ST ANDREWS JUNIOR COLLEGE

JC 1 FINAL EXAMINATION H2 CHEMISTRY

03 October 2011 2 hr 30 min

Additional materials: Data Booklet

INSTRUCTIONS TO CANDIDATES

Sections A and B (20 marks)

There are 20 questions in these sections. Answer all questions.

For each question there are four possible answers A, B, C and D. Choose the one you consider correct

and record your choice in soft pencil on the Optical Answer Sheet.

For Sections C and D

Write in dark blue or black pen.

You may use a soft pencil for any diagrams, graphs or rough working.

Do not use staples, paper clips, highlighters, glue or correction fluid.

You are reminded of the need for good English and clear presentation in your answers.

The number of marks is given in brackets [ ] at the end of each question or part question.

Section C (40 marks)

Answer ALL the questions.

Section D (20 marks)

Answer ALL the questions in the space provided on the question paper.

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SECTION A

For each question there are four possible answers, A, B, C and D. Choose the one you consider to be

correct.

1. Which of the following has the largest amount of particles?

A 6.02 x 1022 atoms of neon

B copper ions in 500 cm3 of 0.1 mol dm-3 of copper(I) sulfate solution

C ions in 3.30 g of solid iron(III) oxide

D molecules in 2.3 x 10-3 m3 of ethane at standard temperature and pressure conditions

2. 25.0 cm3 of 0.025 mol dm-3 acidified potassium manganate(VII) completely reacted with 20.0

cm3 of 0.0625 mol dm-3 hydrogen peroxide solution. What is the final oxidation state of

manganese at the end of this reaction?

A +2 B +3 C +4 D +7

3. Which of the following ions has the most number of unpaired electrons?

A N B C C Ti2+ D Cu2+

4. Which of the following data accurately describes the number of each type of hybrid carbons

present in all the carbon-containing products of the reaction of 2-ethylpenta-1,3-diene with hot

acidified potassium manganate(VII) solution?

sp sp2 sp3

A 0 3 4

B 0 4 3

C 1 2 4

D 1 3 3

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5. Upon mixing water and ethanol, with the following structure, and leaving it to stand would result

in the formation of a homogeneous solution. Which of the following accurately describes their

intermolecular interactions?

Interactions present between

ethanal-ethanal water-water ethanal-water

A hydrogen bonding hydrogen bonding hydrogen bonding

B

permanent dipole-

permanent dipole hydrogen bonding hydrogen bonding

C

permanent dipole-

permanent dipole hydrogen bonding

permanent dipole-

permanent dipole

D

permanent dipole-

permanent dipole

permanent dipole-

permanent dipole

permanent dipole-

permanent dipole

6. A container with a volume of 2 dm3 contains 15 kPa of neon was connected to another container

with a volume of 4 dm3 containing 25 kPa of argon. If the containers are connected at constant

temperature, what is the final pressure exerted by the noble gases?

A 18.3 kPa B 20.0 kPa C 21.7 kPa D 40.0 kPa

7. Using the following data, what is the standard enthalpy change for the reaction between ethane

and chlorine to form liquid 1,2-dichloroethane and white fumes of hydrogen chloride?

Enthalpy change of formation of

ethane(g) -83.9 kJ mol-1

1,2-dichloroethane(l) -169.8 kJ mol-1

hydrogen chloride(g) -91.0 kJ mol-1

A -267.9 kJ mol-1 B -176.9 kJ mol-1 C +176.9 kJ mol-1 D +267.9 kJ mol-1

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8. Which of the following statements is an accurate description of the energy terms?

Equation Enthalpy change of H S

A H2(g) H(g) atomisation positive positive

B Na+(g) + Cl(g) NaCl(s) formation negative negative

C O2-(g) O-(g) + e ionisation energy positive positive

D Ba(OH)2(aq) + H2SO4(aq)

BaSO4(s) + 2H2O(l) neutralisation negative positive

9. Which of the following statements is incorrect?

A During free radical substitution, the bond angle (centred around the carbon radical)

changes.

B During electrophilic addition, a carbocation is formed in the fast step.

C During electrophilic substitution, the carbocation intermediate has 4 electrons delocalised

over 5 carbon atoms in the benzene ring.

D During nucleophilic substitution (SN2), the transition state is made up of a pentavalent

carbon which could be negatively charged.

10. Which of the following statements about but-2-ene is incorrect?

A The trans-isomer has a higher melting point than the cis-isomer.

B It can be obtained from the dehydration of butan-2-ol.

C It decolourises purple acidified potassium manganate(VII) to form only one organic

product.

D It decolourises orange-red bromine water to form 2,3-dibromobutane as the major product.

11. Reaction of propene with chlorine in the presence of aqueous sodium nitrate gives a mixture of

products.

Which set of products will be present in this mixture?

A CH2(OH)CH2CH2Cl CH3CHClCH2Cl CH3CH(ONO2)CH2Cl

B CH3CH(OH)CH2ONO2 CH3CHClCH2ONO2 CH3CHClCH2Cl

C CH2ClCH2CH2Cl CH3CH(ONO2)CH2Cl CH3CH(OH)CH2Cl

D CH3CHClCH2Cl CH3CH(ONO2)CH2Cl CH3CH(OH)CH2Cl

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12. Which of the following accurately depicts the rate of hydrolysis?

A

B

C

D

13. Which of the following pairs of organic compounds would have the same observations upon

addition of aqueous bromine?

A 2-methylphenol and benzene C propene and but-1-ene

B but-2-ene and phenol D hex-1-ene and benzene

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14. After Compound A, with the following structure, has been reacted with hot aqueous alkaline

iodine solution, which of the following options depicts the correct product?

A

C

B

D

15. Which of the following accurately depicts the synthesis process for the production of propanoic

acid from but-2-ene?

A oxidation, electrophilic addition, acidification

B electrophilic addition, acidification, oxidation

C oxidation, acidification, electrophilic addition

D electrophilic addition, oxidation, acidification

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SECTION B

For each of the questions in this section, one or more of the three numbered statements 1 to 3 may be correct. The responses A to D should be selected on the basis of

A B C D

1, 2 and 3 are correct

1 and 2 only are correct

2 and 3 only are correct

1 only is correct

16. Which of the following reactions illustrates disproportionation?

1 MnO

+ Mn2+ 2MnO2

2 Cl2 + 2OH Cl + ClO + H2O

3 2Cu+ Cu + Cu2+

17. Which of the following statements with regards to ideal gases are true?

1 All ideal gases cannot be liquefied.

2 All particles within the ideal gases are stationary at 0 K.

3 The total volume of the particles is equal to the volume of the container.

18. Which reactions represent enthalpy changes of formation?

1

S8(s) + O2(g) SO2(g)

2 C(graphite) C(g)

3 Na(s) + H2O(l) NaOH(aq) + H2(g)

19. Which of the following products can be formed from 4-nitromethylbenzene?

1

2

3

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The responses A to D should be selected on the basis of

A B C D

1, 2 and 3 are correct

1 and 2 only are correct

2 and 3 only are correct

1 only is correct

20. Deuterium (D = 2H) and hydrogen are isotopes and possesses similar chemical properties.

Which reactions yield a carbon compound incorporating deuterium?

1

2

3

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SECTION C Answer ALL questions on the provided writing paper.

1. One of the more common catalysts used in reactions with benzene is aluminium bromide, which

appears as a white powder. Aluminium bromide is formed when aluminium is reacted with

hydrobromic acid.

(a) i) Write out the balanced equation for the standard enthalpy change of formation of

aluminium bromide.

.

ii) Given the following information and relevant information from the Data Booklet,

construct an energy level diagram and calculate the strength of each bond within

aluminium bromide.

Hatm(aluminium) +326 kJ mol-1

Hf(AlBr3(s)) -511.3 kJ mol-1

sublimation of AlBr3(s) +100.8 kJ mol-1

vaporisation of Br2(l) +30.0 kJ mol-1

iii) Describe and name the mechanism of the reaction between liquid bromine and

methylbenzene at 30oC, using aluminium bromide as the halogen carrier. State the

observation.

iv) Explain why the organic product formed in part (iii) could not undergo alkaline

hydrolysis.

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(b) Suggest the reagents and conditions for each step, and draw the structural formula of

every intermediate compound formed, for the conversion of

i) propane to ethanoic acid in 3 steps and

ii) 2-chlorobutane to 2-methylbutanoic acid in 2 steps.

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2. One of the commonly used examples of halogenoalkanes is 2-bromopentane, which is a pale

yellow liquid.

(a) Illustrate with a diagram, using displayed formulae, to show how 2-bromopentane is able to

display optical isomerism.

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(b) i) B is the organic product of the reaction between 2-bromopentane and aqueous

potassium hydroxide. Given that B is able to rotate plane-polarised light, outline the

mechanism of the reaction.

ii) Explain the following observations made of B:

I. B is soluble in water

II. The bond angle about the chiral carbon atom is larger than the bond angle

about oxygen atom.

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(c) 3.28 g of an unknown liquid hydrocarbon, C, was vapourised and found to take up 202 cm3

under 497436 Pa and 29 oC. It was then exploded in the presence of excess amount of

oxygen, which resulted in a contraction of 707 cm3.

Using the information from the Data Booklet and given that water has a boiling point >70 oC

at 497436 Pa, determine the molecular relative mass and the molecular formula of C.

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(d) Another hydrocarbon, D, has the molecular formula C6H10, and does not possess any

stereoisomerism. It decolourises aqueous bromine and reacts with gaseous hydrogen

bromide to form compound E. D also decolourises hot acidified potassium manganate(VII)

to form one organic product having structural formula CH3COCH2COOH.

Suggest the structural formula for D and E, explaining your reasoning. Label any chiral

carbon atoms present in D and E with an asterisk (*). Write balanced equations for all

reactions of D.

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Name: Class:

ST ANDREWS JUNIOR COLLEGE

JC1 Final Year Examinations Section D

Candidates answer in the spaces provided on the question paper.

Additional Materials: Data Booklet

READ THESE INSTRUCTIONS FIRST

You may use a soft pencil for any diagrams, graphs or rough working.

Do not use staples, paper clips, highlighters, glue or correction fluid.

Answer all questions.

You are reminded of the need for good English and clear presentation in your answers.

The number of marks is given in brackets [ ] at the end of each question or part

question.

For Examiners Use:

Question Marks

1

2

Total (20 marks)

--------- This set of question paper consists of 10 printed pages including this page -------------

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1. (a) Chromium is one of the transition metals commonly used in organic chemistry as it is able

to exhibit variable oxidation states and its oxo-anions (CrO42- and Cr2O7

2-) are used

commonly as oxidising agents.

i) Write the electronic configuration of chromium in the following substances:

I. Cr(s) ___________________________________________________

II. Cr(OH)3(s) ___________________________________________________

III. K2Cr2O7(aq) ___________________________________________________

[3]

(b) Given that orange acidified potassium dichromate(VI) solution is able to oxidise primary

alcohols to their respective carboxylic acids while itself is reduced to form green

chromium(III) ion.

i) Given the following half equation for the reduction of dichromate(VI), write the half

equation for the oxidation of butan-1-ol to butanoic acid, and hence write the

balanced redox equation for the reaction of acidified potassium dichromate(VI) with

butan-1-ol.

Cr2O72- + 14H+ + 6e- 2Cr3+ + 7H2O

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1. (b) ii) A chemist extracted 5.00 g from an organic sample labelled as F and dissolved it in

deionised water and diluted it to 250 cm3 through a standard flask, and labelled it as

FA1.

An aliquot of 10.0 cm3 of FA1 was extracted and titrated against a standard solution

of 0.05 mol dm-3 acidified potassium dichromate(VI). The experiment was repeated

and an average titre volume of 25.35 cm3 was obtained. Using your derived

equation in (b)(i) and assuming that butan-1-ol is the only substance that could be

oxidised in F, determine the percentage composition by mass of butan-1-ol in F.

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2. (a) For the following synthesis, suggest the structural formula of compounds G, H and J. For

reactions I and II, suggest reagents and/or conditions. Fill in your answers in the table

below.

Compound G Compound H Compound J

Reagents and Conditions

Reaction I

Reaction II

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2. (b) For each of the following pairs of compounds,

i) suggest a chemical test, stating clearly the reagents and conditions, that could be

used to distinguish the compound on the left from the compound on the right.

ii) state clearly the observations that could be taken, and

iii) write out the balanced equation for the positive tests.

I. C6H5Br and CH3CH2CH2Cl, and

i) Reagents and conditions

ii) Observations

iii) Balanced Equation(s)

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2. (b) For each of the following pairs of compounds,

i) suggest a chemical test, stating clearly the reagents and conditions, that could be

used to distinguish the compound on the left from the compound on the right.

ii) state clearly the observations that could be taken, and

iii) write out the balanced equation for the positive tests.

II. hex-1-ene and hexane

i) Reagents and conditions

ii) Observations

iii) Balanced Equation(s)

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