ZIMSEC A Level Chemistry Paper 2 November 2017

Question 101

[1 marks]electrochemistry

A cell is set up with a platinum electrode in

Fe^{3+}/Fe^{2+}

solution joined to a nickel electrode in

Ni^{2+}

solution. In the external circuit the electrons flow

Ain both directions equally
Bfrom the platinum electrode to the nickel electrode
Cfrom the nickel electrode to the platinum electrode
Dthrough the salt bridge to the nickel electrode

Question 102

[1 marks]electrochemistry

The function of the salt bridge in an electrochemical cell is to

Aincrease the voltage of the cell
Bcarry electrons between the half cells
Cprevent the solutions from evaporating
Dcomplete the circuit and maintain electrical neutrality

Question 103

[1 marks]electrochemistry

Given

E^\theta(Fe^{3+}/Fe^{2+}) = +0.77\ V

and

E^\theta(Ni^{2+}/Ni) = -0.25\ V

, the e.m.f. of the cell is

A $+0.52\ V$
B $+1.02\ V$
C $+1.27\ V$
D $+2.02\ V$

Question 104

[1 marks]electrochemistry

For an electrode to be under standard conditions, its temperature, pressure and solute concentration must be

A310 K, 100 kPa and 2 mol dm^-3
B298 K, 100 kPa and 1 mol dm^-3
C273 K, 100 kPa and 1 mol dm^-3
D298 K, 200 kPa and 0.1 mol dm^-3

Question 105

[2 marks]electrochemistry

Using

E^\theta(Fe^{3+}/Fe^{2+}) = +0.77\ V

and

E^\theta(Ni^{2+}/Ni) = -0.25\ V

, deduce and write the half-equation for the reaction that occurs at the cathode of this cell.

Answer this when you sit the paper.

Question 106

[2 marks]electrochemistry

Using

E^\theta(Fe^{3+}/Fe^{2+}) = +0.77\ V

and

E^\theta(Ni^{2+}/Ni) = -0.25\ V

, deduce and write the half-equation for the reaction that occurs at the anode of this cell.

Answer this when you sit the paper.

Question 201

[1 marks]acids and bases

The number of moles of hydrochloric acid in

25.0\ cm^3

0.03\ mol\,dm^{-3}

solution is

A $7.50 \times 10^{-2}$
B $3.00 \times 10^{-4}$
C $7.50 \times 10^{-4}$
D $1.20 \times 10^{-3}$

Question 202

[1 marks]acids and bases

25.0\ cm^3

0.03\ mol\,dm^{-3}

hydrochloric acid is diluted with

15.0\ cm^3

of water. The concentration of the diluted acid, in

mol\,dm^{-3}

, is

A0.0113
B0.0188
C0.0300
D0.0500

Question 203

[1 marks]acids and bases

25.0\ cm^3

of sodium hydroxide solution contains

1.50 \times 10^{-3}

mol of NaOH. At 298 K its pH is

A1.22
B11.30
C12.78
D13.00

Question 204

[2 marks]acids and bases

A strong acid differs from a weak acid in that a strong acid

Acan only ever be monoprotic, never diprotic or triprotic
Balways has a lower pH than any weak acid of the same concentration
Cdissociates (ionises) completely in aqueous solution
Dcontains a higher percentage of hydrogen by mass than a weak acid

Question 205

[1 marks]acids and bases

Complete the definition: in the Bronsted-Lowry theory, a base is a proton

Answer this when you sit the paper.

Question 206

[2 marks]acids and bases

A 25.0 cm^3 sample of sodium hydroxide solution contains

1.50 \times 10^{-3}

mol of NaOH. Calculate the pOH of this solution.

Answer this when you sit the paper.

Question 207

[2 marks]acids and bases

A buffer solution is best described as one that

Aresists a change in pH when small amounts of acid or base are added to it
Bcontains only a single dissolved acid with no other species present
Chas a pH of exactly 7 regardless of what is added to it
Dneutralises completely any acid or base added to it

Question 208

[1 marks]acids and bases

Give an example of a buffer solution mixture.

Answer this when you sit the paper.

Question 301

[1 marks]transition elements

The electronic configuration of the

Cr^{3+}

ion is

A $[Ar]3d^3$
B $[Ar]3d^4$
C $[Ar]3d^54s^1$
D $[Ar]3d^34s^2$

Question 302

[1 marks]transition elements

The oxidation state of vanadium in

[VO(H_2O)_5]^{2+}

A $+2$
B $+3$
C $+4$
D $+5$

Question 303

[1 marks]transition elements

Iron is used as a catalyst in the Haber process. This is an example of

Ahomogeneous catalysis
Bautocatalysis
Cenzyme catalysis
Dheterogeneous catalysis

Question 304

[1 marks]transition elements

A transition element is best defined as a d-block element that

Ahas a fully filled d subshell in all of its common ions
Bis found only in Groups 1 and 2 of the periodic table
Cdoes not form coloured compounds or complex ions
Dforms at least one stable ion with a partially filled d subshell

Question 305

[2 marks]transition elements

Which row correctly gives the oxidation state of the transition metal in each of

CrO_4^{2-}

and

[CuCl_2]^-

A $CrO_4^{2-}$ : chromium is $+6$ ; $[CuCl_2]^-$ : copper is $+2$
B $CrO_4^{2-}$ : chromium is $+2$ ; $[CuCl_2]^-$ : copper is $+1$
C $CrO_4^{2-}$ : chromium is $+3$ ; $[CuCl_2]^-$ : copper is $+2$
D $CrO_4^{2-}$ : chromium is $+6$ ; $[CuCl_2]^-$ : copper is $+1$

Question 306

[2 marks]transition elements

Which balanced ionic equation correctly represents the oxidation of chromium(III) to chromate(VI) by hydrogen peroxide in alkaline conditions?

A $2Cr^{3+} + 3H_2O_2 + 10OH^- \rightarrow 2CrO_4^{2-} + 8H_2O$
B $2Cr^{3+} + 3H_2O_2 + 4OH^- \rightarrow 2CrO_4^{2-} + 5H_2O$
C $Cr^{3+} + H_2O_2 + 2OH^- \rightarrow CrO_4^{2-} + 2H_2O$
D $2Cr^{3+} + 3H_2O_2 \rightarrow 2CrO_4^{2-} + 6H^+$

Question 307

[2 marks]transition elements

Which pair correctly matches a transition metal catalyst with the industrial process it catalyses?

Anickel - Ostwald process (nitric acid production)
Biron - Haber process (ammonia synthesis)
Ciron - Contact process (sulfuric acid production)
Dvanadium(V) oxide - Haber process

Question 401

[1 marks]organic chemistry

A hydrocarbon contains 90.56 % carbon and 9.44 % hydrogen by mass. Its empirical formula is

A $CH$
B $C_2H_3$
C $C_4H_5$
D $C_8H_{10}$

Question 402

[1 marks]organic chemistry

The hydrocarbon of empirical formula

C_4H_5

has a relative molecular mass of 106. Its molecular formula is

A $C_4H_5$
B $C_6H_6$
C $C_8H_{10}$
D $C_{12}H_{15}$

Question 403

[1 marks]organic chemistry

One isomer of

C_8H_{10}

gives only a single mononitro product on nitration. That isomer is

A1,4-dimethylbenzene
Bethylbenzene
C1,2-dimethylbenzene
D1,3-dimethylbenzene

Question 404

[3 marks]organic chemistry

Which set of names correctly identifies, in order: the

C_8H_{10}

isomer with methyl groups at the 1,2-positions, the isomer with methyl groups at the 1,3-positions, and the isomer with a single ethyl group and no methyl groups?

Aethylbenzene, 1,2-dimethylbenzene, 1,3-dimethylbenzene
B1,2-dimethylbenzene, 1,3-dimethylbenzene, ethylbenzene
C1,3-dimethylbenzene, 1,2-dimethylbenzene, ethylbenzene
D1,2-dimethylbenzene, 1,4-dimethylbenzene, ethylbenzene

Question 405

[2 marks]organic chemistry

Unlike 1,4-dimethylbenzene, both 1,2-dimethylbenzene and 1,3-dimethylbenzene give more than one mononitro product on nitration because

Athey are less soluble in the nitrating mixture than 1,4-dimethylbenzene
Btheir methyl groups withdraw electron density unevenly around the ring
Cthey react by addition rather than electrophilic substitution
Dtheir remaining ring positions are not all chemically equivalent, so substitution can occur at more than one position

Question 406

[1 marks]organic chemistry

The type of mechanism by which the nitrating mixture (conc.

HNO_3

/conc.

H_2SO_4

) reacts with an aromatic ring is called

Answer this when you sit the paper.

Question 501

[1 marks]organic chemistry

Butanal,

CH_3CH_2CH_2CHO

, is converted in one step into compound A, which is used to make an ester. A and the reagent are

Abutanoic acid; acidified $K_2Cr_2O_7$ under reflux
Bbutanone; acidified $KMnO_4$
Cbutane; $H_2$ with a nickel catalyst
Dbutan-1-ol; $NaBH_4$

Question 502

[1 marks]organic chemistry

Propanone is reduced by sodium tetrahydridoborate to compound B. B is

Apropan-1-ol
Bpropan-2-ol
Cpropanoic acid
Dpropanal

Question 503

[1 marks]organic chemistry

Butanoic acid and propan-2-ol are heated with a little concentrated sulphuric acid to give

CH_3(CH_2)_2COOCH(CH_3)_2

. The type of reaction is

Aaddition
Besterification
Chydrolysis
Doxidation

Question 504

[2 marks]organic chemistry

Which pair correctly gives the structural formulas of compound A (from oxidising

CH_3CH_2CH_2CHO

) and compound B (from reducing

CH_3COCH_3

AA = $CH_3CH_2CH_2COOH$ ; B = $(CH_3)_2CHOH$
BA = $CH_3CH_2CH_2CH_2OH$ ; B = $(CH_3)_2CHOH$
CA = $CH_3CH_2CH_2COOH$ ; B = $CH_3CH_2CH_2OH$
DA = $CH_3CH_2CHO$ ; B = $CH_3COCH_2OH$

Question 505

[1 marks]organic chemistry

Besides sodium tetrahydridoborate (

NaBH_4

), propanone could also be reduced to propan-2-ol using

Aacidified potassium dichromate(VI), $K_2Cr_2O_7$ , under reflux
Bconcentrated sulfuric acid, heated
Clithium aluminium hydride ( $LiAlH_4$ ) in dry ether, followed by dilute acid
DTollens' reagent, warmed gently

Question 506

[2 marks]organic chemistry

Name the ester formed in reaction 3,

CH_3(CH_2)_2COOCH(CH_3)_2

Answer this when you sit the paper.

Question 507

[1 marks]organic chemistry

In reaction 3, the role of the concentrated sulfuric acid is to act as a

Answer this when you sit the paper.

Question 508

[1 marks]organic chemistry

The condition needed for the oxidation of butanal to butanoic acid (reaction 1) is

Answer this when you sit the paper.

Question 509

[1 marks]organic chemistry

Besides the ester, the esterification in reaction 3 also produces

Answer this when you sit the paper.

Chemistry Paper 2 November 2017

Sit this paper online

The questions

Question 101

Question 102

Question 103

Question 104

Question 105

Question 106

Question 201

Question 202

Question 203

Question 204

Question 205

Question 206

Question 207

Question 208

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 501

Question 502

Question 503

Question 504

Question 505

Question 506

Question 507

Question 508

Question 509

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