1. The Born-Haber cycle for the formation of sodium chloride from sodium and chlorine may be

represented by a series of stages labelled A to F as shown.

Na (g) + Cl(g) + e

Na (g) + Cl (g) + e

Na(g) + Cl (g)

Na(s) + Cl (g)

+

+

+ 2

2

212

12

12

A

B

C

D

F

E

Na (g) + Cl (g)

NaCl(s)

(a) (i) Write the letters A to F next to the corresponding definition in the table below

definition letter H/kJ mol1

1st ionisation energy of

sodium

+494

1st electron affinity of

chlorine

364

the enthalpy of atomisation

of sodium

+109

the enthalpy of atomisation

of chlorine

+121

the lattice enthalpy of

sodium chloride

770

the enthalpy of formation of

sodium chloride

(3)

(ii) Calculate the enthalpy of formation of sodium chloride from the data given.

(2)

(b) The lattice enthalpies can be calculated from theory as well as determined experimentally.

Experimental

H/kJ mol1

Theoretical

H/kJ mol1

Sodium chloride 770 766

Silver iodide 889 778

Why is the experimental value of the lattice enthalpy of silver iodide (889kJmol1) so different from the value calculated theoretically?

...................................................................................................................................

...................................................................................................................................

................................................................................................................................... (2)

(c) Explain the trend in first ionisation energies of the elements of Group 1 in the Periodic

Table.

...................................................................................................................................

...................................................................................................................................

................................................................................................................................... (3)

(Total 10 marks)

2. Adrenalin is a hormone which raises blood pressure, increases the depth of breathing and delays

fatigue in muscles, thus allowing people to show great strength under stress.

Benzedrine is a pharmaceutical which stimulates the central nervous system in a similar manner

to adrenalin.

CH CH(CH ) NH2 2 2 33

HO

HO CH(OH) CH N

H

CH

Benzedrine Adrenalin

(a) (i) On the structure for benzedrine mark with a (*) any asymmetric carbon atom that

causes chirality. (1)

(ii) Suggest why adrenalin is more soluble in water than is benzedrine.

..........................................................................................................................

..........................................................................................................................

.......................................................................................................................... (2)

(b) Give the structural formulae of the organic products obtained when benzedrine reacts

with:

(i) an aqueous acid such as dilute hydrochloric acid;

(1)

(ii) ethanoyl chloride in the absence of a catalyst;

(1)

(iii) excess ethanoyl chloride in the presence of the catalyst anhydrous aluminium

chloride.

(2)

(d) It is possible to eliminate a molecule of water from adrenalin which for the purpose of

this question may be represented as RCH(OH)CH2NHCH3. Draw the structural

formulae of the two stereoisomers produced.

(2)

(e) The mass spectra of both benzedrine and adrenalin have a peak at a mass/charge ratio of

44. Draw the structure of the species which give these peaks.

(i) in benzedrine;

(1)

(ii) in adrenalin.

(1)

(Total 11 marks)

3. (a) (i) Define the terms:

atomic number ...............................................................................................

......................................................................................................................

mass number .................................................................................................

...................................................................................................................... (2)

(ii) Identify the particle which contains 11 protons, 12 neutrons and 10 electrons.

...................................................................................................................... (1)

(b) Bromine consists of two isotopes, mass numbers 79 and 81. A sample of bromine gas,

Br2, was examined in a mass spectrometer. The mass spectrum showing the molecular

ions is given below.

100

50

Relativeintensity

158 160 162

m/e

(i) Identify the species responsible for the peak at m/e = 160.

...................................................................................................................... (1)

(ii) Deduce the relative abundances of the two isotopes,

(2)

(c) Define the term first electron affinity for bromine atoms, illustrating your answer with

an equation.

................................................................................................................................

................................................................................................................................

................................................................................................................................

................................................................................................................................ (3)

(d) The graph showing the variation of the first ionisation energies of the elements neon to

potassium is given below.

2500

2000

1500

1000

500

0

Firstionisationenergy/kJ mol

1

Ne Na Mg Al Si P S Cl Ar K

(i) Define the term first ionisation energy with reference to neon.

......................................................................................................................

......................................................................................................................

...................................................................................................................... (2)

(ii) Explain the general trend in the first ionisation energies of the elements sodium to

argon.

......................................................................................................................

......................................................................................................................

...................................................................................................................... (2)

(iii) Explain why the first ionisation energy of neon is greater than the first ionisation

energy of argon.

......................................................................................................................

......................................................................................................................

...................................................................................................................... (2)

(Total 15 marks)

4. Hydrogen forms compounds with most non-metallic elements and with some metals.

(a) Calculate the empirical formula of the compound used in the manufacture of artificial

rubber which has the following composition by mass.

Hydrogen 11.1% Carbon 88.9%

(3)

(b) The boiling temperatures of hydrogen chloride and hydrogen iodide are:

Hydrogen chloride 85C

Hydrogen iodide 35C

Explain why hydrogen iodide has a higher boiling temperature than hydrogen chloride.

................................................................................................................................

................................................................................................................................

................................................................................................................................ (2)

(c) Draw and explain the shapes of:

(i) the PH3 molecule;

......................................................................................................................

...................................................................................................................... (2)

(ii) the AlH4 ion.

......................................................................................................................

...................................................................................................................... (2)

(d) Calculate the number of molecules in 8.0 cm3 of gaseous phosphine, PH3, at room

temperature and pressure.

(The molar volume of a gas at room temperature and pressure should be taken as 2.4

104 cm

3 mol

1. The Avogadro constant is 6.0 10

23 mol

1.)

(2)

(Total 11 marks)

5. (a) Define:

(i) the standard enthalpy of formation of benzene, C6H6(l);

......................................................................................................................

......................................................................................................................

...................................................................................................................... (2)

(ii) the standard enthalpy of combustion of benzene, C6H6(l).

......................................................................................................................

......................................................................................................................

...................................................................................................................... (2)

(b) Calculate the standard enthalpy of formation of benzene, C6H6(l), using the following

enthalpy of combustion data:

Substance Hc /kJ mol1

C6H6(l) 3273

H2(g) 286

C(s) 394

(3)

(c) If the standard enthalpy of formation is calculated from average bond enthalpy data

assuming that benzene has three C==C and three CC bonds, its value is found to be

+215 kJ mol1

.

Explain, with reference to the structure and stability of benzene, why this value differs

from that calculated in (b). Use an enthalpy level diagram to illustrate your answer.

................................................................................................................................

................................................................................................................................

................................................................................................................................ (4)

(d) Benzene reacts with bromine when gently warmed in the presence of a catalyst of

anhydrous iron(III) bromide.

(i) The reaction is first order with respect to benzene and first order with respect to

bromine. Write the rate equation for the reaction.

...................................................................................................................... (1)

(ii) The mechanism of this reaction involves an attack by Br+ followed by loss of H

+.

+

+

+

+

Br

H

H

Br

Br

Br+H

Step 1.

Step 2.

Deuterium, symbol D, is an isotope of hydrogen, and the CD bond is slightly stronger than the CH bond. If step 2 were the rate-determining (slower) step, suggest how the rate of this reaction would alter if deuterated benzene, C6D6, were

used instead of ordinary benzene, C6H6, and explain your answer.

......................................................................................................................

......................................................................................................................

...................................................................................................................... (2)

(Total 14 marks)

6. (a) Iron has several isotopes. One of them has the electronic configuration [Ar]3d64s

2 , an

atomic number of 26 and a mass number of 56.

(i) Which of these pieces of information would be the most use in helping a chemist

decide on the likely chemical reactions of iron?

............................................................................................................................

............................................................................................................................ (1)

(ii) State how many of each of the following particles is found in an atom of 56

Fe.

Protons ................ electrons ................ neutrons ................ (2)

(iii) What are isotopes?

............................................................................................................................

............................................................................................................................ (2)

(b) The relative atomic mass of a sample of iron may be found by using a mass spectrometer

to determine the isotopic composition.

(i) The diagram below represents a low-resolution mass spectrometer in which four

areas have been identified. State what happens in each of these areas.

(+)Sample

B

CA

D

To vacuum pump

Area A ..............................................................................................................

Area B ..............................................................................................................

Area C ..............................................................................................................

Area D .............................................................................................................. (4)

(ii) In such a determination the following isotopic composition was found.

Isotope Percentage composition

54Fe 5.8

56Fe 91.6

57Fe 2.2

58Fe 0.33

Calculate the relative atomic mass of this sample of iron, giving your answer to two

decimal places.

(2)

(Total 11 marks)

7. In the Periodic Table, where elements are arranged by atomic number, chlorine is a p-block

element whereas manganese, a transition element, is in the d-block.

(a) (i) Define the term atomic number.

......................................................................................................................

...................................................................................................................... (1)

(ii) Define the term d-block element

......................................................................................................................

...................................................................................................................... (1)

(iii) Define the term transition element.

......................................................................................................................

......................................................................................................................

...................................................................................................................... (1)

(b) The electron configuration of chlorine is 1s2 2s

2 2p

6 3s

2 3p

5. Write the electron

configuration for manganese in a similar manner.

................................................................................................................................ (1)

(c) (i) Define the terrm first ionisation energy of chlorine.

......................................................................................................................

......................................................................................................................

...................................................................................................................... (2)

(ii) Sketch the pattern you would expect to see in a plot of successive ionisation

energies of chlorine against the number of electrons removed.

2 4 6 8 10 12 14 16

Ionisationenergy

Number of electrons removed (3)

(d) Manganese(IV) oxide, MnO2, reacts with concentrated hydrochloric acid to produce

chlorine, water and a salt. The salt has a composition of 43.7% manganese and 56.3%

chlorine by mass.

Determine the empirical formula of the salt.

(3)

(Total 12 marks)

8. (a) The Born-Haber cycle for the formation of sodium chloride is shown below.

Na (g) + Cl(g) + e

Na (g) + Cl (g) + e

Na(g) + Cl (g)

Na(s) + Cl (g)

Na (g) + Cl (g)

Na Cl (s)

+

+

+

+

1

1

1

2

2

2

2

2

2

Use the data below to calculate the lattice enthalpy of sodium chloride.

Enthalpy change

Value of the

enthalpy change

/kJ mol1

Enthalpy of atomisation of sodium +109

1st ionisation energy of sodium +494

Enthalpy of formation of sodium chloride 411

Enthalpy of atomisation of chlorine +121

Electron affinity of chlorine 364

(2)

(b) Sodium chloride and magnesium oxide have very similar crystal lattices. Suggest why

the lattice enthalpy of magnesium oxide is very much larger than that of sodium chloride.

................................................................................................................................

................................................................................................................................

................................................................................................................................

................................................................................................................................ (2)

(c) The lattice enthalpy of silver iodide can be calculated but the experimental value does not

match the calculated value as well as those for sodium chloride match each other.

Explain why the calculated and experimental values for silver iodide are different.

................................................................................................................................

................................................................................................................................

................................................................................................................................

................................................................................................................................ (2)

(Total 6 marks)

9. (a) When a sample of copper is analysed using a mass spectrometer, its atoms are ionised and

then accelerated.

(i) Explain how the atoms of the sample are ionised.

......................................................................................................................

......................................................................................................................

...................................................................................................................... (2)

(ii) State how the resulting ions are then accelerated.

......................................................................................................................

...................................................................................................................... (1)

(b) For a particular sample of copper two peaks were obtained in the mass spectrum.

Peak at m/e Relative abundance

63 69.1

65 30.9

(i) Give the formula of the species responsible for the peak at m/e = 65.

...................................................................................................................... (1)

(ii) State why two peaks, at m/e values of 63 and 65, were obtained in the mass

spectrum.

...................................................................................................................... (1)

(iii) Calculate the relative atomic mass of this sample of copper, using the table of

results above.

(2)

(Total 7 marks)

-

10. (a) But-2-ene,

CH3CH=CHCH3, exists

as geometric isomers.

(i) Draw the

geometric

isomers of but-2-

ene.

(2)

(ii) Explain how

geometric

isomerism arises.

............................

.................

.................

.................

.................

.................

.....

............................

.................

.................

.................

.................

.................

..... (1)

30.9

(b) (i) Draw the

structural

formula of a

compound which

is an isomer of

but-2-ene but

which does not

show geometric

isomerism.

(1)

(ii) Explain why the

isomer drawn in

(i) does not show

geometric

isomerism.

............................

.................

.................

.................

.................

.................

.....

............................

.................

.................

.................

.................

.................

..... (1)

(Total 5 marks)

65

(i) Give the formula of the species responsible for the peak at m/e = 65.

...................................................................................................................... (1)

(ii) State why two peaks, at m/e values of 63 and 65, were obtained in the mass

spectrum.

...................................................................................................................... (1)

(iii) Calculate the relative atomic mass of this sample of copper, using the table of

results above.

(2)

(Total 7 marks)

11. (a) State Hesss Law.

..................................................................................................................................

..................................................................................................................................

.................................................................................................................................. (2)

(b) Define the term standard enthalpy change of combustion.

..................................................................................................................................

..................................................................................................................................

.................................................................................................................................. (3)

(c) The equation for the combustion of ethanol in air is

C2H5OH(l) + 3O2(g) 2CO2(g) + 3H2O(l)

and the structural representation of this is:

H C C O H + 3O O 2O C O + 3H O H

H

H

H

H

(i) Calculate the enthalpy change for this reaction using the average bond enthalpy

values given below.

Bond Average bond

enthalpy/kJ mol1

Bond Average bond

enthalpy/kJ mol1

CH +412 CC +348

CO +360 OH +463

OO +496 CO +743

(3)

(ii) Draw and label an enthalpy level diagram to represent this reaction.

enthalpy

(2)

(Total 10 marks)

12. In an experiment to find the enthalpy change when copper is displaced from a solution of

copper ions excess zinc was added to 50.0 cm3 of 1.00 mol dm

3 aqueous copper(ii) sulphate in

a plastic cup.

Zn(s) + Cu2+

(aq) Zn2+(aq) + Cu(s)

The temperature of the solution in the cup was measured every minute for 10 minutes with the

zinc being added after 3.5 minutes.

The temperature readings are shown on the graph below.

70

60

50

40

30

20

100 1 2 3 4 5 6 7 8 9 10

Time/minutes

Tem

per

atu

re/

C

(a) Suggest two reasons why a series of temperature readings is taken rather than simply

initial and final readings.

First reason..............................................................................................................

................................................................................................................................

Second reason..........................................................................................................

................................................................................................................................ (2)

(b) Use the graph to calculate the maximum temperature change, T, as the reaction takes place.

T = ...........................................C (2)

(c) Calculate the enthalpy change for the reaction using the formula below, giving your

answer to an appropriate number of significant figures.

H = 4.18 T kJ mol1

(2)

(Total 6 marks)

13. (a) Sodium reacts with cold water.

(i) What would you see as the reaction proceeds?

..........................................................................................................................

..........................................................................................................................

.......................................................................................................................... (2)

(ii) Write the balanced chemical equation for this reaction.

.......................................................................................................................... (2)

(b) Calculate the volume of gas produced if 3.0 g of sodium reacts with an excess of water.

(One mole of any gas at the temperature and pressure of the experiment occupies

24 dm3.)

(3)

(Total 7 marks)

14. (a) (i) What is meant by the mass number of an atom?

.......................................................................................................................... (1)

(ii) Define the term relative atomic mass.

.......................................................................................................................... (2)

(iii) What are isotopes?

.......................................................................................................................... (2)

(b) Magnesium has three isotopes. The mass spectrum of magnesium shows peaks at m/e 24

(78.60%), 25 (10.11%), and 26 (11.29%). Calculate the relative atomic mass of

magnesium to 4 significant figures.

(2)

(Total 7 marks)

15. (a) Define the term first ionisation energy for magnesium.

....................................................................................................................................

....................................................................................................................................

....................................................................................................................................

.................................................................................................................................... (3)

(b) The logarithm of successive ionisation energies for magnesium is plotted in the graph

below.

6

5

4

3

2

1

00 1 2 3 4 5 6 7 8 9 10 11 12

Number of electron removed

Lo

g i

on

isat

ion e

ner

gy

/kJ

mo

l1

Explain what this graph tells you about the electron arrangement in the magnesium atom.

....................................................................................................................................

....................................................................................................................................

....................................................................................................................................

.................................................................................................................................... (3)

(c) (i) Give the full electronic configuration of magnesium using the s,p,d notation.

.......................................................................................................................... (1)

(ii) Explain why all isotopes of magnesium have the same chemical properties.

..........................................................................................................................

..........................................................................................................................

.......................................................................................................................... (2)

(Total 9 marks)

16. (a) Boron forms the chloride BCl3. Draw a dot-and-cross diagram for BCl3.

(1)

(b) (i) Draw the shape of the BCl3 molecule.

(1)

(ii) Explain why BCl3 has this shape.

..........................................................................................................................

..........................................................................................................................

.......................................................................................................................... (2)

(c) (i) The BCl bond is polar due to the different electronegativity of the atoms. Explain what is meant by the term electronegativity.

..........................................................................................................................

..........................................................................................................................

(2)

(ii) The BCl bond is polar. Explain why BCl3 is not a polar molecule.

..........................................................................................................................

..........................................................................................................................

.......................................................................................................................... (2)

(Total 8 marks)

17. (a) A compound of sodium, chlorine and oxygen contains, by mass, 21.6% Na, 33.3% Cl and

45.1% O. Show that this is consistent with the formula NaClO3.

(2)

(b) NaClO3 can be obtained from NaOCl(aq) by a disproportionation reaction on heating.

(i) Give the ionic equation for this disproportionation reaction.

.......................................................................................................................... (2)

(ii) By a consideration of the oxidation numbers of the chlorine in the various species,

show why the reaction in (i) is disproportionation.

..........................................................................................................................

..........................................................................................................................

..........................................................................................................................

..........................................................................................................................

.......................................................................................................................... (4)

(c) Chlorine is used in the extraction of bromine from seawater.

(i) Give the half-equation for the reduction of chlorine.

..........................................................................................................................

(1)

(ii) Give the half-equation for the oxidation that is occurring given that the overall

equation for the reaction is:

Cl2(aq) + 2Br(aq) Br2(aq) + 2Cl

(aq)

..........................................................................................................................

.......................................................................................................................... (1)

(Total 10 marks)

18. The table below shows the melting temperatures of the elements of period 3.

m.p./C:

Structuraltype

Na

98

Mg

650

Al

660

Si

1410

P

44

S

119

Cl

101

Ar

189

(a) Write in the spaces in the table the structural type for these elements. (2)

(b) Explain why the melting temperature of sodium is so much lower than that of magnesium

or of aluminium.

....................................................................................................................................

....................................................................................................................................

....................................................................................................................................

(3)

(c) (i) Explain the very low melting temperature of argon.

..........................................................................................................................

.......................................................................................................................... (1)

(ii) Phosphorus exists as P4, sulphur as S8. Explain the difference in the melting

temperature of these substances.

..........................................................................................................................

..........................................................................................................................

.......................................................................................................................... (2)

(Total 8 marks)

19. (a) A sample of 2-bromobutane was heated with potassium hydroxide in ethanolic solution.

A reaction occurred producing a mixture of but-1-ene and but-2-ene.

(i) Write an equation for the above reaction to show the production of either but-1-

ene or but-2-ene.

..........................................................................................................................

.......................................................................................................................... (1)

(ii) State the type of reaction taking place.

.......................................................................................................................... (1)

(b) Some bromine solution was shaken with a sample of but-2-ene, and a reaction occurred.

(i) State what would be seen during this reaction.

..........................................................................................................................

.......................................................................................................................... (1)

(ii) Draw the structural formula of the product of this reaction, and name this product.

Diagram:

Name ............................................................................................................... (2)

(c) But-2-ene can exist as two stereoisomers.

(i) Draw the structural formula of the two stereoisomers of but-2-ene.

(2)

(ii) Explain why but-2-ene exists as two stereoisomers, and name this type of

isomerism.

..........................................................................................................................

..........................................................................................................................

.......................................................................................................................... (2)

(Total 9 marks)

20. (a) (i) Define the term standard enthalpy of formation, Hf .

..........................................................................................................................

..........................................................................................................................

..........................................................................................................................

.......................................................................................................................... (3)

(ii) The following table shows some values of standard enthalpy of formation.

Name Formula Hf /kJ mol1

ethene C2H4(g) +52.3

hydrogen bromide HBr(g) 36.2

bromoethane C2H5Br(g) 60.4

Use the data in the table above to calculate the standard enthalpy change for the

following reaction.

C2H4(g) + HBr(g) C2H5Br(g)

(2)

(iii) State the significance of the sign of the value obtained in part (a)(ii) above.

..........................................................................................................................

.......................................................................................................................... (1)

(b) Enthalpy changes can also be calculated using average bond enthalpy data.

Bond Average bond enthalpy/kJ mol1

C == C +612

C C +348

C H +412

C Br +276

H Br +366

Use the data in the table above to recalculate the enthalpy change for the reaction in part

(a)(ii).

C2H4(g) HBr(g) C2H5Br(g)

(3)

(c) Suggest why the value obtained in part (b) above is likely to be less accurate than that

obtained in part (a)(ii).

....................................................................................................................................

....................................................................................................................................

.................................................................................................................................... (2)

(Total 11 marks)

21. (a) In an experiment to standardise an aqueous solution of sodium hydroxide 0.25 g of solid

sulphamic acid, NH2SO3H, was dissolved in distilled water in a conical flask. When the

aqueous sodium hydroxide was run into the flask from a burette 23.45 cm3 was required

to exactly react with the sulphamic acid solution. The equation for the reaction is:

NH2SO3H(aq) + NaOH(aq) NH2SO3Na(aq) + H2O(l)

(i) Calculate the amount (number of moles) of sulphamic acid in 0.25 g.

Mr(NH2SO3H) = 97.0.

(1)

(ii) State the amount (number of moles) of sodium hydroxide in 23.45 cm3 of solution

and hence calculate the concentration of the solution in mol dm3

.

(3)

(b) The balance used to weigh the sulphamic acid is accurate to 0.01 g. Calculate the

percentage error in the mass of the sulphamic acid weighed.

(1)

(c) An alternative method to that described in (a) involves making an aqueous solution of

sulphamic acid of accurately known concentration.

Describe a procedure bv which you would prepare 250 cm3 of aqueous sulphamic acid of

accurately known concentration. Assume that you are provided with a weighing bottle

containing between 2.40 g and 2.50 g of sulphamic acid and that this is a suitable mass to

use.

In your answer give full practical details including the name of each piece of apparatus

used, how each would be prepared for the procedure and how you would calculate the

concentration (in mol dm3

) of the sulphamic acid solution. State, with a reason, one

appropriate safety precaution that should be taken.

....................................................................................................................................

....................................................................................................................................

....................................................................................................................................

(Allow one lined page) (8)

(Total 13 marks)

22. The formation of magnesium chloride from magnesium and chlorine may be represented by the

following Born-Haber cycle:

Mg (g) + 2Cl(g) + 2e

MgCl (s)

Mg (g) + 2Cl (g)

2+

2+

Mg(g) + Cl (g)2

Mg(s) + Cl (g)2

2

Mg (g) + Cl (g) + 2e2+ 2

(a) Define the terms:

Lattice enthalpy.

....................................................................................................................................

....................................................................................................................................

.................................................................................................................................... (3)

Enthalpy of atomisation.

....................................................................................................................................

....................................................................................................................................

.................................................................................................................................... (2)

(b) (i) Identify on the diagram the chance representing the enthalpy of atomisation of

magnesium. (1)

(ii) Use the data below to calculate the first electron affinity of chlorine.

Enthalpy change Value of the enthalpy

change / kJ mol1

Enthalpy of atomisation of magnesium

1st Ionisation energy of magnesium

2nd Ionisation energy of magnesium

Enthalpy of formation of magnesium chloride

Enthalpy of atomisation of chlorine

Lattice enthalpy of magnesium chloride

+150

+736

+1450

642

+121

2493

(2)

(c) Hydrogen gas reacts with sodium metal to form an ionic solid, NaH, which contains

sodium cations.

Draw a Born-Haber cycle which could be used to determine the electron affinity of

hydrogen.

(3)

(Total 11 marks)

23. (a) Complete and balance the following equations:

(i) Ca + O2 .....................................................................................................

(1)

(ii) Na2O + H2O ...............................................................................................

(1)

(iii) Na2O + HCl ...............................................................................................

(2)

(b) State and explain the trend in thermal stability of the carbonates of the Group 2 elements

as the group is descended.

....................................................................................................................................

....................................................................................................................................

....................................................................................................................................

.................................................................................................................................... (3)

(Total 7 marks)

24. (a) Complete the following table:

Particle Relative charge Relative mass

Proton 1

Electron 1

Neutron 1

(3)

(b) State the number of each of the above particles present in one molecule of CH4, showing

clearly how you arrive at your answer.

....................................................................................................................................

....................................................................................................................................

....................................................................................................................................

.................................................................................................................................... (3)

(c) Complete the electronic configuration of a chlorine atom.

1s2 ............................................................................................................................

(1)

(d) Give the formula of the chlorine species composed of 17 protons, 20 neutrons and 16

electrons.

.................................................................................................................................... (2)

(e) Write one equation in each case to represent the change occurring when the following

quantities are measured.

(i) The first electron affinity of sulphur.

............................................................................................................................ (2)

(ii) The first ionisation energy of sulphur.

........................................................................................................................ (1)

(f) Explain why the first ionisation energy of chlorine is higher than that of sulphur.

....................................................................................................................................

....................................................................................................................................

....................................................................................................................................

.................................................................................................................................... (2)

(Total 14 marks)

25. (a) (i) Calculate the number of moles of potassium nitrate, KNO3, in 10.1 g of KNO3.

(1)

(ii) Potassium nitrate, KNO3, can be prepared from potassium hydroxide solution as

shown in the following equation:

KOH(aq) + HNO3(aq) KNO3(aq) + H2O(l)

Calculate the minimum volume, in cm3, of 2.00 mol dm

3 KOH required to

produce 10.1 g of KNO3.

(2)

(iii) Potassium nitrate decomposes, when heated, to produce oxygen.

2KNO3(s) 2KNO2(s) + O2(g)

Calculate the volume of oxygen gas, in dm3, produced when 10.1 g of potassium

nitrate decomposes in this way.

(1 mole of gas has a volume of 24 dm3 under the conditions of the experiment.)

(2)

(b) A compound of potassium and oxygen contains 70.9% potassium.

(i) Calculate the empirical formula of this compound, using the data above and the

periodic table.

(3)

(ii) 0.200 moles of this compound has a mass of 22.0 g. Use this information to help

you deduce the molecular formula of this compound.

(2)

(Total 10 marks)

26. The reaction of an acid with a base to give a salt is an exothermic reaction. In an experiment to

determine the enthalpy of neutralisation of hydrochloric acid with sodium hydroxide, 50.0cm3

of 1.00 mol dm3

HCl was mixed with 50.0 cm3 of 1.10 mol dm

3 NaOH. The temperature rise

obtained was 6.90 C.

(a) Define the term enthalpy of neutralisation.

....................................................................................................................................

.................................................................................................................................... (1)

(b) Assuming that the density of the final solution is 1.00 g cm3

and that its heat capacity is

4.18 J K1

g1

, calculate the heat evolved during the reaction.

(3)

(c) 0.0500 mol of acid was neutralised in this reaction; calculate Hneutralisation in

kJ mol1

.

(2)

(d) Suggest why sodium hydroxide is used in slight excess in the experiment.

....................................................................................................................................

.................................................................................................................................... (1)

(Total 7 marks)

27. (a) Ethene and propene are in the same homologous series. Explain the term homologous

series.

....................................................................................................................................

....................................................................................................................................

....................................................................................................................................

.................................................................................................................................... (3)

(b) (i) Draw a representative length of the polymer chain of poly(propene).

(2)

(ii) State, with a reason, the empirical formula of poly(propene).

............................................................................................................................

............................................................................................................................

............................................................................................................................

............................................................................................................................ (3)

(c) Poly(propene) does not have a sharp melting temperature, but softens over a range of

temperature. Suggest why this is so.

....................................................................................................................................

................................................................................................................................... (1)

(d) (i) Tetrafluoroethene, C2F4, also forms a polymer. Suggest why this polymer is very

inert.

........................................................................................................................... (1)

(ii) Give one use for poly(tetrafluoroethene).

.......................................................................................................................... (1)

(e) Ethane and ethene both react with bromine. Ethane does not react at room temperature in

the dark, whereas ethene does so extremely quickly. Explain in terms of the bonding in

each molecule why this is so.

....................................................................................................................................

....................................................................................................................................

....................................................................................................................................

.................................................................................................................................... (3)

(Total 14 marks)

28. (a) (i) Define the term standard enthalpy of combustion.

............................................................................................................................

............................................................................................................................

............................................................................................................................

............................................................................................................................ (3)

(ii) The values for the standard enthalpy of combustion of graphite and carbon

monoxide are given below:

Hc /kJ mol1

C (graphite) 394

CO(g) 283

Use these data to find the standard enthalpy change of formation of carbon

monoxide using a Hesss law cycle.

C(graphite) + 2

1O2(g) CO(g)

(3)

(iii) Suggest why it is not possible to find the enthalpy of formation of carbon

monoxide directly.

............................................................................................................................

............................................................................................................................ (1)

(iv) Draw an enthalpy level diagram below for the formation of carbon monoxide from

graphite.

(1)

(b) Natural gas consists of methane, CH4. When methane burns completely in oxygen the

reaction occurs as shown in the equation

CH4(g) + 2O2(g) CO2(g) + 2H2O(l) Hc = 890 kJ mol1

Methane does not burn unless lit.

Use this information to explain the difference between thermodynamic and kinetic

stability.

....................................................................................................................................

....................................................................................................................................

....................................................................................................................................

....................................................................................................................................

.................................................................................................................................... (4)

(Total 12 marks)

29. A student was required to determine the enthalpy change for the reaction between iron and

copper sulphate solution.

The student produced the following account of their experiment.

A piece of iron, mass about 3 g, was placed in a glass beaker. 50 cm of

0.5 mol dm aqueous copper sulphate solution was measured using a

measuring cylinder and added to the beaker. The temperature of the

mixture was measured immediately before the addition and every minute

afterwards until no further change took place.

Fe + CuSO FeSO + Cu4 4

3

3

Timing before

addition

1 min 2 mins 3 mins 4 mins 5 mins

Temperature/C 22 27 29 26 24 22

(a) Suggest two improvements you would make to this experiment. Give a reason for each of

the improvements suggested.

Improvement 1 ...........................................................................................................

....................................................................................................................................

Reason 1 ....................................................................................................................

....................................................................................................................................

Improvement 2 ...........................................................................................................

....................................................................................................................................

Reason 2 ....................................................................................................................

.................................................................................................................................... (4)

(b) In an improved version of the same experiment a maximum temperature rise of

15.2 C occurred when reacting excess iron with 50.0 cm3 of 0.500 mol dm

3 aqueous

copper sulphate solution.

(i) Using this data and taking the specific heat capacity of all aqueous solutions as

4.18 Jg1

deg1

calculate the heat change.

(1)

(ii) Calculate the number of moles of copper sulphate used.

(1)

(iii) Calculate the enthalpy change of this reaction in kJ mol1

.

(2)

(Total 8 marks)

30. (a) (i) Complete the electronic configuration of calcium.

1s2 ....................................................................................................................

(1)

(ii) State the number of electrons in the outer shell of an atom of chlorine.

.. (1)

(b) (i) Write the equation for the reaction of calcium with chlorine to produce

calcium chloride.

.. (1)

(ii) Name the type of bonding in calcium chloride.

.. (1)

(iii) Draw a dot and cross diagram for calcium chloride showing all the outer electrons.

(3)

(Total 7 marks)

31. (a) State the number of protons, neutrons and electrons in a Li3

7 ion.

protons: neutrons: electrons: (3)

(b) The mass spectrum of lithium shows two peaks. Their mass/charge ratios and

percentage abundance are shown below.

Mass/charge % Abundance

6.02 7.39

7.02 92.61

Calculate the relative atomic mass of lithium, giving your answer to three

significant figures.

(2)

(c) Describe a test that you would do to distinguish between solid lithium chloride and

solid sodium chloride. Clearly state what you would do and what you would see with

both substances.

..

..

..

.. (3)

(Total 8.marks)

32. Both magnesium metal and molten magnesium chloride conduct electricity, but solid

magnesium chloride does not.

(a) Describe the structure of magnesium metal and explain why the solid conducts electricity.

..

..

..

.. (3)

(b) Describe, in terms of the position and motion of the particles, what happens when

some solid magnesium chloride, MgCl2, is heated from room temperature to just above

its melting temperature.

..

..

..

..

..

.. (4)

(c) Explain why magnesium chloride can conduct electricity when molten, but not

when solid.

..

..

..

.. (2)

(Total 9 marks)

33. (a) The first ionisation energy of potassium is +419 kJ mol1

and that of sodium

is +496 kJ mol1

.

(i) Define the term first ionisation energy.

....

....

.... (3)

(ii) Explain why the first ionisation energy of potassium is only a little less than the

first ionisation energy of sodium.

....

....

....

....

.... (3)

(b) Potassium forms a superoxide, KO2. This reacts with carbon dioxide according to the

equation:

4KO2(s) + 2CO2(g) 2K2CO3(s) + 3O2(g)

Carbon dioxide gas was reacted with 4.56 g of potassium superoxide.

(i) Calculate the amount, in moles, of KO2 in 4.56 g of potassium superoxide.

(2)

(ii) Calculate the amount, in moles, of carbon dioxide that would react with 4.56 g

of potassium superoxide.

(1)

(iii) Calculate the volume of carbon dioxide, in dm3, that would react with 4.56 g of

potassium superoxide. Assume that 1.00 mol of a gas occupies 24 dm3 under the

conditions of the experiment.

(1)

(iv) What volume of oxygen gas, in dm3, measured under the same conditions of

pressure and temperature, would be released?

(1)

(Total 11 marks)

34. (a) Define the term standard enthalpy of combustion, making clear the meaning of

standard in this context.

...

...

...

...

... (3)

(b) Use the enthalpies of combustion given below to find the enthalpy change for

the reaction:

2C(graphite) + 2H2(g) + O2(g) CH3COOH(l)

Hcombustion/kJ mol1

C(graphite) 394

H2(g) 286

CH3COOH(l) 874

(3)

(c) With reference to ethanoic acid, CH3COOH, what is the enthalpy change obtained

in (b) called?

... (1)

(d) Draw an enthalpy level diagram to represent the enthalpy change for the combustion of

graphite. Show both the enthalpy levels of the reactants and products and an energy

profile which represents the activation energy for the reaction.

(3)

(Total 10 marks)

35. (a) This question is about finding the formula of copper hydroxide. The method is as follows:

20.0 cm3 of an aqueous solution of a copper salt of concentration 1.00 mol dm

3 was

placed in a polystyrene cup and its temperature measured using a thermometer graduated

in 0.1 C intervals.

A burette was filled with aqueous sodium hydroxide, of concentration 2.00 mol dm3

.

2.00 cm3 of sodium hydroxide solution was run into the solution of the copper salt and

the temperature was measured immediately.

As soon as possible a further 2.00 cm3 of sodium hydroxide solution was run in and

the temperature measured again.

This process of adding 2.00 cm3 portions of sodium hydroxide solution and measuring

the temperature was continued until a total of 36.0 cm3 of the sodium hydroxide solution

had been added.

The temperature readings are shown in the graph below.

30

29

28

27

26

25

24

23

22

21

200 4 8 12 16 20 24 28 32 36 40

Volume of NaOH(aq) / cm

Temperature / C

3

(i) Explain why the temperature reaches a maximum and then falls slightly on addition

of further sodium hydroxide solution.

....

....

.... (2)

(ii) From the graph, what volume of the aqueous sodium hydroxide was required

for complete reaction?

.... (1)

(iii) Calculate the amount (number of moles) of sodium hydroxide in this volume

of solution.

(1)

(iv) Calculate the amount (number of moles) of copper ions that have reacted.

(1)

(v) Write the ratio of moles of copper ions to hydroxide ions reacting.

(1)

(vi) Write the formula of the copper hydroxide that is produced.

(1)

(b) The data call be used to find the enthalpy change for the reaction between sodium

hydroxide and the copper salt.

(i) Use the graph to find the temperature rise that occurs for complete reaction.

.... (1)

(ii) Find the heat change, q, that occurs in the polystyrene cup for complete reaction.

Use the formula

q = 168 T joules

(1)

(iii) Use your results from (a)(iv) and (b)(ii) above, to find the molar enthalpy change,

H, for the reaction. Give the correct sign and units to the answer.

(3)

(c) Identify one potential source of error in this experiment, and say what you would do

to reduce its effect.

......

......

......

......

...... (2)

(Total 14 marks)

36. In an experiment to show the migration of ions, silver(I) nitrate solution, AgNO3(aq), and

potassium chromate(VI) solution, K2CrO4(aq), were used. The experiment was set up as shown

in the diagram below. After a short while, a red precipitate formed in the centre of the filter

paper.

(a) Write the formulae, including charges, of the following ions:

(i) Nitrate ions .......................................................................................................

(ii) Chromate (VI) ions .......................................................................................... (2)

(b) Which ions would meet in the centre of the filter paper?

.................................................................................................................................... (1)

(c) Write a balanced ionic equation, including state symbols, for the formation of the red

precipitate.

(2)

(Total 5 marks)

37. An excess of zinc powder was added to 20.0 cm3 of a solution of copper(II) sulphate of

concentration 0.500 mol dm3

. The temperature increased by 26.3 C.

(a) How many moles of copper(II) sulphate were used in this experiment?

(1)

(b) Calculate the enthalpy change, H, in kJ mol1 for this reaction given that:

energy change = specific

heat capacity mass of solution

temperature change

/J /J g1

K1 /g /K

Assume that the mass of solution is 20.0 g and the specific heat capacity of the solution

is 4.18 J g1

K1

.

(2)

(Total 5 marks)

38. A sample of titanium (atomic number 22) is made up of five isotopes. The sample has the

following percentage composition:

Mass number

46

47

48

49

50

% composition

8.0

7.3

74.0

5.5

5.2

(a) (i) What is the average relative atomic mass of titanium? Give your answer to three

significant figures.

(2)

(ii) What instrument would have been used to find this percentage composition?

............................................................................................................................ (1)

(b) (i) Give the electronic configuration of a titanium atom, using s p d notation.

............................................................................................................................ (2)

(ii) Name the part of the Periodic Table where titanium appears.

............................................................................................................................ (1)

(c) Titanium occurs naturally as rutile, TiO2. One possible method of obtaining pure titanium

is to heat rutile with carbon.

TiO2(s) + 2C(s) Ti(s) + 2CO(g)

(i) What type of reaction is this?

............................................................................................................................ (1)

(ii) Calculate H for this reaction given that

Hf [TiO2(s)] = 940 kJ mol

1

Hf [CO(g)] = 110 kJ mol1

Include a sign and units in your answer.

(3)

(iii) Name the law you have used in your calculation.

............................................................................................................................ (1)

(iv) When titanium is manufactured by this method, explain what pollution problem

arises.

............................................................................................................................

............................................................................................................................

............................................................................................................................ (2)

(Total 13 marks)

39. This question is about nitrogen trifluoride, NF3, and nitrogen trichloride, NCl3, which are

covalent compounds. Van der Waals attractions and permanent dipoledipole attractions exist between molecules of both compounds in the liquid state.

(a) (i) Describe how van der Waals attractions are caused.

............................................................................................................................

............................................................................................................................

............................................................................................................................

............................................................................................................................ (1)

(ii) In which of the two compounds would you expect there to be greater van der

Waals attractions? Justify your answer.

............................................................................................................................

............................................................................................................................ (1)

(iii) In which of the two compounds would you expect there to be the greater permanent

dipoledipole attractions? Justify your answer.

............................................................................................................................

............................................................................................................................ (1)

(iv) The boiling point of nitrogen trichloride is much higher than that of nitrogen

trifluoride. How might this be explained in terms of the two types of intermolecular

attractions?

............................................................................................................................

............................................................................................................................ (1)

(b) The standard enthalpy change for the formation of gaseous nitrogen trifluoride is

125 kJ mol1.

21 N2 (g) + 1 2

1 F2 (g) NF3 (g) Hf = 125 kJ mol

1

The standard molar enthalpy changes of atomisation of nitrogen, N2, and of fluorine, F2,

are given below.

Hat/kJ mol1

21 N2 (g) N (g) + 473

21 F2 (g) F (g) + 79

This information can be represented on a Hess cycle in the following way, and then used

to calculate bond energies.

(i) Insert formulae, showing the correct quantities of each element, into the

appropriate boxes. (1)

(ii) Insert arrows between the boxes and write the correct numerical data alongside

the appropriate arrows. (2)

(iii) Use the cycle to calculate the N F bond energy in nitrogen trifluoride.

(2)

(Total 9 marks)

40. Cracking is an important process in the petrochemical industry. Cracking the fraction of crude

oil with a boiling range of 200300 C produces a number of useful alkanes and alkenes.

(a) Why does the original fraction of crude oil have a boiling range rather than a single

boiling point?

.....................................................................................................................................

..................................................................................................................................... (1)

(b) The following equation represents one possible reaction which might occur during

cracking.

(i) Give the name of Product 1.

............................................................................................................................ (1)

(ii) Give the molecular formula of Product 1.

............................................................................................................................ (1)

(iii) Product 1 of this reaction is used as a component of petrol. Suggest ONE reason

why it is more suitable for this use than the original undecane.

............................................................................................................................

............................................................................................................................ (1)

(iv) State TWO necessary conditions used when cracking petroleum fractions.

............................................................................................................................

............................................................................................................................ (2)

(v) Draw a labelled diagram showing suitable apparatus and materials for cracking a liquid such as light paraffin in the laboratory. You should indicate how a gaseous product of the reaction could be collected.

(4)

(c) There are several isomers of Product 2. One of them, an alkene, can be made from

2-bromo-2-methylpropane, which has the following formula:

(i) Draw the structural formula of the alkene produced.

(1)

(ii) Name the type of reaction involved in the conversion of 2-bromo-2-methylpropane

to Product 2.

............................................................................................................................ (1)

(iii) What reagent and conditions would be used to bring about this conversion?

Reagent ..............................................................................................................

Conditions .......................................................................................................... (2)

(Total 14 marks)

41. (a) State the meaning of the terms

(i) relative atomic mass

..........................................................................................................................

..........................................................................................................................

.......................................................................................................................... (2)

(ii) mass number

..........................................................................................................................

.......................................................................................................................... (1)

(iii) isotopes

..........................................................................................................................

..........................................................................................................................

.......................................................................................................................... (2)

(b) The isotopic composition of a sample of sulphur is found using a mass spectrometer.

(i) Explain how atoms of the sample of sulphur are ionised.

..........................................................................................................................

..........................................................................................................................

.......................................................................................................................... (2)

(ii) State the type of charge on the sulphur ions formed in the mass spectrometer.

.......................................................................................................................... (1)

(iii) State how the resulting sulphur ions are then accelerated.

.......................................................................................................................... (1)

(c) For a particular sample of sulphur atoms the following isotopic composition was

recorded.

Isotope Percentage composition

32S 95.00

33S 0.76

34S 4.24

Calculate the relative atomic mass of this sample of sulphur. Give your answer to two

decimal places.

(2)

(d) Predict the electronic configuration of a 34

S atom, using s, p and d notation.

1s2 .........................................................................................................................

(1)

(Total 12 marks)

42. (a) State and explain the trend in the boiling temperatures of the noble gases.

...............................................................................................................................

...............................................................................................................................

...............................................................................................................................

............................................................................................................................... (3)

(b) The graph below shows the melting temperatures of the elements of Period 3 of the

Periodic Table, sodium to argon, plotted against atomic number.

Na Mg Al Si P S Cl Ar

element

me

ltin

g t

em

pera

ture

/ K

1800

1600

1400

1200

1000

800

600

400

200

0

(i) Identify one of the elements above that is composed of simple molecules at room

temperature.

...................................................................................................................... (1)

(ii) Silicon has a giant atomic structure. Explain how this structure results in the high

melting temperature shown on the graph.

......................................................................................................................

......................................................................................................................

......................................................................................................................

...................................................................................................................... (2)

(iii) Explain why the melting temperature of magnesium is higher than that of sodium.

......................................................................................................................

......................................................................................................................

......................................................................................................................

......................................................................................................................

...................................................................................................................... (3)

(Total 9 marks)

43. A compound A is formed when chlorine is bubbled through hot concentrated potassium

hydroxide solution.

(a) Analysis of A shows that it contains 31.84% potassium, 28.98% chlorine and the

remainder is oxygen.

Show that the empirical formula of A is KClO3

(3)

(b) On being heated strongly solid A decomposes completely to give oxygen gas and solid

potassium chloride.

2KClO3 2KCl + 3O2

If 1.00 g of solid A is decomposed completely in this way, calculate the volume of

oxygen gas produced at room temperature and pressure.

(One mole of a gas at room temperature and pressure occupies 24 dm3)

(3)

(Total 6 marks)

44. (a) Bromine reacts with both ethane and ethene.

(i) Write the equations for the reactions below.

Ethane + bromine

...................................................................................................................... (1)

Ethene + bromine

...................................................................................................................... (1)

(ii) Classify the two reactions in terms of the type of reaction occurring.

Ethane + bromine

...................................................................................................................... (2)

Ethene + bromine

...................................................................................................................... (2)

(b) Chloroethene (vinyl chloride), H2C==CHCl, can be polymerised in a similar type of

reaction to the polymerisation of ethene.

(i) Draw the full structural formula of the polymer poly(chloroethene), sufficient to

make the structure of the polymer clear.

(1)

(ii) State one use of poly(chloroethene).

...................................................................................................................... (1)

(iii) State and explain one environmental problem arising from the disposal of

poly(chloroethene).

......................................................................................................................

...................................................................................................................... (2)

(Total 10 marks)

45. Urea, which is used as a fertillser in much of mainland Europe, Asia and Africa, is

manufactured by the reaction of ammonia and carbon dioxide.

2NH3(g) + CO2(g) NH2CONH2(s) + H2O(l)

(a) Define the term standard enthalpy of formation, Hf , of urea.

...............................................................................................................................

...............................................................................................................................

...............................................................................................................................

...............................................................................................................................

............................................................................................................................... (3)

(b) Calculate the enthalpy change, H for the reaction above, given the following standard enthalpies of formation.

Substance Hf / kJ mol1

NH3(g) 46.2

CO2(g) 393.5

NH2CONH2(s) 632.2

H2O(l) 285.8

(3)

(Total 6 marks)

46. (a) Halogenoalkanes react with many nucleophiles.

Define the term nucleophile.

...............................................................................................................................

...............................................................................................................................

............................................................................................................................... (2)

(b) (i) Identify the reagent and conditions necessary for the conversion of iodoethane to

ethylamine, C2H5NH2.

Reagent:.........................................................................................................

Conditions:.....................................................................................................

...................................................................................................................... (3)

(ii) State why the rate of reaction would be slower if bromobutane were used in place

of iodoethane, with all other conditions remaining the same.

......................................................................................................................

...................................................................................................................... (1)

(c) Iodoethane reacts with water to form ethanol and hydrogen iodide.

C2H5I + H2O C2H5OH + HI Hf = +36 kJ mol1

Use some or all of the data below to calculate the CI bond enthalpy.

Bond Bond enthalpy

/ kJ mol1

Bond Bond enthalpy

/ kJ mol1

CH 413 HI 298

CC 347 CO 358

HO 464

(3)

(d) Ethanol was heated under reflux with an excess of a mixture of potassium dichromate(VI)

and dilute sulphuric acid. Draw the full structural formnula of the organic product.

(1)

(Total 10 marks)

47. (a) An atom of gallium has mass number 69.

Complete the table to show the number of sub-atomic particles in this gallium atom.

Electrons Neutrons Protons

(2)

(b) The mass spectrum of a sample of gallium is shown below.

69 71 Mass / charge ratio

60

40

20

Relativeabundance

What is the average relative atomic mass of gallium in this sample? Give your answer to

three significant figures.

(2)

(c) What type of bonding would you expect to find in gallium?

...................................................................................................................................... (1)

(Total 5 marks)

48. (a) (i