chemistry higher level paper 1 - smiletutor · 3 turn over 1. which compound s molecular formula is...

N15/4/CHEMI/HPM/ENG/TZ0/XX

ChemistryHigher levelPaper 1

© International Baccalaureate Organization 201515 pages

Instructions to candidates

• Do not open this examination paper until instructed to do so.• Answer all the questions.• For each question, choose the answer you consider to be the best and indicate your choice on

the answer sheet provided.• The periodic table is provided for reference on page 2 of this examination paper.• The maximum mark for this examination paper is [40 marks].

1 hour

Friday 13 November 2015 (afternoon)

8815 – 6101

– 2 –

88 Ra

(226

)

56 Ba

137.

34

38 Sr87

.62

20 Ca

40.0

8

12 Mg

24.3

1

4 Be

9.012

‡†

89 ‡

Ac

(227

)

57 †

La13

8.91

39 Y88

.91

21 Sc 44.9

6

90 Th23

2.04

58 Ce

140.

12

72 Hf

178.

49

40 Zr 91.2

2

22 Ti47

.90

91 Pa23

1.04

59 Pr14

0.91

73 Ta18

0.95

41 Nb

92.9

1

23 V50

.94

92 U23

8.03

60 Nd

144.

24

74 W18

3.85

42 Mo

95.9

4

24 Cr

52.0

0

55 Cs

132.

91

37 Rb

85.4

7

19 K39

.10

11 Na

22.9

9

3 Li 6.941 H 1.011 Fr87 (223

)

Ato

mic

num

ber

Elem

ent

Rel

ativ

e A

tom

ic M

ass

93 Np

(237

)

61 Pm14

6.92

75 Re

186.

21

43 Tc 98.9

1

25 Mn

54.9

4

94 Pu (242

)

62 Sm15

0.35

76 Os

190.

21

44 Ru

101.

07

26 Fe 55.8

5

95 Am

(243

)

63 Eu15

1.96

77 Ir19

2.22

45 Rh

102.

91

27 Co

58.9

3

96 Cm

(247

)

64 Gd

157.

25

78 Pt19

5.09

46 Pd10

6.42

28 Ni

58.7

1

97 Bk

(247

)

65 Tb15

8.92

79 Au

196.

97

47 Ag

107.

87

29 Cu

63.5

5

The

Perio

dic

Tabl

e

98 Cf

(251

)

66 Dy

162.

50

80 Hg

200.

59

48 Cd

112.

40

30 Zn 65.3

7

99 Es (254

)

67 Ho

164.

93

81 Tl20

4.37

49 In11

4.82

31 Ga

69.7

2

13 Al

26.9

8

5 B10

.81

3

100

Fm (257

)

68 Er16

7.26

82 Pb20

7.19

50 Sn11

8.69

32 Ge

72.5

9

14 Si28

.09

6 C12

.01

4

101

Md

(258

)

69 Tm16

8.93

83 Bi

208.

98

51 Sb12

1.75

33 As

74.9

2

15 P30

.97

7 N14

.01

5

102

No

(259

)

70 Yb17

3.04

84 Po (210

)

52 Te12

7.60

34 Se78

.96

16 S32

.06

8 O16

.00

6

103

Lr (260

)

71 Lu17

4.97

85 At

(210

)

53 I12

6.90

35 Br

79.9

0

17 Cl

35.4

5

9 F19

.00

7

86 Rn

(222

)

54 Xe13

1.30

36 Kr

83.8

0

18 Ar

39.9

5

10 Ne

20.1

8

2 He

4.000


– 3 –

Turn over

1. Which compound’s molecular formula is the same as its empirical formula?

A. C2H5OH

B. CH3COOH

C. C6H6

D. C8H18

2. The equation for the complete combustion of propene, C3H6 , is shown below.

2C3H6 (g) + 9O2 (g) → 6CO2 (g) + 6H2O (l)

Which mixture, when ignited, will lead to incomplete combustion and the formation of CO (g)?

A. 2 dm3 of propene and 10 dm3 of oxygen

B. 0.5 dm3 of propene and 2.3 dm3 of oxygen

C. 1 dm3 of propene and 4 dm3 of oxygen

D. 3 dm3 of propene and 14 dm3 of oxygen

3. What is the percentage yield when 1.1 g of ethanal, CH3CHO, is obtained from 4.6 g of ethanol, CH3CH2OH? Mr (CH3CH2OH) = 46; Mr (CH3CHO) = 44

CH3CH2OH (l) + [O] → CH3CHO (l) + H2O (l)

A. 1 1 46 10044 4 6

..

× ××

B. 1 1 1004 6

..

×

C. 4 6 44 1004 6 1 1

.. .× ×

×

D. 1 1 4644 4 6

..

××


– 4 –

4. Which stage of operation immediately follows ionization in the mass spectrometer?

A. Acceleration

B. Deflection

C. Detection

D. Vaporization

5. Whichstatementiscorrectaboutthefirstionizationenergiesofconsecutiveelementsshownin the graph?

Firs

t ion

izat

ion

ener

gy /

kJ m

ol–1

500

1000

1500

2000

3 4 5 6 7 8 9 10

Atomic number

[Source:ValuesfromNuffiedAdvanceScience-BookofData,RevisedEdition(1984)]

A. ThegraphfallsbetweenBeandBbecausethereisanelectroninthethirdenergylevel.

B. The graph increases from B to N because the atomic radius is increasing.

C. The graph increases from Li to Ne because the number of electrons is increasing.

D. ThegraphfallsbetweenBeandBbecausetheouterelectroninBisinapsub-level.


– 5 –

Turn over

6. Whichelementhasthegreatestfirstionizationenergy?

A. Al

B. Ar

C. Cl

D. Cs

7. Which elements are in the same group of the periodic table?

A. Ca,Na,Rb,Sr

B. Al, Ar, Cl, S

C. Au, Hg, Pb, Pt

D. As, Bi, P, Sb

8. Whichpropertyoftransitionmetalsenablesthemtobehaveascatalysts?

A. High melting point

B. Variable oxidation number

C. High density

D. Splitdsub-levels

9. Which statement best describes the lattice structure of solid sodium chloride?

A. Eachsodiumionissurroundedbyonechlorideion.

B. Eachchlorideionissurroundedbytwosodiumions.

C. Eachchlorideionissurroundedbyfoursodiumions.

D. Eachsodiumionissurroundedbysixchlorideions.

10. Which compound is most likely to contain ionic bonding?

A. ClO2

B. CsCl

C. SCl2

D. SiCl4


– 6 –

11. Which molecule is polar?

A. C2H6

B. CH2Cl2

C. CO2

D. CCl4

12. What is the shape of the hexacyanoferrate(III) ion, [Fe(CN)6]3-?

A. Square planar

B. Hexagonal

C. Octahedral

D. Trigonal bipyramidal

13. Which set contains two or more species with delocalized π electrons?

A. CH3CH3 , H2C=CH2 , H2C=O

B. NaCl , C6H6 , H2C=O

C. CO32- , C6H6 , C6H12

D. O2 , CH3COCH3 , CH3COOCH3

14. Which of the following changes are exothermic?

I. H2SO4 (aq) + 2NaOH (aq) → Na2SO4 (aq) + 2H2O (l)

II. 2C8H18 (g) + 17O2 (g) → 16CO (g) + 18H2O (g)

III. C8H18 (g) → C8H18 (l)

A. I and II only

B. I and III only

C. II and III only

D. I, II and III


– 7 –

Turn over

15. Which change represents the standard enthalpy change of formation?

A. The formation of 1 mol of a compound in its standard state from its gaseous atoms

B. The formation of 1 mol of a compound in its standard state from its elements

C. The formation of 1 mol of a compound in its standard state from its gaseous atoms in their standard states

D. The formation of 1 mol of a compound in its standard state from its elements in their standard states

16. Whichequationrepresentselectronaffinity?

A. C (g) + e- → C- (g)

B. Na+ (aq) + e- → Na (s)

C. 12 Cl2 (g) + e- → Cl- (g)

D. B (g) + e- → B+ (g) + 2e-

17. Whichcombinationresultsinanioniccompoundhavingthegreatest magnitude of lattice enthalpy?

Sum of ionic radii Ionic charges

A. small large

B. large large

C. large small

D. small small

18. Underwhichconditionsdoesasampleofthesamemassofcarbondioxidehavethelowest entropyvalue?

A. Solid at high temperature

B. Solid at low temperature

C. Gas at high temperature

D. Gas at low temperature


– 8 –

19. CurvesIandIIrepresentsamplesofthesamegasataconstantpressurebutatdifferenttemperatures.TheareasundercurvesIandIIareequal.WhatdoescurveIIrepresent?

Pro

babi

lity

of m

olec

ules

w

ith k

inet

ic e

nerg

y E

I

II

Kinetic energy E

A. CurveIIisatthelowertemperatureandtherearelessmoleculesinthesample.

B. CurveIIisatthelowertemperatureandtherearethesamenumberofmoleculesin the samples.

C. CurveIIisatthehighertemperatureandtherearemoremoleculesinthesample.

D. CurveIIisatthehighertemperatureandtherearethesamenumberofmoleculesin the samples.


– 9 –

Turn over

20. Thegraphshowsaplotforareactionwithsecond-orderkinetics.Howshouldtheaxesbelabelled?

y

x

x-axis y-axis

A. concentration time

B. time concentration

C. rate concentration

D. concentration rate

21. Which factors affect the rate constant, k, of a reaction?

I. Catalyst

II. Concentration of reactants

III. Temperature

A. I and II only

B. I and III only

C. II and III only

D. I, II and III


– 10 –

22. Which best describes a reaction in a state of equilibrium?

A. Theratesoftheforwardandreversereactionsarezeroandtheconcentrationsofproducts and reactants are equal.

B. Therateoftheforwardreactionequalstherateofthereversereactionandthe concentrations of products and reactants are equal.

C. Theratesoftheforwardandreversereactionsarezeroandtheconcentrationsofproducts and reactants are constant.

D. Therateoftheforwardreactionequalstherateofthereversereactionandthe concentrations of products and reactants are constant.

23. The equilibrium concentrations of X, Y, Z and W are 1, 2, 4 and 2 mol dm–3respectively.

X (g) + 2Y (g) Z (g) + W (g)

Whatisthevalueoftheequilibriumconstant,Kc?

A. 0.25

B. 0.5

C. 2

D. 4

24. Which of the following molecules can act as a Lewis acid but not as a Brønsted–Lowry acid?

A. BF3

B. PCl3

C. NH3

D. H2O

25. Which is a 0.001 mol dm-3 solution of a weak acid?

Conductivity pH

A. poor 5

B. good 7

C. poor 10

D. good 3


– 11 –

Turn over

26. What is the order of increasing acid strength? Approximate Ka and pKavaluesat298Karegiven.

Ka pKa

ClCH2COOH 1×10-3 C6H5OH 10.0

CH3CH2COOH 1×10-5 C6H5NH3+ 4.6

A. ClCH2COOH < CH3CH2COOH < C6H5NH3+ < C6H5OH

B. C6H5OH < C6H5NH3+ < ClCH2COOH < CH3CH2COOH

C. C6H5OH < C6H5NH3+ < CH3CH2COOH < ClCH2COOH

D. C6H5OH < CH3CH2COOH < C6H5NH3+ < ClCH2COOH

27. Whichsolutions,mixedinequalconcentrationsandvolumes,formanacidbuffersolution?

A. HCl (aq) + NaCl (aq)

B. CH3CO2H (aq) + CH3CO2Na (aq)

C. CH3CO2H (aq) + NaOH (aq)

D. CH3CO2H (aq) + CH3CH2CO2H (aq)

28. Whichsaltformsthemostacidicsolutionwhendissolvedinwater?

Salt Ionic radius of cation / 10–12 m

A. CrCl3 63

B. FeCl2 76

C. MgCl2 65

D. NaCl 98


– 12 –

29. Whatisthebufferregionintheacid–basetitrationcurvesbelow?

Volume of alkali added Volume of alkali added0

5

10

0

5

10

pHpH

A

BC

D

30. Which element undergoes reduction in the following reaction?

(NH4)2Cr2O7 (s) → N2 (g) + 4H2O (l) + Cr2O3 (s)

A. Cr

B. H

C. N

D. O

31. Which best describes reduction?

A. Increase in oxidation number and gain of electrons

B. Increase in oxidation number and loss of electrons

C. Decrease in oxidation number and gain of electrons

D. Decrease in oxidation number and loss of electrons


– 13 –

Turn over

32. What is E À, in V, for the following reaction?

VO2+ (aq) + 2H+ (aq) + V2+ (aq) → 2V3+ (aq) + H2O (l)

Standard electrode potential, E À / V

V2+ (aq) + 2e- V (s) -1.18

V3+ (aq) + e- V2+ (aq) -0.26

VO2+ (aq) + 2H+ (aq) + e- V3+ (aq) + H2O (l) +0.34

VO2+ (aq) + 2H+ (aq) + e- VO2+ (aq) + H2O (l) +1.00

A. -0.60

B. +0.08

C. +0.60

D. +1.26

33. Whatproductisformedatthepositiveelectrode(anode)when0.001moldm–3 H2SO4 (aq) is electrolysed?

A. Hydrogen

B. Oxygen

C. Sulfur

D. Sulfur dioxide

34. Which pair of compounds can be distinguished by reacting them with dilute bromine water in the dark?

A. CH3CH2COOH and CH3CH2CHO

B. CH3CH2CHCHCH3 and CH3CH2CH2CH2CH3

C. CH3CH2CH(CH3)2 and CH3CH2CH2CH2CH3

D. CH3CH2CH2CHBrCH3 and CH3CH2CHBrCH2CH3


– 14 –

35. Which compound is most soluble in water?

A. CH3CH2CHO

B. CH3CH2CH2CHO

C. CH3CH2CO2H

D. CH3CH2CH2CO2H

36. Whicharefeaturesofsuccessivemembersofahomologousseries?

I. Similar chemical properties II. Same general formula III. Differ by -CH2-

A. I and II only

B. I and III only

C. II and III only

D. I, II and III

37. Which formula represents propanenitrile?

A. CH3CH2CN

B. CH3CH2CH2CN

C. CH3CH2CH2NH2

D. CH3CH(NH2)CH3

38. Which halogenoalkane reacts fastest with warm NaOH (aq)?

A. (CH3)3CCl

B. (CH3)3CBr

C. CH3CH2CH2CH2Cl

D. CH3CH2CH2CH2Br


– 15 –

39. Which is the geometric isomer of cis-1,2-dichlorocyclopropane?

C

C C

H

Cl

H

Cl

C

C C

Cl

Cl

H

Cl

C

C C

H

Cl

Cl

H

C

C C

Cl

Cl

.B.A

C. D.

H

H

H

H

H

HH

H

40. Whichisthebest-fitlineorbest-fitcurveforthepointsplottedonthegraph?

A. B.

C. D.


N15/4/CHEMI/HP3/ENG/TZ0/XX

Candidate session number




• Write your session number in the boxes above.• Do not open this examination paper until instructed to do so.• Answer all of the questions from two of the options.• Write your answers in the boxes provided. • A calculator is required for this paper.• A clean copy of the chemistry data booklet is required for this paper.• The maximum mark for this examination paper is [50 marks].

Option Questions

Option A — Modern analytical chemistry 1 – 5

Option B — Human biochemistry 6 – 11

Option C — Chemistry in industry and technology 12 – 16

Option D — Medicines and drugs 17 – 22

Option E — Environmental chemistry 23 – 26

Option F — Food chemistry 27 – 32

Option G — Further organic chemistry 33 – 37

1 hour 15 minutes

Monday 16 November 2015 (morning)

8815 – 6103

44EP01

– 2 –

Option A — Modern analytical chemistry

1. Infrared (IR) spectroscopy is a powerful analytical technique.

(a) Describe how information from an IR spectrum can be used to identify the bonds in a molecule. [2]

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

(b) Explain which of the following compounds would produce the IR spectrum below by referring to the wavenumbers of the relevant peaks found in table 17 of the data booklet.

CH3CH2CH2CH2COOH CH3COOCH2CH (OH)CH3 CH3CH2CH2CH2CH2OH Compound A Compound B Compound C

Tran

smitt

ance

/ %

100

50

0

Wavenumber / cm−14000 3000 2000 1500 1000 500

[3]

[Source SDBSWeb, http://sdbs.db.aist.go.jp (National Institute of Advanced Industrial Science and Technology)]

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

(Option A continues on the following page)

44EP02


– 3 –

Turn over

(Option A, question 1 continued)

(c) Explain how the low resolution 1H NMR spectra of the three compounds in part (b) can be used to distinguish between them. Ignore chemical shifts. [3]

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

2. Atomic absorption (AA) spectroscopy is used to detect very low concentrations of metal ions.

(a) State one application of AA spectroscopy. [1]

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

(b) Describe the uses of the fuel and the monochromatic detector in the AA spectrophotometer. [2]

Fuel:

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

Monochromatic detector:

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


44EP03


– 4 –

(Option A continued)

3. Absorption and emission spectra can be used to identify elements.

(a) Distinguish between the processes within the atom that give rise to absorption and emission spectra. [2]

Absorption spectra:

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

Emission spectra:

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

(b) Outline how the emission spectrum of a sample of gaseous element is produced. [2]

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


44EP04


– 5 –

Turn over


4. Octyl salicylate and dioxybenzone are compounds used in sunscreens to absorb high energy ultraviolet (UV) radiation from the sun.

COO

OH

CH2

CHCH2

H2CCH3

CH2CH2

CH3 HO

C

OCH3

OHO

Octyl salicylate Dioxybenzone

(a) State the structural feature of the molecules that absorbs high energy UV radiation. [1]

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

(b) Predict which of the two molecules provides better protection against high energy UV radiation. Explain your reasoning. [3]

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


44EP05


– 6 –


5. Gas–liquid chromatography (GLC) can be used to determine the concentration of alcohol in a sample of blood. A simplified diagram of the apparatus is shown.

carrier gas

sampleinjection

injector oven ovencontaining coiled

column

detector

waste gases

signal toprocessor

processing unitand display

[Source: Adapted from www.chemguide.co.uk (2014)]

(a) State suitable materials for the stationary and mobile phases in GLC. [2]

Stationary phase:

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

Mobile phase:

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

(b) Explain how the substances in the blood sample are separated by GLC. [2]

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


44EP06


– 7 –

Turn over


(c) Outline how the concentration of alcohol is obtained from the GLC processing unit. [1]

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

(d) Suggest why GLC might not be suitable for determining the concentration of sugar in the blood. [1]

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

End of Option A

44EP07


– 8 –

Option B — Human biochemistry

6. Glucose is a carbohydrate. A skeletal structure is shown for one of the ring structures of glucose.

O

(a) (i) Draw the structure of β-glucose by adding the constituent atoms and groups to the diagram. [1]

(ii) State how the α-glucose would differ from the β-glucose. [1]

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

(b) β-glucose polymerizes by condensation to form cellulose. State the specific type of linkage formed between the monomer units. [1]

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

7. (a) Vitamins are micronutrients which are vital for good health.

Deduce the relative solubilities of vitamins C and D in water by referring to the structures shown in table 21 of the data booklet. [2]

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

(Option B continues on the following page)

44EP08


– 9 –

Turn over

(Option B, question 7 continued)

(b) The absence of micronutrients from the diet can cause significant health problems. Suggest three ways in which these problems could be solved. [3]

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

8. Insulin is a globular protein which controls cellular uptake of glucose. Glucose test strips impregnated with an enzyme can be used to detect glucose in urine.

(a) (i) Describe the mechanism of enzyme action by reference to its three-dimensional structure. [2]

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

(ii) Explain, with reference to the enzyme structure, why it is important to store the test strips below 40 °C. [2]

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


44EP09


– 10 –


(b) Lysine is one of the amino acids found in the polypeptide chain in insulin and its structure is shown in table 19 of the data booklet. It can exist in different structural forms depending on the pH of its solution.

Draw the structure of the most abundant form of lysine present under the following conditions.

[2]

At its isoelectric point:

At a pH well below its isoelectric point:

9. (a) Aerobic and anaerobic respiration in human beings can be represented by the following overall equations.

Aerobic: C6H12O6 + 6O2 → 6CO2 + 6H2O

Anaerobic: C6H12O6 → 2C3H6O3

Identify the process which: [1]

(i) releases most energy per mole of glucose.

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

(ii) is not shown by a redox equation.

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


44EP10


– 11 –

Turn over


(b) Cytochromes and hemoglobin are both involved in the process of respiration.Outline the role of each metal complex in respiration. [2]

Cytochromes:

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

Hemoglobin:

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

10. Hormones are regulatory substances produced in the body.

(a) Deduce the differences between progesterone and estradiol by naming their specific functional groups. The structures are given in table 21 of the data booklet. [2]

Two functional groups in progesterone:

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

Two functional groups in estradiol:

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


44EP11


– 12 –


(b) Anabolic steroids are closely related to testosterone. State one medical use of anabolic steroids and one example of abuse of these compounds. [2]

Medical use:

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

Example of abuse:

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

11. The discovery of the DNA double helix has led to many advances in our understanding of life processes. DNA profiling allows an individual to be identified by DNA analysis.

(a) Explain the key features of the double helical structure of DNA. [3]

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

(b) State one application of DNA profiling. [1]

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

End of Option B

44EP12


– 13 –

Turn over

Option C — Chemistry in industry and technology

12. The nickel–cadmium (NiCad) battery is rechargeable.

During discharge, the following half-reactions take place:

Cd (s) + 2OH− (aq) → Cd (OH)2 (s) + 2e−

NiO (OH) (s) + H2O (l) + e− → Ni (OH)2 (s) + OH− (aq)

(a) State the name of the substance used as the negative electrode (anode) during discharge and the name of the substance used as the electrolyte. [2]

Negative electrode (anode):

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

Electrolyte:

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

(b) When the NiCad battery is recharged, the electrodes are connected to a power supply and electrolysis occurs. State the half-equations for the chemical reactions during recharging. [1]

Negative electrode (cathode):

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

Positive electrode (anode):

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

(Option C continues on the following page)

44EP13


– 14 –

(Option C, question 12 continued)

(c) Compare rechargeable batteries and fuel cells. [3]

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

13. Nanotechnology manipulates the properties of substances by positioning individual atoms or molecules in specific ways. Carbon nanotubes are a product of nanotechnology.

(a) Outline how the bonding in carbon nanotubes causes them to be much stronger than graphite. [2]

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

(b) Suggest two health concerns that arise due to the small size of the substances used in nanotechnology. [2]

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


44EP14


– 15 –

Turn over

(Option C continued)

14. Steel is formed by blowing oxygen into a mixture of iron and lime in the basic oxygen converter.

(a) State the equations for two reactions that occur in the basic oxygen converter. [2]

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

(b) Low-carbon and high-carbon steels are produced in the basic oxygen converter. Distinguish between these two alloys in terms of their properties. [2]

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


44EP15


– 16 –


15. Biphenyl nitriles are thermotropic liquid-crystal materials. An example of a biphenyl nitrile is shown below.

C5H11 CN

4’-pentyl-4-biphenylcarbonitrile

(a) Explain thermotropic behaviour in terms of the arrangement of molecules. [2]

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

(b) Explain the roles of the following groups in the thermotropic behaviour of biphenyl nitriles. [3]

Biphenyl group:

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

Nitrile group:

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

Long alkyl group:

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

(Option C continues on page 18)

44EP16


– 17 –

Turn over

Please do not write on this page.

Answers written on this page will not be marked.

44EP17


– 18 –


16. Consider the following polymers.

Nylon 6,6 C

O

C C C C C N C C C C C C N

H H H H O H H H H H H H H

HHHHHHH H H H

PolyethyneC C C C C C C C

HHHHHHHH

Polypropene

H

C

H

C

CH3

C

H

C

CH3

C

H

C

CH3

C

H

C

CH3

HHHHHHH

Polyethylene terephthalate (PET)

C

O

C O

O

C

H

C

H

O

HH


44EP18


– 19 –

Turn over


(a) Identify an addition polymer and a condensation polymer from the four polymers and the structural formulas of their monomers. [3]

Addition polymer

Name of polymer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Structural formula of monomer(s)

Condensation polymer

Name of polymer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Structural formula of monomer(s)


44EP19


– 20 –


(b) Outline how the properties of the trans isomer of polyethyne change when iodine is added to its monomer during polymerization. [1]

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

(c) Discuss the environmental implications of the use of polyethylene terephthalate (PET). [2]

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

End of Option C

44EP20


– 21 –

Turn over

Option D — Medicines and drugs

17. During the drug development process, clinical trials are carried out on humans to evaluate the effectiveness and safety of a new drug.

Explain the terms therapeutic window and tolerance. [2]

Therapeutic window:

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

Tolerance:

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

18. Diamorphine is a strong analgesic which is synthesized from morphine. Both structures are given in table 20 of the data booklet.

(a) Identify the type of reaction which takes place when morphine is converted to diamorphine. [1]

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

(b) Explain how the function of diamorphine differs from that of mild analgesics in the relief of pain. [2]

Diamorphine:

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

Mild analgesics:

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

(Option D continues on the following page)

44EP21


– 22 –

(Option D continued)

19. Pseudoephedrine is a sympathomimetic drug used as a stimulant and a decongestant.

NHCH3

OH

CH3

(a) (i) Identify the chiral carbons in the molecule of pseudoephedrine by means of asterisks (*). [1]

(ii) Discuss the significance of chirality in drug action with reference to an example. [2]

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

(b) Describe how chiral auxiliaries are used to synthesize the desired enantiomer of a drug. [2]

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


44EP22


– 23 –

Turn over

(Option D, question 19 continued)

(c) (i) State two physiological effects of stimulants. [2]

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

(ii) Outline the meaning of the term sympathomimetic drug. [1]

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

(iii) Explain why the drug is administered as the hydrochloride salt of pseudoephedrine. [2]

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


44EP23


– 24 –


20. The development of new antiviral and antibacterial drugs has become a focus for the pharmaceutical industry owing to significant global health threats from infections.

(a) Describe two ways in which antiviral drugs work. [2]

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

(b) Discuss two effects of the overuse of antibiotics. [2]

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

21. Ethanol consumption by drivers causes motor vehicle accidents. The presence of ethanol in the breath may be detected by using a breathalyser containing acidified potassium dichromate(VI).

(a) State the colour change and the type of reaction occurring when the test detects ethanol. [2]

Colour change:

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

Type of reaction:

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


44EP24


– 25 –

Turn over


(b) Blood ethanol levels can also be measured using an intoximeter which is either a fuel cell or an infrared (IR) spectrometer. Explain how the amount of ethanol can be determined using one of these techniques. [2]

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

22. The structures of the mind-altering drugs lysergic acid diethylamide (LSD) and psilocybin are shown in table 20 in the data booklet.

State the names of two functional groups which are present in both LSD and psilocybin. [2]

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

End of Option D

44EP25


– 26 –

Option E — Environmental chemistry

23. Lowering air pollutant emissions is a major concern for car manufacturers.

(a) Catalytic converters are used in car exhausts to lower the amounts of harmful gases released into the atmosphere.

(i) State an equation for a reaction occurring in the catalytic converter. [1]

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

(ii) Suggest why the palladium-based catalyst is spread into a very thin layer. [1]

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

(b) A car manufacturer conducted tests in which the air/fuel ratio in the engine was altered and the amounts of pollutants released measured. The results are represented below.

Per

cent

age

emis

sion

s

10 11 12 13 14 15 16 17 180

2

4

6

8

10

12

14

16

CO

Rich Lean

NOx

Air/fuel ratio

(Option E continues on the following page)

44EP26


– 27 –

Turn over

(Option E, question 23 continued)

(i) State and explain the effect of increasing the air/fuel ratio on CO emissions. [2]

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

(ii) Explain the changes in nitrogen oxide (NOx) emissions as the air/fuel ratio increases. [4]

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

(iii) NOx contributes to the formation of photochemical smog. Outline the formation of peroxyacylnitrates (PANs) in photochemical smog. [3]

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


44EP27


– 28 –

(Option E continued)

24. Soil degradation is an agricultural concern.

(a) Explain how soil salinization occurs. [2]

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

(b) Describe the chemical functions of soil organic matter (SOM). [3]

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

25. Chlorofluorocarbons (CFCs) play an important role in the depletion of ozone in the atmosphere.

(a) State equations for the stepwise mechanism of ozone depletion catalyzed by the CFC compound dichlorodifluoromethane, CCl2F2. [3]

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


44EP28


– 29 –

Turn over

(Option E, question 25 continued)

(b) Discuss one advantage and one disadvantage of using hydrofluorocarbons (HFCs) as alternatives to CFCs. [2]

Advantage:

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

Disadvantage:

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


44EP29


– 30 –

(Option E continued)

26. Biochemical oxygen demand (BOD) is a measure of oxygen-demanding wastes in water.

(a) State two examples of oxygen-demanding wastes. [1]

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

(b) A student monitored BOD and the concentration of dissolved oxygen downstream along a river starting at a farm. Her results are represented below.

BO

D a

nd d

isso

lved

ox

ygen

con

cent

ratio

n Dissolved oxygen

BOD

Distance downstream from farm

Outline the reasons for the variation in the BOD and the concentration of dissolved oxygen. [3]

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

End of Option E

44EP30


– 31 –

Turn over

Option F — Food chemistry

27. Most fats contain fatty acids which can vary in their health benefits. Some information about three fatty acids is given in the table.

Name of fatty acid

Molecular formula Structural formula Melting

point / °C

Stearic acid C18H36O2CH2

CH2

CH2

CH2

CH2

CH2

CH2

CH2

CH2

CH2

CH2

CH2

CH2

CH2

CH2

CH2

C OH

O

H3C

70

Oleic acid C18H34O2 H3C

CH2

CH2

CH2

CH2

CH2

CH2

CH2

C C

H H

CH2

CH2

CH2

CH2

CH2

CH2

CH2

C

OH

O

13

Elaidic acid C18H34O2C C

H

H

CH2

CH2

CH2

CH2

CH2

CH2

CH2

C

O

OH

CH2

CH2

CH2

CH2

CH2

CH2

CH2

H3C 44

(a) State the name of the unsaturated trans fatty acid in the table. [1]

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

(b) Explain why elaidic acid has a higher melting point than oleic acid. [2]

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

(Option F continues on the following page)

44EP31


– 32 –

(Option F continued)

28. Nutrients are obtained from food and are essential for maintaining a healthy body. Identify a nutrient with each given characteristic.

Characteristic Nutrient

Contains an ester group . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Made up of monosaccharides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Essential for healthy bones . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

[3]

29. The shelf life of a food depends on many factors.

(a) (i) Oily fish may become rancid as the oils present contain a high proportion of polyunsaturated fatty acids. Outline how a customer would observe that food is rancid. [1]

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

(ii) Oxidative rancidity in oily fish occurs when fatty acids react with oxygen to form hydroperoxides. The initiation step involves the homolytic fission of the C−H bond in the fatty acid which is represented as RH.

R−H →h ν R• + H•

State equations for the two propagation steps which result in the formation of the hydroperoxide. [2]

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


44EP32


– 33 –

Turn over

(Option F, question 29 continued)

(b) Many cheeses contain high levels of salt. Suggest why lowering the salt content may lead to a shorter shelf life. [2]

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

30. Lycopene gives tomatoes their red colour and zeaxanthin gives some peppers their orange colour.

H3C CH3

CH3

CH3 CH3

CH3 CH3 H3C CH3

H3C

Lycopene

CH3

CH3 CH3

CH3 CH3

H3C

HO

H3C CH3

CH3H3C

OH

Zeaxanthin

(a) Identify the class of pigments to which lycopene and zeaxanthin belong. [1]

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


44EP33


– 34 –


(b) (i) With reference to their interaction with light, explain why these pigments are coloured. [2]

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

(ii) Explain, by referring to the bonding in the molecule, why the colour of lycopene gradually changes from red to yellow on addition of bromine. [2]

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

31. Salad dressings are examples of food products which consist of stable dispersed systems.

(a) Define the term dispersed system. [1]

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


44EP34


– 35 –

Turn over


(b) Lecithin is an emulsifier which is an essential ingredient of salad dressings. By referring to its structure, describe the role of lecithin in salad dressings.

H3C

CH2

CH2

CH2

CH2

CH2

CH2

CH2

CH2

CH2

CH2

CH2

CH2

C

O

O

CH2

C

CH2

O

O H

P

O

OO

CH2

CH2

N+

CH3

CH3C

CH2

CH2

CH2

CH2

CH2

CH2

CH2

CC

CH2

CH2

CH2

CH2

CH2

CH2

CH2

H3C

OH H

CH3

[2]

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

(c) Salad dressings often contain the antioxidant calcium disodium EDTA which acts as a chelating agent. There are two other types of antioxidant.

Explain the mode of action of the three types of antioxidant. [3]

Chelating agents:

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

Free-radical quenchers:

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

Reducing agents (electron donors):

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


44EP35


– 36 –

(Option F continued)

32. Mint leaves have been used for both medicinal and culinary purposes for many centuries. The strong mint flavour is due to the enantiomer, L-(−)-menthol.

CH

HO

CH3

H3C CH3

(a) Identify the chiral centres in the structure of L-(−)-menthol by means of asterisks (*). [1]

(b) Chiral molecules such as L-(−)-menthol can be differentiated from other enantiomers using either the R, S or the (+) (previously represented by d) and (−) (previously represented by l) system of notation.

Explain the difference between the R, S notation and the (+) and (−) notation for enantiomers. [2]

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

End of Option F

44EP36


– 37 –

Turn over

Option G — Further organic chemistry

33. Mandelic acid is used in antibacterial agents. One possible route for its formation is shown below.

COH

CH OH

CN

C OHH

COOH

HCN H3O+

Benzaldehyde Mandelic acid

The first stage involves nucleophilic addition of hydrogen cyanide, HCN, to the aldehyde group in benzaldehyde.

(a) Explain the mechanism for the reaction of benzaldehyde with HCN using curly arrows to show the movement of electron pairs. [3]

(Option G continues on the following page)

44EP37


– 38 –

(Option G, question 33 continued)

(b) Benzaldehyde can also be used to synthesize 1-phenylethanol, C6H5CH(OH)CH3. This reaction involves the use of a Grignard reagent.

(i) State the formula of a Grignard reagent which could be used in this reaction. [1]

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

(ii) Identify the reagents and conditions for the formation of the Grignard reagent given in (b) (i). [2]

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

(c) 1-phenylethanol, C6H5CH(OH)CH3, can be converted to phenylethene, C6H5CH=CH2, which is used in the polymer industry.

Identify the following for the conversion of 1-phenylethanol to phenylethene.

[3]

Type of reaction:

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

Reagent:

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

Condition:

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


44EP38


– 39 –

Turn over

(Option G continued)

34. 2-methylbut-2-ene, (CH3)2C=CHCH3, reacts readily with HBr by an electrophilic addition reaction. The products are found to consist of two structural isomers with the molecular formula C5H11Br.

(a) Deduce the structural formula of the major product. [1]

(b) Explain why this isomer is the major product. [3]

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


44EP39


– 40 –


35. A halogenated arene is reacted with warm sodium hydroxide solution as shown in the equation below.

CH2CH2Cl

Cl

Cl

+ NaOH

Cl

Cl

CH2CH2OH

+ NaCl

Explain why only one of the three chlorine atoms is substituted by a hydroxyl group. [2]

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


44EP40


– 41 –


36. Draw the structures of products A, B and C in the following addition–elimination reactions.

Reaction 1 H3C CH2 C

O

O C

O

CH2 CH3 CH3OH A B

Reaction 2 H3C C

O

Cl CH3 C lCH CH3

NH2

[3]

A:

B:

C:


44EP41


– 42 –


37. Benzene, C6H6, undergoes electrophilic substitution in the presence of a mixture of concentrated nitric and sulfuric acids to form nitrobenzene, C6H5NO2.

(a) Outline, using an equation, the formation of the electrophile NO2+ from the two acids. [1]

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

(b) Describe the mechanism for the reaction of benzene with the electrophile to form nitrobenzene using curly arrows to represent the movement of electron pairs. [3]

(c) Nitrobenzene can be nitrated further to form 1,3-dinitrobenzene. Suggest why this further nitration of nitrobenzene is more difficult. [1]

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


44EP42


– 43 –

Turn over

(Option G, question 37 continued)

(d) The nitration of methylbenzene, C6H5CH3, results in the formation of 2− and 4− isomers. Explain why the presence of a methyl group leads to the formation of these two isomers. [2]

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

End of Option G

44EP43




44EP44







1 hour


8816 – 6101

– 2 –

88 Ra

(226

)

56 Ba

137.

33

38 Sr87

.62

20 Ca

40.0

8

12 Mg

24.3

1

4 Be

9.012

‡†

89 ‡

Ac

(227

)

57 †

La13

8.91

39 Y88

.91

21 Sc 44.9

6

90 Th23

2.04

58 Ce

140.

12

72 Hf

178.

49

40 Zr 91.2

2

22 Ti47

.87

91 Pa23

1.04

59 Pr14

0.91

73 Ta18

0.95

41 Nb

92.9

1

23 V50

.94

92 U23

8.03

60 Nd

144.

24

74 W18

3.84

42 Mo

95.9

6

24 Cr

52.0

0

55 Cs

132.

91

37 Rb

85.4

7

19 K39

.10

11 Na

22.9

9

3 Li 6.941 H 1.011 Fr87 (223

)

93 Np

(237

)

61 Pm (145

)

75 Re

186.

21

43 Tc (98)25 Mn

54.9

4

94 Pu (244

)

62 Sm15

0.36

76 Os

190.

23

44 Ru

101.

07

26 Fe 55.8

5

95 Am

(243

)

63 Eu15

1.96

77 Ir19

2.22

45 Rh

102.

91

27 Co

58.9

3

96 Cm

(247

)

64 Gd

157.

25

78 Pt19

5.08

46 Pd10

6.42

28 Ni

58.6

9

97 Bk

(247

)

65 Tb15

8.93

79 Au

196.

97

47 Ag

107.

87

29 Cu

63.5

5

The

Perio

dic

Tabl

e

Ato

mic

num

ber

Elem

ent

Rel

ativ

e at

omic

mas

s

98 Cf

(251

)

66 Dy

162.

50

80 Hg

200.

59

48 Cd

112.

41

30 Zn 65.3

8

99 Es (252

)

67 Ho

164.

93

81 Tl20

4.38

49 In11

4.82

31 Ga

69.7

2

13 Al

26.9

8

5 B10

.81

13

100

Fm (257

)

68 Er16

7.26

82 Pb 207.

2

50 Sn11

8.71

32 Ge

72.6

3

14 Si28

.09

6 C12

.01

14

101

Md

(258

)

69 Tm16

8.93

83 Bi

208.

98

51 Sb12

1.76

33 As

74.9

2

15 P30

.97

7 N14

.01

15

102

No

(259

)

70 Yb17

3.05

84 Po (209

)

52 Te12

7.60

34 Se78

.96

16 S32

.07

8 O16

.00

16

103

Lr (262

)

71 Lu17

4.97

85 At

(210

)

53 I12

6.90

35 Br

79.9

0

17 Cl

35.4

5

9 F19

.00

17

86 Rn

(222

)

54 Xe13

1.29

36 Kr

83.9

0

18 Ar

39.9

5

10 Ne

20.1

8

2 He

4.0018

34

56

78

910

1112

1 2 3 4 5 6 710

4 R

f(2

67)

105

Db

(268

)

106

Sg (269

)

107

Bh

(270

)

108

Hs

(269

)

109

Mt

(278

)

110

Ds

(281

)

111

Rg

(281

)

112

Cn

(285

)

113

Unt

(286

)

114

Uug

(289

)

115

Uup

(288

)

116

Uuh

(293

)

117

Uus

(294

)

118

Uuo

(294

)


– 3 –

Turn over

1. Which volume, in cm3, of 0.20 mol dm-3 NaOH (aq) is needed to neutralize 0.050 mol of H2S (g)?

H2S (g) + 2NaOH (aq) → Na2S (aq) + 2H2O (l)

A. 0.25

B. 0.50

C. 250

D. 500

2. The complete combustion of 15.0 cm3 of a gaseous hydrocarbon X produces 60.0 cm3 of carbon dioxide gas and 75.0 cm3 of water vapour. What is the molecular formula of X? (All volumes are measured at the same temperature and pressure.)

A. C4H6

B. C4H8

C. C4H10

D. C6H10

3. 5.0 mol of Fe2O3 (s) and 6.0 mol of CO (g) react according to the equation below. What is the limiting reactant and how many moles of the excess reactant remain unreacted?

Fe2O3 (s) + 3CO (g) → 2Fe (s) + 3CO2 (g)

Limiting reactant Moles of excess reactant remaining

A. CO 2.0

B. CO 3.0

C. Fe2O3 1.0

D. Fe2O3 2.0


– 4 –

4. Which is correct for the line emission spectrum for hydrogen?

M N O P Q R

A. Line M has a higher energy than line N.

B. Line N has a lower frequency than line M.

C. Line M has a longer wavelength than line N.

D. Lines converge at lower energy.

5. Which representation would be correct for a species, Z, which has 31 protons, 40 neutrons and 28 electrons?

A. 73 11 Z

3+

B. 73 11 Z

3-

C. 74 10 Z

3+

D. 72 18 Z

3+

6. A period 3 element, M, forms an oxide of the type M2O. Which represents the first four successive ionization energies of M?

Ionization energy / kJ mol-1

First Second Third Fourth

A. 496 4563 6913 9544

B. 738 1451 7733 10541

C. 578 1817 2745 11578

D. 787 1577 3232 4356


– 5 –

Turn over

7. Which property increases down group 17, the halogens?

A. Electron affinity

B. Boiling point

C. First ionization energy

D. Reactivity

8. Which correctly describes the reaction between potassium and excess water?

A. The reaction is endothermic.

B. The final products of the reaction are potassium oxide and hydrogen.

C. The final products of the reaction are potassium hydroxide and hydrogen.

D. The final pH of the solution is 7.

9. The oxidation state of cobalt in the complex ion [Co(NH3)5Br]x is +3. Which of the following statements are correct?

I. The overall charge, x, of the complex ion is 2+. II. The complex ion is octahedral. III. The cobalt(III) ion has a half-filled d-subshell.

A. I and II only

B. I and III only

C. II and III only

D. I, II and III

10. What is the correct explanation for the colour of [Cu(H2O)6]2+?

A. Light is absorbed when an electron moves to a d orbital of higher energy.

B. Light is released when an electron moves to a d orbital of higher energy.

C. Light is absorbed when electrons move from the ligands to the central metal ion.

D. Light is absorbed when electrons move between d and s orbitals.


– 6 –

11. How many electrons form the carbon–oxygen bond in methanal, HCHO?

A. 2

B. 4

C. 8

D. 12

12. Between which pair of molecules can hydrogen bonding occur?

A. CH4 and H2O

B. CH3OCH3 and CF4

C. CH4 and HF

D. CH3OH and H2O

13. Which substance has a giant covalent structure?

Melting point / °C Solubility in waterElectrical

conductivity in the molten state

A. 186 high none

B. 801 high good

C. 1083 low good

D. 1710 low none

14. Which species has bond angles of 90°?

A. AlCl4-

B. ICl4-

C. NH4+

D. SiCl4


– 7 –

Turn over

15. What is the hybridization of the numbered atoms in ethanoic acid?

H

C

H

H C

O

O H1 2

3

Atom 1 Atom 2 Atom 3

A. sp3 sp sp2

B. sp3 sp2 sp

C. sp2 sp3 sp2

D. sp3 sp2 sp3

16. Hydrazine reacts with oxygen.

N2H4 (l) + O2 (g) → N2 (g) + 2H2O (l) ΔH Ö = - 623 kJ

What is the standard enthalpy of formation of N2H4 (l) in kJ? The standard enthalpy of formation of H2O (l) is - 286 kJ.

A. -623 - 286

B. -623 + 572

C. -572 + 623

D. -286 + 623

17. 5.35 g of solid ammonium chloride, NH4Cl (s), was added to water to form 25.0 g of solution. The maximum decrease in temperature was 14 K. What is the enthalpy change, in kJ mol-1, for this reaction? (Molar mass of NH4Cl = 53.5 g mol-1; the specific heat capacity of the solution is 4.18 J g-1 K-1)

A. ΔH = + 25.0 4.18 (14 273)

0.1 1000× × +

×

B. ΔH = - 25.0 4.18 140.1 1000× ××

C. ΔH = + 25.0 4.18 140.1 1000× ××

D. ΔH = + 25.0 4.18 14

1000× ×


– 8 –

18. Which represents the enthalpy change of hydration of the chloride ion?

A. Cl- (g) H2O Cl- (aq)

B. Cl (g) H2O Cl- (aq)

C. 12

Cl2 (g) H2O Cl- (aq)

D. 12

Cl2 (aq) H2O Cl- (aq)

19. Which ionic compound has the largest value of lattice enthalpy?

A. MgS

B. MgO

C. CaBr2

D. NaF

20. Which experimental methods could be used to observe the progress of the following reaction?

Cr2O72- (aq) + 6I- (aq) + 14H+ (aq) → 2Cr3+ (aq) + 3I2 (aq) + 7H2O (l)

I. Change in colour II. Change in mass III. Change in electrical conductivity

A. I and II only

B. I and III only

C. II and III only

D. I, II and III

21. Which statement describes the characteristics of a transition state relative to the potential energy of the reactants and products?

A. It is an unstable species with lower potential energy.

B. It is an unstable species with higher potential energy.

C. It is a stable species with lower potential energy.

D. It is a stable species with higher potential energy.


– 9 –

Turn over

22. Decomposition of hydrogen peroxide in an aqueous solution proceeds as follows.

2H2O2 (aq) → 2H2O (l) + O2 (g)

The rate expression for the reaction was found to be: rate = k [H2O2].

Which graph is consistent with the given rate expression?

A.

Rate / mol dm-3 s-1

B.

Rate / mol dm-3 s-1

[H2O2] / mol dm-3 [H2O2] / mol dm-3

C.

[H2O2] / mol dm-3

D.

[H2O2] / mol dm-3

Time / s Time / s

23. The rate constant, k, is commonly described by the Arrhenius equation: k AeE

RT=− a

.Which of the following statements are correct?

I. A greater Ea value results in a smaller k value. II. Reactions of less complex molecules usually have a greater value of A. III. The slope (gradient) of ln k versus 1

T equals Ea.

A. I and II only

B. I and III only

C. II and III only

D. I, II and III


– 10 –

24. What happens when the temperature of the following equilibrium system is increased?

CO (g) + 2H2 (g) CH3OH (g) ∆H Ö = -91 kJ

Position of equilibrium Reaction rates of forward and reverse reactions

A. shifts to the left increase

B. shifts to the left decrease

C. shifts to the right decrease

D. shifts to the right increase

25. A mixture of 0.40 mol of CO (g) and 0.40 mol of H2 (g) was placed in a 1.00 dm3 vessel. The following equilibrium was established.

CO (g) + 2H2 (g) CH3OH (g)

At equilibrium, the mixture contained 0.25 mol of CO (g). How many moles of H2 (g) and CH3OH (g) were present at equilibrium?

Equilibrium mol of H2 Equilibrium mol of CH3OH

A. 0.25 0.15

B. 0.50 0.25

C. 0.30 0.25

D. 0.10 0.15

26. Which species behave as Brønsted–Lowry bases in the following reaction?

H2SO4 + HNO3 H2NO3+ + HSO4

-

A. HNO3 and HSO4-

B. HNO3 and H2NO3+

C. H2SO4 and HSO4-

D. H2NO3+ and HSO4

-


– 11 –

Turn over

27. What occurs when solid sodium hydrogen carbonate reacts with aqueous sulfuric acid?

A. Bubbles of sulfur dioxide form.

B. Bubbles of both hydrogen and carbon dioxide form.

C. Bubbles of hydrogen form.

D. Bubbles of carbon dioxide form.

28. Which mixture is a buffer solution?

A. 25 cm3 of 0.10 mol dm-3 NH3 (aq) and 50 cm3 of 0.10 mol dm-3 HCl (aq)

B. 50 cm3 of 0.10 mol dm-3 NH3 (aq) and 25 cm3 of 0.10 mol dm-3 HCl (aq)

C. 25 cm3 of 0.10 mol dm-3 NaOH (aq) and 25 cm3 of 0.10 mol dm-3 HCl (aq)

D. 50 cm3 of 0.10 mol dm-3 NaOH (aq) and 25 cm3 of 0.10 mol dm-3 HCl (aq)

29. Which salt solution has the highest pH?

A. NH4Cl

B. Ca (NO3)2

C. Na2CO3

D. K2SO4

30. Which is a correct statement for the reaction below?

2MnO4- (aq) + 6H+ (aq) + 5NO2

- (aq) → 2Mn2+ (aq) + 5NO3- (aq) + 3H2O (l)

A. MnO4- is the reducing agent and the oxidation number of Mn increases.

B. MnO4- is the oxidizing agent and the oxidation number of Mn decreases.

C. NO2- is the reducing agent and the oxidation number of N decreases.

D. NO2- is the oxidizing agent and the oxidation number of N increases.


– 12 –

31. A voltaic cell is constructed from zinc and copper half-cells. Zinc is more reactive than copper. Which statement is correct when this cell produces electricity?

Voltmeter

Zn

V

Salt bridge

Cu

Zn2+ (aq) Cu2+ (aq)

A. Electrons flow from the copper half-cell to the zinc half-cell.

B. The concentration of Cu2+ (aq) increases.

C. Electrons flow through the salt bridge.

D. Negative ions flow through the salt bridge from the copper half-cell to the zinc half-cell.

32. Which signs for both E Öcell and ∆G Ö result in a spontaneous redox reaction occurring under standard conditions?

E Öcell ∆G Ö

A. + +

B. - +

C. - -

D. + -


– 13 –

Turn over

33. An iron rod is electroplated with silver. Which is a correct condition for this process?

A. The silver electrode is the positive electrode.

B. The iron rod is the positive electrode.

C. The electrolyte is iron(II) sulfate.

D. Oxidation occurs at the negative electrode.

34. The structure of a drug used to treat symptoms of Alzheimer’s disease is shown below. Which functional groups are present in this molecule?

O

N

CH3O

CH3

OH

A. Hydroxyl and ester

B. Hydroxide and ether

C. Hydroxyl and ether

D. Hydroxide and ester

35. Which monomer is used to form the polymer with the following repeating unit?

H

C C

CH3

H

CH3

A. CH3CH=CHCH3

B. CH3CH2CH=CH2

C. CH3CH2CH2CH3

D. (CH3)2C=CH2


– 14 –

36. Which is correct for the conversion of propanal to propyl methanoate?

CH3CH2CHOStep 1 Step 2

Reagent 1 Concentrated H2SO4 and methanoic acid

CH3CH2CH2OH HCO2CH2CH2CH3

Reagent for step 1 Reaction type in step 1 Reaction type in step 2

A. H2O hydration addition

B. K2Cr2O7, dilute H2SO4 oxidation nucleophilic substitution (condensation)

C. NaBH4 reduction oxidation

D. NaBH4 reduction nucleophilic substitution (condensation)

37. Which statement is correct for a pair of enantiomers under the same conditions?

A. A racemic mixture of the enantiomers is optically active.

B. They have the same chemical properties in all their reactions.

C. They have the same melting and boiling points.

D. They rotate the plane of plane-polarized light by different angles.

38. A student carried out a titration to determine the concentration of an acid and found that his value had good precision but poor accuracy. Which process explains this outcome?

A. Consistently overshooting the volume of solution from the burette into the flask.

B. Collection of insufficient titration data.

C. Reading the meniscus in the burette at a different angle each time.

D. Forgetting to rinse the flask after one of the titrations.


– 15 –

39. What is always correct about the molecular ion, M+, in a mass spectrum of a compound?

A. The M+ ion peak has the smallest m/z ratio in the mass spectrum.

B. The m/z ratio of the M+ ion peak gives the relative molecular mass of the molecule.

C. The M+ ion is the most stable fragment formed during electron bombardment.

D. The M+ ion peak has the greatest intensity in the mass spectrum.

40. Which property explains why tetramethylsilane, Si (CH3)4, can be used as a reference standard in 1H NMR spectroscopy?

A. It has a high boiling point.

B. It is a reactive compound.

C. All its protons are in the same chemical environment.

D. It gives multiple signals.


N16/4/CHEMI/HPM/ENG/TZ0/XX/M

2 pages

Markscheme

November 2016

Chemistry

Higher level

Paper 1

– 2 – N16/4/CHEMI/HPM/ENG/TZ0/XX/M

1. D 16. C 31. D 46. – 2. C 17. C 32. D 47. – 3. B 18. A 33. A 48. – 4. C 19. B 34. C 49. – 5. A 20. B 35. A 50. – 6. A 21. B 36. D 51. – 7. B 22. D 37. C 52. – 8. C 23. A 38. A 53. – 9. A 24. A 39. B 54. – 10. A 25. D 40. C 55. – 11. B 26. A 41. – 56. – 12. D 27. D 42. – 57. – 13. D 28. B 43. – 58. – 14. B 29. C 44. – 59. – 15. D 30. B 45. – 60. –


© International Baccalaureate Organization 201623 pages8816 – 6102



2 hours 15 minutes



Write your session number in the boxes above. Do not open this examination paper until instructed to do so. Answer all questions. Write your answers in the boxes provided. A calculator is required for this paper. A clean copy of the chemistry data booklet is required for this paper. The maximum mark for this examination paper is [95 marks].

24EP01

– 2 –

Answer all questions. Write your answers in the boxes provided.

1. Ethane-1,2-diol, HOCH2CH2OH, has a wide variety of uses including the removal of ice from aircraft and heat transfer in a solar cell.

(a) Ethane-1,2-diol can be formed according to the following reaction.

2CO (g) + 3H2 (g) HOCH2CH2OH (g)

(i) Deduce the equilibrium constant expression, Kc , for this reaction. [1]

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

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

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

(ii) State how increasing the pressure of the reaction mixture at constant temperature will affect the position of equilibrium and the value of Kc . [2]

Position of equilibrium:

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

Kc:

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

(iii) Calculatetheenthalpychange,∆H Ö, in kJ, for this reaction using section 11 of the data booklet. The bond enthalpy of the carbon–oxygen bond in CO (g) is 1077 kJ mol-1. [3]

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

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

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

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

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

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

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

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

(This question continues on the following page)

24EP02


– 3 –

Turn over

(Question 1 continued)

(b) (i) Calculate∆H Ö,inkJ,forthissimilarreactionbelowusing∆H Öf data from section 12ofthedatabooklet.∆H Öf of HOCH2CH2OH (l) is -454.8 kJ mol-1.

2CO (g) + 3H2 (g) HOCH2CH2OH (l)

[1]

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

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

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

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

(ii) Deduce why the answers to (a)(iii) and (b)(i) differ. [1]

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

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

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

(iii) ∆S Ö for the reaction in (b)(i) is -620.1 J K-1. Comment on the decrease in entropy. [1]

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

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

(iv) Calculatethevalueof∆G Ö, in kJ, for this reaction at 298 K using your answer to (b)(i). (If you did not obtain an answer to (b)(i), use -244.0 kJ, but this is not the correct value.) [2]

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

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

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

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


24EP03


– 4 –


(v) Comment on the statement that the reaction becomes less spontaneous as temperature is increased. [1]

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

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

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

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

(c) Determine the average oxidation state of carbon in ethene and in ethane-1,2-diol. [2]

Ethene:

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

Ethane-1,2-diol:

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

(d) Explainwhytheboilingpointofethane-1,2-diolissignificantlygreaterthanthatofethene. [2]

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

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

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

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

(e) Ethane-1,2-diolcanbeoxidizedfirsttoethanedioicacid,(COOH)2, and then to carbon dioxide and water. Suggest the reagents needed to oxidize ethane-1,2-diol. [1]

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

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


24EP04


– 5 –

Turn over


(f) Predict the 1H NMR data for ethanedioic acid and ethane-1,2-diol by completing the table. [2]

Number of signals Splitting pattern

Ethanedioic acid: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Ethane-1,2-diol: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Not required

24EP05


– 6 –

2. The concentration of a solution of a weak acid, such as ethanedioic acid, can be determined by titration with a standard solution of sodium hydroxide, NaOH (aq).

(a) Distinguish between a weak acid and a strong acid. [1]

Weak acid:

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

Strong acid:

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

(b) Suggest why it is more convenient to express acidity using the pH scale instead of using the concentration of hydrogen ions. [1]

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

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

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

(c) 5.00 g of an impure sample of hydrated ethanedioic acid, (COOH)2•2H2O, was dissolved in water to make 1.00 dm3 of solution. 25.0 cm3 samples of this solution were titrated against a 0.100 mol dm-3 solution of sodium hydroxide using a suitable indicator.

(COOH)2 (aq) + 2NaOH (aq) → (COONa)2 (aq) + 2H2O (l)

The mean value of the titre was 14.0 cm3.

(i) Suggest a suitable indicator for this titration. Use section 22 of the data booklet. [1]

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


24EP06


– 7 –

Turn over


(ii) Calculate the amount, in mol, of NaOH in 14.0 cm3 of 0.100 mol dm-3 solution. [1]

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

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

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

(iii) Calculate the amount, in mol, of ethanedioic acid in each 25.0 cm3 sample. [1]

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

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

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

(iv) Determine the percentage purity of the hydrated ethanedioic acid sample. [3]

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

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

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

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

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

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

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

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

(d) Draw the Lewis (electron dot) structure of the ethanedioate ion, -OOCCOO-. [1]


24EP07


– 8 –


(e) Outline why all the C–O bond lengths in the ethanedioate ion are the same length and suggest a value for them. Use section 10 of the data booklet. [2]

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

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

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

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

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

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

(f) Explain how ethanedioate ions act as ligands. [2]

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

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

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

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

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

24EP08


– 9 –

Turn over

3. Sodium thiosulfate solution reacts with dilute hydrochloric acid to form a precipitate of sulfur at room temperature.

Na2S2O3 (aq) + 2HCl (aq) → S (s) + SO2 (g) + 2NaCl (aq) + X

(a) Identify the formula and state symbol of X. [1]

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

(b) Suggest why the experiment should be carried out in a fume hood or in a well-ventilated laboratory. [1]

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

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


24EP09


– 10 –


(c) The precipitate of sulfur makes the mixture cloudy, so a mark underneath the reaction mixture becomes invisible with time.

mark mark mark

Glass

mark

10.0 cm3 of 2.00 mol dm-3 hydrochloric acid was added to a 50.0 cm3 solution of sodium thiosulfate at temperature, T1. Students measured the time taken for the mark to be no longer visible to the naked eye. The experiment was repeated at different concentrations of sodium thiosulfate.

Experiment [Na2S2O3 (aq)]/ mol dm-3

Time, t, for mark to disappear / s ± 1 s

1t* / 10-3 s-1

1 0.150 23 43.52 0.120 27 37.03 0.090 36 27.84 0.060 60 16.75 0.030 111 9.0

* The reciprocal of the time in seconds can be used as a measure of the rate of reaction.

[Source:Adaptedfromhttp://www.flinnsci.com/]

Showthatthehydrochloricacidaddedtotheflaskinexperiment1isinexcess. [2]

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

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

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

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

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

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


24EP10


– 11 –

Turn over


(d) Drawthebestfitlineof1t

against concentration of sodium thiosulfate on the axes provided. [2]

Rat

e of

reac

tion 1 t

/ 10-

3 s-1

0.03 0.06 0.09 0.12 0.150

5

10

15

20

25

30

35

40

45

[Na2S2O3] / mol dm-3

(e) (i) Using the graph, explain the order of reaction with respect to sodium thiosulfate. [2]

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

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

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

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


24EP11


– 12 –


(ii) Inadifferentexperiment,thisreactionwasfoundtobefirstorderwithrespecttohydrochloric acid. Deduce the overall rate expression for the reaction. [1]

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

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

(f) A student decided to carry out another experiment using 0.075 mol dm-3 solution of sodium thiosulfate under the same conditions. Determine the time taken for the mark to be no longer visible. [2]

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

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

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

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

(g) An additional experiment was carried out at a higher temperature, T2.

(i) On the same axes, sketch Maxwell–Boltzmann energy distribution curves at the two temperatures T1 and T2, where T2 > T1. [2]


24EP12


– 13 –

Turn over


(ii) Explain why a higher temperature causes the rate of reaction to increase. [2]

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

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

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

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

(h) Suggest one reason why the values of rates of reactions obtained at higher temperatures may be less accurate. [1]

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

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

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

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

24EP13


– 14 –

4. Magnesium is a group 2 metal which exists as a number of isotopes and forms many compounds.

(a) State the nuclear symbol notation, AZ X, for magnesium-26. [1]

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

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

(b) Mass spectroscopic analysis of a sample of magnesium gave the following results:

% abundanceMg-24 78.60Mg-25 10.11Mg-26 11.29

Calculate the relative atomic mass, Ar , of this sample of magnesium to two decimal places. [2]

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

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

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

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

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

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

(c) Magnesium ions produce no emission or absorption lines in the visible region of the electromagnetic spectrum. Suggest why most magnesium compounds tested in a schoollaboratoryshowtracesofyellowintheflame. [1]

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

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


24EP14


– 15 –

Turn over


(d) (i) Explain the convergence of lines in a hydrogen emission spectrum. [1]

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

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

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

(ii) State what can be determined from the frequency of the convergence limit. [1]

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

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

(e) Magnesium burns in air to form a white compound, magnesium oxide. Formulate an equation for the reaction of magnesium oxide with water. [1]

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

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

(f) Describe the trend in acid-base properties of the oxides of period 3, sodium to chlorine. [2]

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

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

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

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

(g) In addition to magnesium oxide, magnesium forms another compound when burned in air. Suggest the formula of this compound. [1]

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


24EP15


– 16 –


(h) Describe the structure and bonding in solid magnesium oxide. [2]

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

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

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

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

(i) Magnesium chloride can be electrolysed.

(i) Deduce the half-equations for the reactions at each electrode when molten magnesium chloride is electrolysed, showing the state symbols of the products. The melting points of magnesium and magnesium chloride are 922 K and 987 K respectively. [2]

Anode (positive electrode):

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

Cathode (negative electrode):

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

(ii) Identify the type of reaction occurring at the cathode (negative electrode). [1]

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

(iii) State the products when a very dilute aqueous solution of magnesium chloride is electrolysed. [2]

Anode (positive electrode):

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

Cathode (negative electrode):

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


24EP16


– 17 –

Turn over


(j) Standard electrode potentials are measured relative to the standard hydrogen electrode. Describe a standard hydrogen electrode. [2]

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

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

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

(k) A magnesium half-cell, Mg (s)/Mg2+ (aq), can be connected to a copper half-cell, Cu (s)/Cu2+ (aq).

(i) Formulate an equation for the spontaneous reaction that occurs when the circuit is completed. [1]

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

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

(ii) Determine the standard cell potential, in V, for the cell. Refer to section 24 of the data booklet. [1]

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

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

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

(iii) Predict, giving a reason, the change in cell potential when the concentration of copper ions increases. [2]

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

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

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

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

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

24EP17


– 18 –

5. Propane and propene are members of different homologous series.

(a) Draw the full structural formulas of propane and propene. [1]

Propane:

Propene:

(b) (i) Draw diagrams to show how sigma (σ) and pi (π) bonds are formed between atoms. [2]

Sigma (σ):

Pi (π):


24EP18


– 19 –

Turn over


(ii) State the number of sigma (σ) and pi (π) bonds in propane and propene. [2]

Number of sigma (σ) bonds Number of pi (π) bonds

Propane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Propene . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

(c) Both propane and propene react with bromine.

(i) State an equation and the condition required for the reaction of 1 mol of propane with 1 mol of bromine. [2]

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

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

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

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

(ii) State an equation for the reaction of 1 mol of propene with 1 mol of bromine. [1]

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

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

(iii) State the type of each reaction with bromine. [1]

Propane:

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

Propene:

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


24EP19


– 20 –


(d) Construct the mechanism of the formation of 2-bromopropane from hydrogen bromide and propene using curly arrows to denote the movement of electrons. [3]

24EP20


– 21 –

Turn over

6. One structural isomer of C4H9Br is a chiral molecule.

(a) Draw the three-dimensional shape of each enantiomer of this isomer showing their spatial relationship to each other. [2]

(b) When one enantiomer undergoes substitution by alkaline hydrolysis approximately 75%oftheproductmoleculesshowinversionofconfiguration.Commentonthemechanisms that occur. [2]

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

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

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

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

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

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

(c) Suggest why the rate of alkaline hydrolysis of an enantiomer of iodopropane is greater than that of an enantiomer of bromopropane. [1]

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

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

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

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

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

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

24EP21


– 22 –

7. This question is about the weak acid methanoic acid, HCOOH.

(a) Calculate the pH of 0.0100 mol dm-3 methanoic acid stating any assumption you make. Ka = 1.6 × 10-4. [3]

Calculation:

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

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

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

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

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

Assumption:

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

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

(b) (i) Sketch a graph of pH against volume of a strong base added to a weak acid showing how you would determine pKa for the weak acid. [2]

pH

7

Volume at equivalenceVolume of strong base added


24EP22


– 23 –


(ii) Explain, using an equation, why the pH increases very little in the buffer region when a small amount of alkali is added. [2]

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

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

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

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

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

24EP23




24EP24





1 hour 15 minutes

Tuesday 15 November 2016 (morning)

8816 – 6103


• Write your session number in the boxes above.• Do not open this examination paper until instructed to do so.• Answers must be written within the answer boxes provided. • A calculator is required for this paper.• A clean copy of the chemistry data booklet is required for this paper.• The maximum mark for this examination paper is [45 marks].

Section A Questions

Answer all questions. 1 – 2

Section B Questions

Answer all of the questions from one of the options.

Option A — Materials 3 – 10

Option B — Biochemistry 11 – 16

Option C — Energy 17 – 22

Option D — Medicinal chemistry 23 – 29

44EP01

– 2 –

Section A


1. In order to provide safe drinking water, a water supply is often treated with disinfectants, which aim to inactivate disease-causing bacteria in the water.

To compare the effectiveness of different disinfectants, a CT value is used as a measure of the dosage of disinfectant needed to achieve a certain level of inactivation of specific bacteria.

CT value (mg min dm−3) = C (mg dm−3) × T (min) concentration contact time of disinfectant with water

(a) The table below compares the CT values of different disinfectants necessary to achieve 99 % inactivation of two types of bacteria, listed as A and B.

DisinfectantCT value / mg min dm−3 for 99 % inactivation of bacteria

Bacterium A Bacterium BHypochlorous acid, HOCl 4 × 10−2 8 × 10−2

Hypochlorite ion, OCl− 9.2 × 10−1 3.3Chlorine dioxide, ClO2 1.8 × 10−1 1.3 × 10−1

Monochloramine, NH2Cl 64 94

(i) Deduce the oxidation state of chlorine in the following disinfectants. [1]

HOCl:

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

ClO2:

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



44EP02

– 3 –

Turn over


(ii) From the data on CT values, justify the statement that bacterium B is generally more resistant to disinfection than bacterium A. [1]

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

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

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

(iii) CT values can be used to determine whether a particular treatment process is adequate. Calculate the CT value, in mg min dm−3, when 1.50 × 10−5 g dm−3 of chlorine dioxide is added to a water supply with a contact time of 9.82 minutes. [1]

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

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

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

(iv) From your answer to (a) (iii) and the data in the table, comment on whether this treatment will be sufficient to inactivate 99 % of bacteria A. [1]

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

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

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



44EP03

– 4 –


(b) CT values are influenced by temperature and by pH. The table below shows the CT values for chlorine needed to achieve 99 % inactivation of a specific bacterium at stated values of pH and temperature.

pHTemperature / °C

0.5 5.0 10.0 15.0 20.06.0 97 69 52 35 267.0 137 97 73 49 378.0 197 140 105 70 539.0 281 201 151 101 75

(i) With reference to the temperature data in the table, suggest why it may be more difficult to treat water effectively with chlorine in cold climates. [1]

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

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

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

(ii) Sketch a graph on the axes below to show how the CT value (at any temperature) varies with pH. [1]



44EP04

– 5 –

Turn over


(iii) Comment on the relative CT values at pH 6.0 and pH 9.0 at each temperature. [1]

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

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

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

(iv) Chlorine reacts with water as follows:

Cl2 (g) + H2O (l) HOCl (aq) + HCl (aq)

HOCl (aq) OCl− (aq) + H+ (aq)

Predict how the concentrations of each of the species HOCl (aq) and OCl− (aq) will change if the pH of the disinfected water increases. [1]

HOCl (aq):

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

OCl− (aq):

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

(c) Despite widespread improvements in the provision of safe drinking water, the sale of bottled water has increased dramatically in recent years. State one problem caused by this trend. [1]

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

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

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


44EP05

– 6 –

2. In a class experiment, students were asked to determine the value of x in the formula of a hydrated salt, BaCl2･ xH2O. They followed these instructions:

1. Measure the mass of an empty crucible and lid.2. Add approximately 2 g sample of hydrated barium chloride to the crucible and record

the mass.3. Heat the crucible using a Bunsen burner for five minutes, holding the lid at an angle

so gas can escape.4. After cooling, reweigh the crucible, lid and contents.5. Repeat steps 3 and 4.

Their results in three trials were as follows:

Trial 1 Trial 2 Trial 3Mass of crucible + lid / g ±0.001 20.088 20.122 20.105Mass of crucible + lid + BaCl2･ xH2O before heating / g ±0.001 22.166 22.184 22.186Mass of crucible + lid + BaCl2 after 1st heating / g ±0.001 21.859 22.080 21.926Mass of crucible + lid + BaCl2 after 2nd heating / g ±0.001 21.859 21.865 21.927

(a) State and explain the further work students need to carry out in trial 2 before they can process the results alongside trial 1. [2]

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

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

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

(b) In trial 3, the students noticed that after heating, the crucible had turned black on the outside. Suggest what may have caused this, and how this might affect the calculated value for x in the hydrated salt. [2]

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

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

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

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



44EP06

– 7 –

Turn over


(c) List two assumptions made in this experiment. [2]

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

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

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

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

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

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


44EP07

– 8 –

Section B

Answer all of the questions from one of the options.

Option A — Materials

3. Materials science involves understanding the properties of materials and applying those properties to desired structures.

(a) Magnesium oxide, MgO, and silicon carbide, SiC, are examples of ceramic materials. State the name of the predominant type of bonding in each material. [1]

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

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

(b) Predict the predominant type of bonding for a binary compound AB in which the electronegativity of both atoms is low. Use section 29 of the data booklet. [1]

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

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

4. A student wanted to determine the formula of indium sulfate. She applied an electrical current of 0.300 A to an aqueous solution of indium sulfate for 9.00 × 103 s and found that 1.07 g of indium metal deposited on the cathode.

(a) Calculate the charge, in coulombs, passed during the electrolysis.

currentchargetime

IQt

=

[1]

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

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



44EP08

– 9 –

Turn over


(b) Calculate the amount, in mol, of electrons passed using section 2 of the data booklet. [1]

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

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

(c) Calculate the mass of indium deposited by one mole of electrons. [1]

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

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

(d) Calculate the number of moles of electrons required to deposit one mole of indium. Relative atomic mass of indium, Ar = 114.82. [1]

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

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

(e) Deduce the charge on the indium ion and the formula of indium sulfate. [1]

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

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



44EP09

– 10 –


5. Research has led to the discovery of new catalysts that are in high demand and used in many chemical industries.

(a) Explain, with reference to their structure, the great selectivity of zeolites as catalysts. [2]

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

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

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

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

(b) Nanocatalysts play an essential role in the manufacture of industrial chemicals.

(i) Describe the high pressure carbon monoxide (HIPCO) method for the production of carbon nanotubes. [2]

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

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

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

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

(ii) Outline one benefit of using nanocatalysts compared to traditional catalysts in industry. [1]

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

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

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



44EP10

– 11 –

Turn over


6. Polymers are made up of repeating monomer units which can be manipulated in various ways to give structures with desired properties.

(a) Deduce the repeating unit of poly(2-methylpropene). [1]

(b) Deduce the percentage atom economy for polymerization of 2-methylpropene. [1]

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

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

(c) (i) Suggest why incomplete combustion of plastic, such as polyvinyl chloride, is common in industrial and house fires. [1]

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

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

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



44EP11

– 12 –


(ii) Phthalate plasticizers such as DEHP, shown below, are frequently used in polyvinyl chloride.

C

C

O

O

O

O

CH2

CH2

CH

CH CH2

CH2

CH2

CH2

CH3

CH3

CH2

CH2

CH2

CH2

CH3

CH3

With reference to bonding, suggest a reason why many adults have measurable levels of phthalates in their bodies. [1]

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

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

(d) Fermentation of sugars from corn starch produces propane-1,3-diol, which can be polymerized with benzene-1,4-dicarboxylic acid to produce the PTT polymer (polytrimethylene terephthalate).

(i) Draw the molecular structure of each monomer. [1]



44EP12

– 13 –

Turn over


(ii) Deduce the name of the linkage formed on polymerization between the two monomers and the name of the inorganic product. [1]

Name of linkage:

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

Name of inorganic product:

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

7. Liquid crystals have many applications.

Outline how a lyotropic liquid crystal differs from a thermotropic liquid crystal. [2]

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

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

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

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



44EP13

– 14 –


8. Chromium forms coloured compounds and is used to make stainless and hard steel. The distance between layers of chromium atoms in the metal can be obtained using X-ray crystallography.

(a) (i) The diagram below shows the diffraction of two X-ray beams, y and z of wavelength λ, shining on a chromium crystal whose planes are a distance d nm apart.

d nm

Crystal plane

DetectorBeam y

90°

A C

B

90°

Beam z

X-raysource

Crystal plane

θ

Deduce the extra distance travelled by the second beam, z, compared to the first one, y. [1]

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

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

(ii) State the Bragg’s condition for the observed diffraction to be at its strongest (constructive interference). [1]

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

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



44EP14

– 15 –

Turn over


(b) (i) The mass of one unit cell of chromium metal is 17.28 × 10−23 g. Calculate the number of unit cells in one mole of chromium. Ar (Cr) = 52.00. [1]

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

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

(ii) Deduce the number of atoms of chromium per unit cell. [1]

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

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

9. Superconductors are materials that conduct electric current with practically zero resistance.

(a) Describe the Meissner effect. [1]

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

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

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

(b) Outline one difference between type 1 and type 2 superconductors. [1]

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

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

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

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



44EP15

– 16 –


10. The Fenton and Haber–Weiss reactions convert organic matter in waste water to carbon dioxide and water.

(a) Compare and contrast the Fenton and Haber–Weiss reaction mechanisms. [2]

One similarity:

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

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

One difference:

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

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

(b) Adsorption and chelation are two methods of removing heavy metal ion pollution from the environment.

(i) Describe the process of adsorption. [1]

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

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

(ii) Deduce the structure of the complex ion formed by the reaction of three H2N−CH2−CH2−NH2 chelating molecules with a mercury(II) ion. [1]

End of Option A


44EP16

– 17 –

Turn over

Option B — Biochemistry

11. Lipids are an important part of the human diet.

(a) Fatty acids react with glycerol to form fats and oils. State the name of the chemical link formed in this reaction and the name of the other product. [1]

Name of the chemical link:

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

Name of the other product:

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

(b) The table below shows average figures for the percentage fatty acid composition of some common fats and oils.

Source of fat or oil

% saturated fatty acids

(total)

% monounsaturated fatty acid oleic

% polyunsaturated fatty acids

linoleic linolenic

Beef fat 59 38 3 -Coconut oil 90 8 2 -Corn oil 25 26 47 2Cotton seed oil 22 35 43 -Olive oil 15 78 7 -Soybean oil 14 28 50 8

(i) Deduce, with a reason, which fat or oil from the table above has the lowest iodine number. [1]

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

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

(ii) Deduce, with a reason, which fat or oil from the table above is most likely to become rancid when exposed to the air. [1]

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

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

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



44EP17

– 18 –


(iii) The P/S index of a fat or oil is the ratio of polyunsaturated fat to saturated fat present. It is sometimes used to compare the relative health benefits of different lipids in the diet. Calculate the P/S index of beef fat and soybean oil. [1]

Beef fat:

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

Soybean oil:

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

(iv) Suggest why a P/S index of greater than 1 is considered beneficial to health. [1]

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

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

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

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

(v) Cotton seed oil and corn oil have similar iodine numbers but the melting point of cotton seed oil is higher than that of corn oil. Suggest an explanation in terms of the structure and bonding in these two oils. [2]

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

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

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

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

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



44EP18

– 19 –

Turn over

(Option B continued)

12. Carbohydrates are energy-rich molecules which can be synthesized in some plant cells from inorganic compounds.

(a) State the raw materials and source of energy used in the process described above. [1]

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

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

(b) The structures of two molecules, X and Y, are shown below.

X: Y:H

C

O

CH OH

CH OH

H

C

C O

CH OH

H

H

OHH

H

C

O

CH OH

CH OH

H

C

C O

CH OH

H

H

OHH

(i) Justify why both these molecules are carbohydrates. [1]

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

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

(ii) Distinguish between these molecules in terms of their functional groups. [1]

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

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

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

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



44EP19

– 20 –


(c) Amylose is an unbranched polysaccharide composed of repeating units of glucose.

(i) Draw the structure of the repeating unit of amylose. Use section 34 of the data booklet. [1]

(ii) Amylose is a major component of starch. Corn starch can be used to make replacements for plastics derived from oil, especially for packaging. Discuss one potential advantage and one disadvantage of this use of starch. [2]

Advantage:

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

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

Disadvantage:

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

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



44EP20

– 21 –

Turn over


13. Amino acids are usually identified by their common names. Use section 33 of the data booklet.

(a) State the IUPAC name for leucine. [1]

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

(b) A mixture of amino acids is separated by gel electrophoresis at pH 6.0. The amino acids are then stained with ninhydrin.

(i) On the diagram below draw the relative positions of the following amino acids at the end of the process: Val, Asp, Lys and Thr. [2]

Origin

(+)Anode

(−)Cathode

(ii) Suggest why glycine and isoleucine separate slightly at pH 6.5. [1]

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

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

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



44EP21

– 22 –


(c) Amino acids act as buffers in solution. In aspartic acid, the side chain (R group) carboxyl has pKa = 4.0. Determine the percentage of the side chain carboxyl that will be ionized (–COO−) in a solution of aspartic acid with pH = 3.0. Use section 1 of the data booklet. [3]

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

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

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

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

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

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

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

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

14. Glucokinase and hexokinase are both enzymes that catalyse the conversion of glucose to glucose-6-phosphate. The enzymes differ, however, in their affinity for the substrate, as shown in the graph below.

Rel

ativ

e ve

loci

ty /

V

Hexokinase

Glucokinase

normal concentrationof blood glucose

00

10

20

30

40

50

60

70

80

90

100

5 10 15 20 25 30Glucose concentration / mmol dm−3

[Source: http://themedicalbiochemistrypage.org/glycolysis.php]



44EP22

– 23 –

Turn over


(a) (i) Estimate the Km values of the two enzymes. [1]

Km hexokinase:

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

Km glucokinase:

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

(ii) Suggest, with a reason, which enzyme will be more responsive to changes in the concentration of glucose in the blood. [1]

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

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

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

(b) (i) Outline what is meant by product inhibition as it applies to hexokinase. [1]

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

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

(ii) Product inhibition of hexokinase does not affect its Km value. Using this information, deduce the type of binding site that the inhibitor attaches to. [1]

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

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



44EP23

– 24 –


15. The structure of DNA (deoxyribonucleic acid) has been studied in many different ways.

(a) State the name of the component of DNA responsible for the migration of its fragments to the positive electrode in gel electrophoresis. [1]

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

(b) In 2010, scientists claimed that they had discovered a species of bacteria capable of incorporating arsenic in place of phosphorus into the bacterial DNA. This claim has since proved controversial. Suggest one technique or evidence that might help support the claim. [1]

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

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

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

16. Anthocyanins are pigments that give colour to many flowers and fruits. The red colour of ripe strawberries is mainly due to the anthocyanin pigment whose structure is shown below.

O+

O

O

OH

HO

OH

CH2OH

OH

HO

OH



44EP24

– 25 –

Turn over


(a) Outline why this molecule absorbs visible light. [1]

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

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

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

(b) With reference to its chemical structure, outline whether this pigment is found in aqueous solution in the cells or in the lipid-based membranes. [1]

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

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

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



44EP25

– 26 –


(c) A student investigated the ability of anthocyanins to act as pH indicators. He extracted juice from blackberries and used a UV-vis spectrophotometer to produce absorption spectra at different pH values. His results are shown below.

Abs

orba

nce

1.4

1.2

1.0

0.8

0.6

0.4

0.2

0400 450 500 550 600 650 700

pH 2

pH 11

Wavelength / nm

Deduce the colour of the juice at each pH, giving your reasoning. Use section 17 of the data booklet. [2]

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

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

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

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

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

End of Option B


44EP26

– 27 –

Turn over

Option C — Energy

17. Chemical energy from redox reactions can be used as a portable source of electrical energy. A hybrid car uses a lithium ion battery in addition to gasoline as fuel.

(a) (i) Calculate the specific energy of the lithium ion battery, in MJ kg−1, when 80.0 kg of fuel in the battery releases 1.58 × 107 J. Use section 1 of the data booklet. [1]

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

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

(ii) The specific energy of gasoline is 46.0 MJ kg−1. Suggest why gasoline may be considered a better energy source than the lithium ion battery based on your answer to part (a) (i). [1]

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

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

(b) (i) The energy density of gasoline is 34.3 MJ dm−3. Calculate the volume of gasoline, in dm3, that is equivalent to the energy in 80.0 kg of fuel in the lithium ion battery. Use section 1 of the data booklet. [1]

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

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

(ii) The efficiency of energy transfer by this lithium ion battery is four times greater than that of gasoline. Determine the distance, in km, the car can travel on the lithium ion battery power alone if the gasoline-powered car uses 1.00 dm3 gasoline to travel 32.0 km. [1]

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

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



44EP27

– 28 –


18. Auto-ignition of hydrocarbon fuel in a car engine causes “knocking”. The tendency of a fuel to knock depends on its molecular structure.

(a) Discuss how the octane number changes with the molecular structure of the alkanes. [2]

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

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

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

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

(b) Catalytic reforming and cracking reactions are used to produce more efficient fuels. Deduce the equation for the conversion of heptane to methylbenzene. [1]

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

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

19. Carbon dioxide and water vapour are greenhouse gases produced by the combustion of fossil fuels.

(a) Explain the effect of the increasing concentration of atmospheric carbon dioxide on the acidity of oceans. [2]

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

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

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

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

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



44EP28

– 29 –

Turn over


(b) Describe the changes that occur at the molecular level when atmospheric carbon dioxide gas absorbs infrared radiation emitted from the Earth’s surface. [2]

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

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

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

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

20. Biofuels are renewable energy sources derived mainly from plants.

State the equation for the complete transesterification of the triglyceride given below with methanol. [2]

H2 CO C17H33

HC

H2C

O CO C17H33

O CO C17H33



44EP29

– 30 –


21. A fuel cell is an energy conversion device that generates electricity from a spontaneous redox reaction.

(a) The Geobacter species of bacteria can be used in microbial fuel cells to oxidise aqueous ethanoate ions, CH3COO−(aq), to carbon dioxide gas.

State the half-equations for the reactions at both electrodes. [2]


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

Positive electrode (cathode):

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

(b) A concentration cell is an example of an electrochemical cell.

(i) State the difference between a concentration cell and a standard voltaic cell. [1]

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

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

(ii) The overall redox equation and the standard cell potential for a voltaic cell are:

Zn (s) + Cu2+ (aq) → Zn2+ (aq) + Cu (s) E Àcell = +1.10 V

Determine the cell potential E at 298 K to three significant figures given the following concentrations in mol dm−3:

[Zn2+] = 1.00 × 10−4 [Cu2+] = 1.00 × 10−1

Use sections 1 and 2 of the data booklet. [1]

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

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

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

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



44EP30

– 31 –

Turn over


(iii) Deduce, giving your reason, whether the reaction in (b) (ii) is more or less spontaneous than in the standard cell. [1]

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

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

(c) Dye-sensitized solar cells (DSSC) convert solar energy into electrical energy.

(i) Describe how a DSSC converts sunlight into electrical energy. [2]

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

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

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

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

(ii) Explain the role of the electrolyte solution containing iodide ions, I−, and triiodide ions, I3

−, in the DSSC. [2]

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

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

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

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



44EP31

– 32 –


22. Nuclear reactions transform one nuclide into another. Fission, splitting a large nucleus into two smaller nuclei, releases vast amounts of energy.

(a) (i) Explain why fusion, combining two smaller nuclei into a larger nucleus, releases vast amounts of energy. Use section 36 of the data booklet. [2]

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

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

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

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

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

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

(ii) Outline one advantage of fusion as a source of energy. [1]

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

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

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

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

(b) Radioactive phosphorus, 33P, has a half-life of 25.3 days.

(i) Calculate 33P decay constant λ and state its unit. Use section 1 of the data booklet. [1]

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

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

(ii) Determine the fraction of the 33P sample remaining after 101.2 days. [1]

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

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



44EP32

– 33 –

Turn over


(c) (i) Uranium hexafluoride, UF6, is used in the uranium enrichment process that produces fuel for nuclear reactors.State the molecular shape of uranium hexafluoride. [1]

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

(ii) Explain why uranium dioxide, UO2, has a very high melting point whereas uranium hexafluoride vapourises easily into gas. [2]

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

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

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

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

End of Option C


44EP33

– 34 –

Option D — Medicinal chemistry

23. Penicillin is an antibiotic which contains a beta-lactam ring. Its general structure is shown below.

R

C

HN

O

N

O

SCH3

CH3

CO

HO

(a) (i) Outline what is meant by the term “ring strain”. [1]

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

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

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

(ii) On the diagram above, label with asterisk/s (*) the carbon atom/s that experience ring strain. [1]

(b) (i) Some antibiotic-resistant bacteria produce a beta-lactamase enzyme which destroys penicillin activity. Suggest how adding clavulanic acid to penicillin enables the antibiotic to retain its activity.

O

N

O

COOH

H

CH2OH

Clavulanic acid

[1]

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

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

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

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



44EP34

– 35 –

Turn over


(ii) Populations of antibiotic-resistant bacteria have increased significantly over the last 60 years. Outline why antibiotics such as penicillin should not be prescribed to people suffering from a viral infection. [2]

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

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

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

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

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

24. Oseltamivir (Tamiflu) and zanamivir (Relenza) are both used as antivirals to help prevent the spread of the flu virus, but are administered by different methods.

(a) Zanamivir must be taken by inhalation, not orally. Deduce what this suggests about the bioavailability of zanamivir if taken orally. [1]

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

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

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

(b) Oseltamivir does not possess the carboxyl group needed for activity until it is chemically changed in the body. Deduce the name of the functional group in oseltamivir which changes into a carboxyl group in the body. Use section 37 of the data booklet. [1]

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



44EP35

– 36 –


25. The mild analgesic aspirin can be prepared in the laboratory from salicylic acid.

(CH3CO)2O + HOC6H4COOH → CH3CO2C6H4COOH + CH3COOH

Salicylic acid Aspirin

After the reaction is complete, the product is isolated, recrystallized, tested for purity and the experimental yield is measured. A student’s results in a single trial are as follows.

Mass / g ±0.001 Melting point / °C ±1Initial salicylic acid 1.552Crude product 1.398 106–114Product after recrystallization 1.124 122–125

Literature melting point data: aspirin = 138–140 °C

(a) Determine the percentage experimental yield of the product after recrystallization. The molar masses are as follows: M (salicylic acid) = 138.13 g mol−1, M (aspirin) = 180.17 g mol−1. (You do not need to process the uncertainties in the calculation.) [2]

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

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

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

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

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

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

(b) Suggest why isolation of the crude product involved the addition of ice-cold water. [1]

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

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

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

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



44EP36

– 37 –

Turn over


(c) Justify the conclusion that recrystallization increased the purity of the product, by reference to two differences between the melting point data of the crude and recrystallized products. [2]

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

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

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

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

26. Excess stomach acid leads to medical conditions that affect many people worldwide. These conditions can be treated with several types of medical drugs.

(a) Ranitidine (Zantac) is a drug that inhibits stomach acid production. Outline why the development of this drug was based on a detailed knowledge of the structure of histamine, shown below. [1]

HN

N

NH2

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

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

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

(b) Two other drugs, omeprazole (Prilosec) and esomeprazole (Nexium), directly prevent the release of acid into the stomach. Identify the site of action in the body. [1]

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

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



44EP37

– 38 –


(c) Omeprazole exists as a racemic mixture whereas esomeprazole is a single enantiomer. Outline how, starting from a non-chiral molecule, esomeprazole but not omeprazole, could be synthesized. Details of chemicals and conditions are not required. [2]

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

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

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

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

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

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

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

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



44EP38

– 39 –

Turn over


27. Methadone, a synthetic opioid, binds to opioid receptors in the brain.

CH2

O

CH2

H3C CH

H3C N

H3C

CH3

Methadone

(a) Compare and contrast the functional groups present in methadone and diamorphine (heroin), giving their names. Use section 37 of the data booklet. [2]

One similarity:

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

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

One difference:

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

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

(b) Methadone is sometimes used to help reduce withdrawal symptoms in the treatment of heroin addiction. Outline one withdrawal symptom that an addict may experience. [1]

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

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

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



44EP39

– 40 –


28. Technetium-99m is the most widely used medical radioisotope. It is usually made on-site in medical facilities from isotopes of molybdenum.

(a) Deduce equations for the following nuclear reactions:

(i) Molybdenum-98 absorbs a neutron. [1]

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

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

(ii) The isotope produced in (a) (i) decays into technetium-99m. [1]

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

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

(b) Molybdenum-99 has a half-life of 66 hours, while technetium-99m has a half-life of 6 hours. Outline why technetium-99m is made on-site. [1]

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

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

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

(c) Outline two reasons, other than its half-life, why technetium-99m is so useful in medical diagnosis. [2]

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

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

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

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

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

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



44EP40

– 41 –

Turn over


(d) Outline the nature of the radioactive waste that is generated by the use of technetium-99m in medical diagnosis. [1]

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

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

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

29. The use of performance-enhancing drugs presents a challenge in the world of competitive sports. New regulations have lowered the acceptable concentrations of certain drugs in athletes’ bodies.

(a) Suggest what may have led to these changes in acceptable concentrations. [1]

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

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

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

(b) One class of performance-enhancing drugs is the anabolic steroids. Detection of these drugs in urine samples uses a combination of gas chromatography and mass spectrometry (GC/MS).

(i) Describe how gas chromatography enables the components of urine to be analysed. [2]

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

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

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

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

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

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



44EP41

– 42 –


(ii) The structures of two steroids, testosterone and nandrolone, are given below.

CH3

O

CH3OH CH3

OH

O

Testosterone C19H28O2 Nandrolone C18H26O2

With reference to the molar masses of the two steroids, determine, with a reason, which can be identified from the mass spectrum below.

Rel

ativ

e in

tens

ity

100

80

60

40

20

50 100 150 200 250 3000

m/z

[2]

[Source: http://sdbs.db.aist.go.jp/ accessed 2015-08-23]

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

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

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

End of Option D


44EP42



44EP43



44EP44

Markschem

e

Novem

ber 2016

Chem

istry

Higher level

Paper 3

30 pages

N16/4/C

HE

MI/H

P3/E

NG

/TZ0/XX

/M

–2 –

This markschem

e is the property of the International B

accalaureate and must not be reproduced or distributed

to any other person without the authorization of the IB

A

ssessment C

entre.

N16/4/C

HE

MI/H

P3/E

NG

/TZ0/XX

/M

– 3 –

Section A

Question

Answ

ersN

otesTotal

1.a

iH

OCl: +1

AN

DClO

2 : +4

Accept “I” and “IV

” but not “1+/1” and “4+/4” notations.

1

1.a

ii«m

ost» CT values are higher for «bacterium

» BO

R«generally» higher dosage needed for «bacterium

» B

Accept converse argum

ents.A

ccept “concentration” for “dosage”.1

1.a

iii«C

T = 1.50 × 10-5 × 10

3 mg dm

-3 × 9.82 min =» 1.47 × 10

-1 «m

g min dm

-3» 1

1.a

ivlow

er than CT value/m

inimum

dosage/1.8 × 10-1 «m

g min dm

-3»A

ND

no/insufficienttreatment

Accept “concentration” for “dosage”.

1

1.b

ihigher C

T value at lower tem

perature O

Rhigher dosage «of chlorine» needed at low

temperature

Accept “effectiveness decreases at low

er tem

perature”.A

ccept “concentration” for “dosage”.A

ccept converse arguments.

1

1.b

iilabeled axes ( y: C

T and x: pH)

AN

Dcurve w

ith increasing gradient

Do not accept axes the w

rong way round.

Accept a linear graph.

1

1.b

iiivalues at pH

9.0 approximately 3 tim

es values at pH 6.0

OR

increase in CT values in sam

e ratio

The exact ratio is 2.9 times.

Do not accept just “increase in value”.

1

1.b

iv[H

OC

l] decreases AN

D [O

Cl - ] increases

1

(continued)

N16/4/C

HE

MI/H

P3/E

NG

/TZ0/XX

/M

–4 –


Question

Answ

ersN

otesTotal

1.c

plastic disposal/pollutionO

Rplastic bottles use up petroleum

/non-renewable raw

material

OR

chemicals in plastic bottles can contam

inate water

OR

«prolonged» storage in plastic bottles can cause contamination of w

aterO

Rplastic w

ater bottles sometim

es reused without proper hygiene

considerations

Accept other valid answ

ers.

Accept econom

ic considerations such as “greater production costs”, “greater transport costs” or “bottled w

ater more expensive than

tap water”.

1

2.a

repeat steps 3 and 4O

Rrepeat step 5O

Rconduct a third heatingO

R«re»heat A

ND

«re»weigh

water still present

OR

need two consistent readings

OR

heat to constant mass

Do not accept “cleaning/w

ashing the crucible”.

2

(continued)

N16/4/C

HE

MI/H

P3/E

NG

/TZ0/XX

/M

– 5 –


Question

Answ

ersN

otesTotal

2.b

soot/carbon depositedO

Rincom

plete combustion

OR

air hole of Bunser burner closed/not fully open

«value of x» lower

Accept “using a yellow

«Bunsen burner»

flame” for M

1.

Only aw

ard M2 if M

1 correct.

2

2.c

all mass loss is due to w

ater loss

all the water «of crystallization» is lost

crucible does not absorb/lose water

crystal/BaC

l2 does not decompose/hydrolyse/oxidize/react w

ith oxygen/air «w

hen heated»

Accept “no loss of crystals/B

aCl2 occurs”, “no

impurities in the «w

eighed hydrated» salt”, “reaction goes to com

pletion”, “heat was

consistent/strong”, “crystal/BaC

l2 does not absorb w

ater during cooling”, “balance has been calibrated” or “crucible w

as clean at the start”.

Do not accept ”heat loss to surroundings” or

“no carbon deposited on crucible”.

Reference to defects in apparatus not

accepted.

Do not penalize if B

aCl2 .xH

2 O is used for

BaC

l2 .

2 max

N16/4/C

HE

MI/H

P3/E

NG

/TZ0/XX

/M

– 6 –

Section B

Option A —

Materials

Question

Answ

ersN

otesTotal

3.a

MgO

: ionic AN

D S

iC: covalent

Accept “covalent netw

ork/network covalent”

for “covalent” but not just “network”.

1

3.b

metallic «bonding»

1

4.a

«0.300 A × 9.00 × 103 s =» 2.70 × 10

3 «C»

14.

b«m

ol e- =

2700C

96500

Cmol

1- =» 2.80 × 10-2 «m

ol» 1

4.c

«1.07

g0.0280m

ol =» 38.2 «g» 1

4.d

«114.82

g38.2

gmol -1 e

- =» 3.01/3.00 «mol e

-» 1

4.e

In3 +/3+ A

ND

In2 (S

O4 )3

Do not accept “+3/3”.

1

5.a

pores/cavities/channels/holes/cage-like structures

«only»reactantswithappropriate/specificsize/geom

etryfitinside/gothrough/are activated/can react

Accept “m

olecules/ions” for reactants.

2

(continued)

N16/4/C

HE

MI/H

P3/E

NG

/TZ0/XX

/M

– 7 –


Question

Answ

ersN

otesTotal

5.b

iiron«0»«penta»carbonyl/Fe (C

O)5 «catalyst» decom

posesO

RFe (C

O)5 (g) →

Fe (s) + 5CO

(g)O

Rm

etal nanocatalyst/clusters/particles formed «in situ»

2CO

(g) → C

O2 (g) +C

(s)

Accept “cobalt-m

olybdenum/C

o-Mo/C

oMo” as a

catalyst.

Accept “conversion of C

O m

olecules into CN

Ts/S

WN

Ts” for M2.

2

5.b

iihigherefficiencyperunitm

ass/volumeofcatalyst«due to higher

surface to mass/volum

e ratio»O

Rgreater selectivity «due to m

etal nanoclusters/surface topology/pore size»O

Rhigher stability of catalyst «due to low

er tendency to aggregation»O

Rreduced cost of catalyst/product/chem

icals «as precious metals can be

replaced with nanocatalysts m

ade of inexpensive materials»

Accept “high conversion efficiency”.

Accept specific exam

ples such as use of nanocatalysts in fuel cells/catalytic converters «leading to reduced use of P

t/Rh/P

d».

Accept “low

er energy consumption / reduced

carbon footprint / reduced global warm

ing”, “often operate under m

ilder conditions «so less energy consum

ption involved/promoting principles of

green chemistry», “often have long lifetim

es «so m

ore economical»” or “have enzym

e mim

icking activities”.

1

(continued)

N16/4/C

HE

MI/H

P3/E

NG

/TZ0/XX

/M

– 8 –

Question

Answ

ersN

otesTotal

6.a

HCH

C CH3

CH3

OR

-CH

2 C(C

H3 )2 -

Continuation bonds needed for m

ark. N

o penalty if brackets present or “n” appears after the bracket/form

ula.

1

6.b

«same m

ass of product as reactant, thus» 100 «%»

Accept “less than 100 %

” only if a reason is given (eg, the catalyst is not converted into the product, or other reasonable answ

er).1

6.c

idue to stability of plastics / strong covalent bonds O

Rlow

volatility preventing good mixing w

ith oxygen «gas»O

Rlackof/insufficientoxygenO

R

plastics are often parts of devices with non-com

bustible components

«which m

echanically prevent the combustion of plastic com

ponents»O

R

PV

C already partly oxidized «because som

e C–H

bonds are replaced with

C–C

l bonds», so it cannot produce enough heat for complete com

bustionO

Rm

any industrial/household materials contain additives that reduce their

flammability/actasflam

eretardants

1

(continued)

N16/4/C

HE

MI/H

P3/E

NG

/TZ0/XX

/M

– 9 –


Question

Answ

ersN

otesTotal

6.c

iiw

eakly bound to PV

C/no covalent bonds to P

VC

/only London/dispersion/instantaneous induced dipole-induced dipole forces betw

een DE

HP and

PV

C A

ND

leach/evaporate «from P

VC

» to atmosphere/food chain

OR

has low polarity/contains non-polar hydrocarbon chains A

ND

fat-soluble/deposits in the fatty tissuesO

Rhasunusualstructuralfragm

ents/isaxenobiotic/difficulttometabolise

AN

D stays in the body for a long tim

e

1

6.d

iH

O–C

H2 –C

H2 –C

H2 –O

H A

ND

HO

OC

–C6 H

4 –CO

OH

A

ccept full or condensed structural formulas.

Labelling of monom

ers not required but penalize incorrect labels.

1

6.d

iiN

ame of linkage: ester

AN

DN

ame of inorganic product: w

ater

Do not accept “esterification”.

Do not accept form

ulas.1

7.a

Lyotropic LCs

Thermotropic LC

ssolutions

AN

Dpure substances

LC over certain concentration

rangeA

ND

LC over a tem

perature range«betw

een solid and liquid phases»

Do not aw

ard any credit if one type only is described as the question asks how

they differ.

2

(continued)

N16/4/C

HE

MI/H

P3/E

NG

/TZ0/XX

/M

– 10 –

Question

Answ

ersN

otesTotal

8.a

i2d sin θO

R2|A

B| / 2|B

C| / |A

B| + |B

C| / |A

B| A

ND

|BC

|

Vertical lines indicating lengths not required. A

nswer m

ay be conveyed in words also.

Do not accept |A

C| – reference m

ust be m

ade to B.

1

8.a

iiextra distance travelled/|A

B| + |B

C| = nλ/a w

hole number of w

avelengths A

ccept notations of extra distance as in (a)(i).

1

8.b

i«

52.00gm

ol17.28

10gunitcell

1

231

−

−×

− =» 3.009 × 10

23 «unit cells mol -1»

1

8.b

ii«

6.0210

atomsm

ol3.01

10unit cells

mol

231

231

×

×

−

− =» 2 «atom

s per unit cell» 1

9.a

creationofamirrorim

agemagneticfieldofanexternalfield«below

the critical tem

perature/Tc of the superconductor»

OR

expulsionofamagneticfieldfrom

asuperconductor«below its critical

temperature/T

c »

1

9.b

Type 1 superconductorsType 2 superconductors

sharp transitions to superconductivity

AN

Dm

ore gradual transitions to superconductivity

OR

lower critical tem

peratures/Tc

AN

Dhigher critical tem

peratures/Tc

Accept “Type 1: «m

ost» metals A

ND

Type 2: alloys/m

etal oxide ceramics/

perovskites”.1

(continued)

N16/4/C

HE

MI/H

P3/E

NG

/TZ0/XX

/M

– 11 –

Question

Answ

ersN

otesTotal

10.a

One sim

ilarity:both involve hydroxyl/•O

H «radicals»

One difference:

Fenton reaction mechanism

Haber-W

eiss reaction m

echanismhydroxyl «radical»/•O

H

«concentration» dependent m

echanismO

R

AN

Dhydroxyl «radical»/•O

H

«concentration» independent m

echanism

Fe2+ is the catalyst

OR

Fe3+ is the interm

ediateO

R

AN

D

AN

D

Fe3+ is the catalyst

Fe2+ is the interm

ediate

Fe2+ + H

2 O2 →

Fe3+ + H

O• + O

H–

andFe

3+ + H2 O

2 → Fe

2+ + HO

O• + H

+

OR

2H2 O

2 → H

O• + H

OO

• + H2 O

AN

D

AN

D

Fe3+ + •O

2 - → Fe

2+ + O2

andFe

2+ + H2 O

2 → Fe

3+ + HO

• + OH

–

H2 O

2 + •O2 - →

O2 + •O

H + O

H-

Accept “hydroxy” for “hydroxyl”.

Do not penalize m

issing radical symbols

if consistent throughout.

Accept “H

2 O2 →

2•OH

” for the Fenton m

echanism.

2

(continued)

N16/4/C

HE

MI/H

P3/E

NG

/TZ0/XX

/M

– 12 –


Question

Answ

ersN

otesTotal

10.b

im

olecules/ions/substances are attracted to/form «non-covalent» interactions

with the surface of the adsorbent

1

10.b

ii

Hg

H2 N

NH2

NH2

H2 N

H2 N

H2 N

CH2CH2

CH2 CH2

H2 C

H2 C

2+

OR

Hg

H2 N

NH2

NH2

H2 N

NH2

H2

NOR

Hg

H2

NNH2

CH2

CH2

3

2+2+

Do not penalize m

issing charge or square brackets.

Bonds to H

g must be show

n (in any form

at).

1

N16/4/C

HE

MI/H

P3/E

NG

/TZ0/XX

/M

–13 –

Option B

— B

iochemistry

Question

Answ

ersN

otesTotal

11.a

Nam

e of the chemical link: ester

AN

DN

ame of the other product: w

ater

Do not accept form

ulas. D

o not accept “esterification”.1

11.b

icoconut oil A

ND

lowest «percentage of» unsaturated fatty acids

OR

coconut oil AN

D sm

allest number of C

=C bonds

OR

coconut oil AN

D highest «percentage of» saturated fatty acids

Accept “fats” for “fatty acids”.

1

11.b

iisoybean oil A

ND

highest «percentage of» polyunsaturated fatty acidsO

Rsoybean oil A

ND

greatest number of C

=C bonds

OR

soybean oil AN

D low

est «percentage of» saturated fatty acids

Accept “fats” for “fatty acids”.

1

11.b

iiiB

eef fat: «P/S

= 359

=» 0.05A

ND

Soybean oil: «P

/S = 50

814 +

=» 4.1

1

11.b

iv«higher proportion of» polyunsaturated fatty acids decrease risk of atherosclerosis/heart disease/cardiovascular disease/C

VD

OR

«higher proportion of» polyunsaturated fatty acids which are less likely to

be deposited on the walls of arteries «than saturated fatty acids»


ents.

Accept correct argum

ents in terms of H

DL

and LDL but not in term

s of “good” and “bad” cholesterol.A

ccept “fats” for “fatty acids”.

1

(continued)

N16/4/C

HE

MI/H

P3/E

NG

/TZ0/XX

/M

– 14 –


Question

Answ

ersN

otesTotal

11.b

vA

ny two of:

cotton seed oil has «a higher proportion of» longer chain/greater molar

mass fatty acids

molecules of cotton seed oil have greater surface area/higher electron

density

stronger London/dispersion/instantaneous induced dipole-induced dipole forces «betw

een chains» in cotton seed oil


ents.

Accept “m

olecules of cotton seed oil are packed m

ore closely/have more regular

structure” for M2.

2 max

12.a

CO

2 AN

D H

2 O A

ND

sun A

ccept names.

Accept “sunlight/light/photons” instead of

“sun”.1

12.b

iboth have form

ula Cx (H

2 O)y

OR

both contain several OH

/hydroxyl «groups» AN

D a C

=O/carbonyl «group»

Accept “both have form

ula Cn H

2n On /em

pirical form

ula CH

2 O” but do not accept “both

have same m

olecular formula/have form

ula C

3 H6 O

3 ”.

Accept “hydroxy” but not “hydroxide/O

H -” for

“hydroxyl”.

Accept “aldehyde or ketone” for “carbonyl”.

1

(continued)

N16/4/C

HE

MI/H

P3/E

NG

/TZ0/XX

/M

– 15 –


Question

Answ

ersN

otesTotal

12.b

iiX

YR

CH

O/C

HO

OR

C=O

/carbonyl «group with

C» bonded to H

OR

formyl «group»

OR

C=O

/carbonyl «group» at end of chain/at C

–1 «atom»

AN

D

R2 C

O/R

CO

R’

OR

carbonyl/C=O

«group with

C» bonded to tw

o C/R

«groups»O

RC

=O/carbonyl «group»

in middle of chain/at C

–2 «atom

»

Accept “alkyl” for “R

”.A

ccept “X: aldose/aldehyde A

ND

Y: ketose/

ketone”.A

ccept “CO

” for “C=O

”.

1

12.c

iH

OHOH

OH

H CH2 O

H

H

O

H

continuation bonds AN

D open O

on either but not both ends

Brackets are not necessary for the m

ark.D

o not accept β-isomer.

Mark m

ay be awarded if a polym

er is shown

but with the repeating unit clearly identified.

3D representation is not required.

1

(continued)

N16/4/C

HE

MI/H

P3/E

NG

/TZ0/XX

/M

–16 –


Question

Answ

ersN

otesTotal

12.c

iiA

dvantage:A

ny one of:biodegradable / break dow

n naturally/by bacteria com

postable does not contribute toland-fillrenew

able/sustainable resource starch grains sw

ell AN

D help break up plastic

lower greenhouse gas em

issions uses less fossil fuels than traditional plastics less energy needed for production

Disadvantage:

Any one of:

land use «affects biodiversity/loss of habitats» grow

ing corn for plastics instead of food «starch» breakdow

n can increase acidity of soil/compost

«starch» breakdown can produce m

ethane «especially when buried»

sensitive to moisture/bacteria/acidic foods

«bioplastics sometim

es» degrade quickly/before end of use cannot be reused poor m

echanical strength eutrophication increased use of fertilizers/pesticides/phosphorus/nitrogen «has negative environm

ental effects»

Ignore any reference to cost.D

o not accept just “decompose

easily”.

Accept “prone to site explosions/

fires” or “low heat resistance” for

disadvantage.

Only aw

ard [1 max] if the

same exam

ple is used for the advantage and disadvantage.

2 max

(continued)

N16/4/C

HE

MI/H

P3/E

NG

/TZ0/XX

/M

– 17 –

Question

Answ

ersN

otesTotal

13.a

2-amino-4-m

ethylpentanoic acid A

ccept “4-methyl-2-

aminopentanoic acid”.

1

13.b

iO

rigin

( +)A

node(-)

Cathode

Lys on cathode side AN

D A

sp on anode side Val at origin A

ND

Thr on anode side but closer to origin than Asp

Val and Thr need not overlap.

Accept any (reasonable) size

and demarcation of position so

long as position relative to origin is correct.A

ccept crosses for spots.

Award [1 m

ax] for any two

correct.Aw

ard [1 max] if net direction of

spots is reversed.

Award [1 m

ax] if the four points are in the correct order but not in a straight line.

2

13.b

iidifferent sizes/m

olar masses/chain lengths «so m

ove with different speeds»

113.

c«-C

OO

H

-CO

O- + H

+ (-C

OO

H = H

A ; -CO

O- = A

-)»

pH = pK

a + log [A]

[HA] -

/ 3.0 = 4.0 + log [COO]

[COOH]

--

-

«percentage ionized/–CO

O– =

11

10+

× 100 =» 9.1 «%»

Award [3] for correct final

answer.

3

(continued)

Asp

LysThr

Val

N16/4/C

HE

MI/H

P3/E

NG

/TZ0/XX

/M

-1.0 = log-

-[COO]

-[COOH]

/

10–1 =

--[COO]

-[COOH]

– 18 –

Question

Answ

ersN

otesTotal

14.a

iK

m hexokinase: approx. 1.7 «mm

ol dm-3»

AN

DK

m glucokinase: approx. 8.5 «mm

ol dm-3»

Accept answ

ers in the range1.0-2.0 for hexokinase and 7.0-9.0 for glucokinase.

1

14.a

iiglucokinase as it is not saturated «w

ith substrate at normal concentration of blood

glucose»O

Rglucokinase as its saturation increases w

ith increased glucose concentration in the blood

Accept “at the norm

al levels of blood glucose concentration, relative velocity of glucokinase still dependent on concentration of glucose”.

1

14.b

iglucose-6-phosphate low

ers enzyme activity/acts as enzym

e inhibitor 1

14.b

ii«inhibitor binds at» allosteric site

Accept “outside/aw

ay from active

site”.1

15.a

phosphato/phosphate «group» D

o not accept “phosphoric acid”, “phosphorus” or any form

ula.1

15.b

mass spectrom

etry / X ray diffraction/crystallography / nuclear m

agnetic resonance «spectroscopy»O

Rbacteria able to grow

in absence of phosphorus O

Rreproducible data

Accept abbreviations (eg, M

S,

NM

R).

Accept “elem

ental analysis” or “atom

ic absorption spectroscopy/A

A(S

)”.

1

16.a

«extensive» conjugation «of double bonds»/delocalization «of electrons»O

R«m

any» alternating single/C–C

AN

D double/m

ultiple/C=C

bonds 1

16.b

in aqueous solution AN

D hydroxyl/O

H/ionic/oxonium

/O+ «groups»

Accept “polar/hydroxy” for

“hydroxyl”.D

o not accept “OH

-/hydroxide/oxygen”.

1

(continued)

N16/4/C

HE

MI/H

P3/E

NG

/TZ0/XX

/M

– 19 –


Question

Answ

ersN

otesTotal

16.c

pH 2: «absorption peak 520 nm

» red AN

D pH

11: «absorption peak 620 nm» blue

complem

entary/opposite colour observed «to wavelength absorbed»

OR

pH 2: «absorption peak 520 nm

» green absorbed AN

D pH

11: «absorption peak 620 nm»

orange absorbed

Award [1 m

ax] if colour absorbed and colour observed are correct for either at pH

2 or pH

11.2

N16/4/C

HE

MI/H

P3/E

NG

/TZ0/XX

/M

– 20 –

Option C

— Energy

Question

Answ

ersN

otesTotal

17.a

i«1.58

10J

80.0kg15.8M

J80.0kg

7×

==

» 1.98 × 10-1 «M

J kg-1»

1

17.a

iigasoline releases m

ore energy from a given m

ass of fuelO

Rgasolinehashigherspecificenergy

Do not accept volum

e in place of mass as

question refers to specific energy, not energy density.

1

17.b

i«

15.8MJ

34.3MJdm

3- »= 4.61 × 10

-1 «dm3»

1

17.b

ii«4.61 × 10

-1 dm3 × 32.0 km

dm−3 × 4» = 59.0/59.1 «km

» 1

18.a

«tends to» decrease with longer/larger/heavier alkanes

«tends to» increase with bulkier/m

ore branched alkanes

Accept “octane num

ber decreases with the

separation between branches” O

R “increases

with the m

ore central position of branches”.


ent.

2

18.b

C7 H

16 → C

6 H5 C

H3 + 4H

2 A

ccept “C7 H

8 ” for “C6 H

5 CH

3 ”.1

(continued)

N16/4/C

HE

MI/H

P3/E

NG

/TZ0/XX

/M

– 21 –

Question

Answ

ersN

otesTotal

19.a

Any tw

o of:

H2 O

(l)C

O2 (g)

C

O2 (aq)

CO

2 (aq) + H2 O

(l)

H+ (aq) + H

CO

3 - (aq)O

RH

CO

3 - and H+ ions are form

ed «by dissolved CO

2 »

«increasing [CO

2 ]» shifts equilibrium to right/increases acidity/decreases pH

H2 O

(l) not required over equilibrium

sign for M1.

State sym

bols required in the equation in M

1.A

ccept “H2 C

O3 ” at either side of

the equilibrium in M

2. E

quilibrium sign required for M

1 but not for M

2.

2 max

19.b

bond length/C=O

changesO

R«asym

metric» stretching «of bonds»

OR

bond angle/OC

O changes

photon re-emitted in random

directionO

Rpolarity/dipole «m

oment» changes

OR

dipole «mom

ent» created «when m

olecule absorbs IR»

Accept “bonds/atom

s vibrate” for M

1.

Accept appropriate diagram

s.2

(continued)

N16/4/C

HE

MI/H

P3/E

NG

/TZ0/XX

/M

– 22 –

Question

Answ

ersN

otesTotal

20.CH2O

CO

C17 H

33

CH

OCO

C17 H

33

CH2O

CO

C17 H

33

+3CH3OH

CO

C17 H

33+CH

CH2

CH2

OH

OH

OH

O3CH3

methyl ester form

ula AN

D glycerol form

ula

correct balancing Aw

ard M2 only if M

1 correct.

2

21.a

Negative electrode (anode): C

H3 C

OO

- (aq) + 2H2 O

(l) → 2C

O2 (g) + 7H

+ (aq) + 8e-

Positive electrode (cathode): O

2 (g) + 4H+ (aq) + 4e

- → 2H

2 O (l)

Accept equilibrium

signs in equations.Aw

ard [1 max] if correct

equations are given at wrong

electrodes.

2

21.b

iconcentration cell has different concentrations of electrolyte «solutions» «but sam

e electrodes and electrolytes»O

Rstandard voltaic cell has different electrodes/electrolytes «but sam

e concentration of electrolytes»

Accept “both half-cells in

concentration cell made from

sam

e materials”.

1

21.b

ii«E

= 1.10 - RTnF

++

lnZn

Cu

22= 1.10 -

8.31298

296500

ln1010

41

×

×

−− = 1.10 + 0.0886 =»

(+) 1.19 «V»

3 significant figures needed for m

ark.1

21.b

iiim

ore spontaneous because E > E

Àcell

1

(continued)

N16/4/C

HE

MI/H

P3/E

NG

/TZ0/XX

/M

– 23 –


Question

Answ

ersN

otesTotal

21.c

iphoton/«sun»light absorbed by the dye/photosensitizer/«transition» m

etal com

plexO

Rdye/photosensitizer/«transition» m

etal complex excited by photon/«sun»light

electron«s» move«s» to conduction band

OR

electron«s» transferred to semiconductor/TiO

2

2

21.c

iiI3 - + 2e

- → 3I - «at cathode»

OR

triiodide ions/ I3 - reduced into/produce iodide ions/I - «at cathode»

iodide ions/I - reduce dye/act as reducing agent AN

D oxidized into/produce

triiodide ions/ I3 -

OR

dye+ + e

- → dye A

ND

3I - → I3 - + 2e

-

2

22.a

iproduct has higher binding energy «per nucleon»/m

ore stableO

Rnucleons in product m

ore tightly bound «with one another»

lighter elements «than Fe» can fuse/com

bine with loss of m

ass/mass defect

«and release vast amount of energy»

Accept “m

ass converted into energy” for M

2.

2

(continued)

N16/4/C

HE

MI/H

P3/E

NG

/TZ0/XX

/M

– 24 –


Question

Answ

ersN

otesTotal

22.a

iiA

ny one of:deuterium

/fuel is abundant/cheap «helium

» products not radioactive fusionm

uchlessdangerousthanfissionlarge am

ounts/shipments of radioactive fuel not required

far less radioactive waste «created by fast m

oving neutrons» has to be stored

Accept “reduces greenhouse gas

emissions/global w

arming” O

R “no

radioactive waste” O

R “m

ore reliable pow

er” OR

“fewer safety issues”.

Do not accept “gives out a large am

ount of energy” as it is in the stem

of the question.

1

22.b

i«λ =

=ln2

0.69325.3

days12

t =» 2.74 × 10

-2 day-1

Need correct unit for m

ark.1

22.b

ii«4 half-lives; 1 →

12→

14→

18→

116 =»

116 / 6.25 × 10

-2

OR

«NN0 = e

-λt = e-0.0274 × 101.2 =» 6.25 × 10

-2

Accept “6.25%

”.

1

22.c

ioctahedral

Accept “square bipyram

idal”.1

22.c

iiU

O2 strong bonding throughout crystal structure

UF

6 molecular «covalent bonds betw

een atoms» A

ND

London/dispersion/instantaneous induced dipole-induced dipole forces betw

een molecules

Accept “U

O2 has ionic lattice”.

2

(continued)

N16/4/C

HE

MI/H

P3/E

NG

/TZ0/XX

/M

– 25 –

Option D

— M

edicinal chemistry

Question

Answ

ersN

otesTotal

23.a

ibond angles sm

aller/distortedO

Rinstability resulting from

abnormal bond angles

OR

bond angles «approximately» 90° instead of 109.5°/120°

Accept “109/110°” for “109.5°”.

1

23.a

iiasterisks (*) on all 3 lactam

ring carbon atoms

Must m

ark all 3 carbon atoms.

Ignore asterisks on the RH

S carbon atom

s of the five-m

embered ring.

1

23.b

ibeta-lactam

/four-mem

bered ring «in clavulanic acid» reacts with enzym

e/beta-lactam

ase A

ccept “acts as enzyme inhibitor/suicide

substrate/preferentially binds to enzyme”.

1

23.b

iiantibiotics not effective against virusesO

Rviruses have no cell w

all/cell structure/target structures to attack

increasing exposure of bacteria «to antibiotic» increases resistance A

ccept “antibiotics kill beneficial bacteria” for M

2.

2

24.a

«oral bioavailability is» lowO

Rdrug is broken dow

n/pH is too low

/unable to be absorbed from gut

OR

only a small proportion of the drug «taken by m

outh» reaches the target organ

1

24.b

ethoxycarbonyl/carbonyl attached to oxygen A

ccept “ester”.1

(continued)

N16/4/C

HE

MI/H

P3/E

NG

/TZ0/XX

/M

– 26 –

Question

Answ

ersN

otesTotal

25.a

ALTER

NATIVE 1:

«theoretical yield = 1.552

g138.13

gmol

1- × 180.17 g mol -1 =» 2.024 «g»

«experimental yield = 1.124

g2.024

g × 100 =» 55.53 «%

»

ALTER

NATIVE 2:

«1552

13813

1

..g

gmol -

»= 0.01124 «m

ol salicylic acid/aspirin theoretical» AN

D

«1124

18017

1

..g

gmol -

»= 0.006239 «m

ol aspirin experimental»

«experimental yield = 0

006239001124..

mol

mol

x 100 =» 55.51 «%»

Accept answ

ers in the range 55.4 % to

55.7 %.

Award [2] for correct final answ

er.

2

25.b

low tem

perature gives greater difference between solubility of aspirin and

impurities

OR

«product» crystallizes out from cold solution/«ice-cold w

ater/lower

temperature» speeds up crystallization process

OR

aspirin/product has low solubility «in w

ater» at low tem

peratures

1

25.c

recrystallized melting point is higher

OR

recrystallized melting point is closer to pure substance/literature value

smaller range of values

2

(continued)

N16/4/C

HE

MI/H

P3/E

NG

/TZ0/XX

/M

– 27 –

Question

Answ

ersN

otesTotal

26.a

«ranitidine» blocks/inhibits histamine binding to «H

2» receptor O

Rranitidine binds to sam

e «H2» receptors «as histam

ine»O

Rcom

petes with histam

ine for binding

1

26.b

proton pump

OR

H+/K

+ ATPase enzym

e

Accept “«secretary surface of» parietal

cells”.D

o not accept “stomach/stom

ach wall”.

1

26.c

Any tw

o of:chiral m

olecule/auxiliary/optically active species is used/added/connected «to the starting m

olecule to force reaction to follow a certain path»

chiral intermediate form

s «only» one enantiomer

OR

auxiliary creates stereochemical condition «necessary to follow

a certain pathw

ay» / stereochemical induction

OR

existingchiralcentreaffectsconfigurationofnewchiralcentres

«after new chiral centre created» chiral auxiliary rem

oved «to obtain desired product»

2 max

(continued)

N16/4/C

HE

MI/H

P3/E

NG

/TZ0/XX

/M

– 28 –

Question

Answ

ersN

otesTotal

27.a

Sim

ilarity:both contain «at least one» benzene/arom

atic ringO

Rboth contain am

ino «group»

Difference:

diamorphine has one benzene/arom

atic ring AN

D m

ethadone has two phenyl

«groups»O

Rdiam

orphine has one vinylene/ethenylene/1,2-ethenediyl «group» AN

D

methadone has no vinylene/ethenylene/1,2-ethenediyl «group»

OR

diamorphine has one ether «group» A

ND

methadone has no ether «group»

OR

diamorphine has «tw

o» ethanoate/acetate «groups» AN

D m

ethadone has no ethanoate/acetate «group»

Accept “both contain carbonyl «groups»”.

Accept “am

ine” for “amino «group»”.

Accept “phenyl” for “benzene ring” in M

1 and M

2 although there are no phenyl groups in diam

orphine, as the benzene ring in this com

pound is a part of a polycyclic structure.D

o not accept “arene” or “benzene” alone in M

1 and M2.

Accept “alkenyl/alkene” for “vinylene/

ethenylene/1,2-ethenediyl” and “ester” for “ethanoate/acetate”.

Accept “m

ethadone has a ketone/carbonyl A

ND

diamorphine does not/has an ester/

ethanoate/acetate”.

Accept “diam

orphine is a heterocycle/heterocyclic com

pound AN

D m

ethadone is not a heterocycle/heterocyclic com

pound”.

2

27.b

feeling depressed/anxious/irritableO

Rcraving for opioids/heroinO

Rexperience fever/cold sw

eats/nausea/vomiting/insom

nia/muscle pain/cram

ps/diarrhea/increased rate of respiration/increased heartbeat/lacrim

ation

Accept listed sym

ptoms (eg, depression,

anxiety, fever etc.).

Som

e of the most com

mon sym

ptoms are

listed here – there may be other valid ones.

Accept “headaches”.

1

(continued)

N16/4/C

HE

MI/H

P3/E

NG

/TZ0/XX

/M

– 29 –

Question

Answ

ersN

otesTotal

28.a

i42 98M

o + 0 1n →

42 99mM

o A

ccept 98Mo + 1n/n →

99Mo.

128.

aii

42 99mMo →

43 99mTc +

-1 0β A

ccept “ 0–1 e” for “ 0–1 β”.A

ccept “ 99Mo →

99mTc + β”.A

ccept “ 0–1 e/e–/e” for “β”.

Do not penalize “ 99Tc” for “ 99mTc”.

1

28.b

molybdenum

-99 can be easily transported «before it decays»/more stable

OR

«most of» technetium

-99m w

ill decay during transportation

Do not accept just “short half-life of Tc-

99m”.

1

28.c

emits gam

ma rays

OR

emissions escape from

bodyO

Rem

issions detected by gamm

a camera

OR

radiation dose is low

chemically reactive/versatile/transition m

etal bonds to a range of «biologically active» substances

Do not accept “short half-life of Tc-99m

”.A

ccept “energy of photons produced is «relatively» low

” and “no high energy beta em

ission” for M1.

Accept “…

has ability to form tracers” for

“…bonds to a range of «biologically active»

substances”.

2

28.d

low-level «radioactive» w

aste/LLWO

Rsm

all amounts of ionizing radiation for short tim

e 1

(continued)

N16/4/C

HE

MI/H

P3/E

NG

/TZ0/XX

/M

– 30 –

Question

Answ

ersN

otesTotal

29.a

improvem

ents in technology/instrumentation/analytical techniques/precision

of measurem

ents A

ccept “greater awareness/know

ledge of the negative effects of the drugs”.

1

29.b

i«com

ponents have»differentaffinitiesfor/partitionbetween2phases/m

obileand stationary phase

move at different rates through instrum

entO

Rhave different retention tim

es

2

29.b

iinandrolone M

= 274 «g mol -1»

OR

testosterone M = 288 «g m

ol -1»

nandroloneidentifiedbecause«molecular ion peak of» m

/z = 274

Accept non-integer m

olar masses, ie,

274.44 «g mol -1» and 288.47 «g m

ol -1».

Accept also “m

/z = 275” for “m/z = 274” in

M2.

Accept “absence of peak w

ith m/z = 288”.

2

N16/4/C

HE

MI/H

P3/E

NG

/TZ0/XX

/M


17 pages

Wednesday 8 November 2017 (afternoon)

1 hour


© International Baccalaureate Organization 20178817 – 6101




88 Ra

(226

)

56 Ba

137.

33

38 Sr87

.62

20 Ca

40.0

8

12 Mg

24.3

1

4 Be

9.012

‡†

89 ‡

Ac

(227

)

57 †

La13

8.91

39 Y88

.91

21 Sc 44.9

6

90 Th23

2.04

58 Ce

140.

12

72 Hf

178.

49

40 Zr 91.2

2

22 Ti47

.87

91 Pa23

1.04

59 Pr14

0.91

73 Ta18

0.95

41 Nb

92.9

1

23 V50

.94

92 U23

8.03

60 Nd

144.

24

74 W18

3.84

42 Mo

95.9

6

24 Cr

52.0

0

55 Cs

132.

91

37 Rb

85.4

7

19 K39

.10

11 Na

22.9

9

3 Li 6.941 H 1.011 Fr87 (223

)

93 Np

(237

)

61 Pm (145

)

75 Re

186.

21

43 Tc (98)25 Mn

54.9

4

94 Pu (244

)

62 Sm15

0.36

76 Os

190.

23

44 Ru

101.

07

26 Fe 55.8

5

95 Am

(243

)

63 Eu15

1.96

77 Ir19

2.22

45 Rh

102.

91

27 Co

58.9

3

96 Cm

(247

)

64 Gd

157.

25

78 Pt19

5.08

46 Pd10

6.42

28 Ni

58.6

9

97 Bk

(247

)

65 Tb15

8.93

79 Au

196.

97

47 Ag

107.

87

29 Cu

63.5

5

The

Perio

dic

Tabl

e

Ato

mic

num

ber

Elem

ent

Rel

ativ

e at

omic

mas

s

98 Cf

(251

)

66 Dy

162.

50

80 Hg

200.

59

48 Cd

112.

41

30 Zn 65.3

8

99 Es (252

)

67 Ho

164.

93

81 Tl20

4.38

49 In11

4.82

31 Ga

69.7

2

13 Al

26.9

8

5 B10

.81

13

100

Fm (257

)

68 Er16

7.26

82 Pb 207.

2

50 Sn11

8.71

32 Ge

72.6

3

14 Si28

.09

6 C12

.01

14

101

Md

(258

)

69 Tm16

8.93

83 Bi

208.

98

51 Sb12

1.76

33 As

74.9

2

15 P30

.97

7 N14

.01

15

102

No

(259

)

70 Yb17

3.05

84 Po (209

)

52 Te12

7.60

34 Se78

.96

16 S32

.07

8 O16

.00

16

103

Lr (262

)

71 Lu17

4.97

85 At

(210

)

53 I12

6.90

35 Br

79.9

0

17 Cl

35.4

5

9 F19

.00

17

86 Rn

(222

)

54 Xe13

1.29

36 Kr

83.9

0

18 Ar

39.9

5

10 Ne

20.1

8

2 He

4.0018

34

56

78

910

1112

1 2 3 4 5 6 710

4 R

f(2

67)

105

Db

(268

)

106

Sg (269

)

107

Bh

(270

)

108

Hs

(269

)

109

Mt

(278

)

110

Ds

(281

)

111

Rg

(281

)

112

Cn

(285

)

113

Unt

(286

)

114

Uug

(289

)

115

Uup

(288

)

116

Uuh

(293

)

117

Uus

(294

)

118

Uuo

(294

)

– 2 – N17/4/CHEMI/HPM/ENG/TZ0/XX

1. How many atoms of nitrogen are there in 0.50 mol of (NH4)2CO3?

A. 1

B. 2

C. 3.01 × 1023

D. 6.02 × 1023

2. Which solution neutralizes 50.0 cm3 of 0.120 mol dm-3 NaOH (aq)?

A. 12.5 cm3 of 0.080 mol dm-3 H3PO4

B. 25.0 cm3 of 0.120 mol dm-3 CH3COOH

C. 25.0 cm3 of 0.120 mol dm-3 H2SO4

D. 50.0 cm3 of 0.060 mol dm-3 HNO3

3. What is the pressure, in Pa, inside a 1.0 m3 cylinder containing 10 kg of H2 (g) at 25 ºC? R = 8.31 J K-1 mol-1; pV = nRT

A. 4

3

1 10 8.31 251.0 10

× × ×

×

B. 25 10 8.31 298

1.0× × ×

C. 3

1 8.31 251.0 10× ×

×

D. 35 10 8.31 298

1.0× × ×

4. A compound with Mr = 102 contains 58.8 % carbon, 9.80 % hydrogen and 31 % oxygen by mass.What is its molecular formula?

Ar: C = 12.0; H = 1.0; O = 16.0

A. C2H14O4

B. C3H4O4

C. C5H10O2

D. C6H14O

Turn over


5. What is the number of protons and the number of neutrons in 131I?

Protons Neutrons

A. 53 78

B. 53 131

C. 78 53

D. 131 53

6. Thegraphrepresentsthefirsttenionisationenergies(IE)ofanelement.

1 2 3 4 5 6 7 8 9 10 11

Ionisationenergy/eV

Number of electrons removed

What is the element?

A. O

B. S

C. Ne

D. Cl


7. Whichelectronconfigurationisthatofatransitionmetalatominthegroundstate?

A. [Ne]3s23p64s1

B. [Ar]3d9

C. 1s22s22p63s23p64s23d104p2

D. [Ar]4s13d5

8. Which trends are correct across period 3 (from Na to Cl)?

I. AtomicradiusdecreasesII. MeltingpointincreasesIII. Firstionizationenergyincreases

A. IandIIonly

B. IandIIIonly

C. IIandIIIonly

D. I,IIandIII

9. Which oxide dissolves in water to give a solution with a pH below 7?

A. MgO

B. Li2O

C. CaO

D. P4O10

10. [CoCl6]3- is orange while [Co(NH3)6]

3+ is yellow. Which statement is correct?

A. [CoCl6]3- absorbs orange light.

B. Theoxidationstateofcobaltisdifferentineachcomplex.

C. Thedifferentcoloursareduetothedifferentchargesonthecomplex.

D. Thedifferentligandscausedifferentsplittinginthe3dorbitals.

Turn over


11. Which of the following series shows increasing hydrogen bonding with water?

A. Propane < propanal < propanol < propanoic acid

B. Propane < propanol < propanal < propanoic acid

C. Propanal < propane < propanoic acid < propanol

D. Propanoic acid < propanol < propanal < propane

12. The electronegativity values of four elements are given.

C N O F2.6 3.0 3.4 4.0

What is the order of increasing polarity of the bonds in the following compounds?

A. CO <OF2 < NO <CF4

B. CF4 < CO <OF2 < NO

C. NO <OF2 < CO <CF4

D. CF4 < NO <OF2 < CO

13. What is the hybridization state and electron domain geometry around the circled C, N and O atoms?

N

N N

N

O

O

CH3

H3C

CH3

C O N

A. sp3 and tetrahedral sp2 and trigonal planar sp2 and trigonal planar

B. sp2 and trigonal planar sp and linear sp3 and tetrahedral

C. sp3 and tetrahedral sp and linear sp2 and trigonal planar

D. sp3 and trigonal pyramidal sp2 and trigonal planar sp3 and trigonal pyramidal


14. How many sigma (σ) and pi (π) bonds are present in this molecule?

CN

COOH

σ π

A. 12 6

B. 14 5

C. 16 6

D. 17 5

15. Which statements are correct for ionic compounds?

I. Latticeenergyincreasesasionicradiiincrease.II. Withinthesamegroup,themeltingpointofsaltstendstodecreaseastheradiusofthe

cation increases.III. Solubilityinwaterdependsontherelativemagnitudeofthelatticeenergycomparedto

the hydration energy.

A. IandIIonly

B. IandIIIonly

C. IIandIIIonly

D. I,IIandIII

Turn over


16. What is the standard enthalpy of formation, in kJ mol-1, of IF (g)?

IF7 (g) + I2 (s) → IF5 (g) + 2IF(g)∆H Ö = -89 kJ

∆H Öf (IF7) = -941 kJ mol–1

∆H Öf (IF5) = -840 kJ mol–1

A. -190

B. -95

C. +6

D. +95

17. The combustion of glucose is exothermic and occurs according to the following equation:

C6H12O6 (s) + 6O2 (g) → 6CO2 (g) + 6H2O (g)

Which is correct for this reaction?

∆H Ö ∆S Ö Spontaneous/ non-spontaneous

A. negative positive spontaneous

B. negative positive non-spontaneous

C. positive negative spontaneous

D. positive positive non-spontaneous

18. Whichequationrepresentsthelatticeenthalpyofmagnesiumsulfide?

A. MgS(s)→Mg(g)+ S (g)

B. MgS(s)→Mg+ (g) + S- (g)

C. MgS(s)→Mg2+ (g) + S2- (g)

D. MgS(s)→Mg(s)+ S (s)


19. The enthalpy change for the dissolution of NH4NO3 is +26 kJ mol-1 at 25 °C. Which statement about this reaction is correct?

A. The reaction is exothermic and the solubility decreases at higher temperature.

B. The reaction is exothermic and the solubility increases at higher temperature.

C. The reaction is endothermic and the solubility decreases at higher temperature.

D. The reaction is endothermic and the solubility increases at higher temperature.

20. Thediagramshowstheenergyprofileforacatalysedanduncatalysedreaction.Whichrepresentstheenthalpychange,∆H, and the activation energy, Ea, for the catalysed reaction?

x

y

zPote

ntia

l ene

rgy

Reaction coordinate

∆H Ea (catalysed reaction)

A. z x + z

B. z z + y

C. -z x

D. z + x x

Turn over


21. The rate expression for the reaction X (g) + 2Y (g) → 3Z (g) is

rate = k [X]0 [Y]2

By which factor will the rate of reaction increase when the concentrations of X and Y are both increased by a factor of 3?

A. 6

B. 9

C. 18

D. 27

22. Which pair of statements explains the increase in rate of reaction when the temperature is increased or a catalyst is added?

Increasing temperature Adding a catalyst

A. average kinetic energy of particles increases activation energy increases

B. enthalpy change of reaction decreases average kinetic energy of particles increases

C. average kinetic energy of particles increases activation energy decreases

D. activation energy increases enthalpy change of reaction decreases

23. At 700 ºC, the equilibrium constant, Kc, for the reaction is 1.075 × 108.

2H2 (g) + S2 (g) � 2H2S (g)

Which relationship is always correct for the equilibrium at this temperature?

A. [H2S]2 < [H2]2 [S2]

B. [S2] = 2[H2S]

C. [H2S] < [S2]

D. [H2S]2 > [H2]2[S2]


24. What will happen if the pressure is increased in the following reaction mixture at equilibrium?

CO2 (g) + H2O (l) � H+ (aq) + HCO3- (aq)

A. The equilibrium will shift to the right and pH will decrease.

B. The equilibrium will shift to the right and pH will increase.

C. The equilibrium will shift to the left and pH will increase.

D. The equilibrium will shift to the left and pH will decrease.

25. 10.0 cm3 of an aqueous solution of sodium hydroxide of pH = 10 is mixed with 990.0 cm3 of distilled water. What is the pH of the resulting solution?

A. 8

B. 9

C. 11

D. 12

26. Whichofthefollowingwillformabuffersolutionifcombinedinappropriatemolarratios?

A. HCl and NaCl

B. NaOH and HCOONa

C. NH4Cl and HCl

D. HCl and NH3

Turn over


27. Which indicator is appropriate for the acid-base titration shown below?

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

10.0

11.0

12.0

13.0

14.0

pH

Volume/cm3

A. Thymol blue (pKa = 1.5)

B. Methylorange(pKa = 3.7)

C. Bromophenol blue (pKa = 4.2)

D. Phenolphthalein (pKa = 9.6)

28. Which statement is incorrect for a 0.10 mol dm-3 HCOOH solution?

A. pH = 1

B. [H+ ] << 0.10 mol dm-3

C. [HCOO- ] is approximately equal to [H+ ]

D. HCOOH is partially ionized


29. Which of the following is a redox reaction?

A. 3Mg(s)+ 2AlCl3 (aq) → 2Al (s) +3MgCl2 (aq)

B. SiO2 (s) + 2NaOH (aq) → Na2SiO3 (aq) + H2O (l)

C. KCl (aq) + AgNO3 (aq) → AgCl (s) + KNO3 (aq)

D. 2NaHCO3 (aq) → Na2CO3 (aq) + CO2 (g) + H2O (l)

30. Consider the following half-equations:

I2 (s) + 2e- � 2I- (aq) E Ö = +0.54V(brown) (colourless)

MnO4- (aq) + 8H+ (aq) + 5e- � Mn2+ (aq) + 4H2O (l) E Ö = +1.51V

(purple) (colourless)

WhichstatementiscorrectforthereactionbetweenKMnO4 (aq) and KI (aq) in acidic conditions?

A. MnO4- reduces I- to I2.

B. I-reducesMnO4-toMn2+.

C. The colour changes from brown to purple.

D. MnO4-isoxidizedtoMn2+.

31. Whataretheproductswhenanaqueoussolutionofcopper(II)sulfateiselectrolysedusinginertgraphite electrodes?

Cathode (negative electrode) Anode (positive electrode)

A. Cu (s) H2 (g)

B. O2 (g) Cu (s)

C. Cu (s) O2 (g)

D. H2 (g) O2 (g)

Turn over


32. What are the oxidation states of chromium in (NH4)2Cr2O7 (s) and Cr2O3 (s)?

(NH4)2Cr2O7 (s) Cr2O3 (s)

A. +7 +3

B. +6 +3

C. +6 +6

D. +7 +6

33. Propene reacts separately with H2O/H+ and H2/NitogiveproductsX and Z respectively.

X H2O/H+

CH3–CH═CH2 H2/Ni Z

What are the major products of the reactions?

X Z

A. CH3CH(OH)CH3 CH3CH2CH3

B. CH3CH2CH2OH CH3C≡CH

C. CH3C(O)CH3 CH3CH2CH3

D. CH3CH(OH)CH3 CH3C≡CH


34. Whatisthenameofthiscompound,usingIUPACrules?

C

C

O

C

C

C HH

HH

HH

HHH

H

H H

A. 3-methylbutan-3-ol

B. 2-ethylpropan-2-ol

C. 2-methylbutan-2-ol

D. 3-methylbutan-2-ol

35. What is the product of the reaction between pentan-2-one and sodium borohydride, NaBH4?

A. Pentan-1-ol

B. Pentan-2-ol

C. Pentanoic acid

D. Pentanal

36. Whichcompoundcanbeoxidizedwhenheatedwithanacidifiedsolutionofpotassiumdichromate(VI)?

A. CH3C(O)CH2CH3

B. CH3CH2CH(OH)CH3

C. (CH3)3COH

D. CH3(CH2)2COOH

Turn over


37. What is the number of optical isomers of isoleucine?

O

HO

NH2

H3C

CH3

A. 0

B. 2

C. 4

D. 8

38. Which functional group is responsible for the pKb of 4.1 in this compound?

H

H

H

H

H

H

H

H

HH

H

H

Cl

N

NC

C

C

C

C C

C

C

O

O

C

C C

C

C

C

N

H

H

H

HH

H

H

HH

A. Amido

B. Amino

C. Chloro

D. Ether


39. Which compound gives this 1HNMRspectrum?

Chemicalshift/ppm

012345678

A. CH3CH2OCH2CH3

B. CH3CH2OH

C. CH3CH2CH3

D. CH3CH2CH2OH

40. A student performs an acid-base titration using a pH meter, but forgets to calibrate it. Which type oferrorwilloccurandhowwillitaffectthequalityofthemeasurements?

A. Random error and lower precision

B. Systematic error and lower accuracy

C. Systematic error and lower precision

D. Random error and lower accuracy


N17/4/CHEMI/HPM/ENG/TZ0/XX/M N

2 pages

Markscheme

November 2017

Chemistry

Higher level

Paper 1

– 2 – N17/4/CHEMI/HPM/ENG/TZ0/XX/M

1. D 16. B 31. C 46. – 2. C 17. A 32. B 47. – 3. D 18. C 33. A 48. – 4. C 19. D 34. C 49. – 5. A 20. A 35. B 50. – 6. B 21. B 36. B 51. – 7. D 22. C 37. C 52. – 8. B 23. D 38. B 53. – 9. D 24. A 39. D 54. – 10. D 25. A 40. B 55. – 11. A 26. D 41. – 56. – 12. C 27. D 42. – 57. – 13. A 28. A 43. – 58. – 14. C 29. A 44. – 59. – 15. C 30. B 45. – 60. –



19 pages

Wednesday 8 November 2017 (afternoon)

2 hours 15 minutes

20EP01




Write your session number in the boxes above. Do not open this examination paper until instructed to do so. Answer all questions. Write your answers in the boxes provided. A calculator is required for this paper. A clean copy of the chemistry data booklet is required for this paper. The maximum mark for this examination paper is [95 marks].


1. A student titrated two acids, hydrochloric acid, HCl (aq) and ethanoic acid, CH3COOH (aq), against 50.0 cm3 of 0.995 mol dm-3 sodium hydroxide, NaOH (aq), to determine their concentration. The temperature of the reaction mixture was measured after each acid addition and plotted against the volume of each acid.

5 10 15 20 25 30 35 40 45 500

20

21

22

23

24

25

26

27

28

29

30

31

32

Tem

pera

ture

/ ûC

Volume of acid / cm3

CH3COOH

HCl

(a) Using the graph, estimate the initial temperature of the solutions. [1]

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

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


20EP02

– 2 – N17/4/CHEMI/HP2/ENG/TZ0/XX


(b) Determine the maximum temperature reached in each experiment by analysing the graph. [2]

HCl: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

CH3COOH: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

(c) Calculate the concentration of ethanoic acid, CH3COOH, in mol dm-3. [2]

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

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

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

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

(d) (i) Determine the heat change, q , in kJ, for the neutralization reaction between ethanoic acid and sodium hydroxide.Assume the specific heat capacities of the solutions and their densities are those of water. [2]

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

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

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

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

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

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

(ii) Calculate the enthalpy change, ∆H, in kJ mol-1, for the reaction between ethanoic acid and sodium hydroxide. [2]

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

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

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

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


Turn over

20EP03



(e) Suggest why the enthalpy change of neutralization of CH3COOH is less negative than that of HCl. [2]

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

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

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

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

(f) Curves X and Y were obtained when a metal carbonate reacted with the same volume of ethanoic acid under two different conditions.

X

Y

Volu

me

of g

as

Time

(i) Explain the shape of curve X in terms of the collision theory. [2]

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

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

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

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


20EP04



(ii) Suggest one possible reason for the differences between curves X and Y. [1]

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

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

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

2. Analytical chemistry uses instruments to separate, identify, and quantify matter.

(a) Describe the emission spectrum of hydrogen. [2]

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

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

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

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

(b) Outline how this spectrum is related to the energy levels in the hydrogen atom. [1]

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

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

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

(c) A sample of magnesium has the following isotopic composition.

Isotope 24Mg 25Mg 26MgRelative abundance / % 78.6 10.1 11.3

Calculate the relative atomic mass of magnesium based on this data, giving your answer to two decimal places. [2]

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

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

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

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


Turn over

20EP05



(d) Menthol is an organic compound containing carbon, hydrogen and oxygen.

(i) Complete combustion of 0.1595 g of menthol produces 0.4490 g of carbon dioxide and 0.1840 g of water. Determine the empirical formula of the compound showing your working. [3]

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

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

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

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

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

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

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

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

(ii) 0.150 g sample of menthol, when vaporized, had a volume of 0.0337 dm3 at 150ûC and 100.2 kPa. Calculate its molar mass showing your working. [2]

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

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

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

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

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

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

(iii) Determine the molecular formula of menthol using your answers from parts (d)(i) and (ii). [1]

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

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


20EP06



(e) Nitric oxide reacts with chlorine.

2NO (g) + Cl2 (g) → 2NOCl (g)

The following experimental data were obtained at 101.3 kPa and 263 K.

Experiment Initial [NO] / mol dm–3

Initial [Cl2] / mol dm–3

Initial rate / mol dm–3 min–1

1 1.30 × 10-1 1.30 × 10-1 3.95 × 10-1

2 1.30 × 10-1 2.60 × 10-1 7.90 × 10-1

3 2.60 × 10-1 2.60 × 10-1 3.16

(i) Deduce the order of reaction with respect to Cl2 and NO. [2]

Cl2:

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

NO:

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

(ii) State the rate expression for the reaction. [1]

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

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

(iii) Calculate the value of the rate constant at 263 K. [1]

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

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

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

Turn over

20EP07


3. Trends in physical and chemical properties are useful to chemists.

(a) Explain the general increasing trend in the first ionization energies of the period 3 elements, Na to Ar. [2]

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

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

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

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

(b) Explain why the melting points of the group 1 metals (Li → Cs) decrease down the group whereas the melting points of the group 17 elements (F → I) increase down the group. [3]

Group 1:

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

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

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

Group 17:

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

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

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


20EP08



(c) State an equation for the reaction of phosphorus(V) oxide, P4O10 (s), with water. [1]

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

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

(d) Cobalt forms the transition metal complex [Co(NH3)4 (H2O)Cl]Br.

(i) State the shape of the complex ion. [1]

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

(ii) Deduce the charge on the complex ion and the oxidation state of cobalt. [2]

Charge on complex ion:

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

Oxidation state of cobalt:

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

(e) Describe, in terms of acid-base theories, the type of reaction that takes place between the cobalt ion and water to form the complex ion. [2]

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

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

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

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

Turn over

20EP09


4. Lewis (electron dot) structures are useful models.

(a) Draw the Lewis (electron dot) structures of PF3 and PF5 and use the VSEPR theory to deduce the molecular geometry of each species including bond angles.

PF3 PF5

Lewis (electron dot) structure

Molecular geometry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Bond angles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

[6]

(b) Predict whether the molecules PF3 and PF5 are polar or non-polar. [1]

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

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

(c) State the type of hybridization shown by the phosphorus atom in PF3. [1]

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

20EP10


5. Ethane-1,2-diol, HOCH2CH2OH, reacts with thionyl chloride, SOCl2, according to the reaction below.

HOCH2CH2OH (l) + 2SOCl2 (l) → ClCH2CH2Cl (l) + 2SO2 (g) + 2HCl (g)

(a) Calculate the standard enthalpy change for this reaction using the following data.

HOCH2CH2OH (l) SOCl2 (l) ClCH2CH2Cl (l) SO2 (g) HCl (g)∆H Öf / kJ mol–1 – 454.7 –245.7 –165.2 –296.9 –92.3

[2]

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

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

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

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

(b) Calculate the standard entropy change for this reaction using the following data.

HOCH2CH2OH (l) SOCl2 (l) ClCH2CH2Cl (l) SO2 (g) HCl (g)S Ö/J K–1 mol–1 166.9 278.6 208.5 248.1 186.8

[1]

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

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

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

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

(c) The standard free energy change, ∆G Ö, for the above reaction is –103 kJ mol–1 at 298 K.Suggest why ∆G Ö has a large negative value considering the sign of ∆H Ö in part (a). [2]

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

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

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

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

Turn over

20EP11


6. Many reactions are in a state of equilibrium.

(a) The following reaction was allowed to reach equilibrium at 761 K.

H2 (g) + I2 (g) � 2HI (g) ∆H Ö < 0

(i) State the equilibrium constant expression, Kc , for this reaction. [1]

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

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

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

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

(ii) The following equilibrium concentrations in mol dm–3 were obtained at 761 K.

[H2 (g)] [I2 (g)] [HI (g)]8.72 × 10-4 2.72 × 10-3 1.04 × 10-2

Calculate the value of the equilibrium constant at 761 K. [1]

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

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

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

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

(iii) Determine the value of ∆G Ö, in kJ, for the above reaction at 761 K using section 1 of the data booklet. [1]

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

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

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


20EP12



(iv) Outline the effect, if any, of each of the following changes on the position of equilibrium, giving a reason in each case.

Effect Reason

Increasing the volume, at constant temperature

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

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

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

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

Increasing the temperature, at constant pressure

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

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

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

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

[2]

(b) The equations for two acid-base reactions are given below.

HCO3- (aq) + H2O (l) � H2CO3 (aq) + OH- (aq)

HCO3- (aq) + H2O (l) � CO3

2- (aq) + H3O+ (aq)

(i) Identify two different amphiprotic species in the above reactions. [1]

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

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

(ii) State what is meant by the term conjugate base. [1]

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

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

(iii) State the conjugate base of the hydroxide ion, OH–. [1]

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


Turn over

20EP13



(c) The pH of 0.010 mol dm-3 carbonic acid, H2CO3 (aq), is 4.17 at 25 °C.

H2CO3 (aq) + H2O (l) � HCO3– (aq) + H3O

+ (aq).

(i) Calculate [H3O+] in the solution and the dissociation constant, Ka , of the acid at

25 °C. [3]

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

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

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

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

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

(ii) Calculate Kb for HCO3– acting as a base. [1]

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

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

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

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

(d) A student working in the laboratory classified HNO3, H2SO4, H3PO4 and HClO4 as acids based on their pH. He hypothesized that “all acids contain oxygen and hydrogen”. Evaluate his hypothesis. [2]

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

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

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

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

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

20EP14


7. Consider the following half-cell reactions and their standard electrode potentials.

E Ö / VMn2+ (aq) + 2e- � Mn (s) -1.18Ni2+ (aq) + 2e- � Ni (s) -0.26I2 (aq) + 2e- � 2I- (aq) +0.54

(a) Deduce a balanced equation for the overall reaction when the standard nickel and iodine half-cells are connected. [1]

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

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

(b) Predict, giving a reason, the direction of movement of electrons when the standard nickel and manganese half-cells are connected. [2]

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

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

(c) Calculate the cell potential, in V, when the standard iodine and manganese half-cells are connected. [1]

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

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

(d) Identify the best reducing agent in the table above. [1]

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

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


Turn over

20EP15



(e) State and explain the products of electrolysis of a concentrated aqueous solution of sodium chloride using inert electrodes. Your answer should include half-equations for the reaction at each electrode. [4]

Positive electrode (anode):

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

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

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

Negative electrode (cathode):

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

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

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

8. The reactivity of organic compounds depends on the nature and positions of their functional groups.

(a) The structural formulas of two organic compounds are shown below.

H C C CH3

CH3COOH

OH H

H C C CH3

CH3COOH

H OH

A B

(i) Deduce the type of chemical reaction and the reagents used to distinguish between these compounds. [1]

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

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


20EP16



(ii) State the observation expected for each reaction giving your reasons. [2]

Compound A:

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

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

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

Compound B:

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

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

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

(iii) Deduce the number of signals and the ratio of areas under the signals in the 1H NMR spectra of the two compounds.

Compound Number of signals Ratio of areas

A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

B . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

[4]

(iv) Deduce, giving a reason, which of the two compounds can show optical activity. [1]

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

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


Turn over

20EP17



(v) Draw three-dimensional representations of the two enantiomers. [1]

(b) Explain, with the help of equations, the mechanism of the free-radical substitution reaction of ethane with bromine in presence of sunlight. [4]

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

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

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

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

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

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

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

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

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

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

(c) State the reagents used in the nitration of benzene. [1]

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

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

(d) State an equation for the formation of NO2+. [1]

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

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


20EP18



(e) Explain the mechanism of the reaction between 2-bromo-2-methylpropane, (CH3)3CBr, and aqueous sodium hydroxide, NaOH (aq), using curly arrows to represent the movement of electron pairs. [4]

20EP19






20EP20

40EP01



40 pages

Thursday 9 November 2017 (morning)

1 hour 15 minutes




• Write your session number in the boxes above.• Do not open this examination paper until instructed to do so.• Answers must be written within the answer boxes provided. • A calculator is required for this paper.• A clean copy of the chemistry data booklet is required for this paper.• The maximum mark for this examination paper is [45 marks].

Section A QuestionsAnswer all questions. 1 – 3

Section B QuestionsAnswer all of the questions from one of the options.

Option A — Materials 4 – 9

Option B — Biochemistry 10 – 15

Option C — Energy 16 – 20

Option D — Medicinal chemistry 21 – 27

40EP02




Section A


1. A student set up a simple voltaic cell consisting of a copper electrode and a zinc electrode dipped in sodium chloride solution.

d

Ammeter

NaCl (aq)

Cu Zn

The student gradually increased the distance, d,betweentheelectrodestostudytheeffecton the initial current, I, passing through the light bulb.

The student hypothesized that the initial current would be inversely proportional to the distance between the electrodes.

(a) Sketch a graph that would support the student’s hypothesis. [1]


40EP03

Turn over

– 3 – N 17 / 4 /CHEMI/ H P 3/ ENG /TZ0 / XX


(b) Thefollowingdatawascollectedoverfivetrials.

d / ±0.1 cm Average I / ±0.04 A4.0 0.093

10.0 0.08316.0 0.07320.0 0.06726.0 0.057

The data did not support the student’s hypothesis. He investigated other possible relationships by plotting a graph of the average current against the distance between theelectrodes.Heobtainedthefollowingbest-fitlinewithacorrelationcoefficient(r)of −0.9999.

0.10

0.05

0.000 10 20

d / cm

I / A

Linearfitfordatasety =m x + bm (Slope): −0.001631 A cm−1

b ( y-intercept): 0.09939 ACorrelation: −0.9999

(i) Suggestwhatthecorrelationcoefficientof−0.9999 indicates. [1]

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

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


40EP04



(ii) State the equation of the straight line obtained using the data. [1]

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

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

(iii) Outlinehowcurrentflowsinthesodiumchloridesolution. [1]

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

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

40EP05

Turn over


2. Antacids react with hydrochloric acid in the stomach to relieve indigestion. A student investigateddifferentbrandsofantacidtoseewhichcausedthelargestincreaseinpHina given time. She added the antacids to hydrochloric acid, and recorded the change in pH overfiveminutes.

Antacid brand

Active ingredient(s) Recommended dosage

Dose used

Initial pH ±0.02

Final pH ±0.02

Change in pH

A magnesium hydroxidealuminium hydroxide

2–3tablets

2tablets

1.68 4.53 +2.85

B sodium hydrogen carbonatecalcium carbonate

2–4tablets

2tablets

1.70 5.31 +3.61

C calcium carbonate 1–2tablets

1tablet

1.70 4.52 +2.82

D magnesium hydroxidealuminium oxidealuminium hydroxide

1–2tablets

1tablet

1.69 2.21 +0.52

(a) State an equation for the reaction of magnesium hydroxide with hydrochloric acid. [1]

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


40EP06



(b) Suggest two variables, besides the time of reaction, which the student should have controlled in the experiment to ensure a fair comparison of the antacids. [2]

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

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

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

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

(c) Calculate the uncertainty in the change in pH. [1]

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

(d) The student concluded that antacid Bwasthemosteffective,followedbyA then C and finallyD. Discuss two arguments that reduce the validity of the conclusion. [2]

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

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

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

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

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

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

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

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

40EP07

Turn over


3. Sodium chloride, NaCl, can be spread on icy roads to lower the freezing point of water. ThediagramshowstheeffectsoftemperatureandpercentagebymassofNaCl on the composition of a mixture of NaCl and H2O.

10 20 30 40 500

–30

–20

–10

10

20

30

40

0101010 202020 303030 404040 5050404030302020101010 20 30 40 5050404030302020101010 20 30 40

Tem

pera

ture

/ °C

Percentage of NaCl by mass / %

ice + NaCl (aq)

ice + NaCl·2H2O (s)

NaCl (aq) NaCl (aq) + NaCl·2H2O (s)

(a) Estimate the lowest freezing point of water that can be reached by adding sodium chloride. [1]

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

(b) Estimate the percentage by mass of NaCl dissolved in a saturated sodium chloride solution at +10 ûC. [1]

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


40EP08

– 8 – N 17 / 4 /CHEMI/ H P 3/ ENG /TZ0 / XX


(c) Calculate the percentage of water by mass in the NaCl·2H2O crystals. Use the data from section 6 of the data booklet and give your answer to two decimal places. [2]

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

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

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

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

(d) Suggest a concern about spreading sodium chloride on roads. [1]

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

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

40EP09

Turn over


Section B

Answer all of the questions from one of the options. Write your answers in the boxes provided.

Option A — Materials

4. Itiswisetofilldentalcavitiesbeforeirreversibletoothdecaysetsin.Anamalgam(alloyof mercury, silver, and other metals) is often used although many prefer a white composite material.

(a) Outline the composition of an alloy and a composite. [2]

Alloy:

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

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

Composite:

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

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

(b) Outline why an alloy is usually harder than its components by referring to its structure. [1]

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

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

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


40EP10



(c) Explain how Inductively Coupled Plasma (ICP) Spectroscopy could be used to determinetheconcentrationofmercuryinasampleofdentalfilling. [3]

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

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

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

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

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

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

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

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

5. Catalysts can take many forms and are used in many industrial processes.

Suggest two reasons why it might be worth using a more expensive catalyst to increase the rate of a reaction. [2]

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

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

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

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


40EP11

Turn over



6. The development of materials with unique properties is critical to advances in industry.

(a) Outline two properties a substance should have to be used as liquid-crystal in a liquid-crystal display. [2]

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

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

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

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

(b) Explain why Type 2 superconductors are generally more useful than Type 1. [2]

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

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

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

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

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

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

(c) Nanotechnology has many applications.

(i) State equations for the formation of iron nanoparticles and carbon atoms from Fe(CO)5 in the HIPCO process. [2]

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

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

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

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .


40EP12



(ii) Outline why the iron nanoparticle catalysts produced by the HIPCO process are moreefficientthansolidironcatalysts. [1]

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

7. Low density polyethene (LDPE) and high density polyethene (HDPE) are both addition polymers.

(a) DescribehowthestructuresofLDPEandHDPEaffectonemechanicalpropertyoftheplastics. [2]

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

(b) Describehowthemonomersofadditionpolymersandofcondensationpolymersdiffer. [1]

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

(c) Identify the type of intermolecular bonding that is responsible for Kevlar®’s strength. [1]

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .


40EP13

Turn over



(d) One of the two infrared (IR) spectra is that of polyethene and the other of polytetrafluoroethene(PTFE).


Removed for copyright reasons

40EP14



Deduce, with a reason, which spectrum is that of PTFE. Infrared data is given in section 26 of the data booklet. [1]

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

(e) Many plastics used to be incinerated. Deduce an equation for the complete combustion of two repeating units of PVC, (−C2H3Cl−)2. [2]

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .


40EP15

Turn over



8. Metals have various crystal structures. Cobalt forms a face-centred cubic (FCC) lattice. Two representations of FCC are shown.

b

ar

(a) Calculate the total number of cobalt atoms within its unit cell. [1]

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

(b) (i) The atomic radius, r, of cobalt is 1.18 × 10–8 cm. Determine the edge length, in cm, of the unit cell, a, using the second diagram. [1]

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .


40EP16



(ii) Determine a value for the density of cobalt, in g cm–3, using data from sections 2 and 6 of the data booklet and your answers from (a) and (b) (i).

If you did not obtain an answer to (b) (i), use 3.00 × 10–8 cm but this is not the correct answer. [2]

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .


40EP17

Turn over



9. Heavy metal ions are an important environmental concern.

(a) State the name of one method, other than precipitation, of removing heavy metal ions from solution in water. [1]

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

(b) The solubility product, Ksp,ofcadmiumsulfide,CdS,is8.0× 10–27. Determine the concentration of cadmium ions in 1.0 dm3ofasaturatedsolutionofcadmiumsulfidetowhich0.10molofsolidsodiumsulfidehasbeenadded,statinganyassumptionyoumake. [3]

Calculation:

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Assumption:

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

End of Option A

40EP18


Option B — Biochemistry

10. Consider the following lipid and carbohydrate.

CH3(CH2)4(CH=CHCH2)2(CH2)6COOH

CH2OH

H

OH H

OH

CH2OH

OHHO

Linoleic acid, Mr = 280.50 Fructose, Mr = 180.18

(a) (i) Determine the empirical formula of linoleic acid. [1]

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

(ii) The empirical formula of fructose is CH2O. Suggest why linoleic acid releases more energy per gram than fructose. [1]

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

(b) In order to determine the number of carbon-carbon double bonds in a molecule of linoleic acid, 1.24 g of the lipid were dissolved in 10.0 cm3 of non-polar solvent. The solution was titrated with a 0.300 mol dm−3 solution of iodine, I2 .

Calculate the volume of iodine solution used to reach the end-point. [3]

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .


40EP19

Turn over



(c) Outline the importance of linoleic acid for human health. [2]

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .


40EP20



11. An enzyme catalyses the conversion of succinate to fumarate ions in a cell, as part of the process of respiration.

O

C

O

CH2

CH2

C

O O

enzyme

O

C

O

C

C

C

O O

H

H

Succinate ion Fumarate ion

The rate of the reaction was monitored and the following graph was plotted.

0 10 20 30 40 50 60

10

90

80

70

60

50

40

30

20

[succinate ion] / × 10−3 mol dm−3

Rea

ctio

n ra

te /

arbi

trary

sca

le

(a) Determine the value of the Michaelis constant, Km , by annotating the graph. [2]

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .


40EP21

Turn over



(b) (i) The malonate ion acts as an inhibitor for the enzyme.

O

C

O

CH2

C

O OMalonate ion

Suggest, on the molecular level, how the malonate ion is able to inhibit the enzyme. [2]

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

(ii) Drawacurveonthegraphonpage21showingtheeffectofthepresenceofthemalonate ion inhibitor on the rate of reaction. [1]

(c) Enzyme activity depends on many factors. Explain how pH change causes loss of activity of an enzyme. [4]

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .


40EP22



12. Lactose is a disaccharide formed by the condensation reaction of the monosaccharides galactose and glucose.

OOH

H H

O

OH H

OH

H OH

H OH

CH2OH

CH2OH

H

OH H

H

OH H

Lactose

(a) Describe what is meant by a condensation reaction. [2]

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

(b) Draw the structure of galactose on the skeleton provided. [1]

O


40EP23

Turn over



(c) Explain how the inclusion of carbohydrates in plastics makes them biodegradable. [2]

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .


40EP24



13. The stability of DNA is due to interactions of its hydrophilic and hydrophobic components.

O– OO NH2

P NO–O

HN OHN

O N N

NO

O

O NH2 O N O O–

OP P

OO–O N HN N O

O NN

O H2NO

O–

NO O

O H2N PO O

P N O–O O

NH NO N N O

O O O–

P

O O H2N O

O OP N

–O ONH N

O N N

N ONH2

OO O–

PO

OH–O

phosphate-deoxyribosebackbone

Outline the interactions of the phosphate groups in DNA with water and with surrounding proteins (histones). [2]

Water:

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Proteins:

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .


40EP25

Turn over



14. The heme groups in cytochromes contain iron ions that are involved in the reduction of molecular oxygen.

(a) State the half-equation for the reduction of molecular oxygen to water in acidic conditions. [1]

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

(b) Outline the change in oxidation state of the iron ions in heme groups that occurs when molecular oxygen is converted to water. [1]

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

15. Vitamins can be water-soluble or fat-soluble.

(a) Explain, at the molecular level, why vitamin D is soluble in fats. Use section 35 of the data booklet. [2]

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .


40EP26



(b) Retinal is the key molecule involved in vision. Explain the roles of cis and trans-retinal in vision and how the isomers are formed in the visual cycle. [3]

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

End of Option B

40EP27

Turn over


Option C — Energy

16. Onemethodofcomparingfuelsisbyconsideringtheirspecificenergies.

(a) Calculatethespecificenergyofoctane,C8H18 , in kJ kg–1 using sections 1, 6 and 13 of the data booklet. [2]

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

(b) Atypicalwoodhasaspecificenergyof17× 103 kJ kg–1. Comment on the usefulness of octane and wood for powering a moving vehicle, using your answer to (a).If you did not work out an answer for (a), use 45 × 103 kJ kg–1 but this is not the correct answer. [1]

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

(c) State the name of one renewable source of energy other than wood. [1]

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .


40EP28



17. Muchofourenergyneedsarestillprovidedbytherefinedproductsofcrudeoil.

(a) “Knocking” in an automobile (car) engine can be prevented by increasing the octane number of the fuel. Explain, including an equation with structural formulas, how heptane, C7H16 , could be chemically converted to increase its octane number. [3]

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

(b) Manyliketorefertoour“carbonfootprint”.Outlineonedifficultyinquantifyingsuchaconcept. [1]

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

(c) Climate change or global warming is a consequence of increased levels of carbon dioxideintheatmosphere.Explainhowthegreenhouseeffectwarmsthesurfaceofthe earth. [3]

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .


40EP29

Turn over



18. Inthe20thCentury,bothfissionandfusionwereconsideredassourcesofenergybutfusionwaseconomically and technically unattainable.

(a) (i) Compareandcontrastfissionandfusionintermsofbindingenergyandthetypesof nuclei involved. [2]

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

(ii) Suggest twoadvantagesthatfusionhasoverfission. [2]

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

(b) The amount of 228Ac in a sample decreases to one eighth of its original value in

about 18 hours due to β-decay. Estimate the half-life of 228Ac. [1]

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .


18( (

40EP30



(c) (i) Calculate the loss in mass, in kg, and the energy released, in J, when 0.00100 mol of 228Ac decays, each atom losing an electron. Use section 2 of the data booklet and E = mc2.

228Ac → e + 228Th

Particle 228Ac e 228ThMass / kg 3.78532 × 10–25 9.109383 × 10–31 3.78528 × 10–25

[2]

Loss in mass:

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Energy released:

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

(ii) Determine the energy released, in J, by 0.00100 mol of 228Ac over the course of 18 hours. [1]

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .


40EP31

Turn over



(d) Outline how nuclear ionising radiation can damage DNA and enzymes in living cells. [1]

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

19. Vegetable oils and the sun can be used as sources of energy.

(a) Vegetable oils are too viscous for use as liquid fuels. Describe, using an equation, how a vegetable oil, such as that shown, is converted to oils with lower viscosity by reaction with methanol, CH3OH. [2]

O

H2C O C (CH2)6CH3O

HC O C (CH2)6CH3O

H2C O C (CH2)6CH3


40EP32



(b) The natural absorption of light by chlorophyll has been copied by those developing dye-sensitized solar cells (DSSCs). Outline how a DSSC works. [3]

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

20. A fuel cell converts chemical energy directly to electrical energy.

(a) Deduce the half-equations and the overall equation for the reactions taking place in a direct methanol fuel cell (DMFC) under acidic conditions. [3]


. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Positive electrode (cathode):

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Overall equation:

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .


40EP33

Turn over



(b) Outline one advantage and one disadvantage of the methanol cell (DMFC) compared with a hydrogen-oxygen fuel cell. [2]

Advantage:

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Disadvantage:

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

End of Option C

40EP34


Option D — Medicinal chemistry

21. Lutetium-177 is used in radiotherapy. It emits beta radiation when it decays.

(a) State a nuclear equation to show the decay of lutetium-177. [2]

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

(b) The half-life of lutetium-177 is 6.73 days. Determine the percentage of a sample of lutetium-177 remaining after 14.0 days. [2]

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

(c) Explain the low environmental impact of most medical nuclear waste. [2]

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .


40EP35

Turn over



22. Ibuprofen and paracetamol are mild analgesics. One of the IR spectra below belongs to ibuprofen and the other to paracetamol. The structures of both compounds are given in section 37 of the data booklet.


Removed for copyright reasons

40EP36



(a) (i) Both spectra show a peak at wavenumber 1700 cm−1. Identify the bond responsible for this peak. [1]

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

(ii) Deduce which spectrum belongs to paracetamol, giving two reasons for your choice. Use section 26 of the data booklet. [2]

X or Y:

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Reason 1:

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Reason 2:

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

(b) Describe how mild analgesics function. [2]

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

(c) (i) The strong analgesics morphine and codeine are opiates. Outline how codeine can be synthesized from morphine. The structures of morphine and codeine are in section 37 of the data booklet. [1]

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .


40EP37

Turn over



(ii) Explain why opiates are addictive. [2]

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

23. Some drugs are extracted from natural sources and others are synthetic.

(a) New drugs undergo thorough clinical trials before they are approved. Outline the differencebetweenthetherapeuticindexinanimalstudiesandthetherapeuticindexinhumans. [1]

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

(b) Explain the role of the chiral auxiliary in the synthesis of Taxol. [3]

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

(c) State the method of drug administration that gives the maximum bioavailability. [1]

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .


40EP38



24. Oseltamivir(Tamiflu)andzanamivir(Relenza)areantiviraldrugsusedtopreventflu.State the names of two functional groups that both compounds contain, using section 37 of the data booklet. [2]

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

25. Excess acid in the stomach can cause discomfort and more serious health issues.

(a) Explain how ranitidine (Zantac) reduces stomach acid production. [2]

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

(b) ThepHismaintainedindifferentfluidsinthebodybytheuseofbuffers.

CalculatethepHofabuffersolutionof0.0200moldm−3 carbonic acid, H2CO3 , and 0.400 mol dm−3 sodium hydrogen carbonate, NaHCO3 . The pKa of carbonic acid is 6.35. [2]

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .


40EP39

Turn over



26. Molecules of antibiotics often contain a beta-lactam ring. Explain the importance of the beta-lactam ring in the action of penicillin, using section 37 of the data booklet. [3]

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

27. Ethanolslowsdownthereactiontimeofadriverleadingtotrafficaccidents.Explainhowthe concentration of ethanol in a sample of breath can be determined using a fuel cell breathalyser. [2]

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

End of Option D

40EP40


chemistry higher level paper 1 - smiletutor · 3 turn over 1. which compound s molecular formula is...

Documents