need to stay mixed within the product Skin care products also need to spread easily and remain on the skin for a period of time as well as provide physical and chemical protection from the sun In order to do this skin care products contain a range of chemicals including water fats and oils antioxidants minerals and sun blockUsing your knowledge of chemistry explain the role of different chemicals in skin care products (3)

General Questions

1 A mixture of carbon monoxide and hydrogen can be converted into water and a mixture of hydrocarbons

nCO + (2n + 1)H2 rarr nH2O + hydrocarbons

What is the general formula for the hydrocarbons producedA CnH2nndash2B CnH2nC CnH2n+1D CnH2n+2

2 Butadiene is the first member of a homologous series of hydrocarbons called dienesWhat is the general formula for this seriesA CnHn+2B CnHn+3C CnH2nD CnH2nndash2

3 Which of the following statements about methanol is falseA It can be made from synthesis gasB It can be dehydrated to form an alkeneC It can be oxidised to give a carboxylic acidD It reacts with acidified potassium dichromate solution

56

4

Which line in the table correctly describes reactions X and Y

5

Which line in the table correctly describes reactions X and Y

6 Which of the following fuels when burned would make no contribution to globalwarming

57

A HydrogenB Natural gasC PetrolD Coal

7 Which of the following hydrocarbons always gives the same product when one of itshydrogen atoms is replaced by a chlorine atomA HexaneB Hex-1-eneC CyclohexaneD Cyclohexene

8 Which of the following compounds does not have isomeric structuresA C2HCl3B C2H4Cl2C PropeneD Propan-1-ol

9 What organic compound is produced by the dehydration of ethanol A EthaneB EtheneC EthanalD Ethanoic acid

10

The above equation representsA hydrationB hydrogenationC condensationD hydrolysis

11

Which of the following compounds is an isomer of the structure shown aboveA ButanalB ButanoneC Butan-1-olD Butanoic acid

58

12 A compound with molecular formula C6H12O2 could beA hexanalB hexan-2-olC hexan-2-oneD hexanoic acid

13 Propan-2-ol can be prepared from propane as follows

Which line in the table correctly describes the types of reaction taking place at Steps 1 and 2

14 Which of the following compounds would be the most water soluble

15 Cyanohydrin compounds can be made from carbonyl compounds by reacting the carbonyl compound with hydrogen cyanide (HCN)

59

Which carbonyl compound would react with hydrogen cyanide (HCN) to form the following compound

16 Ethyne is the first member of the homologous series called the alkynes

Ethyne can undergo addition reactions as shown in the flow diagram

(a) Compound 2 is an isomer of 12-dichloroethaneDraw a structural formula for compound 2 (1)

(b) Reagents A B and C are three different diatomic gasesUsing information in the flow diagram identify reagents A B and C (1)

60

Reagent Gas

A

B

C

17 In 1865 the German chemist Kekuleacute proposed a ring structure for benzene This structure was based on alternating single and double bonds

(a) (i) Describe a chemical test that would indicate that the above chemical structure for benzene is incorrect (1)

(ii) Briefly describe the correct structure for benzene (1)

(b) Benzene can be formed from cyclohexaneC6H12 rarr C6H6 + 3H2

What name is given to this type of reaction (1)18 Infra-red spectroscopy is a technique that can be used to identify the bonds that

arepresent in a molecule Different bonds absorb infra-red radiation of different wavenumbers This is due to differences in the bond lsquostretchrsquo These absorptions are recorded in a spectrumA spectrum for propan-1-ol is shown

61

The correlation table on page 13 of the data booklet shows the wavenumber ranges for the absorptions due to different bonds

(a) Use the correlation table to identify the bonds responsible for the two absorptions x and y that are circled in the propan-1-ol spectrum (1)

(b) Propan-1-ol reacts with ethanoic acid(i) What name is given to this type of reaction (1)(ii) Draw a spectrum that could be obtained for the organic product of this

reaction (1)

19 Paracetamol is a widely used painkiller

(a) Write the molecular formula for paracetamol (1)

(b) One antidote for paracetamol overdose is methionine

62

To what family of organic compounds does methionine belong (1)

(c) The concentration of paracetamol in a solution can be determined by measuring how much UV radiation it absorbs

The graph shows how the absorbance of a sample containing 0middot040 g l ndash1 paracetamol varies with wavelength

The quantity of UV radiation of wavelength 245 nm absorbed is directly proportional to the concentration of paracetamolThe absorbance of a second sample of paracetamol solution measured at 245 nm was 0middot90 What is the concentration in g l ndash1 of this second paracetamol solution (1)

20 Many carbon compounds containing oxygen are very flammableThe table shows information about two families of isomersThe lowest temperature at which a compound will ignite is called its flash point

(a) A compound with the molecular formula C6H14O has a boiling point of 158 degC63

Draw a structural formula for this compound (1)

(b) For a family of isomers in the table write a general statement linking the flash points of the compounds to their structures (1)

21 Hydrogels are used in disposable nappies They are fine powders that can absorb up to 500 times their own weight in waterA hydrogel is a very long molecule with carboxyl groups at regular intervals along its length A short section of a hydrogel molecule is shown below

Hydrogels are extremely good at soaking up water because the water molecules are strongly attracted to them

Using your knowledge of chemistry comment on how suitable hydrogels would be for absorbing liquids or solutions spilled in a chemistry lab (1)

64

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

(a) What is the systematic name for linolenic acid (1)(b) Stearic acid reacts with sodium hydroxide solution to form sodium stearate

(i) Name the type of reaction taking place when stearic acid reacts with sodium hydroxide (1)

(ii) Explain fully how sodium stearate acts to keep grease and non-polar substances suspended in water during cleaning (3)

5 Small children can find it difficult to swallow tablets or pills so ibuprofen is supplied as an ldquoinfant formulardquo emulsion(a) The emulsifier used is polysorbate 80 Its structure is shown below

Explain why this molecule acts as an emulsifier (2)

(b) The emulsion contains 2 g of ibuprofen in every 100 cm3 of emulsion The recommended dose for treating a 6 month old baby is 0middot050 g Calculate the volume in cm3 of ldquoinfant formulardquo needed to treat a 6 month old baby (1)

6 Occasionally seabirds can become contaminated with hydrocarbons from oil spills This causes problems for birds because their feathers lose their waterproofing making the birds susceptible to temperature changes and

44

affecting their buoyancy If the birds attempt to clean themselves to remove the oil they may swallow the hydrocarbons causing damage to their internal organsContaminated seabirds can be cleaned by rubbing vegetable oil into their feathers and feet before the birds are rinsed with diluted washing-up liquidUsing your knowledge of chemistry comment on the problems created for seabirds by oil spills and the actions taken to treat affected birds (3)

7 Dishwasher tablets contain chemicals which remove dirt from dishesDishwasher tablets include detergents These molecules act like soaps to allow mixing of fat-soluble dirt and water(a)During the cleaning process the detergent molecules combine with fat-

soluble dirtA simplified diagram of a detergent molecule is shown

Complete the diagram below to show how detergent molecules combine with fat-soluble dirt (1)

(b)State the term used to describe the non-polar hydrocarbon tail of a detergent molecule (1)

45

26 Fragrances1 Myrcene is a simple terpene

Terpenes contain at least one isoprene unit Which of the following shows a correctly highlighted isoprene unit

2 Limonene is one of the terpene molecules responsible for the flavour of lemons

How many isoprene units are used in the production of one limonene moleculeA 1B 2C 3D 4

46

3 The structure of caryophyllene which can be extracted from clove oil is

Which of the following would be the best solvent for extracting caryophylleneA HexaneB HexanalC HexanolD Hexanone

4 The structure of isoprene is

Limonene is a terpene molecule present in lemons

How many isoprene units are joined together in a limonene molecule

A 1B 2

47

C 3D 4

5 Essential oils are

A non-water soluble non-volatile compoundsB non-water soluble volatile compoundsC water soluble non-volatile compoundsD water soluble volatile compounds

6 Two typical compounds that are present in many perfumes are shown

(a) Why does geraniol evaporate more slowly than limonene (1)

(b) The structure of one of the first synthetic scents used in perfume is shown below

(i) Name the family of carbonyl compounds to which this synthetic scent belongs (1)

(ii) Complete the structure below to show the product formed when this scent is

oxidised (1)

(c) Traces of a liquid were discovered in a bottle believed to contain perfume belonging to Queen Hatshepsut ruler of Egypt over 3500 years ago

Perfumes were made by dissolving plant extracts containing pleasant smelling terpenes and esters in an edible oil A little ethanol and water may also have been addedUsing your knowledge of chemistry comment on the possible smell(s) when such a bottle is opened after being stored for thousands of years (3)

48

49

7 A team of chemists are developing a fragrance for use in a shower gel for men(a) To give the gel a fruity smell the chemists are considering adding an ester

They synthesise six isomeric esters Volunteers smell each ester and give it a rating out of one hundred depending on how fruity the smell is

(i) Name the ester with the fruit-smell rating of 92 (1)

(ii) Shown below are the structures of three more isomers

Arrange these esters in order of decreasing fruit-smell rating (1)

50

(b) To create a fragrance for men the compound civetone is added

Draw a structural formula for the alcohol that can be oxidised to form civetone (1)

(c) To make the shower gel produce a cold tingling sensation when applied to the skin menthol is added

Like terpenes menthol is formed from isoprene (2-methylbuta-13-diene)Circle an isoprene unit on the menthol structure above (1)

8 Many of the compounds in perfumes are molecules consisting of joined isoprene units

(a) State the name that is given to molecules consisting of joined isoprene units (1)

(b)Geraniol is one of the compounds found in perfume It has the following structural formula and systematic name

Linalool can also be present Its structural formula is shown

51

(i) State the systematic name for linalool (1)(ii) Explain why linalool can be classified as a tertiary alcohol (1)

9 The component molecules found in lavender oils are terpenes or terpenoids(a)A chiral carbon is a carbon atom attached to four different atoms or groups of

atomsAn example is shown below

A molecule of the terpenoid linalool has a chiral carbon Linalool has the following structure

Circle the chiral carbon atom in the linalool structure (1)

(b)Farnesene is a terpene consisting of three isoprene units (2-methylbuta-13-diene) joined togetherWrite the molecular formula of farnesene (1)

52

27 Skin Care

1 Which of the following is not a step in a free radical chain reaction

A ActivationB InitiationC PropagationD Termination

2 Fluorine reacts with methane via a free radical chain reaction Some steps in the chain reaction are shown in the table below

Complete the table by(a) inserting the missing name for the first step (1)

(b) showing another possible termination reaction in the final row of the table (1)

3 Suncreams contain antioxidantsThe antioxidant compound A can prevent damage to skin by reacting with free

radicalssuch as NO2bull

53

Why can compound A be described as a free radical scavenger in the reaction shown above

4 Hydrogen and chlorine gases are used in an experiment to demonstrate a free radical reaction A plastic bottle is wrapped with black tape leaving a ldquowindowrdquo on one sideThe bottle is filled with a mixture of hydrogen and chlorine When bright light shines on the bottle there is an explosion

A free radical chain reaction is initiated when light energy causes chlorine radicals to form as shown below

(a) Complete the equations below showing possible propagation and termination steps

(2)

54

(b) Why is the plastic bottle used in the experiment wrapped in black tape (1)

5 Chloramines can be removed from water using ultraviolet light treatment

One step in the process is the formation of free radicals

(a)State what is meant by the term free radical (1)

(b)Another step in the process is shown below

State the name for this type of step in a free radical reaction (1)

6 Modern shellac nail varnishes are more durable and so last longer than traditional nail polish

The shellac nail varnish is applied in thin layers to the nails and then the fingers are placed under a UV lamp

(a) The Skin Care Foundation has recommended that a sun-block is applied to the fingers and hand before using the lampSuggest why the Skin Care Foundation makes this recommendation (1)

(b) A free radical chain reaction takes place and the varnish hardens (i) State what is meant by the term free radical (1)

(ii) The shellac nail varnish contains a mixture of ingredients that take part in the free radical chain reactionOne of the steps in the free radical chain reaction is

55

State the term used to describe this type of step in a free radical chain reaction(1)

7 Skin care products contain a mixture of polar covalent non-polar covalent and ionic compounds The compounds need to stay mixed within the product Skin care products also need to spread easily and remain on the skin for a period of time as well as provide physical and chemical protection from the sun In order to do this skin care products contain a range of chemicals including water fats and oils antioxidants minerals and sun blockUsing your knowledge of chemistry explain the role of different chemicals in skin care products (3)

General Questions

1 A mixture of carbon monoxide and hydrogen can be converted into water and a mixture of hydrocarbons

nCO + (2n + 1)H2 rarr nH2O + hydrocarbons

What is the general formula for the hydrocarbons producedA CnH2nndash2B CnH2nC CnH2n+1D CnH2n+2

2 Butadiene is the first member of a homologous series of hydrocarbons called dienesWhat is the general formula for this seriesA CnHn+2B CnHn+3C CnH2nD CnH2nndash2

3 Which of the following statements about methanol is falseA It can be made from synthesis gasB It can be dehydrated to form an alkeneC It can be oxidised to give a carboxylic acidD It reacts with acidified potassium dichromate solution

56

4

Which line in the table correctly describes reactions X and Y

5

Which line in the table correctly describes reactions X and Y

6 Which of the following fuels when burned would make no contribution to globalwarming

57

A HydrogenB Natural gasC PetrolD Coal

7 Which of the following hydrocarbons always gives the same product when one of itshydrogen atoms is replaced by a chlorine atomA HexaneB Hex-1-eneC CyclohexaneD Cyclohexene

8 Which of the following compounds does not have isomeric structuresA C2HCl3B C2H4Cl2C PropeneD Propan-1-ol

9 What organic compound is produced by the dehydration of ethanol A EthaneB EtheneC EthanalD Ethanoic acid

10

The above equation representsA hydrationB hydrogenationC condensationD hydrolysis

11

Which of the following compounds is an isomer of the structure shown aboveA ButanalB ButanoneC Butan-1-olD Butanoic acid

58

12 A compound with molecular formula C6H12O2 could beA hexanalB hexan-2-olC hexan-2-oneD hexanoic acid

13 Propan-2-ol can be prepared from propane as follows

Which line in the table correctly describes the types of reaction taking place at Steps 1 and 2

14 Which of the following compounds would be the most water soluble

15 Cyanohydrin compounds can be made from carbonyl compounds by reacting the carbonyl compound with hydrogen cyanide (HCN)

59

Which carbonyl compound would react with hydrogen cyanide (HCN) to form the following compound

16 Ethyne is the first member of the homologous series called the alkynes

Ethyne can undergo addition reactions as shown in the flow diagram

(a) Compound 2 is an isomer of 12-dichloroethaneDraw a structural formula for compound 2 (1)

(b) Reagents A B and C are three different diatomic gasesUsing information in the flow diagram identify reagents A B and C (1)

60

Reagent Gas

A

B

C

17 In 1865 the German chemist Kekuleacute proposed a ring structure for benzene This structure was based on alternating single and double bonds

(a) (i) Describe a chemical test that would indicate that the above chemical structure for benzene is incorrect (1)

(ii) Briefly describe the correct structure for benzene (1)

(b) Benzene can be formed from cyclohexaneC6H12 rarr C6H6 + 3H2

What name is given to this type of reaction (1)18 Infra-red spectroscopy is a technique that can be used to identify the bonds that

arepresent in a molecule Different bonds absorb infra-red radiation of different wavenumbers This is due to differences in the bond lsquostretchrsquo These absorptions are recorded in a spectrumA spectrum for propan-1-ol is shown

61

The correlation table on page 13 of the data booklet shows the wavenumber ranges for the absorptions due to different bonds

(a) Use the correlation table to identify the bonds responsible for the two absorptions x and y that are circled in the propan-1-ol spectrum (1)

(b) Propan-1-ol reacts with ethanoic acid(i) What name is given to this type of reaction (1)(ii) Draw a spectrum that could be obtained for the organic product of this

reaction (1)

19 Paracetamol is a widely used painkiller

(a) Write the molecular formula for paracetamol (1)

(b) One antidote for paracetamol overdose is methionine

62

To what family of organic compounds does methionine belong (1)

(c) The concentration of paracetamol in a solution can be determined by measuring how much UV radiation it absorbs

The graph shows how the absorbance of a sample containing 0middot040 g l ndash1 paracetamol varies with wavelength

The quantity of UV radiation of wavelength 245 nm absorbed is directly proportional to the concentration of paracetamolThe absorbance of a second sample of paracetamol solution measured at 245 nm was 0middot90 What is the concentration in g l ndash1 of this second paracetamol solution (1)

20 Many carbon compounds containing oxygen are very flammableThe table shows information about two families of isomersThe lowest temperature at which a compound will ignite is called its flash point

(a) A compound with the molecular formula C6H14O has a boiling point of 158 degC63

Draw a structural formula for this compound (1)

(b) For a family of isomers in the table write a general statement linking the flash points of the compounds to their structures (1)

21 Hydrogels are used in disposable nappies They are fine powders that can absorb up to 500 times their own weight in waterA hydrogel is a very long molecule with carboxyl groups at regular intervals along its length A short section of a hydrogel molecule is shown below

Hydrogels are extremely good at soaking up water because the water molecules are strongly attracted to them

Using your knowledge of chemistry comment on how suitable hydrogels would be for absorbing liquids or solutions spilled in a chemistry lab (1)

64

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

affecting their buoyancy If the birds attempt to clean themselves to remove the oil they may swallow the hydrocarbons causing damage to their internal organsContaminated seabirds can be cleaned by rubbing vegetable oil into their feathers and feet before the birds are rinsed with diluted washing-up liquidUsing your knowledge of chemistry comment on the problems created for seabirds by oil spills and the actions taken to treat affected birds (3)

7 Dishwasher tablets contain chemicals which remove dirt from dishesDishwasher tablets include detergents These molecules act like soaps to allow mixing of fat-soluble dirt and water(a)During the cleaning process the detergent molecules combine with fat-

soluble dirtA simplified diagram of a detergent molecule is shown

Complete the diagram below to show how detergent molecules combine with fat-soluble dirt (1)

(b)State the term used to describe the non-polar hydrocarbon tail of a detergent molecule (1)

45

26 Fragrances1 Myrcene is a simple terpene

Terpenes contain at least one isoprene unit Which of the following shows a correctly highlighted isoprene unit

2 Limonene is one of the terpene molecules responsible for the flavour of lemons

How many isoprene units are used in the production of one limonene moleculeA 1B 2C 3D 4

46

3 The structure of caryophyllene which can be extracted from clove oil is

Which of the following would be the best solvent for extracting caryophylleneA HexaneB HexanalC HexanolD Hexanone

4 The structure of isoprene is

Limonene is a terpene molecule present in lemons

How many isoprene units are joined together in a limonene molecule

A 1B 2

47

C 3D 4

5 Essential oils are

A non-water soluble non-volatile compoundsB non-water soluble volatile compoundsC water soluble non-volatile compoundsD water soluble volatile compounds

6 Two typical compounds that are present in many perfumes are shown

(a) Why does geraniol evaporate more slowly than limonene (1)

(b) The structure of one of the first synthetic scents used in perfume is shown below

(i) Name the family of carbonyl compounds to which this synthetic scent belongs (1)

(ii) Complete the structure below to show the product formed when this scent is

oxidised (1)

(c) Traces of a liquid were discovered in a bottle believed to contain perfume belonging to Queen Hatshepsut ruler of Egypt over 3500 years ago

Perfumes were made by dissolving plant extracts containing pleasant smelling terpenes and esters in an edible oil A little ethanol and water may also have been addedUsing your knowledge of chemistry comment on the possible smell(s) when such a bottle is opened after being stored for thousands of years (3)

48

49

7 A team of chemists are developing a fragrance for use in a shower gel for men(a) To give the gel a fruity smell the chemists are considering adding an ester

They synthesise six isomeric esters Volunteers smell each ester and give it a rating out of one hundred depending on how fruity the smell is

(i) Name the ester with the fruit-smell rating of 92 (1)

(ii) Shown below are the structures of three more isomers

Arrange these esters in order of decreasing fruit-smell rating (1)

50

(b) To create a fragrance for men the compound civetone is added

Draw a structural formula for the alcohol that can be oxidised to form civetone (1)

(c) To make the shower gel produce a cold tingling sensation when applied to the skin menthol is added

Like terpenes menthol is formed from isoprene (2-methylbuta-13-diene)Circle an isoprene unit on the menthol structure above (1)

8 Many of the compounds in perfumes are molecules consisting of joined isoprene units

(a) State the name that is given to molecules consisting of joined isoprene units (1)

(b)Geraniol is one of the compounds found in perfume It has the following structural formula and systematic name

Linalool can also be present Its structural formula is shown

51

(i) State the systematic name for linalool (1)(ii) Explain why linalool can be classified as a tertiary alcohol (1)

9 The component molecules found in lavender oils are terpenes or terpenoids(a)A chiral carbon is a carbon atom attached to four different atoms or groups of

atomsAn example is shown below

A molecule of the terpenoid linalool has a chiral carbon Linalool has the following structure

Circle the chiral carbon atom in the linalool structure (1)

(b)Farnesene is a terpene consisting of three isoprene units (2-methylbuta-13-diene) joined togetherWrite the molecular formula of farnesene (1)

52

27 Skin Care

1 Which of the following is not a step in a free radical chain reaction

A ActivationB InitiationC PropagationD Termination

2 Fluorine reacts with methane via a free radical chain reaction Some steps in the chain reaction are shown in the table below

Complete the table by(a) inserting the missing name for the first step (1)

(b) showing another possible termination reaction in the final row of the table (1)

3 Suncreams contain antioxidantsThe antioxidant compound A can prevent damage to skin by reacting with free

radicalssuch as NO2bull

53

Why can compound A be described as a free radical scavenger in the reaction shown above

4 Hydrogen and chlorine gases are used in an experiment to demonstrate a free radical reaction A plastic bottle is wrapped with black tape leaving a ldquowindowrdquo on one sideThe bottle is filled with a mixture of hydrogen and chlorine When bright light shines on the bottle there is an explosion

A free radical chain reaction is initiated when light energy causes chlorine radicals to form as shown below

(a) Complete the equations below showing possible propagation and termination steps

(2)

54

(b) Why is the plastic bottle used in the experiment wrapped in black tape (1)

5 Chloramines can be removed from water using ultraviolet light treatment

One step in the process is the formation of free radicals

(a)State what is meant by the term free radical (1)

(b)Another step in the process is shown below

State the name for this type of step in a free radical reaction (1)

6 Modern shellac nail varnishes are more durable and so last longer than traditional nail polish

The shellac nail varnish is applied in thin layers to the nails and then the fingers are placed under a UV lamp

(a) The Skin Care Foundation has recommended that a sun-block is applied to the fingers and hand before using the lampSuggest why the Skin Care Foundation makes this recommendation (1)

(b) A free radical chain reaction takes place and the varnish hardens (i) State what is meant by the term free radical (1)

(ii) The shellac nail varnish contains a mixture of ingredients that take part in the free radical chain reactionOne of the steps in the free radical chain reaction is

55

State the term used to describe this type of step in a free radical chain reaction(1)

7 Skin care products contain a mixture of polar covalent non-polar covalent and ionic compounds The compounds need to stay mixed within the product Skin care products also need to spread easily and remain on the skin for a period of time as well as provide physical and chemical protection from the sun In order to do this skin care products contain a range of chemicals including water fats and oils antioxidants minerals and sun blockUsing your knowledge of chemistry explain the role of different chemicals in skin care products (3)

General Questions

1 A mixture of carbon monoxide and hydrogen can be converted into water and a mixture of hydrocarbons

nCO + (2n + 1)H2 rarr nH2O + hydrocarbons

What is the general formula for the hydrocarbons producedA CnH2nndash2B CnH2nC CnH2n+1D CnH2n+2

2 Butadiene is the first member of a homologous series of hydrocarbons called dienesWhat is the general formula for this seriesA CnHn+2B CnHn+3C CnH2nD CnH2nndash2

3 Which of the following statements about methanol is falseA It can be made from synthesis gasB It can be dehydrated to form an alkeneC It can be oxidised to give a carboxylic acidD It reacts with acidified potassium dichromate solution

56

4

Which line in the table correctly describes reactions X and Y

5

Which line in the table correctly describes reactions X and Y

6 Which of the following fuels when burned would make no contribution to globalwarming

57

A HydrogenB Natural gasC PetrolD Coal

7 Which of the following hydrocarbons always gives the same product when one of itshydrogen atoms is replaced by a chlorine atomA HexaneB Hex-1-eneC CyclohexaneD Cyclohexene

8 Which of the following compounds does not have isomeric structuresA C2HCl3B C2H4Cl2C PropeneD Propan-1-ol

9 What organic compound is produced by the dehydration of ethanol A EthaneB EtheneC EthanalD Ethanoic acid

10

The above equation representsA hydrationB hydrogenationC condensationD hydrolysis

11

Which of the following compounds is an isomer of the structure shown aboveA ButanalB ButanoneC Butan-1-olD Butanoic acid

58

12 A compound with molecular formula C6H12O2 could beA hexanalB hexan-2-olC hexan-2-oneD hexanoic acid

13 Propan-2-ol can be prepared from propane as follows

Which line in the table correctly describes the types of reaction taking place at Steps 1 and 2

14 Which of the following compounds would be the most water soluble

15 Cyanohydrin compounds can be made from carbonyl compounds by reacting the carbonyl compound with hydrogen cyanide (HCN)

59

Which carbonyl compound would react with hydrogen cyanide (HCN) to form the following compound

16 Ethyne is the first member of the homologous series called the alkynes

Ethyne can undergo addition reactions as shown in the flow diagram

(a) Compound 2 is an isomer of 12-dichloroethaneDraw a structural formula for compound 2 (1)

(b) Reagents A B and C are three different diatomic gasesUsing information in the flow diagram identify reagents A B and C (1)

60

Reagent Gas

A

B

C

17 In 1865 the German chemist Kekuleacute proposed a ring structure for benzene This structure was based on alternating single and double bonds

(a) (i) Describe a chemical test that would indicate that the above chemical structure for benzene is incorrect (1)

(ii) Briefly describe the correct structure for benzene (1)

(b) Benzene can be formed from cyclohexaneC6H12 rarr C6H6 + 3H2

What name is given to this type of reaction (1)18 Infra-red spectroscopy is a technique that can be used to identify the bonds that

arepresent in a molecule Different bonds absorb infra-red radiation of different wavenumbers This is due to differences in the bond lsquostretchrsquo These absorptions are recorded in a spectrumA spectrum for propan-1-ol is shown

61

The correlation table on page 13 of the data booklet shows the wavenumber ranges for the absorptions due to different bonds

(a) Use the correlation table to identify the bonds responsible for the two absorptions x and y that are circled in the propan-1-ol spectrum (1)

(b) Propan-1-ol reacts with ethanoic acid(i) What name is given to this type of reaction (1)(ii) Draw a spectrum that could be obtained for the organic product of this

reaction (1)

19 Paracetamol is a widely used painkiller

(a) Write the molecular formula for paracetamol (1)

(b) One antidote for paracetamol overdose is methionine

62

To what family of organic compounds does methionine belong (1)

(c) The concentration of paracetamol in a solution can be determined by measuring how much UV radiation it absorbs

The graph shows how the absorbance of a sample containing 0middot040 g l ndash1 paracetamol varies with wavelength

The quantity of UV radiation of wavelength 245 nm absorbed is directly proportional to the concentration of paracetamolThe absorbance of a second sample of paracetamol solution measured at 245 nm was 0middot90 What is the concentration in g l ndash1 of this second paracetamol solution (1)

20 Many carbon compounds containing oxygen are very flammableThe table shows information about two families of isomersThe lowest temperature at which a compound will ignite is called its flash point

(a) A compound with the molecular formula C6H14O has a boiling point of 158 degC63

Draw a structural formula for this compound (1)

(b) For a family of isomers in the table write a general statement linking the flash points of the compounds to their structures (1)

21 Hydrogels are used in disposable nappies They are fine powders that can absorb up to 500 times their own weight in waterA hydrogel is a very long molecule with carboxyl groups at regular intervals along its length A short section of a hydrogel molecule is shown below

Hydrogels are extremely good at soaking up water because the water molecules are strongly attracted to them

Using your knowledge of chemistry comment on how suitable hydrogels would be for absorbing liquids or solutions spilled in a chemistry lab (1)

64

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

26 Fragrances1 Myrcene is a simple terpene

Terpenes contain at least one isoprene unit Which of the following shows a correctly highlighted isoprene unit

2 Limonene is one of the terpene molecules responsible for the flavour of lemons

How many isoprene units are used in the production of one limonene moleculeA 1B 2C 3D 4

46

3 The structure of caryophyllene which can be extracted from clove oil is

Which of the following would be the best solvent for extracting caryophylleneA HexaneB HexanalC HexanolD Hexanone

4 The structure of isoprene is

Limonene is a terpene molecule present in lemons

How many isoprene units are joined together in a limonene molecule

A 1B 2

47

C 3D 4

5 Essential oils are

A non-water soluble non-volatile compoundsB non-water soluble volatile compoundsC water soluble non-volatile compoundsD water soluble volatile compounds

6 Two typical compounds that are present in many perfumes are shown

(a) Why does geraniol evaporate more slowly than limonene (1)

(b) The structure of one of the first synthetic scents used in perfume is shown below

(i) Name the family of carbonyl compounds to which this synthetic scent belongs (1)

(ii) Complete the structure below to show the product formed when this scent is

oxidised (1)

(c) Traces of a liquid were discovered in a bottle believed to contain perfume belonging to Queen Hatshepsut ruler of Egypt over 3500 years ago

Perfumes were made by dissolving plant extracts containing pleasant smelling terpenes and esters in an edible oil A little ethanol and water may also have been addedUsing your knowledge of chemistry comment on the possible smell(s) when such a bottle is opened after being stored for thousands of years (3)

48

49

7 A team of chemists are developing a fragrance for use in a shower gel for men(a) To give the gel a fruity smell the chemists are considering adding an ester

They synthesise six isomeric esters Volunteers smell each ester and give it a rating out of one hundred depending on how fruity the smell is

(i) Name the ester with the fruit-smell rating of 92 (1)

(ii) Shown below are the structures of three more isomers

Arrange these esters in order of decreasing fruit-smell rating (1)

50

(b) To create a fragrance for men the compound civetone is added

Draw a structural formula for the alcohol that can be oxidised to form civetone (1)

(c) To make the shower gel produce a cold tingling sensation when applied to the skin menthol is added

Like terpenes menthol is formed from isoprene (2-methylbuta-13-diene)Circle an isoprene unit on the menthol structure above (1)

8 Many of the compounds in perfumes are molecules consisting of joined isoprene units

(a) State the name that is given to molecules consisting of joined isoprene units (1)

(b)Geraniol is one of the compounds found in perfume It has the following structural formula and systematic name

Linalool can also be present Its structural formula is shown

51

(i) State the systematic name for linalool (1)(ii) Explain why linalool can be classified as a tertiary alcohol (1)

9 The component molecules found in lavender oils are terpenes or terpenoids(a)A chiral carbon is a carbon atom attached to four different atoms or groups of

atomsAn example is shown below

A molecule of the terpenoid linalool has a chiral carbon Linalool has the following structure

Circle the chiral carbon atom in the linalool structure (1)

(b)Farnesene is a terpene consisting of three isoprene units (2-methylbuta-13-diene) joined togetherWrite the molecular formula of farnesene (1)

52

27 Skin Care

1 Which of the following is not a step in a free radical chain reaction

A ActivationB InitiationC PropagationD Termination

2 Fluorine reacts with methane via a free radical chain reaction Some steps in the chain reaction are shown in the table below

Complete the table by(a) inserting the missing name for the first step (1)

(b) showing another possible termination reaction in the final row of the table (1)

3 Suncreams contain antioxidantsThe antioxidant compound A can prevent damage to skin by reacting with free

radicalssuch as NO2bull

53

Why can compound A be described as a free radical scavenger in the reaction shown above

4 Hydrogen and chlorine gases are used in an experiment to demonstrate a free radical reaction A plastic bottle is wrapped with black tape leaving a ldquowindowrdquo on one sideThe bottle is filled with a mixture of hydrogen and chlorine When bright light shines on the bottle there is an explosion

A free radical chain reaction is initiated when light energy causes chlorine radicals to form as shown below

(a) Complete the equations below showing possible propagation and termination steps

(2)

54

(b) Why is the plastic bottle used in the experiment wrapped in black tape (1)

5 Chloramines can be removed from water using ultraviolet light treatment

One step in the process is the formation of free radicals

(a)State what is meant by the term free radical (1)

(b)Another step in the process is shown below

State the name for this type of step in a free radical reaction (1)

6 Modern shellac nail varnishes are more durable and so last longer than traditional nail polish

The shellac nail varnish is applied in thin layers to the nails and then the fingers are placed under a UV lamp

(a) The Skin Care Foundation has recommended that a sun-block is applied to the fingers and hand before using the lampSuggest why the Skin Care Foundation makes this recommendation (1)

(b) A free radical chain reaction takes place and the varnish hardens (i) State what is meant by the term free radical (1)

(ii) The shellac nail varnish contains a mixture of ingredients that take part in the free radical chain reactionOne of the steps in the free radical chain reaction is

55

State the term used to describe this type of step in a free radical chain reaction(1)

7 Skin care products contain a mixture of polar covalent non-polar covalent and ionic compounds The compounds need to stay mixed within the product Skin care products also need to spread easily and remain on the skin for a period of time as well as provide physical and chemical protection from the sun In order to do this skin care products contain a range of chemicals including water fats and oils antioxidants minerals and sun blockUsing your knowledge of chemistry explain the role of different chemicals in skin care products (3)

General Questions

1 A mixture of carbon monoxide and hydrogen can be converted into water and a mixture of hydrocarbons

nCO + (2n + 1)H2 rarr nH2O + hydrocarbons

What is the general formula for the hydrocarbons producedA CnH2nndash2B CnH2nC CnH2n+1D CnH2n+2

2 Butadiene is the first member of a homologous series of hydrocarbons called dienesWhat is the general formula for this seriesA CnHn+2B CnHn+3C CnH2nD CnH2nndash2

3 Which of the following statements about methanol is falseA It can be made from synthesis gasB It can be dehydrated to form an alkeneC It can be oxidised to give a carboxylic acidD It reacts with acidified potassium dichromate solution

56

4

Which line in the table correctly describes reactions X and Y

5

Which line in the table correctly describes reactions X and Y

6 Which of the following fuels when burned would make no contribution to globalwarming

57

A HydrogenB Natural gasC PetrolD Coal

7 Which of the following hydrocarbons always gives the same product when one of itshydrogen atoms is replaced by a chlorine atomA HexaneB Hex-1-eneC CyclohexaneD Cyclohexene

8 Which of the following compounds does not have isomeric structuresA C2HCl3B C2H4Cl2C PropeneD Propan-1-ol

9 What organic compound is produced by the dehydration of ethanol A EthaneB EtheneC EthanalD Ethanoic acid

10

The above equation representsA hydrationB hydrogenationC condensationD hydrolysis

11

Which of the following compounds is an isomer of the structure shown aboveA ButanalB ButanoneC Butan-1-olD Butanoic acid

58

12 A compound with molecular formula C6H12O2 could beA hexanalB hexan-2-olC hexan-2-oneD hexanoic acid

13 Propan-2-ol can be prepared from propane as follows

Which line in the table correctly describes the types of reaction taking place at Steps 1 and 2

14 Which of the following compounds would be the most water soluble

15 Cyanohydrin compounds can be made from carbonyl compounds by reacting the carbonyl compound with hydrogen cyanide (HCN)

59

Which carbonyl compound would react with hydrogen cyanide (HCN) to form the following compound

16 Ethyne is the first member of the homologous series called the alkynes

Ethyne can undergo addition reactions as shown in the flow diagram

(a) Compound 2 is an isomer of 12-dichloroethaneDraw a structural formula for compound 2 (1)

(b) Reagents A B and C are three different diatomic gasesUsing information in the flow diagram identify reagents A B and C (1)

60

Reagent Gas

A

B

C

17 In 1865 the German chemist Kekuleacute proposed a ring structure for benzene This structure was based on alternating single and double bonds

(a) (i) Describe a chemical test that would indicate that the above chemical structure for benzene is incorrect (1)

(ii) Briefly describe the correct structure for benzene (1)

(b) Benzene can be formed from cyclohexaneC6H12 rarr C6H6 + 3H2

What name is given to this type of reaction (1)18 Infra-red spectroscopy is a technique that can be used to identify the bonds that

arepresent in a molecule Different bonds absorb infra-red radiation of different wavenumbers This is due to differences in the bond lsquostretchrsquo These absorptions are recorded in a spectrumA spectrum for propan-1-ol is shown

61

The correlation table on page 13 of the data booklet shows the wavenumber ranges for the absorptions due to different bonds

(a) Use the correlation table to identify the bonds responsible for the two absorptions x and y that are circled in the propan-1-ol spectrum (1)

(b) Propan-1-ol reacts with ethanoic acid(i) What name is given to this type of reaction (1)(ii) Draw a spectrum that could be obtained for the organic product of this

reaction (1)

19 Paracetamol is a widely used painkiller

(a) Write the molecular formula for paracetamol (1)

(b) One antidote for paracetamol overdose is methionine

62

To what family of organic compounds does methionine belong (1)

(c) The concentration of paracetamol in a solution can be determined by measuring how much UV radiation it absorbs

The graph shows how the absorbance of a sample containing 0middot040 g l ndash1 paracetamol varies with wavelength

The quantity of UV radiation of wavelength 245 nm absorbed is directly proportional to the concentration of paracetamolThe absorbance of a second sample of paracetamol solution measured at 245 nm was 0middot90 What is the concentration in g l ndash1 of this second paracetamol solution (1)

20 Many carbon compounds containing oxygen are very flammableThe table shows information about two families of isomersThe lowest temperature at which a compound will ignite is called its flash point

(a) A compound with the molecular formula C6H14O has a boiling point of 158 degC63

Draw a structural formula for this compound (1)

(b) For a family of isomers in the table write a general statement linking the flash points of the compounds to their structures (1)

21 Hydrogels are used in disposable nappies They are fine powders that can absorb up to 500 times their own weight in waterA hydrogel is a very long molecule with carboxyl groups at regular intervals along its length A short section of a hydrogel molecule is shown below

Hydrogels are extremely good at soaking up water because the water molecules are strongly attracted to them

Using your knowledge of chemistry comment on how suitable hydrogels would be for absorbing liquids or solutions spilled in a chemistry lab (1)

64

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

3 The structure of caryophyllene which can be extracted from clove oil is

Which of the following would be the best solvent for extracting caryophylleneA HexaneB HexanalC HexanolD Hexanone

4 The structure of isoprene is

Limonene is a terpene molecule present in lemons

How many isoprene units are joined together in a limonene molecule

A 1B 2

47

C 3D 4

5 Essential oils are

A non-water soluble non-volatile compoundsB non-water soluble volatile compoundsC water soluble non-volatile compoundsD water soluble volatile compounds

6 Two typical compounds that are present in many perfumes are shown

(a) Why does geraniol evaporate more slowly than limonene (1)

(b) The structure of one of the first synthetic scents used in perfume is shown below

(i) Name the family of carbonyl compounds to which this synthetic scent belongs (1)

(ii) Complete the structure below to show the product formed when this scent is

oxidised (1)

(c) Traces of a liquid were discovered in a bottle believed to contain perfume belonging to Queen Hatshepsut ruler of Egypt over 3500 years ago

Perfumes were made by dissolving plant extracts containing pleasant smelling terpenes and esters in an edible oil A little ethanol and water may also have been addedUsing your knowledge of chemistry comment on the possible smell(s) when such a bottle is opened after being stored for thousands of years (3)

48

49

7 A team of chemists are developing a fragrance for use in a shower gel for men(a) To give the gel a fruity smell the chemists are considering adding an ester

They synthesise six isomeric esters Volunteers smell each ester and give it a rating out of one hundred depending on how fruity the smell is

(i) Name the ester with the fruit-smell rating of 92 (1)

(ii) Shown below are the structures of three more isomers

Arrange these esters in order of decreasing fruit-smell rating (1)

50

(b) To create a fragrance for men the compound civetone is added

Draw a structural formula for the alcohol that can be oxidised to form civetone (1)

(c) To make the shower gel produce a cold tingling sensation when applied to the skin menthol is added

Like terpenes menthol is formed from isoprene (2-methylbuta-13-diene)Circle an isoprene unit on the menthol structure above (1)

8 Many of the compounds in perfumes are molecules consisting of joined isoprene units

(a) State the name that is given to molecules consisting of joined isoprene units (1)

(b)Geraniol is one of the compounds found in perfume It has the following structural formula and systematic name

Linalool can also be present Its structural formula is shown

51

(i) State the systematic name for linalool (1)(ii) Explain why linalool can be classified as a tertiary alcohol (1)

9 The component molecules found in lavender oils are terpenes or terpenoids(a)A chiral carbon is a carbon atom attached to four different atoms or groups of

atomsAn example is shown below

A molecule of the terpenoid linalool has a chiral carbon Linalool has the following structure

Circle the chiral carbon atom in the linalool structure (1)

(b)Farnesene is a terpene consisting of three isoprene units (2-methylbuta-13-diene) joined togetherWrite the molecular formula of farnesene (1)

52

27 Skin Care

1 Which of the following is not a step in a free radical chain reaction

A ActivationB InitiationC PropagationD Termination

2 Fluorine reacts with methane via a free radical chain reaction Some steps in the chain reaction are shown in the table below

Complete the table by(a) inserting the missing name for the first step (1)

(b) showing another possible termination reaction in the final row of the table (1)

3 Suncreams contain antioxidantsThe antioxidant compound A can prevent damage to skin by reacting with free

radicalssuch as NO2bull

53

Why can compound A be described as a free radical scavenger in the reaction shown above

4 Hydrogen and chlorine gases are used in an experiment to demonstrate a free radical reaction A plastic bottle is wrapped with black tape leaving a ldquowindowrdquo on one sideThe bottle is filled with a mixture of hydrogen and chlorine When bright light shines on the bottle there is an explosion

A free radical chain reaction is initiated when light energy causes chlorine radicals to form as shown below

(a) Complete the equations below showing possible propagation and termination steps

(2)

54

(b) Why is the plastic bottle used in the experiment wrapped in black tape (1)

5 Chloramines can be removed from water using ultraviolet light treatment

One step in the process is the formation of free radicals

(a)State what is meant by the term free radical (1)

(b)Another step in the process is shown below

State the name for this type of step in a free radical reaction (1)

6 Modern shellac nail varnishes are more durable and so last longer than traditional nail polish

The shellac nail varnish is applied in thin layers to the nails and then the fingers are placed under a UV lamp

(a) The Skin Care Foundation has recommended that a sun-block is applied to the fingers and hand before using the lampSuggest why the Skin Care Foundation makes this recommendation (1)

(b) A free radical chain reaction takes place and the varnish hardens (i) State what is meant by the term free radical (1)

(ii) The shellac nail varnish contains a mixture of ingredients that take part in the free radical chain reactionOne of the steps in the free radical chain reaction is

55

State the term used to describe this type of step in a free radical chain reaction(1)

7 Skin care products contain a mixture of polar covalent non-polar covalent and ionic compounds The compounds need to stay mixed within the product Skin care products also need to spread easily and remain on the skin for a period of time as well as provide physical and chemical protection from the sun In order to do this skin care products contain a range of chemicals including water fats and oils antioxidants minerals and sun blockUsing your knowledge of chemistry explain the role of different chemicals in skin care products (3)

General Questions

1 A mixture of carbon monoxide and hydrogen can be converted into water and a mixture of hydrocarbons

nCO + (2n + 1)H2 rarr nH2O + hydrocarbons

What is the general formula for the hydrocarbons producedA CnH2nndash2B CnH2nC CnH2n+1D CnH2n+2

2 Butadiene is the first member of a homologous series of hydrocarbons called dienesWhat is the general formula for this seriesA CnHn+2B CnHn+3C CnH2nD CnH2nndash2

3 Which of the following statements about methanol is falseA It can be made from synthesis gasB It can be dehydrated to form an alkeneC It can be oxidised to give a carboxylic acidD It reacts with acidified potassium dichromate solution

56

4

Which line in the table correctly describes reactions X and Y

5

Which line in the table correctly describes reactions X and Y

6 Which of the following fuels when burned would make no contribution to globalwarming

57

A HydrogenB Natural gasC PetrolD Coal

7 Which of the following hydrocarbons always gives the same product when one of itshydrogen atoms is replaced by a chlorine atomA HexaneB Hex-1-eneC CyclohexaneD Cyclohexene

8 Which of the following compounds does not have isomeric structuresA C2HCl3B C2H4Cl2C PropeneD Propan-1-ol

9 What organic compound is produced by the dehydration of ethanol A EthaneB EtheneC EthanalD Ethanoic acid

10

The above equation representsA hydrationB hydrogenationC condensationD hydrolysis

11

Which of the following compounds is an isomer of the structure shown aboveA ButanalB ButanoneC Butan-1-olD Butanoic acid

58

12 A compound with molecular formula C6H12O2 could beA hexanalB hexan-2-olC hexan-2-oneD hexanoic acid

13 Propan-2-ol can be prepared from propane as follows

Which line in the table correctly describes the types of reaction taking place at Steps 1 and 2

14 Which of the following compounds would be the most water soluble

15 Cyanohydrin compounds can be made from carbonyl compounds by reacting the carbonyl compound with hydrogen cyanide (HCN)

59

Which carbonyl compound would react with hydrogen cyanide (HCN) to form the following compound

16 Ethyne is the first member of the homologous series called the alkynes

Ethyne can undergo addition reactions as shown in the flow diagram

(a) Compound 2 is an isomer of 12-dichloroethaneDraw a structural formula for compound 2 (1)

(b) Reagents A B and C are three different diatomic gasesUsing information in the flow diagram identify reagents A B and C (1)

60

Reagent Gas

A

B

C

17 In 1865 the German chemist Kekuleacute proposed a ring structure for benzene This structure was based on alternating single and double bonds

(a) (i) Describe a chemical test that would indicate that the above chemical structure for benzene is incorrect (1)

(ii) Briefly describe the correct structure for benzene (1)

(b) Benzene can be formed from cyclohexaneC6H12 rarr C6H6 + 3H2

What name is given to this type of reaction (1)18 Infra-red spectroscopy is a technique that can be used to identify the bonds that

arepresent in a molecule Different bonds absorb infra-red radiation of different wavenumbers This is due to differences in the bond lsquostretchrsquo These absorptions are recorded in a spectrumA spectrum for propan-1-ol is shown

61

The correlation table on page 13 of the data booklet shows the wavenumber ranges for the absorptions due to different bonds

(a) Use the correlation table to identify the bonds responsible for the two absorptions x and y that are circled in the propan-1-ol spectrum (1)

(b) Propan-1-ol reacts with ethanoic acid(i) What name is given to this type of reaction (1)(ii) Draw a spectrum that could be obtained for the organic product of this

reaction (1)

19 Paracetamol is a widely used painkiller

(a) Write the molecular formula for paracetamol (1)

(b) One antidote for paracetamol overdose is methionine

62

To what family of organic compounds does methionine belong (1)

(c) The concentration of paracetamol in a solution can be determined by measuring how much UV radiation it absorbs

The graph shows how the absorbance of a sample containing 0middot040 g l ndash1 paracetamol varies with wavelength

The quantity of UV radiation of wavelength 245 nm absorbed is directly proportional to the concentration of paracetamolThe absorbance of a second sample of paracetamol solution measured at 245 nm was 0middot90 What is the concentration in g l ndash1 of this second paracetamol solution (1)

20 Many carbon compounds containing oxygen are very flammableThe table shows information about two families of isomersThe lowest temperature at which a compound will ignite is called its flash point

(a) A compound with the molecular formula C6H14O has a boiling point of 158 degC63

Draw a structural formula for this compound (1)

(b) For a family of isomers in the table write a general statement linking the flash points of the compounds to their structures (1)

21 Hydrogels are used in disposable nappies They are fine powders that can absorb up to 500 times their own weight in waterA hydrogel is a very long molecule with carboxyl groups at regular intervals along its length A short section of a hydrogel molecule is shown below

Hydrogels are extremely good at soaking up water because the water molecules are strongly attracted to them

Using your knowledge of chemistry comment on how suitable hydrogels would be for absorbing liquids or solutions spilled in a chemistry lab (1)

64

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

C 3D 4

5 Essential oils are

A non-water soluble non-volatile compoundsB non-water soluble volatile compoundsC water soluble non-volatile compoundsD water soluble volatile compounds

6 Two typical compounds that are present in many perfumes are shown

(a) Why does geraniol evaporate more slowly than limonene (1)

(b) The structure of one of the first synthetic scents used in perfume is shown below

(i) Name the family of carbonyl compounds to which this synthetic scent belongs (1)

(ii) Complete the structure below to show the product formed when this scent is

oxidised (1)

(c) Traces of a liquid were discovered in a bottle believed to contain perfume belonging to Queen Hatshepsut ruler of Egypt over 3500 years ago

Perfumes were made by dissolving plant extracts containing pleasant smelling terpenes and esters in an edible oil A little ethanol and water may also have been addedUsing your knowledge of chemistry comment on the possible smell(s) when such a bottle is opened after being stored for thousands of years (3)

48

49

7 A team of chemists are developing a fragrance for use in a shower gel for men(a) To give the gel a fruity smell the chemists are considering adding an ester

They synthesise six isomeric esters Volunteers smell each ester and give it a rating out of one hundred depending on how fruity the smell is

(i) Name the ester with the fruit-smell rating of 92 (1)

(ii) Shown below are the structures of three more isomers

Arrange these esters in order of decreasing fruit-smell rating (1)

50

(b) To create a fragrance for men the compound civetone is added

Draw a structural formula for the alcohol that can be oxidised to form civetone (1)

(c) To make the shower gel produce a cold tingling sensation when applied to the skin menthol is added

Like terpenes menthol is formed from isoprene (2-methylbuta-13-diene)Circle an isoprene unit on the menthol structure above (1)

8 Many of the compounds in perfumes are molecules consisting of joined isoprene units

(a) State the name that is given to molecules consisting of joined isoprene units (1)

(b)Geraniol is one of the compounds found in perfume It has the following structural formula and systematic name

Linalool can also be present Its structural formula is shown

51

(i) State the systematic name for linalool (1)(ii) Explain why linalool can be classified as a tertiary alcohol (1)

9 The component molecules found in lavender oils are terpenes or terpenoids(a)A chiral carbon is a carbon atom attached to four different atoms or groups of

atomsAn example is shown below

A molecule of the terpenoid linalool has a chiral carbon Linalool has the following structure

Circle the chiral carbon atom in the linalool structure (1)

(b)Farnesene is a terpene consisting of three isoprene units (2-methylbuta-13-diene) joined togetherWrite the molecular formula of farnesene (1)

52

27 Skin Care

1 Which of the following is not a step in a free radical chain reaction

A ActivationB InitiationC PropagationD Termination

2 Fluorine reacts with methane via a free radical chain reaction Some steps in the chain reaction are shown in the table below

Complete the table by(a) inserting the missing name for the first step (1)

(b) showing another possible termination reaction in the final row of the table (1)

3 Suncreams contain antioxidantsThe antioxidant compound A can prevent damage to skin by reacting with free

radicalssuch as NO2bull

53

Why can compound A be described as a free radical scavenger in the reaction shown above

4 Hydrogen and chlorine gases are used in an experiment to demonstrate a free radical reaction A plastic bottle is wrapped with black tape leaving a ldquowindowrdquo on one sideThe bottle is filled with a mixture of hydrogen and chlorine When bright light shines on the bottle there is an explosion

A free radical chain reaction is initiated when light energy causes chlorine radicals to form as shown below

(a) Complete the equations below showing possible propagation and termination steps

(2)

54

(b) Why is the plastic bottle used in the experiment wrapped in black tape (1)

5 Chloramines can be removed from water using ultraviolet light treatment

One step in the process is the formation of free radicals

(a)State what is meant by the term free radical (1)

(b)Another step in the process is shown below

State the name for this type of step in a free radical reaction (1)

6 Modern shellac nail varnishes are more durable and so last longer than traditional nail polish

The shellac nail varnish is applied in thin layers to the nails and then the fingers are placed under a UV lamp

(a) The Skin Care Foundation has recommended that a sun-block is applied to the fingers and hand before using the lampSuggest why the Skin Care Foundation makes this recommendation (1)

(b) A free radical chain reaction takes place and the varnish hardens (i) State what is meant by the term free radical (1)

(ii) The shellac nail varnish contains a mixture of ingredients that take part in the free radical chain reactionOne of the steps in the free radical chain reaction is

55

State the term used to describe this type of step in a free radical chain reaction(1)

7 Skin care products contain a mixture of polar covalent non-polar covalent and ionic compounds The compounds need to stay mixed within the product Skin care products also need to spread easily and remain on the skin for a period of time as well as provide physical and chemical protection from the sun In order to do this skin care products contain a range of chemicals including water fats and oils antioxidants minerals and sun blockUsing your knowledge of chemistry explain the role of different chemicals in skin care products (3)

General Questions

1 A mixture of carbon monoxide and hydrogen can be converted into water and a mixture of hydrocarbons

nCO + (2n + 1)H2 rarr nH2O + hydrocarbons

What is the general formula for the hydrocarbons producedA CnH2nndash2B CnH2nC CnH2n+1D CnH2n+2

2 Butadiene is the first member of a homologous series of hydrocarbons called dienesWhat is the general formula for this seriesA CnHn+2B CnHn+3C CnH2nD CnH2nndash2

3 Which of the following statements about methanol is falseA It can be made from synthesis gasB It can be dehydrated to form an alkeneC It can be oxidised to give a carboxylic acidD It reacts with acidified potassium dichromate solution

56

4

Which line in the table correctly describes reactions X and Y

5

Which line in the table correctly describes reactions X and Y

6 Which of the following fuels when burned would make no contribution to globalwarming

57

A HydrogenB Natural gasC PetrolD Coal

7 Which of the following hydrocarbons always gives the same product when one of itshydrogen atoms is replaced by a chlorine atomA HexaneB Hex-1-eneC CyclohexaneD Cyclohexene

8 Which of the following compounds does not have isomeric structuresA C2HCl3B C2H4Cl2C PropeneD Propan-1-ol

9 What organic compound is produced by the dehydration of ethanol A EthaneB EtheneC EthanalD Ethanoic acid

10

The above equation representsA hydrationB hydrogenationC condensationD hydrolysis

11

Which of the following compounds is an isomer of the structure shown aboveA ButanalB ButanoneC Butan-1-olD Butanoic acid

58

12 A compound with molecular formula C6H12O2 could beA hexanalB hexan-2-olC hexan-2-oneD hexanoic acid

13 Propan-2-ol can be prepared from propane as follows

Which line in the table correctly describes the types of reaction taking place at Steps 1 and 2

14 Which of the following compounds would be the most water soluble

15 Cyanohydrin compounds can be made from carbonyl compounds by reacting the carbonyl compound with hydrogen cyanide (HCN)

59

Which carbonyl compound would react with hydrogen cyanide (HCN) to form the following compound

16 Ethyne is the first member of the homologous series called the alkynes

Ethyne can undergo addition reactions as shown in the flow diagram

(a) Compound 2 is an isomer of 12-dichloroethaneDraw a structural formula for compound 2 (1)

(b) Reagents A B and C are three different diatomic gasesUsing information in the flow diagram identify reagents A B and C (1)

60

Reagent Gas

A

B

C

17 In 1865 the German chemist Kekuleacute proposed a ring structure for benzene This structure was based on alternating single and double bonds

(a) (i) Describe a chemical test that would indicate that the above chemical structure for benzene is incorrect (1)

(ii) Briefly describe the correct structure for benzene (1)

(b) Benzene can be formed from cyclohexaneC6H12 rarr C6H6 + 3H2

What name is given to this type of reaction (1)18 Infra-red spectroscopy is a technique that can be used to identify the bonds that

arepresent in a molecule Different bonds absorb infra-red radiation of different wavenumbers This is due to differences in the bond lsquostretchrsquo These absorptions are recorded in a spectrumA spectrum for propan-1-ol is shown

61

The correlation table on page 13 of the data booklet shows the wavenumber ranges for the absorptions due to different bonds

(a) Use the correlation table to identify the bonds responsible for the two absorptions x and y that are circled in the propan-1-ol spectrum (1)

(b) Propan-1-ol reacts with ethanoic acid(i) What name is given to this type of reaction (1)(ii) Draw a spectrum that could be obtained for the organic product of this

reaction (1)

19 Paracetamol is a widely used painkiller

(a) Write the molecular formula for paracetamol (1)

(b) One antidote for paracetamol overdose is methionine

62

To what family of organic compounds does methionine belong (1)

(c) The concentration of paracetamol in a solution can be determined by measuring how much UV radiation it absorbs

The graph shows how the absorbance of a sample containing 0middot040 g l ndash1 paracetamol varies with wavelength

The quantity of UV radiation of wavelength 245 nm absorbed is directly proportional to the concentration of paracetamolThe absorbance of a second sample of paracetamol solution measured at 245 nm was 0middot90 What is the concentration in g l ndash1 of this second paracetamol solution (1)

20 Many carbon compounds containing oxygen are very flammableThe table shows information about two families of isomersThe lowest temperature at which a compound will ignite is called its flash point

(a) A compound with the molecular formula C6H14O has a boiling point of 158 degC63

Draw a structural formula for this compound (1)

(b) For a family of isomers in the table write a general statement linking the flash points of the compounds to their structures (1)

21 Hydrogels are used in disposable nappies They are fine powders that can absorb up to 500 times their own weight in waterA hydrogel is a very long molecule with carboxyl groups at regular intervals along its length A short section of a hydrogel molecule is shown below

Hydrogels are extremely good at soaking up water because the water molecules are strongly attracted to them

Using your knowledge of chemistry comment on how suitable hydrogels would be for absorbing liquids or solutions spilled in a chemistry lab (1)

64

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

49

7 A team of chemists are developing a fragrance for use in a shower gel for men(a) To give the gel a fruity smell the chemists are considering adding an ester

They synthesise six isomeric esters Volunteers smell each ester and give it a rating out of one hundred depending on how fruity the smell is

(i) Name the ester with the fruit-smell rating of 92 (1)

(ii) Shown below are the structures of three more isomers

Arrange these esters in order of decreasing fruit-smell rating (1)

50

(b) To create a fragrance for men the compound civetone is added

Draw a structural formula for the alcohol that can be oxidised to form civetone (1)

(c) To make the shower gel produce a cold tingling sensation when applied to the skin menthol is added

Like terpenes menthol is formed from isoprene (2-methylbuta-13-diene)Circle an isoprene unit on the menthol structure above (1)

8 Many of the compounds in perfumes are molecules consisting of joined isoprene units

(a) State the name that is given to molecules consisting of joined isoprene units (1)

(b)Geraniol is one of the compounds found in perfume It has the following structural formula and systematic name

Linalool can also be present Its structural formula is shown

51

(i) State the systematic name for linalool (1)(ii) Explain why linalool can be classified as a tertiary alcohol (1)

9 The component molecules found in lavender oils are terpenes or terpenoids(a)A chiral carbon is a carbon atom attached to four different atoms or groups of

atomsAn example is shown below

A molecule of the terpenoid linalool has a chiral carbon Linalool has the following structure

Circle the chiral carbon atom in the linalool structure (1)

(b)Farnesene is a terpene consisting of three isoprene units (2-methylbuta-13-diene) joined togetherWrite the molecular formula of farnesene (1)

52

27 Skin Care

1 Which of the following is not a step in a free radical chain reaction

A ActivationB InitiationC PropagationD Termination

2 Fluorine reacts with methane via a free radical chain reaction Some steps in the chain reaction are shown in the table below

Complete the table by(a) inserting the missing name for the first step (1)

(b) showing another possible termination reaction in the final row of the table (1)

3 Suncreams contain antioxidantsThe antioxidant compound A can prevent damage to skin by reacting with free

radicalssuch as NO2bull

53

Why can compound A be described as a free radical scavenger in the reaction shown above

4 Hydrogen and chlorine gases are used in an experiment to demonstrate a free radical reaction A plastic bottle is wrapped with black tape leaving a ldquowindowrdquo on one sideThe bottle is filled with a mixture of hydrogen and chlorine When bright light shines on the bottle there is an explosion

A free radical chain reaction is initiated when light energy causes chlorine radicals to form as shown below

(a) Complete the equations below showing possible propagation and termination steps

(2)

54

(b) Why is the plastic bottle used in the experiment wrapped in black tape (1)

5 Chloramines can be removed from water using ultraviolet light treatment

One step in the process is the formation of free radicals

(a)State what is meant by the term free radical (1)

(b)Another step in the process is shown below

State the name for this type of step in a free radical reaction (1)

6 Modern shellac nail varnishes are more durable and so last longer than traditional nail polish

The shellac nail varnish is applied in thin layers to the nails and then the fingers are placed under a UV lamp

(a) The Skin Care Foundation has recommended that a sun-block is applied to the fingers and hand before using the lampSuggest why the Skin Care Foundation makes this recommendation (1)

(b) A free radical chain reaction takes place and the varnish hardens (i) State what is meant by the term free radical (1)

(ii) The shellac nail varnish contains a mixture of ingredients that take part in the free radical chain reactionOne of the steps in the free radical chain reaction is

55

State the term used to describe this type of step in a free radical chain reaction(1)

7 Skin care products contain a mixture of polar covalent non-polar covalent and ionic compounds The compounds need to stay mixed within the product Skin care products also need to spread easily and remain on the skin for a period of time as well as provide physical and chemical protection from the sun In order to do this skin care products contain a range of chemicals including water fats and oils antioxidants minerals and sun blockUsing your knowledge of chemistry explain the role of different chemicals in skin care products (3)

General Questions

1 A mixture of carbon monoxide and hydrogen can be converted into water and a mixture of hydrocarbons

nCO + (2n + 1)H2 rarr nH2O + hydrocarbons

What is the general formula for the hydrocarbons producedA CnH2nndash2B CnH2nC CnH2n+1D CnH2n+2

2 Butadiene is the first member of a homologous series of hydrocarbons called dienesWhat is the general formula for this seriesA CnHn+2B CnHn+3C CnH2nD CnH2nndash2

3 Which of the following statements about methanol is falseA It can be made from synthesis gasB It can be dehydrated to form an alkeneC It can be oxidised to give a carboxylic acidD It reacts with acidified potassium dichromate solution

56

4

Which line in the table correctly describes reactions X and Y

5

Which line in the table correctly describes reactions X and Y

6 Which of the following fuels when burned would make no contribution to globalwarming

57

A HydrogenB Natural gasC PetrolD Coal

7 Which of the following hydrocarbons always gives the same product when one of itshydrogen atoms is replaced by a chlorine atomA HexaneB Hex-1-eneC CyclohexaneD Cyclohexene

8 Which of the following compounds does not have isomeric structuresA C2HCl3B C2H4Cl2C PropeneD Propan-1-ol

9 What organic compound is produced by the dehydration of ethanol A EthaneB EtheneC EthanalD Ethanoic acid

10

The above equation representsA hydrationB hydrogenationC condensationD hydrolysis

11

Which of the following compounds is an isomer of the structure shown aboveA ButanalB ButanoneC Butan-1-olD Butanoic acid

58

12 A compound with molecular formula C6H12O2 could beA hexanalB hexan-2-olC hexan-2-oneD hexanoic acid

13 Propan-2-ol can be prepared from propane as follows

Which line in the table correctly describes the types of reaction taking place at Steps 1 and 2

14 Which of the following compounds would be the most water soluble

15 Cyanohydrin compounds can be made from carbonyl compounds by reacting the carbonyl compound with hydrogen cyanide (HCN)

59

Which carbonyl compound would react with hydrogen cyanide (HCN) to form the following compound

16 Ethyne is the first member of the homologous series called the alkynes

Ethyne can undergo addition reactions as shown in the flow diagram

(a) Compound 2 is an isomer of 12-dichloroethaneDraw a structural formula for compound 2 (1)

(b) Reagents A B and C are three different diatomic gasesUsing information in the flow diagram identify reagents A B and C (1)

60

Reagent Gas

A

B

C

17 In 1865 the German chemist Kekuleacute proposed a ring structure for benzene This structure was based on alternating single and double bonds

(a) (i) Describe a chemical test that would indicate that the above chemical structure for benzene is incorrect (1)

(ii) Briefly describe the correct structure for benzene (1)

(b) Benzene can be formed from cyclohexaneC6H12 rarr C6H6 + 3H2

What name is given to this type of reaction (1)18 Infra-red spectroscopy is a technique that can be used to identify the bonds that

arepresent in a molecule Different bonds absorb infra-red radiation of different wavenumbers This is due to differences in the bond lsquostretchrsquo These absorptions are recorded in a spectrumA spectrum for propan-1-ol is shown

61

The correlation table on page 13 of the data booklet shows the wavenumber ranges for the absorptions due to different bonds

(a) Use the correlation table to identify the bonds responsible for the two absorptions x and y that are circled in the propan-1-ol spectrum (1)

(b) Propan-1-ol reacts with ethanoic acid(i) What name is given to this type of reaction (1)(ii) Draw a spectrum that could be obtained for the organic product of this

reaction (1)

19 Paracetamol is a widely used painkiller

(a) Write the molecular formula for paracetamol (1)

(b) One antidote for paracetamol overdose is methionine

62

To what family of organic compounds does methionine belong (1)

(c) The concentration of paracetamol in a solution can be determined by measuring how much UV radiation it absorbs

The graph shows how the absorbance of a sample containing 0middot040 g l ndash1 paracetamol varies with wavelength

The quantity of UV radiation of wavelength 245 nm absorbed is directly proportional to the concentration of paracetamolThe absorbance of a second sample of paracetamol solution measured at 245 nm was 0middot90 What is the concentration in g l ndash1 of this second paracetamol solution (1)

20 Many carbon compounds containing oxygen are very flammableThe table shows information about two families of isomersThe lowest temperature at which a compound will ignite is called its flash point

(a) A compound with the molecular formula C6H14O has a boiling point of 158 degC63

Draw a structural formula for this compound (1)

(b) For a family of isomers in the table write a general statement linking the flash points of the compounds to their structures (1)

21 Hydrogels are used in disposable nappies They are fine powders that can absorb up to 500 times their own weight in waterA hydrogel is a very long molecule with carboxyl groups at regular intervals along its length A short section of a hydrogel molecule is shown below

Hydrogels are extremely good at soaking up water because the water molecules are strongly attracted to them

Using your knowledge of chemistry comment on how suitable hydrogels would be for absorbing liquids or solutions spilled in a chemistry lab (1)

64

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

7 A team of chemists are developing a fragrance for use in a shower gel for men(a) To give the gel a fruity smell the chemists are considering adding an ester

They synthesise six isomeric esters Volunteers smell each ester and give it a rating out of one hundred depending on how fruity the smell is

(i) Name the ester with the fruit-smell rating of 92 (1)

(ii) Shown below are the structures of three more isomers

Arrange these esters in order of decreasing fruit-smell rating (1)

50

(b) To create a fragrance for men the compound civetone is added

Draw a structural formula for the alcohol that can be oxidised to form civetone (1)

(c) To make the shower gel produce a cold tingling sensation when applied to the skin menthol is added

Like terpenes menthol is formed from isoprene (2-methylbuta-13-diene)Circle an isoprene unit on the menthol structure above (1)

8 Many of the compounds in perfumes are molecules consisting of joined isoprene units

(a) State the name that is given to molecules consisting of joined isoprene units (1)

(b)Geraniol is one of the compounds found in perfume It has the following structural formula and systematic name

Linalool can also be present Its structural formula is shown

51

(i) State the systematic name for linalool (1)(ii) Explain why linalool can be classified as a tertiary alcohol (1)

9 The component molecules found in lavender oils are terpenes or terpenoids(a)A chiral carbon is a carbon atom attached to four different atoms or groups of

atomsAn example is shown below

A molecule of the terpenoid linalool has a chiral carbon Linalool has the following structure

Circle the chiral carbon atom in the linalool structure (1)

(b)Farnesene is a terpene consisting of three isoprene units (2-methylbuta-13-diene) joined togetherWrite the molecular formula of farnesene (1)

52

27 Skin Care

1 Which of the following is not a step in a free radical chain reaction

A ActivationB InitiationC PropagationD Termination

2 Fluorine reacts with methane via a free radical chain reaction Some steps in the chain reaction are shown in the table below

Complete the table by(a) inserting the missing name for the first step (1)

(b) showing another possible termination reaction in the final row of the table (1)

3 Suncreams contain antioxidantsThe antioxidant compound A can prevent damage to skin by reacting with free

radicalssuch as NO2bull

53

Why can compound A be described as a free radical scavenger in the reaction shown above

4 Hydrogen and chlorine gases are used in an experiment to demonstrate a free radical reaction A plastic bottle is wrapped with black tape leaving a ldquowindowrdquo on one sideThe bottle is filled with a mixture of hydrogen and chlorine When bright light shines on the bottle there is an explosion

A free radical chain reaction is initiated when light energy causes chlorine radicals to form as shown below

(a) Complete the equations below showing possible propagation and termination steps

(2)

54

(b) Why is the plastic bottle used in the experiment wrapped in black tape (1)

5 Chloramines can be removed from water using ultraviolet light treatment

One step in the process is the formation of free radicals

(a)State what is meant by the term free radical (1)

(b)Another step in the process is shown below

State the name for this type of step in a free radical reaction (1)

6 Modern shellac nail varnishes are more durable and so last longer than traditional nail polish

The shellac nail varnish is applied in thin layers to the nails and then the fingers are placed under a UV lamp

(a) The Skin Care Foundation has recommended that a sun-block is applied to the fingers and hand before using the lampSuggest why the Skin Care Foundation makes this recommendation (1)

(b) A free radical chain reaction takes place and the varnish hardens (i) State what is meant by the term free radical (1)

(ii) The shellac nail varnish contains a mixture of ingredients that take part in the free radical chain reactionOne of the steps in the free radical chain reaction is

55

State the term used to describe this type of step in a free radical chain reaction(1)

7 Skin care products contain a mixture of polar covalent non-polar covalent and ionic compounds The compounds need to stay mixed within the product Skin care products also need to spread easily and remain on the skin for a period of time as well as provide physical and chemical protection from the sun In order to do this skin care products contain a range of chemicals including water fats and oils antioxidants minerals and sun blockUsing your knowledge of chemistry explain the role of different chemicals in skin care products (3)

General Questions

1 A mixture of carbon monoxide and hydrogen can be converted into water and a mixture of hydrocarbons

nCO + (2n + 1)H2 rarr nH2O + hydrocarbons

What is the general formula for the hydrocarbons producedA CnH2nndash2B CnH2nC CnH2n+1D CnH2n+2

2 Butadiene is the first member of a homologous series of hydrocarbons called dienesWhat is the general formula for this seriesA CnHn+2B CnHn+3C CnH2nD CnH2nndash2

3 Which of the following statements about methanol is falseA It can be made from synthesis gasB It can be dehydrated to form an alkeneC It can be oxidised to give a carboxylic acidD It reacts with acidified potassium dichromate solution

56

4

Which line in the table correctly describes reactions X and Y

5

Which line in the table correctly describes reactions X and Y

6 Which of the following fuels when burned would make no contribution to globalwarming

57

A HydrogenB Natural gasC PetrolD Coal

7 Which of the following hydrocarbons always gives the same product when one of itshydrogen atoms is replaced by a chlorine atomA HexaneB Hex-1-eneC CyclohexaneD Cyclohexene

8 Which of the following compounds does not have isomeric structuresA C2HCl3B C2H4Cl2C PropeneD Propan-1-ol

9 What organic compound is produced by the dehydration of ethanol A EthaneB EtheneC EthanalD Ethanoic acid

10

The above equation representsA hydrationB hydrogenationC condensationD hydrolysis

11

Which of the following compounds is an isomer of the structure shown aboveA ButanalB ButanoneC Butan-1-olD Butanoic acid

58

12 A compound with molecular formula C6H12O2 could beA hexanalB hexan-2-olC hexan-2-oneD hexanoic acid

13 Propan-2-ol can be prepared from propane as follows

Which line in the table correctly describes the types of reaction taking place at Steps 1 and 2

14 Which of the following compounds would be the most water soluble

15 Cyanohydrin compounds can be made from carbonyl compounds by reacting the carbonyl compound with hydrogen cyanide (HCN)

59

Which carbonyl compound would react with hydrogen cyanide (HCN) to form the following compound

16 Ethyne is the first member of the homologous series called the alkynes

Ethyne can undergo addition reactions as shown in the flow diagram

(a) Compound 2 is an isomer of 12-dichloroethaneDraw a structural formula for compound 2 (1)

(b) Reagents A B and C are three different diatomic gasesUsing information in the flow diagram identify reagents A B and C (1)

60

Reagent Gas

A

B

C

17 In 1865 the German chemist Kekuleacute proposed a ring structure for benzene This structure was based on alternating single and double bonds

(a) (i) Describe a chemical test that would indicate that the above chemical structure for benzene is incorrect (1)

(ii) Briefly describe the correct structure for benzene (1)

(b) Benzene can be formed from cyclohexaneC6H12 rarr C6H6 + 3H2

What name is given to this type of reaction (1)18 Infra-red spectroscopy is a technique that can be used to identify the bonds that

arepresent in a molecule Different bonds absorb infra-red radiation of different wavenumbers This is due to differences in the bond lsquostretchrsquo These absorptions are recorded in a spectrumA spectrum for propan-1-ol is shown

61

The correlation table on page 13 of the data booklet shows the wavenumber ranges for the absorptions due to different bonds

(a) Use the correlation table to identify the bonds responsible for the two absorptions x and y that are circled in the propan-1-ol spectrum (1)

(b) Propan-1-ol reacts with ethanoic acid(i) What name is given to this type of reaction (1)(ii) Draw a spectrum that could be obtained for the organic product of this

reaction (1)

19 Paracetamol is a widely used painkiller

(a) Write the molecular formula for paracetamol (1)

(b) One antidote for paracetamol overdose is methionine

62

To what family of organic compounds does methionine belong (1)

(c) The concentration of paracetamol in a solution can be determined by measuring how much UV radiation it absorbs

The graph shows how the absorbance of a sample containing 0middot040 g l ndash1 paracetamol varies with wavelength

The quantity of UV radiation of wavelength 245 nm absorbed is directly proportional to the concentration of paracetamolThe absorbance of a second sample of paracetamol solution measured at 245 nm was 0middot90 What is the concentration in g l ndash1 of this second paracetamol solution (1)

20 Many carbon compounds containing oxygen are very flammableThe table shows information about two families of isomersThe lowest temperature at which a compound will ignite is called its flash point

(a) A compound with the molecular formula C6H14O has a boiling point of 158 degC63

Draw a structural formula for this compound (1)

(b) For a family of isomers in the table write a general statement linking the flash points of the compounds to their structures (1)

21 Hydrogels are used in disposable nappies They are fine powders that can absorb up to 500 times their own weight in waterA hydrogel is a very long molecule with carboxyl groups at regular intervals along its length A short section of a hydrogel molecule is shown below

Hydrogels are extremely good at soaking up water because the water molecules are strongly attracted to them

Using your knowledge of chemistry comment on how suitable hydrogels would be for absorbing liquids or solutions spilled in a chemistry lab (1)

64

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

(b) To create a fragrance for men the compound civetone is added

Draw a structural formula for the alcohol that can be oxidised to form civetone (1)

(c) To make the shower gel produce a cold tingling sensation when applied to the skin menthol is added

Like terpenes menthol is formed from isoprene (2-methylbuta-13-diene)Circle an isoprene unit on the menthol structure above (1)

8 Many of the compounds in perfumes are molecules consisting of joined isoprene units

(a) State the name that is given to molecules consisting of joined isoprene units (1)

(b)Geraniol is one of the compounds found in perfume It has the following structural formula and systematic name

Linalool can also be present Its structural formula is shown

51

(i) State the systematic name for linalool (1)(ii) Explain why linalool can be classified as a tertiary alcohol (1)

9 The component molecules found in lavender oils are terpenes or terpenoids(a)A chiral carbon is a carbon atom attached to four different atoms or groups of

atomsAn example is shown below

A molecule of the terpenoid linalool has a chiral carbon Linalool has the following structure

Circle the chiral carbon atom in the linalool structure (1)

(b)Farnesene is a terpene consisting of three isoprene units (2-methylbuta-13-diene) joined togetherWrite the molecular formula of farnesene (1)

52

27 Skin Care

1 Which of the following is not a step in a free radical chain reaction

A ActivationB InitiationC PropagationD Termination

2 Fluorine reacts with methane via a free radical chain reaction Some steps in the chain reaction are shown in the table below

Complete the table by(a) inserting the missing name for the first step (1)

(b) showing another possible termination reaction in the final row of the table (1)

3 Suncreams contain antioxidantsThe antioxidant compound A can prevent damage to skin by reacting with free

radicalssuch as NO2bull

53

Why can compound A be described as a free radical scavenger in the reaction shown above

4 Hydrogen and chlorine gases are used in an experiment to demonstrate a free radical reaction A plastic bottle is wrapped with black tape leaving a ldquowindowrdquo on one sideThe bottle is filled with a mixture of hydrogen and chlorine When bright light shines on the bottle there is an explosion

A free radical chain reaction is initiated when light energy causes chlorine radicals to form as shown below

(a) Complete the equations below showing possible propagation and termination steps

(2)

54

(b) Why is the plastic bottle used in the experiment wrapped in black tape (1)

5 Chloramines can be removed from water using ultraviolet light treatment

One step in the process is the formation of free radicals

(a)State what is meant by the term free radical (1)

(b)Another step in the process is shown below

State the name for this type of step in a free radical reaction (1)

6 Modern shellac nail varnishes are more durable and so last longer than traditional nail polish

The shellac nail varnish is applied in thin layers to the nails and then the fingers are placed under a UV lamp

(a) The Skin Care Foundation has recommended that a sun-block is applied to the fingers and hand before using the lampSuggest why the Skin Care Foundation makes this recommendation (1)

(b) A free radical chain reaction takes place and the varnish hardens (i) State what is meant by the term free radical (1)

(ii) The shellac nail varnish contains a mixture of ingredients that take part in the free radical chain reactionOne of the steps in the free radical chain reaction is

55

State the term used to describe this type of step in a free radical chain reaction(1)

7 Skin care products contain a mixture of polar covalent non-polar covalent and ionic compounds The compounds need to stay mixed within the product Skin care products also need to spread easily and remain on the skin for a period of time as well as provide physical and chemical protection from the sun In order to do this skin care products contain a range of chemicals including water fats and oils antioxidants minerals and sun blockUsing your knowledge of chemistry explain the role of different chemicals in skin care products (3)

General Questions

1 A mixture of carbon monoxide and hydrogen can be converted into water and a mixture of hydrocarbons

nCO + (2n + 1)H2 rarr nH2O + hydrocarbons

What is the general formula for the hydrocarbons producedA CnH2nndash2B CnH2nC CnH2n+1D CnH2n+2

2 Butadiene is the first member of a homologous series of hydrocarbons called dienesWhat is the general formula for this seriesA CnHn+2B CnHn+3C CnH2nD CnH2nndash2

3 Which of the following statements about methanol is falseA It can be made from synthesis gasB It can be dehydrated to form an alkeneC It can be oxidised to give a carboxylic acidD It reacts with acidified potassium dichromate solution

56

4

Which line in the table correctly describes reactions X and Y

5

Which line in the table correctly describes reactions X and Y

6 Which of the following fuels when burned would make no contribution to globalwarming

57

A HydrogenB Natural gasC PetrolD Coal

7 Which of the following hydrocarbons always gives the same product when one of itshydrogen atoms is replaced by a chlorine atomA HexaneB Hex-1-eneC CyclohexaneD Cyclohexene

8 Which of the following compounds does not have isomeric structuresA C2HCl3B C2H4Cl2C PropeneD Propan-1-ol

9 What organic compound is produced by the dehydration of ethanol A EthaneB EtheneC EthanalD Ethanoic acid

10

The above equation representsA hydrationB hydrogenationC condensationD hydrolysis

11

Which of the following compounds is an isomer of the structure shown aboveA ButanalB ButanoneC Butan-1-olD Butanoic acid

58

12 A compound with molecular formula C6H12O2 could beA hexanalB hexan-2-olC hexan-2-oneD hexanoic acid

13 Propan-2-ol can be prepared from propane as follows

Which line in the table correctly describes the types of reaction taking place at Steps 1 and 2

14 Which of the following compounds would be the most water soluble

15 Cyanohydrin compounds can be made from carbonyl compounds by reacting the carbonyl compound with hydrogen cyanide (HCN)

59

Which carbonyl compound would react with hydrogen cyanide (HCN) to form the following compound

16 Ethyne is the first member of the homologous series called the alkynes

Ethyne can undergo addition reactions as shown in the flow diagram

(a) Compound 2 is an isomer of 12-dichloroethaneDraw a structural formula for compound 2 (1)

(b) Reagents A B and C are three different diatomic gasesUsing information in the flow diagram identify reagents A B and C (1)

60

Reagent Gas

A

B

C

17 In 1865 the German chemist Kekuleacute proposed a ring structure for benzene This structure was based on alternating single and double bonds

(a) (i) Describe a chemical test that would indicate that the above chemical structure for benzene is incorrect (1)

(ii) Briefly describe the correct structure for benzene (1)

(b) Benzene can be formed from cyclohexaneC6H12 rarr C6H6 + 3H2

What name is given to this type of reaction (1)18 Infra-red spectroscopy is a technique that can be used to identify the bonds that

arepresent in a molecule Different bonds absorb infra-red radiation of different wavenumbers This is due to differences in the bond lsquostretchrsquo These absorptions are recorded in a spectrumA spectrum for propan-1-ol is shown

61

The correlation table on page 13 of the data booklet shows the wavenumber ranges for the absorptions due to different bonds

(a) Use the correlation table to identify the bonds responsible for the two absorptions x and y that are circled in the propan-1-ol spectrum (1)

(b) Propan-1-ol reacts with ethanoic acid(i) What name is given to this type of reaction (1)(ii) Draw a spectrum that could be obtained for the organic product of this

reaction (1)

19 Paracetamol is a widely used painkiller

(a) Write the molecular formula for paracetamol (1)

(b) One antidote for paracetamol overdose is methionine

62

To what family of organic compounds does methionine belong (1)

(c) The concentration of paracetamol in a solution can be determined by measuring how much UV radiation it absorbs

The graph shows how the absorbance of a sample containing 0middot040 g l ndash1 paracetamol varies with wavelength

The quantity of UV radiation of wavelength 245 nm absorbed is directly proportional to the concentration of paracetamolThe absorbance of a second sample of paracetamol solution measured at 245 nm was 0middot90 What is the concentration in g l ndash1 of this second paracetamol solution (1)

20 Many carbon compounds containing oxygen are very flammableThe table shows information about two families of isomersThe lowest temperature at which a compound will ignite is called its flash point

(a) A compound with the molecular formula C6H14O has a boiling point of 158 degC63

Draw a structural formula for this compound (1)

(b) For a family of isomers in the table write a general statement linking the flash points of the compounds to their structures (1)

21 Hydrogels are used in disposable nappies They are fine powders that can absorb up to 500 times their own weight in waterA hydrogel is a very long molecule with carboxyl groups at regular intervals along its length A short section of a hydrogel molecule is shown below

Hydrogels are extremely good at soaking up water because the water molecules are strongly attracted to them

Using your knowledge of chemistry comment on how suitable hydrogels would be for absorbing liquids or solutions spilled in a chemistry lab (1)

64

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

(i) State the systematic name for linalool (1)(ii) Explain why linalool can be classified as a tertiary alcohol (1)

9 The component molecules found in lavender oils are terpenes or terpenoids(a)A chiral carbon is a carbon atom attached to four different atoms or groups of

atomsAn example is shown below

A molecule of the terpenoid linalool has a chiral carbon Linalool has the following structure

Circle the chiral carbon atom in the linalool structure (1)

(b)Farnesene is a terpene consisting of three isoprene units (2-methylbuta-13-diene) joined togetherWrite the molecular formula of farnesene (1)

52

27 Skin Care

1 Which of the following is not a step in a free radical chain reaction

A ActivationB InitiationC PropagationD Termination

2 Fluorine reacts with methane via a free radical chain reaction Some steps in the chain reaction are shown in the table below

Complete the table by(a) inserting the missing name for the first step (1)

(b) showing another possible termination reaction in the final row of the table (1)

3 Suncreams contain antioxidantsThe antioxidant compound A can prevent damage to skin by reacting with free

radicalssuch as NO2bull

53

Why can compound A be described as a free radical scavenger in the reaction shown above

4 Hydrogen and chlorine gases are used in an experiment to demonstrate a free radical reaction A plastic bottle is wrapped with black tape leaving a ldquowindowrdquo on one sideThe bottle is filled with a mixture of hydrogen and chlorine When bright light shines on the bottle there is an explosion

A free radical chain reaction is initiated when light energy causes chlorine radicals to form as shown below

(a) Complete the equations below showing possible propagation and termination steps

(2)

54

(b) Why is the plastic bottle used in the experiment wrapped in black tape (1)

5 Chloramines can be removed from water using ultraviolet light treatment

One step in the process is the formation of free radicals

(a)State what is meant by the term free radical (1)

(b)Another step in the process is shown below

State the name for this type of step in a free radical reaction (1)

6 Modern shellac nail varnishes are more durable and so last longer than traditional nail polish

The shellac nail varnish is applied in thin layers to the nails and then the fingers are placed under a UV lamp

(a) The Skin Care Foundation has recommended that a sun-block is applied to the fingers and hand before using the lampSuggest why the Skin Care Foundation makes this recommendation (1)

(b) A free radical chain reaction takes place and the varnish hardens (i) State what is meant by the term free radical (1)

(ii) The shellac nail varnish contains a mixture of ingredients that take part in the free radical chain reactionOne of the steps in the free radical chain reaction is

55

State the term used to describe this type of step in a free radical chain reaction(1)

7 Skin care products contain a mixture of polar covalent non-polar covalent and ionic compounds The compounds need to stay mixed within the product Skin care products also need to spread easily and remain on the skin for a period of time as well as provide physical and chemical protection from the sun In order to do this skin care products contain a range of chemicals including water fats and oils antioxidants minerals and sun blockUsing your knowledge of chemistry explain the role of different chemicals in skin care products (3)

General Questions

1 A mixture of carbon monoxide and hydrogen can be converted into water and a mixture of hydrocarbons

nCO + (2n + 1)H2 rarr nH2O + hydrocarbons

What is the general formula for the hydrocarbons producedA CnH2nndash2B CnH2nC CnH2n+1D CnH2n+2

2 Butadiene is the first member of a homologous series of hydrocarbons called dienesWhat is the general formula for this seriesA CnHn+2B CnHn+3C CnH2nD CnH2nndash2

3 Which of the following statements about methanol is falseA It can be made from synthesis gasB It can be dehydrated to form an alkeneC It can be oxidised to give a carboxylic acidD It reacts with acidified potassium dichromate solution

56

4

Which line in the table correctly describes reactions X and Y

5

Which line in the table correctly describes reactions X and Y

6 Which of the following fuels when burned would make no contribution to globalwarming

57

A HydrogenB Natural gasC PetrolD Coal

7 Which of the following hydrocarbons always gives the same product when one of itshydrogen atoms is replaced by a chlorine atomA HexaneB Hex-1-eneC CyclohexaneD Cyclohexene

8 Which of the following compounds does not have isomeric structuresA C2HCl3B C2H4Cl2C PropeneD Propan-1-ol

9 What organic compound is produced by the dehydration of ethanol A EthaneB EtheneC EthanalD Ethanoic acid

10

The above equation representsA hydrationB hydrogenationC condensationD hydrolysis

11

Which of the following compounds is an isomer of the structure shown aboveA ButanalB ButanoneC Butan-1-olD Butanoic acid

58

12 A compound with molecular formula C6H12O2 could beA hexanalB hexan-2-olC hexan-2-oneD hexanoic acid

13 Propan-2-ol can be prepared from propane as follows

Which line in the table correctly describes the types of reaction taking place at Steps 1 and 2

14 Which of the following compounds would be the most water soluble

15 Cyanohydrin compounds can be made from carbonyl compounds by reacting the carbonyl compound with hydrogen cyanide (HCN)

59

Which carbonyl compound would react with hydrogen cyanide (HCN) to form the following compound

16 Ethyne is the first member of the homologous series called the alkynes

Ethyne can undergo addition reactions as shown in the flow diagram

(a) Compound 2 is an isomer of 12-dichloroethaneDraw a structural formula for compound 2 (1)

(b) Reagents A B and C are three different diatomic gasesUsing information in the flow diagram identify reagents A B and C (1)

60

Reagent Gas

A

B

C

17 In 1865 the German chemist Kekuleacute proposed a ring structure for benzene This structure was based on alternating single and double bonds

(a) (i) Describe a chemical test that would indicate that the above chemical structure for benzene is incorrect (1)

(ii) Briefly describe the correct structure for benzene (1)

(b) Benzene can be formed from cyclohexaneC6H12 rarr C6H6 + 3H2

What name is given to this type of reaction (1)18 Infra-red spectroscopy is a technique that can be used to identify the bonds that

arepresent in a molecule Different bonds absorb infra-red radiation of different wavenumbers This is due to differences in the bond lsquostretchrsquo These absorptions are recorded in a spectrumA spectrum for propan-1-ol is shown

61

The correlation table on page 13 of the data booklet shows the wavenumber ranges for the absorptions due to different bonds

(a) Use the correlation table to identify the bonds responsible for the two absorptions x and y that are circled in the propan-1-ol spectrum (1)

(b) Propan-1-ol reacts with ethanoic acid(i) What name is given to this type of reaction (1)(ii) Draw a spectrum that could be obtained for the organic product of this

reaction (1)

19 Paracetamol is a widely used painkiller

(a) Write the molecular formula for paracetamol (1)

(b) One antidote for paracetamol overdose is methionine

62

To what family of organic compounds does methionine belong (1)

(c) The concentration of paracetamol in a solution can be determined by measuring how much UV radiation it absorbs

The graph shows how the absorbance of a sample containing 0middot040 g l ndash1 paracetamol varies with wavelength

The quantity of UV radiation of wavelength 245 nm absorbed is directly proportional to the concentration of paracetamolThe absorbance of a second sample of paracetamol solution measured at 245 nm was 0middot90 What is the concentration in g l ndash1 of this second paracetamol solution (1)

20 Many carbon compounds containing oxygen are very flammableThe table shows information about two families of isomersThe lowest temperature at which a compound will ignite is called its flash point

(a) A compound with the molecular formula C6H14O has a boiling point of 158 degC63

Draw a structural formula for this compound (1)

(b) For a family of isomers in the table write a general statement linking the flash points of the compounds to their structures (1)

21 Hydrogels are used in disposable nappies They are fine powders that can absorb up to 500 times their own weight in waterA hydrogel is a very long molecule with carboxyl groups at regular intervals along its length A short section of a hydrogel molecule is shown below

Hydrogels are extremely good at soaking up water because the water molecules are strongly attracted to them

Using your knowledge of chemistry comment on how suitable hydrogels would be for absorbing liquids or solutions spilled in a chemistry lab (1)

64

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

27 Skin Care

1 Which of the following is not a step in a free radical chain reaction

A ActivationB InitiationC PropagationD Termination

2 Fluorine reacts with methane via a free radical chain reaction Some steps in the chain reaction are shown in the table below

Complete the table by(a) inserting the missing name for the first step (1)

(b) showing another possible termination reaction in the final row of the table (1)

3 Suncreams contain antioxidantsThe antioxidant compound A can prevent damage to skin by reacting with free

radicalssuch as NO2bull

53

Why can compound A be described as a free radical scavenger in the reaction shown above

4 Hydrogen and chlorine gases are used in an experiment to demonstrate a free radical reaction A plastic bottle is wrapped with black tape leaving a ldquowindowrdquo on one sideThe bottle is filled with a mixture of hydrogen and chlorine When bright light shines on the bottle there is an explosion

A free radical chain reaction is initiated when light energy causes chlorine radicals to form as shown below

(a) Complete the equations below showing possible propagation and termination steps

(2)

54

(b) Why is the plastic bottle used in the experiment wrapped in black tape (1)

5 Chloramines can be removed from water using ultraviolet light treatment

One step in the process is the formation of free radicals

(a)State what is meant by the term free radical (1)

(b)Another step in the process is shown below

State the name for this type of step in a free radical reaction (1)

6 Modern shellac nail varnishes are more durable and so last longer than traditional nail polish

The shellac nail varnish is applied in thin layers to the nails and then the fingers are placed under a UV lamp

(a) The Skin Care Foundation has recommended that a sun-block is applied to the fingers and hand before using the lampSuggest why the Skin Care Foundation makes this recommendation (1)

(b) A free radical chain reaction takes place and the varnish hardens (i) State what is meant by the term free radical (1)

(ii) The shellac nail varnish contains a mixture of ingredients that take part in the free radical chain reactionOne of the steps in the free radical chain reaction is

55

State the term used to describe this type of step in a free radical chain reaction(1)

7 Skin care products contain a mixture of polar covalent non-polar covalent and ionic compounds The compounds need to stay mixed within the product Skin care products also need to spread easily and remain on the skin for a period of time as well as provide physical and chemical protection from the sun In order to do this skin care products contain a range of chemicals including water fats and oils antioxidants minerals and sun blockUsing your knowledge of chemistry explain the role of different chemicals in skin care products (3)

General Questions

1 A mixture of carbon monoxide and hydrogen can be converted into water and a mixture of hydrocarbons

nCO + (2n + 1)H2 rarr nH2O + hydrocarbons

What is the general formula for the hydrocarbons producedA CnH2nndash2B CnH2nC CnH2n+1D CnH2n+2

2 Butadiene is the first member of a homologous series of hydrocarbons called dienesWhat is the general formula for this seriesA CnHn+2B CnHn+3C CnH2nD CnH2nndash2

3 Which of the following statements about methanol is falseA It can be made from synthesis gasB It can be dehydrated to form an alkeneC It can be oxidised to give a carboxylic acidD It reacts with acidified potassium dichromate solution

56

4

Which line in the table correctly describes reactions X and Y

5

Which line in the table correctly describes reactions X and Y

6 Which of the following fuels when burned would make no contribution to globalwarming

57

A HydrogenB Natural gasC PetrolD Coal

7 Which of the following hydrocarbons always gives the same product when one of itshydrogen atoms is replaced by a chlorine atomA HexaneB Hex-1-eneC CyclohexaneD Cyclohexene

8 Which of the following compounds does not have isomeric structuresA C2HCl3B C2H4Cl2C PropeneD Propan-1-ol

9 What organic compound is produced by the dehydration of ethanol A EthaneB EtheneC EthanalD Ethanoic acid

10

The above equation representsA hydrationB hydrogenationC condensationD hydrolysis

11

Which of the following compounds is an isomer of the structure shown aboveA ButanalB ButanoneC Butan-1-olD Butanoic acid

58

12 A compound with molecular formula C6H12O2 could beA hexanalB hexan-2-olC hexan-2-oneD hexanoic acid

13 Propan-2-ol can be prepared from propane as follows

Which line in the table correctly describes the types of reaction taking place at Steps 1 and 2

14 Which of the following compounds would be the most water soluble

15 Cyanohydrin compounds can be made from carbonyl compounds by reacting the carbonyl compound with hydrogen cyanide (HCN)

59

Which carbonyl compound would react with hydrogen cyanide (HCN) to form the following compound

16 Ethyne is the first member of the homologous series called the alkynes

Ethyne can undergo addition reactions as shown in the flow diagram

(a) Compound 2 is an isomer of 12-dichloroethaneDraw a structural formula for compound 2 (1)

(b) Reagents A B and C are three different diatomic gasesUsing information in the flow diagram identify reagents A B and C (1)

60

Reagent Gas

A

B

C

17 In 1865 the German chemist Kekuleacute proposed a ring structure for benzene This structure was based on alternating single and double bonds

(a) (i) Describe a chemical test that would indicate that the above chemical structure for benzene is incorrect (1)

(ii) Briefly describe the correct structure for benzene (1)

(b) Benzene can be formed from cyclohexaneC6H12 rarr C6H6 + 3H2

What name is given to this type of reaction (1)18 Infra-red spectroscopy is a technique that can be used to identify the bonds that

arepresent in a molecule Different bonds absorb infra-red radiation of different wavenumbers This is due to differences in the bond lsquostretchrsquo These absorptions are recorded in a spectrumA spectrum for propan-1-ol is shown

61

The correlation table on page 13 of the data booklet shows the wavenumber ranges for the absorptions due to different bonds

(a) Use the correlation table to identify the bonds responsible for the two absorptions x and y that are circled in the propan-1-ol spectrum (1)

(b) Propan-1-ol reacts with ethanoic acid(i) What name is given to this type of reaction (1)(ii) Draw a spectrum that could be obtained for the organic product of this

reaction (1)

19 Paracetamol is a widely used painkiller

(a) Write the molecular formula for paracetamol (1)

(b) One antidote for paracetamol overdose is methionine

62

To what family of organic compounds does methionine belong (1)

(c) The concentration of paracetamol in a solution can be determined by measuring how much UV radiation it absorbs

The graph shows how the absorbance of a sample containing 0middot040 g l ndash1 paracetamol varies with wavelength

The quantity of UV radiation of wavelength 245 nm absorbed is directly proportional to the concentration of paracetamolThe absorbance of a second sample of paracetamol solution measured at 245 nm was 0middot90 What is the concentration in g l ndash1 of this second paracetamol solution (1)

20 Many carbon compounds containing oxygen are very flammableThe table shows information about two families of isomersThe lowest temperature at which a compound will ignite is called its flash point

(a) A compound with the molecular formula C6H14O has a boiling point of 158 degC63

Draw a structural formula for this compound (1)

(b) For a family of isomers in the table write a general statement linking the flash points of the compounds to their structures (1)

21 Hydrogels are used in disposable nappies They are fine powders that can absorb up to 500 times their own weight in waterA hydrogel is a very long molecule with carboxyl groups at regular intervals along its length A short section of a hydrogel molecule is shown below

Hydrogels are extremely good at soaking up water because the water molecules are strongly attracted to them

Using your knowledge of chemistry comment on how suitable hydrogels would be for absorbing liquids or solutions spilled in a chemistry lab (1)

64

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

Why can compound A be described as a free radical scavenger in the reaction shown above

4 Hydrogen and chlorine gases are used in an experiment to demonstrate a free radical reaction A plastic bottle is wrapped with black tape leaving a ldquowindowrdquo on one sideThe bottle is filled with a mixture of hydrogen and chlorine When bright light shines on the bottle there is an explosion

A free radical chain reaction is initiated when light energy causes chlorine radicals to form as shown below

(a) Complete the equations below showing possible propagation and termination steps

(2)

54

(b) Why is the plastic bottle used in the experiment wrapped in black tape (1)

5 Chloramines can be removed from water using ultraviolet light treatment

One step in the process is the formation of free radicals

(a)State what is meant by the term free radical (1)

(b)Another step in the process is shown below

State the name for this type of step in a free radical reaction (1)

6 Modern shellac nail varnishes are more durable and so last longer than traditional nail polish

The shellac nail varnish is applied in thin layers to the nails and then the fingers are placed under a UV lamp

(a) The Skin Care Foundation has recommended that a sun-block is applied to the fingers and hand before using the lampSuggest why the Skin Care Foundation makes this recommendation (1)

(b) A free radical chain reaction takes place and the varnish hardens (i) State what is meant by the term free radical (1)

(ii) The shellac nail varnish contains a mixture of ingredients that take part in the free radical chain reactionOne of the steps in the free radical chain reaction is

55

State the term used to describe this type of step in a free radical chain reaction(1)

7 Skin care products contain a mixture of polar covalent non-polar covalent and ionic compounds The compounds need to stay mixed within the product Skin care products also need to spread easily and remain on the skin for a period of time as well as provide physical and chemical protection from the sun In order to do this skin care products contain a range of chemicals including water fats and oils antioxidants minerals and sun blockUsing your knowledge of chemistry explain the role of different chemicals in skin care products (3)

General Questions

1 A mixture of carbon monoxide and hydrogen can be converted into water and a mixture of hydrocarbons

nCO + (2n + 1)H2 rarr nH2O + hydrocarbons

What is the general formula for the hydrocarbons producedA CnH2nndash2B CnH2nC CnH2n+1D CnH2n+2

2 Butadiene is the first member of a homologous series of hydrocarbons called dienesWhat is the general formula for this seriesA CnHn+2B CnHn+3C CnH2nD CnH2nndash2

3 Which of the following statements about methanol is falseA It can be made from synthesis gasB It can be dehydrated to form an alkeneC It can be oxidised to give a carboxylic acidD It reacts with acidified potassium dichromate solution

56

4

Which line in the table correctly describes reactions X and Y

5

Which line in the table correctly describes reactions X and Y

6 Which of the following fuels when burned would make no contribution to globalwarming

57

A HydrogenB Natural gasC PetrolD Coal

7 Which of the following hydrocarbons always gives the same product when one of itshydrogen atoms is replaced by a chlorine atomA HexaneB Hex-1-eneC CyclohexaneD Cyclohexene

8 Which of the following compounds does not have isomeric structuresA C2HCl3B C2H4Cl2C PropeneD Propan-1-ol

9 What organic compound is produced by the dehydration of ethanol A EthaneB EtheneC EthanalD Ethanoic acid

10

The above equation representsA hydrationB hydrogenationC condensationD hydrolysis

11

Which of the following compounds is an isomer of the structure shown aboveA ButanalB ButanoneC Butan-1-olD Butanoic acid

58

12 A compound with molecular formula C6H12O2 could beA hexanalB hexan-2-olC hexan-2-oneD hexanoic acid

13 Propan-2-ol can be prepared from propane as follows

Which line in the table correctly describes the types of reaction taking place at Steps 1 and 2

14 Which of the following compounds would be the most water soluble

15 Cyanohydrin compounds can be made from carbonyl compounds by reacting the carbonyl compound with hydrogen cyanide (HCN)

59

Which carbonyl compound would react with hydrogen cyanide (HCN) to form the following compound

16 Ethyne is the first member of the homologous series called the alkynes

Ethyne can undergo addition reactions as shown in the flow diagram

(a) Compound 2 is an isomer of 12-dichloroethaneDraw a structural formula for compound 2 (1)

(b) Reagents A B and C are three different diatomic gasesUsing information in the flow diagram identify reagents A B and C (1)

60

Reagent Gas

A

B

C

17 In 1865 the German chemist Kekuleacute proposed a ring structure for benzene This structure was based on alternating single and double bonds

(a) (i) Describe a chemical test that would indicate that the above chemical structure for benzene is incorrect (1)

(ii) Briefly describe the correct structure for benzene (1)

(b) Benzene can be formed from cyclohexaneC6H12 rarr C6H6 + 3H2

What name is given to this type of reaction (1)18 Infra-red spectroscopy is a technique that can be used to identify the bonds that

arepresent in a molecule Different bonds absorb infra-red radiation of different wavenumbers This is due to differences in the bond lsquostretchrsquo These absorptions are recorded in a spectrumA spectrum for propan-1-ol is shown

61

The correlation table on page 13 of the data booklet shows the wavenumber ranges for the absorptions due to different bonds

(a) Use the correlation table to identify the bonds responsible for the two absorptions x and y that are circled in the propan-1-ol spectrum (1)

(b) Propan-1-ol reacts with ethanoic acid(i) What name is given to this type of reaction (1)(ii) Draw a spectrum that could be obtained for the organic product of this

reaction (1)

19 Paracetamol is a widely used painkiller

(a) Write the molecular formula for paracetamol (1)

(b) One antidote for paracetamol overdose is methionine

62

To what family of organic compounds does methionine belong (1)

(c) The concentration of paracetamol in a solution can be determined by measuring how much UV radiation it absorbs

The graph shows how the absorbance of a sample containing 0middot040 g l ndash1 paracetamol varies with wavelength

The quantity of UV radiation of wavelength 245 nm absorbed is directly proportional to the concentration of paracetamolThe absorbance of a second sample of paracetamol solution measured at 245 nm was 0middot90 What is the concentration in g l ndash1 of this second paracetamol solution (1)

20 Many carbon compounds containing oxygen are very flammableThe table shows information about two families of isomersThe lowest temperature at which a compound will ignite is called its flash point

(a) A compound with the molecular formula C6H14O has a boiling point of 158 degC63

Draw a structural formula for this compound (1)

(b) For a family of isomers in the table write a general statement linking the flash points of the compounds to their structures (1)

21 Hydrogels are used in disposable nappies They are fine powders that can absorb up to 500 times their own weight in waterA hydrogel is a very long molecule with carboxyl groups at regular intervals along its length A short section of a hydrogel molecule is shown below

Hydrogels are extremely good at soaking up water because the water molecules are strongly attracted to them

Using your knowledge of chemistry comment on how suitable hydrogels would be for absorbing liquids or solutions spilled in a chemistry lab (1)

64

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

(b) Why is the plastic bottle used in the experiment wrapped in black tape (1)

5 Chloramines can be removed from water using ultraviolet light treatment

One step in the process is the formation of free radicals

(a)State what is meant by the term free radical (1)

(b)Another step in the process is shown below

State the name for this type of step in a free radical reaction (1)

6 Modern shellac nail varnishes are more durable and so last longer than traditional nail polish

The shellac nail varnish is applied in thin layers to the nails and then the fingers are placed under a UV lamp

(a) The Skin Care Foundation has recommended that a sun-block is applied to the fingers and hand before using the lampSuggest why the Skin Care Foundation makes this recommendation (1)

(b) A free radical chain reaction takes place and the varnish hardens (i) State what is meant by the term free radical (1)

(ii) The shellac nail varnish contains a mixture of ingredients that take part in the free radical chain reactionOne of the steps in the free radical chain reaction is

55

State the term used to describe this type of step in a free radical chain reaction(1)

7 Skin care products contain a mixture of polar covalent non-polar covalent and ionic compounds The compounds need to stay mixed within the product Skin care products also need to spread easily and remain on the skin for a period of time as well as provide physical and chemical protection from the sun In order to do this skin care products contain a range of chemicals including water fats and oils antioxidants minerals and sun blockUsing your knowledge of chemistry explain the role of different chemicals in skin care products (3)

General Questions

1 A mixture of carbon monoxide and hydrogen can be converted into water and a mixture of hydrocarbons

nCO + (2n + 1)H2 rarr nH2O + hydrocarbons

What is the general formula for the hydrocarbons producedA CnH2nndash2B CnH2nC CnH2n+1D CnH2n+2

2 Butadiene is the first member of a homologous series of hydrocarbons called dienesWhat is the general formula for this seriesA CnHn+2B CnHn+3C CnH2nD CnH2nndash2

3 Which of the following statements about methanol is falseA It can be made from synthesis gasB It can be dehydrated to form an alkeneC It can be oxidised to give a carboxylic acidD It reacts with acidified potassium dichromate solution

56

4

Which line in the table correctly describes reactions X and Y

5

Which line in the table correctly describes reactions X and Y

6 Which of the following fuels when burned would make no contribution to globalwarming

57

A HydrogenB Natural gasC PetrolD Coal

7 Which of the following hydrocarbons always gives the same product when one of itshydrogen atoms is replaced by a chlorine atomA HexaneB Hex-1-eneC CyclohexaneD Cyclohexene

8 Which of the following compounds does not have isomeric structuresA C2HCl3B C2H4Cl2C PropeneD Propan-1-ol

9 What organic compound is produced by the dehydration of ethanol A EthaneB EtheneC EthanalD Ethanoic acid

10

The above equation representsA hydrationB hydrogenationC condensationD hydrolysis

11

Which of the following compounds is an isomer of the structure shown aboveA ButanalB ButanoneC Butan-1-olD Butanoic acid

58

12 A compound with molecular formula C6H12O2 could beA hexanalB hexan-2-olC hexan-2-oneD hexanoic acid

13 Propan-2-ol can be prepared from propane as follows

Which line in the table correctly describes the types of reaction taking place at Steps 1 and 2

14 Which of the following compounds would be the most water soluble

15 Cyanohydrin compounds can be made from carbonyl compounds by reacting the carbonyl compound with hydrogen cyanide (HCN)

59

Which carbonyl compound would react with hydrogen cyanide (HCN) to form the following compound

16 Ethyne is the first member of the homologous series called the alkynes

Ethyne can undergo addition reactions as shown in the flow diagram

(a) Compound 2 is an isomer of 12-dichloroethaneDraw a structural formula for compound 2 (1)

(b) Reagents A B and C are three different diatomic gasesUsing information in the flow diagram identify reagents A B and C (1)

60

Reagent Gas

A

B

C

17 In 1865 the German chemist Kekuleacute proposed a ring structure for benzene This structure was based on alternating single and double bonds

(a) (i) Describe a chemical test that would indicate that the above chemical structure for benzene is incorrect (1)

(ii) Briefly describe the correct structure for benzene (1)

(b) Benzene can be formed from cyclohexaneC6H12 rarr C6H6 + 3H2

What name is given to this type of reaction (1)18 Infra-red spectroscopy is a technique that can be used to identify the bonds that

arepresent in a molecule Different bonds absorb infra-red radiation of different wavenumbers This is due to differences in the bond lsquostretchrsquo These absorptions are recorded in a spectrumA spectrum for propan-1-ol is shown

61

The correlation table on page 13 of the data booklet shows the wavenumber ranges for the absorptions due to different bonds

(a) Use the correlation table to identify the bonds responsible for the two absorptions x and y that are circled in the propan-1-ol spectrum (1)

(b) Propan-1-ol reacts with ethanoic acid(i) What name is given to this type of reaction (1)(ii) Draw a spectrum that could be obtained for the organic product of this

reaction (1)

19 Paracetamol is a widely used painkiller

(a) Write the molecular formula for paracetamol (1)

(b) One antidote for paracetamol overdose is methionine

62

To what family of organic compounds does methionine belong (1)

(c) The concentration of paracetamol in a solution can be determined by measuring how much UV radiation it absorbs

The graph shows how the absorbance of a sample containing 0middot040 g l ndash1 paracetamol varies with wavelength

The quantity of UV radiation of wavelength 245 nm absorbed is directly proportional to the concentration of paracetamolThe absorbance of a second sample of paracetamol solution measured at 245 nm was 0middot90 What is the concentration in g l ndash1 of this second paracetamol solution (1)

20 Many carbon compounds containing oxygen are very flammableThe table shows information about two families of isomersThe lowest temperature at which a compound will ignite is called its flash point

(a) A compound with the molecular formula C6H14O has a boiling point of 158 degC63

Draw a structural formula for this compound (1)

(b) For a family of isomers in the table write a general statement linking the flash points of the compounds to their structures (1)

21 Hydrogels are used in disposable nappies They are fine powders that can absorb up to 500 times their own weight in waterA hydrogel is a very long molecule with carboxyl groups at regular intervals along its length A short section of a hydrogel molecule is shown below

Hydrogels are extremely good at soaking up water because the water molecules are strongly attracted to them

Using your knowledge of chemistry comment on how suitable hydrogels would be for absorbing liquids or solutions spilled in a chemistry lab (1)

64

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

State the term used to describe this type of step in a free radical chain reaction(1)

7 Skin care products contain a mixture of polar covalent non-polar covalent and ionic compounds The compounds need to stay mixed within the product Skin care products also need to spread easily and remain on the skin for a period of time as well as provide physical and chemical protection from the sun In order to do this skin care products contain a range of chemicals including water fats and oils antioxidants minerals and sun blockUsing your knowledge of chemistry explain the role of different chemicals in skin care products (3)

General Questions

1 A mixture of carbon monoxide and hydrogen can be converted into water and a mixture of hydrocarbons

nCO + (2n + 1)H2 rarr nH2O + hydrocarbons

What is the general formula for the hydrocarbons producedA CnH2nndash2B CnH2nC CnH2n+1D CnH2n+2

2 Butadiene is the first member of a homologous series of hydrocarbons called dienesWhat is the general formula for this seriesA CnHn+2B CnHn+3C CnH2nD CnH2nndash2

3 Which of the following statements about methanol is falseA It can be made from synthesis gasB It can be dehydrated to form an alkeneC It can be oxidised to give a carboxylic acidD It reacts with acidified potassium dichromate solution

56

4

Which line in the table correctly describes reactions X and Y

5

Which line in the table correctly describes reactions X and Y

6 Which of the following fuels when burned would make no contribution to globalwarming

57

A HydrogenB Natural gasC PetrolD Coal

7 Which of the following hydrocarbons always gives the same product when one of itshydrogen atoms is replaced by a chlorine atomA HexaneB Hex-1-eneC CyclohexaneD Cyclohexene

8 Which of the following compounds does not have isomeric structuresA C2HCl3B C2H4Cl2C PropeneD Propan-1-ol

9 What organic compound is produced by the dehydration of ethanol A EthaneB EtheneC EthanalD Ethanoic acid

10

The above equation representsA hydrationB hydrogenationC condensationD hydrolysis

11

Which of the following compounds is an isomer of the structure shown aboveA ButanalB ButanoneC Butan-1-olD Butanoic acid

58

12 A compound with molecular formula C6H12O2 could beA hexanalB hexan-2-olC hexan-2-oneD hexanoic acid

13 Propan-2-ol can be prepared from propane as follows

Which line in the table correctly describes the types of reaction taking place at Steps 1 and 2

14 Which of the following compounds would be the most water soluble

15 Cyanohydrin compounds can be made from carbonyl compounds by reacting the carbonyl compound with hydrogen cyanide (HCN)

59

Which carbonyl compound would react with hydrogen cyanide (HCN) to form the following compound

16 Ethyne is the first member of the homologous series called the alkynes

Ethyne can undergo addition reactions as shown in the flow diagram

(a) Compound 2 is an isomer of 12-dichloroethaneDraw a structural formula for compound 2 (1)

(b) Reagents A B and C are three different diatomic gasesUsing information in the flow diagram identify reagents A B and C (1)

60

Reagent Gas

A

B

C

17 In 1865 the German chemist Kekuleacute proposed a ring structure for benzene This structure was based on alternating single and double bonds

(a) (i) Describe a chemical test that would indicate that the above chemical structure for benzene is incorrect (1)

(ii) Briefly describe the correct structure for benzene (1)

(b) Benzene can be formed from cyclohexaneC6H12 rarr C6H6 + 3H2

What name is given to this type of reaction (1)18 Infra-red spectroscopy is a technique that can be used to identify the bonds that

arepresent in a molecule Different bonds absorb infra-red radiation of different wavenumbers This is due to differences in the bond lsquostretchrsquo These absorptions are recorded in a spectrumA spectrum for propan-1-ol is shown

61

The correlation table on page 13 of the data booklet shows the wavenumber ranges for the absorptions due to different bonds

(a) Use the correlation table to identify the bonds responsible for the two absorptions x and y that are circled in the propan-1-ol spectrum (1)

(b) Propan-1-ol reacts with ethanoic acid(i) What name is given to this type of reaction (1)(ii) Draw a spectrum that could be obtained for the organic product of this

reaction (1)

19 Paracetamol is a widely used painkiller

(a) Write the molecular formula for paracetamol (1)

(b) One antidote for paracetamol overdose is methionine

62

To what family of organic compounds does methionine belong (1)

(c) The concentration of paracetamol in a solution can be determined by measuring how much UV radiation it absorbs

The graph shows how the absorbance of a sample containing 0middot040 g l ndash1 paracetamol varies with wavelength

The quantity of UV radiation of wavelength 245 nm absorbed is directly proportional to the concentration of paracetamolThe absorbance of a second sample of paracetamol solution measured at 245 nm was 0middot90 What is the concentration in g l ndash1 of this second paracetamol solution (1)

20 Many carbon compounds containing oxygen are very flammableThe table shows information about two families of isomersThe lowest temperature at which a compound will ignite is called its flash point

(a) A compound with the molecular formula C6H14O has a boiling point of 158 degC63

Draw a structural formula for this compound (1)

(b) For a family of isomers in the table write a general statement linking the flash points of the compounds to their structures (1)

21 Hydrogels are used in disposable nappies They are fine powders that can absorb up to 500 times their own weight in waterA hydrogel is a very long molecule with carboxyl groups at regular intervals along its length A short section of a hydrogel molecule is shown below

Hydrogels are extremely good at soaking up water because the water molecules are strongly attracted to them

Using your knowledge of chemistry comment on how suitable hydrogels would be for absorbing liquids or solutions spilled in a chemistry lab (1)

64

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

4

Which line in the table correctly describes reactions X and Y

5

Which line in the table correctly describes reactions X and Y

6 Which of the following fuels when burned would make no contribution to globalwarming

57

A HydrogenB Natural gasC PetrolD Coal

7 Which of the following hydrocarbons always gives the same product when one of itshydrogen atoms is replaced by a chlorine atomA HexaneB Hex-1-eneC CyclohexaneD Cyclohexene

8 Which of the following compounds does not have isomeric structuresA C2HCl3B C2H4Cl2C PropeneD Propan-1-ol

9 What organic compound is produced by the dehydration of ethanol A EthaneB EtheneC EthanalD Ethanoic acid

10

The above equation representsA hydrationB hydrogenationC condensationD hydrolysis

11

Which of the following compounds is an isomer of the structure shown aboveA ButanalB ButanoneC Butan-1-olD Butanoic acid

58

12 A compound with molecular formula C6H12O2 could beA hexanalB hexan-2-olC hexan-2-oneD hexanoic acid

13 Propan-2-ol can be prepared from propane as follows

Which line in the table correctly describes the types of reaction taking place at Steps 1 and 2

14 Which of the following compounds would be the most water soluble

15 Cyanohydrin compounds can be made from carbonyl compounds by reacting the carbonyl compound with hydrogen cyanide (HCN)

59

Which carbonyl compound would react with hydrogen cyanide (HCN) to form the following compound

16 Ethyne is the first member of the homologous series called the alkynes

Ethyne can undergo addition reactions as shown in the flow diagram

(a) Compound 2 is an isomer of 12-dichloroethaneDraw a structural formula for compound 2 (1)

(b) Reagents A B and C are three different diatomic gasesUsing information in the flow diagram identify reagents A B and C (1)

60

Reagent Gas

A

B

C

17 In 1865 the German chemist Kekuleacute proposed a ring structure for benzene This structure was based on alternating single and double bonds

(a) (i) Describe a chemical test that would indicate that the above chemical structure for benzene is incorrect (1)

(ii) Briefly describe the correct structure for benzene (1)

(b) Benzene can be formed from cyclohexaneC6H12 rarr C6H6 + 3H2

What name is given to this type of reaction (1)18 Infra-red spectroscopy is a technique that can be used to identify the bonds that

arepresent in a molecule Different bonds absorb infra-red radiation of different wavenumbers This is due to differences in the bond lsquostretchrsquo These absorptions are recorded in a spectrumA spectrum for propan-1-ol is shown

61

The correlation table on page 13 of the data booklet shows the wavenumber ranges for the absorptions due to different bonds

(a) Use the correlation table to identify the bonds responsible for the two absorptions x and y that are circled in the propan-1-ol spectrum (1)

(b) Propan-1-ol reacts with ethanoic acid(i) What name is given to this type of reaction (1)(ii) Draw a spectrum that could be obtained for the organic product of this

reaction (1)

19 Paracetamol is a widely used painkiller

(a) Write the molecular formula for paracetamol (1)

(b) One antidote for paracetamol overdose is methionine

62

To what family of organic compounds does methionine belong (1)

(c) The concentration of paracetamol in a solution can be determined by measuring how much UV radiation it absorbs

The graph shows how the absorbance of a sample containing 0middot040 g l ndash1 paracetamol varies with wavelength

The quantity of UV radiation of wavelength 245 nm absorbed is directly proportional to the concentration of paracetamolThe absorbance of a second sample of paracetamol solution measured at 245 nm was 0middot90 What is the concentration in g l ndash1 of this second paracetamol solution (1)

20 Many carbon compounds containing oxygen are very flammableThe table shows information about two families of isomersThe lowest temperature at which a compound will ignite is called its flash point

(a) A compound with the molecular formula C6H14O has a boiling point of 158 degC63

Draw a structural formula for this compound (1)

(b) For a family of isomers in the table write a general statement linking the flash points of the compounds to their structures (1)

21 Hydrogels are used in disposable nappies They are fine powders that can absorb up to 500 times their own weight in waterA hydrogel is a very long molecule with carboxyl groups at regular intervals along its length A short section of a hydrogel molecule is shown below

Hydrogels are extremely good at soaking up water because the water molecules are strongly attracted to them

Using your knowledge of chemistry comment on how suitable hydrogels would be for absorbing liquids or solutions spilled in a chemistry lab (1)

64

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

A HydrogenB Natural gasC PetrolD Coal

7 Which of the following hydrocarbons always gives the same product when one of itshydrogen atoms is replaced by a chlorine atomA HexaneB Hex-1-eneC CyclohexaneD Cyclohexene

8 Which of the following compounds does not have isomeric structuresA C2HCl3B C2H4Cl2C PropeneD Propan-1-ol

9 What organic compound is produced by the dehydration of ethanol A EthaneB EtheneC EthanalD Ethanoic acid

10

The above equation representsA hydrationB hydrogenationC condensationD hydrolysis

11

Which of the following compounds is an isomer of the structure shown aboveA ButanalB ButanoneC Butan-1-olD Butanoic acid

58

12 A compound with molecular formula C6H12O2 could beA hexanalB hexan-2-olC hexan-2-oneD hexanoic acid

13 Propan-2-ol can be prepared from propane as follows

Which line in the table correctly describes the types of reaction taking place at Steps 1 and 2

14 Which of the following compounds would be the most water soluble

15 Cyanohydrin compounds can be made from carbonyl compounds by reacting the carbonyl compound with hydrogen cyanide (HCN)

59

Which carbonyl compound would react with hydrogen cyanide (HCN) to form the following compound

16 Ethyne is the first member of the homologous series called the alkynes

Ethyne can undergo addition reactions as shown in the flow diagram

(a) Compound 2 is an isomer of 12-dichloroethaneDraw a structural formula for compound 2 (1)

(b) Reagents A B and C are three different diatomic gasesUsing information in the flow diagram identify reagents A B and C (1)

60

Reagent Gas

A

B

C

17 In 1865 the German chemist Kekuleacute proposed a ring structure for benzene This structure was based on alternating single and double bonds

(a) (i) Describe a chemical test that would indicate that the above chemical structure for benzene is incorrect (1)

(ii) Briefly describe the correct structure for benzene (1)

(b) Benzene can be formed from cyclohexaneC6H12 rarr C6H6 + 3H2

What name is given to this type of reaction (1)18 Infra-red spectroscopy is a technique that can be used to identify the bonds that

arepresent in a molecule Different bonds absorb infra-red radiation of different wavenumbers This is due to differences in the bond lsquostretchrsquo These absorptions are recorded in a spectrumA spectrum for propan-1-ol is shown

61

The correlation table on page 13 of the data booklet shows the wavenumber ranges for the absorptions due to different bonds

(a) Use the correlation table to identify the bonds responsible for the two absorptions x and y that are circled in the propan-1-ol spectrum (1)

(b) Propan-1-ol reacts with ethanoic acid(i) What name is given to this type of reaction (1)(ii) Draw a spectrum that could be obtained for the organic product of this

reaction (1)

19 Paracetamol is a widely used painkiller

(a) Write the molecular formula for paracetamol (1)

(b) One antidote for paracetamol overdose is methionine

62

To what family of organic compounds does methionine belong (1)

(c) The concentration of paracetamol in a solution can be determined by measuring how much UV radiation it absorbs

The graph shows how the absorbance of a sample containing 0middot040 g l ndash1 paracetamol varies with wavelength

The quantity of UV radiation of wavelength 245 nm absorbed is directly proportional to the concentration of paracetamolThe absorbance of a second sample of paracetamol solution measured at 245 nm was 0middot90 What is the concentration in g l ndash1 of this second paracetamol solution (1)

20 Many carbon compounds containing oxygen are very flammableThe table shows information about two families of isomersThe lowest temperature at which a compound will ignite is called its flash point

(a) A compound with the molecular formula C6H14O has a boiling point of 158 degC63

Draw a structural formula for this compound (1)

(b) For a family of isomers in the table write a general statement linking the flash points of the compounds to their structures (1)

21 Hydrogels are used in disposable nappies They are fine powders that can absorb up to 500 times their own weight in waterA hydrogel is a very long molecule with carboxyl groups at regular intervals along its length A short section of a hydrogel molecule is shown below

Hydrogels are extremely good at soaking up water because the water molecules are strongly attracted to them

Using your knowledge of chemistry comment on how suitable hydrogels would be for absorbing liquids or solutions spilled in a chemistry lab (1)

64

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

12 A compound with molecular formula C6H12O2 could beA hexanalB hexan-2-olC hexan-2-oneD hexanoic acid

13 Propan-2-ol can be prepared from propane as follows

Which line in the table correctly describes the types of reaction taking place at Steps 1 and 2

14 Which of the following compounds would be the most water soluble

15 Cyanohydrin compounds can be made from carbonyl compounds by reacting the carbonyl compound with hydrogen cyanide (HCN)

59

Which carbonyl compound would react with hydrogen cyanide (HCN) to form the following compound

16 Ethyne is the first member of the homologous series called the alkynes

Ethyne can undergo addition reactions as shown in the flow diagram

(a) Compound 2 is an isomer of 12-dichloroethaneDraw a structural formula for compound 2 (1)

(b) Reagents A B and C are three different diatomic gasesUsing information in the flow diagram identify reagents A B and C (1)

60

Reagent Gas

A

B

C

17 In 1865 the German chemist Kekuleacute proposed a ring structure for benzene This structure was based on alternating single and double bonds

(a) (i) Describe a chemical test that would indicate that the above chemical structure for benzene is incorrect (1)

(ii) Briefly describe the correct structure for benzene (1)

(b) Benzene can be formed from cyclohexaneC6H12 rarr C6H6 + 3H2

What name is given to this type of reaction (1)18 Infra-red spectroscopy is a technique that can be used to identify the bonds that

arepresent in a molecule Different bonds absorb infra-red radiation of different wavenumbers This is due to differences in the bond lsquostretchrsquo These absorptions are recorded in a spectrumA spectrum for propan-1-ol is shown

61

The correlation table on page 13 of the data booklet shows the wavenumber ranges for the absorptions due to different bonds

(a) Use the correlation table to identify the bonds responsible for the two absorptions x and y that are circled in the propan-1-ol spectrum (1)

(b) Propan-1-ol reacts with ethanoic acid(i) What name is given to this type of reaction (1)(ii) Draw a spectrum that could be obtained for the organic product of this

reaction (1)

19 Paracetamol is a widely used painkiller

(a) Write the molecular formula for paracetamol (1)

(b) One antidote for paracetamol overdose is methionine

62

To what family of organic compounds does methionine belong (1)

(c) The concentration of paracetamol in a solution can be determined by measuring how much UV radiation it absorbs

The graph shows how the absorbance of a sample containing 0middot040 g l ndash1 paracetamol varies with wavelength

The quantity of UV radiation of wavelength 245 nm absorbed is directly proportional to the concentration of paracetamolThe absorbance of a second sample of paracetamol solution measured at 245 nm was 0middot90 What is the concentration in g l ndash1 of this second paracetamol solution (1)

20 Many carbon compounds containing oxygen are very flammableThe table shows information about two families of isomersThe lowest temperature at which a compound will ignite is called its flash point

(a) A compound with the molecular formula C6H14O has a boiling point of 158 degC63

Draw a structural formula for this compound (1)

(b) For a family of isomers in the table write a general statement linking the flash points of the compounds to their structures (1)

21 Hydrogels are used in disposable nappies They are fine powders that can absorb up to 500 times their own weight in waterA hydrogel is a very long molecule with carboxyl groups at regular intervals along its length A short section of a hydrogel molecule is shown below

Hydrogels are extremely good at soaking up water because the water molecules are strongly attracted to them

Using your knowledge of chemistry comment on how suitable hydrogels would be for absorbing liquids or solutions spilled in a chemistry lab (1)

64

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

Which carbonyl compound would react with hydrogen cyanide (HCN) to form the following compound

16 Ethyne is the first member of the homologous series called the alkynes

Ethyne can undergo addition reactions as shown in the flow diagram

(a) Compound 2 is an isomer of 12-dichloroethaneDraw a structural formula for compound 2 (1)

(b) Reagents A B and C are three different diatomic gasesUsing information in the flow diagram identify reagents A B and C (1)

60

Reagent Gas

A

B

C

17 In 1865 the German chemist Kekuleacute proposed a ring structure for benzene This structure was based on alternating single and double bonds

(a) (i) Describe a chemical test that would indicate that the above chemical structure for benzene is incorrect (1)

(ii) Briefly describe the correct structure for benzene (1)

(b) Benzene can be formed from cyclohexaneC6H12 rarr C6H6 + 3H2

What name is given to this type of reaction (1)18 Infra-red spectroscopy is a technique that can be used to identify the bonds that

arepresent in a molecule Different bonds absorb infra-red radiation of different wavenumbers This is due to differences in the bond lsquostretchrsquo These absorptions are recorded in a spectrumA spectrum for propan-1-ol is shown

61

The correlation table on page 13 of the data booklet shows the wavenumber ranges for the absorptions due to different bonds

(a) Use the correlation table to identify the bonds responsible for the two absorptions x and y that are circled in the propan-1-ol spectrum (1)

(b) Propan-1-ol reacts with ethanoic acid(i) What name is given to this type of reaction (1)(ii) Draw a spectrum that could be obtained for the organic product of this

reaction (1)

19 Paracetamol is a widely used painkiller

(a) Write the molecular formula for paracetamol (1)

(b) One antidote for paracetamol overdose is methionine

62

To what family of organic compounds does methionine belong (1)

(c) The concentration of paracetamol in a solution can be determined by measuring how much UV radiation it absorbs

The graph shows how the absorbance of a sample containing 0middot040 g l ndash1 paracetamol varies with wavelength

The quantity of UV radiation of wavelength 245 nm absorbed is directly proportional to the concentration of paracetamolThe absorbance of a second sample of paracetamol solution measured at 245 nm was 0middot90 What is the concentration in g l ndash1 of this second paracetamol solution (1)

20 Many carbon compounds containing oxygen are very flammableThe table shows information about two families of isomersThe lowest temperature at which a compound will ignite is called its flash point

(a) A compound with the molecular formula C6H14O has a boiling point of 158 degC63

Draw a structural formula for this compound (1)

(b) For a family of isomers in the table write a general statement linking the flash points of the compounds to their structures (1)

21 Hydrogels are used in disposable nappies They are fine powders that can absorb up to 500 times their own weight in waterA hydrogel is a very long molecule with carboxyl groups at regular intervals along its length A short section of a hydrogel molecule is shown below

Hydrogels are extremely good at soaking up water because the water molecules are strongly attracted to them

Using your knowledge of chemistry comment on how suitable hydrogels would be for absorbing liquids or solutions spilled in a chemistry lab (1)

64

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

Reagent Gas

A

B

C

17 In 1865 the German chemist Kekuleacute proposed a ring structure for benzene This structure was based on alternating single and double bonds

(a) (i) Describe a chemical test that would indicate that the above chemical structure for benzene is incorrect (1)

(ii) Briefly describe the correct structure for benzene (1)

(b) Benzene can be formed from cyclohexaneC6H12 rarr C6H6 + 3H2

What name is given to this type of reaction (1)18 Infra-red spectroscopy is a technique that can be used to identify the bonds that

arepresent in a molecule Different bonds absorb infra-red radiation of different wavenumbers This is due to differences in the bond lsquostretchrsquo These absorptions are recorded in a spectrumA spectrum for propan-1-ol is shown

61

The correlation table on page 13 of the data booklet shows the wavenumber ranges for the absorptions due to different bonds

(a) Use the correlation table to identify the bonds responsible for the two absorptions x and y that are circled in the propan-1-ol spectrum (1)

(b) Propan-1-ol reacts with ethanoic acid(i) What name is given to this type of reaction (1)(ii) Draw a spectrum that could be obtained for the organic product of this

reaction (1)

19 Paracetamol is a widely used painkiller

(a) Write the molecular formula for paracetamol (1)

(b) One antidote for paracetamol overdose is methionine

62

To what family of organic compounds does methionine belong (1)

(c) The concentration of paracetamol in a solution can be determined by measuring how much UV radiation it absorbs

The graph shows how the absorbance of a sample containing 0middot040 g l ndash1 paracetamol varies with wavelength

The quantity of UV radiation of wavelength 245 nm absorbed is directly proportional to the concentration of paracetamolThe absorbance of a second sample of paracetamol solution measured at 245 nm was 0middot90 What is the concentration in g l ndash1 of this second paracetamol solution (1)

20 Many carbon compounds containing oxygen are very flammableThe table shows information about two families of isomersThe lowest temperature at which a compound will ignite is called its flash point

(a) A compound with the molecular formula C6H14O has a boiling point of 158 degC63

Draw a structural formula for this compound (1)

(b) For a family of isomers in the table write a general statement linking the flash points of the compounds to their structures (1)

21 Hydrogels are used in disposable nappies They are fine powders that can absorb up to 500 times their own weight in waterA hydrogel is a very long molecule with carboxyl groups at regular intervals along its length A short section of a hydrogel molecule is shown below

Hydrogels are extremely good at soaking up water because the water molecules are strongly attracted to them

Using your knowledge of chemistry comment on how suitable hydrogels would be for absorbing liquids or solutions spilled in a chemistry lab (1)

64

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

The correlation table on page 13 of the data booklet shows the wavenumber ranges for the absorptions due to different bonds

(a) Use the correlation table to identify the bonds responsible for the two absorptions x and y that are circled in the propan-1-ol spectrum (1)

(b) Propan-1-ol reacts with ethanoic acid(i) What name is given to this type of reaction (1)(ii) Draw a spectrum that could be obtained for the organic product of this

reaction (1)

19 Paracetamol is a widely used painkiller

(a) Write the molecular formula for paracetamol (1)

(b) One antidote for paracetamol overdose is methionine

62

To what family of organic compounds does methionine belong (1)

(c) The concentration of paracetamol in a solution can be determined by measuring how much UV radiation it absorbs

The graph shows how the absorbance of a sample containing 0middot040 g l ndash1 paracetamol varies with wavelength

The quantity of UV radiation of wavelength 245 nm absorbed is directly proportional to the concentration of paracetamolThe absorbance of a second sample of paracetamol solution measured at 245 nm was 0middot90 What is the concentration in g l ndash1 of this second paracetamol solution (1)

20 Many carbon compounds containing oxygen are very flammableThe table shows information about two families of isomersThe lowest temperature at which a compound will ignite is called its flash point

(a) A compound with the molecular formula C6H14O has a boiling point of 158 degC63

Draw a structural formula for this compound (1)

(b) For a family of isomers in the table write a general statement linking the flash points of the compounds to their structures (1)

21 Hydrogels are used in disposable nappies They are fine powders that can absorb up to 500 times their own weight in waterA hydrogel is a very long molecule with carboxyl groups at regular intervals along its length A short section of a hydrogel molecule is shown below

Hydrogels are extremely good at soaking up water because the water molecules are strongly attracted to them

Using your knowledge of chemistry comment on how suitable hydrogels would be for absorbing liquids or solutions spilled in a chemistry lab (1)

64

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

To what family of organic compounds does methionine belong (1)

(c) The concentration of paracetamol in a solution can be determined by measuring how much UV radiation it absorbs

The graph shows how the absorbance of a sample containing 0middot040 g l ndash1 paracetamol varies with wavelength

The quantity of UV radiation of wavelength 245 nm absorbed is directly proportional to the concentration of paracetamolThe absorbance of a second sample of paracetamol solution measured at 245 nm was 0middot90 What is the concentration in g l ndash1 of this second paracetamol solution (1)

20 Many carbon compounds containing oxygen are very flammableThe table shows information about two families of isomersThe lowest temperature at which a compound will ignite is called its flash point

(a) A compound with the molecular formula C6H14O has a boiling point of 158 degC63

Draw a structural formula for this compound (1)

(b) For a family of isomers in the table write a general statement linking the flash points of the compounds to their structures (1)

21 Hydrogels are used in disposable nappies They are fine powders that can absorb up to 500 times their own weight in waterA hydrogel is a very long molecule with carboxyl groups at regular intervals along its length A short section of a hydrogel molecule is shown below

Hydrogels are extremely good at soaking up water because the water molecules are strongly attracted to them

Using your knowledge of chemistry comment on how suitable hydrogels would be for absorbing liquids or solutions spilled in a chemistry lab (1)

64

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

Draw a structural formula for this compound (1)

(b) For a family of isomers in the table write a general statement linking the flash points of the compounds to their structures (1)

21 Hydrogels are used in disposable nappies They are fine powders that can absorb up to 500 times their own weight in waterA hydrogel is a very long molecule with carboxyl groups at regular intervals along its length A short section of a hydrogel molecule is shown below

Hydrogels are extremely good at soaking up water because the water molecules are strongly attracted to them

Using your knowledge of chemistry comment on how suitable hydrogels would be for absorbing liquids or solutions spilled in a chemistry lab (1)

64

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

22 Dental anaesthetics are substances used to reduce discomfort during treatment

(a) Lidocaine is a dental anaesthetic

Lidocaine causes numbness when applied to the gums This effect wears off as the lidocaine is hydrolysedOne of the products of the hydrolysis of lidocaine is compound C

(i) Name the functional group circled above (1)

(ii) Draw a structural formula for the other compound produced when lidocaine is hydrolysed (1)

(iii) Draw a structural formula for the organic compound formed when compound C reacts with NaOH(aq) (1)

(b) The table below shows the duration of numbness for common anaesthetics

65

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

Estimate the duration of numbness in minutes for anaesthetic X (1)(c) The maximum safe dose of lidocaine for an adult is 4middot5 mg of lidocaine per kgof body mass 1middot0 cm3 of lidocaine solution contains 10 mg of lidocaine Calculate the maximum volume of lidocaine solution that could be given to a 70 kg adult Show your working clearly (3)

23 Soft drinks contain many ingredients Aspartame is added to many soft drinks as a sweetener Its structure is shown below

(a) Name the functional group circled (1)

66

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

(b) In the stomach aspartame is hydrolysed by acid to produce methanol and two amino acids phenylalanine and aspartic acid

Two of the products of the hydrolysis of aspartame are shown below

Draw a structural formula for aspartic acid (1)

(c) The body cannot make all the amino acids it requires and is dependent on protein in the diet for the supply of certain amino acids

What term is used to describe the amino acids the body cannot make (1)

24 Cycloalkanes are found in nature A representation of cyclohexane is shown below

The six hydrogen atoms marked in bold are said to be in axial positions In the molecule of 12-dimethylcyclohexane shown below two methyl groups are in axial positions

67

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

(a) Complete the structure shown below to show a molecule of 13-dimethylcyclohexane in which both the methyl groups are in axial positions (1)

68

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

(b) Axial groups on the same side of a cyclohexane ring can repel each otherThe strength of the repulsion is known as the ldquosteric strainrdquoThe table below shows values which allow the steric strain to be calculated

For example

(i) Write a general statement linking the size of the steric strain to the type of axial group present (1)

(ii) Calculate in kJ molminus1 the steric strain for the molecule shown below (1)

69

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

25 The table shows the boiling points and structures of some isomers with molecular formula C6H12O2

70

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71

(a) Name the intermolecular force which accounts for the higher boiling points of isomers 1 2 and 3 (1)

(b) Using the information in the table describe two ways in which differences in structure affect the boiling points of isomeric esters 4ndash8 (2)

(c) Predict the boiling point in ordmC for the isomer shown below (1)

71