ZIMSEC A Level Chemistry Paper 2 November 2006

Question 101

[1 marks]chemical equilibrium

0.6 mol of

SO_2

and 2.0 mol of

O_2

were mixed and allowed to reach equilibrium,

2SO_2(g) + O_2(g) \rightleftharpoons 2SO_3(g)

. At equilibrium 0.4 mol of

SO_3

was present. The amounts of

SO_2

and

O_2

remaining are

A0.4 mol and 1.8 mol
B0.6 mol and 1.8 mol
C0.2 mol and 1.6 mol
D0.2 mol and 1.8 mol

Question 102

[1 marks]chemical equilibrium

At equilibrium the mixture contained 0.2 mol

SO_2

, 1.8 mol

O_2

and 0.4 mol

SO_3

at a total pressure of 1.2 atm.

K_p

, in

atm^{-1}

, is

A0.22
B2.22
C4.44
D8.89

Question 103

[1 marks]chemical equilibrium

The forward reaction

2SO_2(g) + O_2(g) \rightleftharpoons 2SO_3(g)

has

\Delta H = -197\ kJ\,mol^{-1}

. Lowering the temperature from 400 °C to 300 °C would

Aincrease the equilibrium partial pressure of $SO_3$
Bdecrease the equilibrium partial pressure of $SO_3$
Chave no effect on the position of equilibrium
Dincrease the value of $K_p$ but not the yield

Question 104

[2 marks]chemical equilibrium

Which row correctly gives the shapes of the

SO_2

and

SO_3

molecules predicted by VSEPR theory?

A $SO_2$ : trigonal planar; $SO_3$ : bent
B $SO_2$ : pyramidal; $SO_3$ : linear
C $SO_2$ : bent; $SO_3$ : trigonal planar
D $SO_2$ : linear; $SO_3$ : pyramidal

Question 105

[2 marks]chemical equilibrium

In the accepted dot-and-cross diagram of

SO_2

, the bonding between the sulphur atom and each oxygen atom consists of

Atwo dative covalent bonds, with both oxygen atoms donating the shared electron pairs to sulphur
Bone triple covalent bond to one oxygen atom and no covalent bond at all to the other oxygen atom
Cone double covalent bond to one oxygen atom and one dative (coordinate) bond to the other oxygen atom
Dtwo separate single covalent bonds, one to each oxygen atom, similar to two ordinary single bonds

Question 106

[2 marks]chemical equilibrium

Which statement about the accepted dot-and-cross structure of

SO_3

is correct?

AIt has three dative (coordinate) bonds, with each oxygen atom donating its own shared pair.
BIt has one triple covalent bond and two single covalent bonds, with no lone pair on sulphur.
CIt has three separate single covalent bonds, one to each oxygen atom, with no dative bonds present.
DIt has one double covalent bond and two dative (coordinate) bonds, each donated entirely by sulphur.

Question 107

[1 marks]chemical equilibrium

For the equilibrium

2SO_2(g) + O_2(g) \rightleftharpoons 2SO_3(g)

, the correct expression for

K_p

in terms of the equilibrium partial pressures is

A $K_p = \dfrac{p(SO_2)^2\cdot p(O_2)}{p(SO_3)^2}$
B $K_p = \dfrac{p(SO_3)^2}{p(SO_2)^2\cdot p(O_2)^2}$
C $K_p = \dfrac{p(SO_3)^2}{p(SO_2)^2\cdot p(O_2)}$
D $K_p = \dfrac{p(SO_3)}{p(SO_2)\cdot p(O_2)}$

Question 108

[2 marks]chemical equilibrium

Sulphur dioxide emissions into the atmosphere must be carefully controlled mainly because

SO_2

Adissolves in atmospheric moisture to form acidic solutions, contributing to acid rain and irritating the respiratory tract.
Breacts with atmospheric oxygen high in the stratosphere to destroy the ozone layer directly.
Ccombines with atmospheric nitrogen to form harmless, insoluble nitrogen-sulphur salts.
Dis rapidly converted to elemental sulphur in air, forming yellow deposits on buildings.

Question 109

[1 marks]chemical equilibrium

State one possible source of atmospheric sulphur dioxide other than the contact process.

Answer this when you sit the paper.

Question 201

[1 marks]group VII chemistry

Excess chlorine was bubbled into

100\ cm^3

of hot concentrated sodium hydroxide according to

3Cl_2 + 6NaOH \rightarrow NaClO_3 + 5NaCl + 3H_2O

, giving 21.3 g of

NaClO_3

(

M_r = 106.5

). The concentration of the sodium hydroxide, in

mol\,dm^{-3}

, is

A2.0
B6.0
C12.0
D20.0

Question 202

[1 marks]group VII chemistry

The oxidation number of chlorine in

NaClO_4

A $+1$
B $+3$
C $+5$
D $+7$

Question 203

[1 marks]group VII chemistry

On heating just above its melting point, sodium chlorate(V) reacts as

4ClO_3^- \rightarrow 3ClO_4^- + Cl^-

. This reaction is an example of

Ahydrolysis
Bdisproportionation
Cpolymerisation
Dneutralisation

Question 204

[2 marks]group VII chemistry

The correctly balanced equation for chlorine reacting with hot concentrated sodium hydroxide to give sodium chlorate(V), sodium chloride and water is

A $2Cl_2 + 4NaOH \rightarrow NaClO_3 + 3NaCl + 2H_2O$
B $3Cl_2 + 6NaOH \rightarrow NaClO_3 + 5NaCl + 3H_2O$
C $3Cl_2 + 6NaOH \rightarrow NaClO_3 + 3NaCl + 3H_2O$
D $3Cl_2 + 5NaOH \rightarrow NaClO_3 + 5NaCl + 3H_2O$

Question 205

[2 marks]group VII chemistry

Which row correctly pairs each chlorine-containing compound with one of its everyday uses?

A $NaClO_3$ : bleaching agent; $NaCl$ : weedkiller
B $NaClO_3$ : weedkiller; $NaCl$ : food seasoning
C $NaClO_3$ : food seasoning; $NaCl$ : weedkiller
D $NaClO_3$ : food seasoning; $NaCl$ : bleaching agent

Question 206

[2 marks]group VII chemistry

For the disproportionation

4ClO_3^- \rightarrow 3ClO_4^- + Cl^-

, which row correctly gives the mole ratio of

ClO_4^-

Cl^-

formed, and the oxidation number of chlorine in the

Cl^-

product?

Aratio 3:1; oxidation number $-1$
Bratio 3:1; oxidation number $+1$
Cratio 1:3; oxidation number $+7$
Dratio 4:1; oxidation number $+5$

Question 207

[1 marks]group VII chemistry

When excess chlorine is bubbled into hot concentrated sodium hydroxide, sodium chlorate(V) forms alongside a second chlorine-containing product. This second product is

Answer this when you sit the paper.

Question 301

[1 marks]organic chemistry / polymers

The reagent and conditions used to convert ethanol into ethene are

Aaqueous NaOH under reflux
Bacidified $K_2Cr_2O_7$ under reflux
Csteam at 300 °C and 60 atm
Dconcentrated $H_2SO_4$ at 170 °C

Question 302

[1 marks]organic chemistry / polymers

Ethane-1,2-diol reacts with a second monomer to give polymer B. The second monomer is

Aphenylethene
Bbenzene-1,4-dicarboxylic acid
Cethanedioic acid
D1,6-diaminohexane

Question 303

[1 marks]organic chemistry / polymers

Polymer B is formed by condensation polymerisation and is commonly known as

Apolythene
Bnylon
Cperspex
DTerylene

Question 304

[2 marks]organic chemistry / polymers

Which row correctly gives the type of reaction I (ethanol to ethene) and the reagent/conditions for reaction II (ethene to ethane-1,2-diol)?

Aelimination (dehydration); cold dilute acidified $KMnO_4(aq)$
Baddition; steam at 300 °C and 60 atm with a phosphoric acid catalyst
Csubstitution; hot concentrated $KMnO_4(aq)$
Delimination (dehydration); concentrated $H_2SO_4$ under reflux

Question 305

[2 marks]organic chemistry / polymers

Reaction III, in which ethane-1,2-diol and benzene-1,4-dicarboxylic acid join to form polymer B, is classified as condensation polymerisation because

Aone monomer type reacts with itself only, releasing hydrogen gas as the only by-product.
Ba single monomer with a C=C double bond opens up and joins to the next monomer with no by-product formed.
Ctwo different monomers, each with two reactive functional groups, join together with the elimination of a small molecule (water) at every linkage.
Dthe monomers join purely through weak intermolecular forces, with no covalent bonds formed between them.

Question 306

[2 marks]organic chemistry / polymers

Which row correctly describes the class of compound that reacts with ethane-1,2-diol to form polymer B, and the type of bond formed between them?

Aa monocarboxylic acid; joined by an ester bond
Ba dicarboxylic acid; joined by an ester bond
Ca diol; joined by an ester bond
Da diamine; joined by an amide bond

Question 307

[1 marks]organic chemistry / polymers

A polymer formed by condensing a diol with a dicarboxylic acid, joined by ester linkages, is generally called a

Answer this when you sit the paper.

Question 401

[1 marks]organic chemistry

2-propylgallate is the propan-2-yl ester of 3,4,5-trihydroxybenzoic acid. Two functional groups present in it are

Acarboxylic acid and amide
Baldehyde and ester
Cphenol and ester
Dphenol and ketone

Question 402

[1 marks]organic chemistry

2-propylgallate is refluxed with dilute sulphuric acid to give two organic compounds. The type of reaction is

Acondensation
Besterification
Chydrolysis
Doxidation

Question 403

[1 marks]organic chemistry

One product, A, gives a yellow precipitate with alkaline iodine solution. A is

Apropan-2-ol
Bpropanoic acid
Cethanol
Dpropan-1-ol

Question 404

[2 marks]organic chemistry

Which row correctly gives the colour change observed and the organic product formed when ethane-1,2-diol is refluxed with excess acidified potassium dichromate(VI)?

Aorange to green; ethanol
Bpurple to colourless; ethanedioic acid
Cgreen to orange; ethanoic acid
Dorange to green; ethanedioic acid

Question 405

[2 marks]organic chemistry

Phenol is a stronger acid than ethanol mainly because

Athe ethoxide ion formed on ionisation is stabilised by delocalisation of its negative charge into an alkyl chain.
Bthe phenoxide ion formed on ionisation is stabilised by delocalisation of its negative charge into the benzene ring.
Cphenol has a lower relative molecular mass than ethanol, so it ionises more readily in water.
Dthe O-H bond in phenol is a weaker, longer bond than the O-H bond in ethanol, purely due to ring strain.

Question 406

[1 marks]organic chemistry

Ranked from strongest to weakest acid, the correct order for ethanol, phenol and water is

Answer this when you sit the paper.

Question 407

[1 marks]organic chemistry

Hydrolysis of 2-propylgallate with dilute sulphuric acid gives propan-2-ol (A) and a second organic product, B. B is

Answer this when you sit the paper.

Question 408

[2 marks]organic chemistry

Which row correctly gives the observation when A (propan-2-ol) is treated with alkaline iodine solution, and when B (gallic acid) is treated with neutral iron(III) chloride?

AA: yellow precipitate of triiodomethane; B: violet colouration
BA: no visible change; B: no visible change
CA: yellow precipitate of triiodomethane; B: no colour change
DA: no visible change; B: violet colouration

Chemistry Paper 2 November 2006

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The questions

Question 101

Question 102

Question 103

Question 104

Question 105

Question 106

Question 107

Question 108

Question 109

Question 201

Question 202

Question 203

Question 204

Question 205

Question 206

Question 207

Question 301

Question 302

Question 303

Question 304

Question 305

Question 306

Question 307

Question 401

Question 402

Question 403

Question 404

Question 405

Question 406

Question 407

Question 408

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