MINISTRY OF EDUCATION, SINGAPORE

in collaboration with
CAMBRIDGE ASSESSMENT INTERNATIONAL EDUCATION
General Certificate of Education Ordinary Level

CHEMISTRY 6092/02
*0123456789*

Paper 2 For examination from 2024

SPECIMEN PAPER
 1 hour 45 minutes
Candidates answer on the Question Paper.
No Additional Materials are required.

READ THESE INSTRUCTIONS FIRST

Write your Centre number, index number and name on all the work you hand in.
Write in dark blue or black pen.
You may use an HB pencil for any diagrams or graphs.
Do not use staples, paper clips, glue or correction fluid.
DO NOT WRITE ON ANY BARCODES.

Section A
Answer all questions.
Write your answers in the spaces provided.

Section B
Answer one question.
Write your answers in the spaces provided.

The number of marks is given in brackets [ ] at the end of each question or part question.
A copy of the Periodic Table is printed on page 24.

The use of an approved scientific calculator is expected, where appropriate.

This document consists of 22 printed pages and 2 blank pages.

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BLANK PAGE

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Section A

Answer all questions.

1 Fig. 1.1 shows part of the Periodic Table.

He
C N O F Ne
S Cl Ar
Br Kr

Fig. 1.1

Select elements from Fig. 1.1 to answer the following questions. You may use each element once,
more than once or not at all.

Write down the symbol for an element which:

(a) has five electrons in its outer shell,

............................................................................................................................................... [1]

(b) exists as diatomic molecules,

............................................................................................................................................... [1]

(c) reacts with sodium to form an ionic compound with Mr less than 60,

............................................................................................................................................... [1]

(d) is a noble gas,

............................................................................................................................................... [1]

(e) has a giant covalent structure,

............................................................................................................................................... [1]

(f) has a smaller proton number than fluorine,

............................................................................................................................................... [1]

(g) is the most abundant gas in the air.

............................................................................................................................................... [1]

 [Total: 7]

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2 A new type of electroplating is known as ‘brush electroplating’.

It is used to electroplate zinc onto very large iron supports to be used in buildings.
The iron supports are too big to be plated in a normal electrolysis tank.

During the process, a metal brush spreads a layer of aqueous zinc sulfate over the iron surface.
A battery gives the brush a positive charge and gives the iron support a negative charge.
A layer of zinc forms on the surface of the iron support.

battery positively charged

brush
+ layer of aqueous zinc sulfate

negatively charged
iron support
thin coating of zinc
forms on surface

Fig. 2.1

(a) The surface of the iron acts as a cathode.

Zinc ions from the solution form zinc on the surface of the iron.

Write an ionic half-equation, with state symbols, for this reaction.

............................................................................................................................................... [2]

(b) Two different designs of metal brush are available.

One type of brush is made from zinc, one type is made from platinum.

As the electrolysis takes place, each brush has a different effect on the concentration of zinc
ions in the solution.

(i) What will happen to the concentration of the zinc ions during the electrolysis if the brush
is made from platinum?

....................................................................................................................................... [1]

(ii) What will happen to the concentration of the zinc ions during the electrolysis if the brush
is made from zinc?

....................................................................................................................................... [1]

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(iii) Platinum brushes are much more expensive than zinc brushes.

However, zinc brushes need replacing regularly but platinum brushes do not.

Explain why.

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

....................................................................................................................................... [2]

(c) During the process, a worker needs to hold the brush.

Which of the following materials would be a good choice for the handle of the brush?
Give a reason for your answer.

chromium copper graphite iron poly(ethene)

material ......................................................................................................................................

reason ........................................................................................................................................
[2]

(d) Explain why iron supports coated with zinc do not rust, even if the zinc coating is damaged.

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

............................................................................................................................................... [2]

 [Total: 10]

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3 The space ship Curiosity landed an analytical lab on Mars in 2012. The lab contained equipment
which can determine the percentages of elements in rocks.

The percentage by mass of the elements in compound Z, determined using this type of equipment,
is given in Table 3.1.

Table 3.1

element percentage by mass

potassium 39.4
iron 28.3
oxygen 32.3

(a) Show that the empirical formula of Z is K2FeO4.

[2]

(b) Compound Z, K2FeO4, can be prepared in the laboratory by the reaction between iron(III)
oxide, Fe2O3, chlorine, Cl 2, and potassium hydroxide, KOH.

Fe2O3 + 3Cl 2 + 10KOH → 2K2FeO4 + 6KCl + 5H2O

A 2.00 g sample of Fe2O3 is added to 20.0 cm3 of 4.00 mol / dm3 KOH.

(i) Calculate the amount of Fe2O3 used.

amount of Fe2O3 used = ..................................................... mol [2]

(ii) Calculate the amount of KOH used.

amount of KOH used = ..................................................... mol [1]

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(iii) Which reagent, Fe2O3 or KOH, is in excess in this reaction?

Explain your answer.

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

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

�������������������������������������������������������������������������������������������������������������������������������������� [1]

(c) A few drops of aqueous Z are added to a test-tube containing 3 cm3 of aqueous potassium
iodide. The solution in the test-tube changes from colourless to pale brown.

Given this information, what can you deduce about the chemical properties of Z?

............................................................................................................................................... [1]

 [Total: 7]

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4 This question is about hydrogen and some compounds containing hydrogen.

(a) Hydrogen is a gas at room temperature.

Describe the arrangement and motion of the molecules in hydrogen gas.

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

............................................................................................................................................... [2]

(b) The symbols for two isotopes of hydrogen are shown below.
1 2
1
H 1
H

Complete Table 4.1 to show the number of subatomic particles in these two isotopes of
hydrogen.

Table 4.1

1 2
1
H 1
H

number of electrons
number of neutrons
number of protons
[2]

(c) The isotope 21 H can be called deuterium and is given the symbol D. This isotope is present in
heavy water, D2O, which is used to absorb neutrons in nuclear reactors.

A sample of water vapour containing a small percentage of D2O is introduced into a long,
heated tube.

H2O(g)
and
D2O(g)

Fig. 4.1

The percentage of D2O in the vapour that first comes out of the tube is less than the
percentage of D2O as it enters the tube. Explain this difference.

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

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

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

............................................................................................................................................... [3]

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(d) Hydrochloric acid, HCl, is an acid because it produces H+ ions in aqueous solution.
Hydrochloric acid reacts both with metals and with metal oxides.

(i) A student observed the reaction of hydrochloric acid with four different metals. The
student used the same concentration and volume of hydrochloric acid and the same
mass of metal in each experiment.

Table 4.2

metal observations
cobalt dissolved very slowly and very few bubbles produced
iron dissolved slowly and a few bubbles produced slowly
magnesium dissolved very quickly and many bubbles produced very rapidly
zinc dissolved quickly and many bubbles produced rapidly

Use the information in Table 4.2 to suggest the order of reactivity of these metals.

most least
reactive .................... .................... .................... .................... reactive [2]

(ii) Magnesium oxide is classified as a basic oxide but zinc oxide is classified as an
amphoteric oxide.

Explain the meaning of the terms basic and amphoteric as applied to these oxides.
Include one equation in your explanation.

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

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

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

....................................................................................................................................... [2]

 [Total: 11]

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5 Some versions of the Periodic Table place hydrogen in Group 1 (Fig. 5.1). Other versions place
hydrogen alone and not with any other group (Fig. 5.2).

H H

Li
Na
K

Fig. 5.1 Fig. 5.2

(a) Give two similarities between hydrogen and the elements in Group 1.

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

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

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

............................................................................................................................................... [2]

(b) Give two properties of hydrogen that do not fit with the properties of the elements in Group 1.

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

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

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

............................................................................................................................................... [2]

(c) Hydrogen is in Period 1 of the Periodic Table.

Explain why Period 1 only contains 2 elements.

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

............................................................................................................................................... [1]

(d) Hydrogen is used to make margarine from vegetable oil.

Describe, in terms of bonds, what happens when hydrogen reacts with vegetable oil.

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

............................................................................................................................................... [2]

 [Total: 7]

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6 Fig. 6.1 shows a fractionating column for separating crude oil.

The fractions produced are labelled A, B, C, D and E.

crude oil

Fig. 6.1

(a) (i) Which fraction, A, B, C, D or E, is most likely to be a solid at room temperature?

....................................................................................................................................... [1]

(ii) Which fraction, A, B, C, D or E, has the smallest molecules?

....................................................................................................................................... [1]

(b) Fraction C is a liquid.

Explain how C is produced from crude oil.

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

............................................................................................................................................... [2]

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(c) Long chain alkanes can be cracked to produce shorter chain alkanes and alkenes.

(i) What is the molecular formula of an alkane with 12 carbon atoms in each molecule?

....................................................................................................................................... [1]

(ii) The alkane in (c)(i) can be cracked to produce butene and one other product. Write the
equation to show this reaction.

....................................................................................................................................... [1]

(iii) Explain why cracking makes the oil industry more profitable.

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

....................................................................................................................................... [1]

(d) Ethene is also produced by cracking.

Ethene is used in a further process to make ethanol. Ethanol can also be made from
sugarcane.

Explain why burning ethanol made from sugarcane causes less harm to the environment
than burning ethanol made from ethene.

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

............................................................................................................................................... [1]

 [Total: 8]

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7 Car engines produce carbon monoxide and nitrogen monoxide as waste gases.

(a) Describe how carbon monoxide and nitrogen monoxide form in the car engine and identify a
health problem caused by each gas.

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

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

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

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

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

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

............................................................................................................................................... [4]

(b) Carbon monoxide reacts with nitrogen monoxide in a catalytic converter.

2CO + 2NO → 2CO2 + N2

State and explain, with reference to oxidation states, which element is oxidised and which
element is reduced in this reaction.

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

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

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

............................................................................................................................................... [2]

(c) Explain why the reaction in the catalytic converter does not solve all of the environmental
problems caused by the waste gases.

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

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

............................................................................................................................................... [2]

 [Total: 8]

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8 Instrumental techniques in analysis

Flame tests for Group 1 elements

Flame tests were used in the 1850s. Robert Bunsen developed the Bunsen burner and used
it to show that many metals give characteristic colours when they are heated in the flame. The
colour comes from light emitted by individual atoms when they become very hot. For example,
sodium gives a very intense yellow-orange colour. The table shows the flame colours of Group 1
elements.

Table 8.1

element flame colour

lithium red
sodium yellow-orange
potassium pale violet
rubidium red-violet
caesium blue-violet

Group 1 element emission spectra

Bunsen realised that, in practice, it was difficult to use flame tests to identify elements in mixtures.
In the 1860s, Bunsen worked with fellow scientist, Gustav Kirchhoff. They used a spectroscope
to split the colours of the flames into individual lines. They found that atoms of an element each
give a characteristic pattern of lines which is known as an emission spectrum. Fig. 8.1 shows the
emission spectra of some Group 1 elements.

Emission spectra from elements can be used as a reference. They can be compared with the
emission spectrum of a mixture so that individual elements in the mixture can be identified. This
technique is used today to analyse light from stars to work out which elements are present in the
star.

Element Emission spectrum

lithium

sodium

potassium

rubidium
400 700
arbitrary scale

Fig. 8.1

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Ion chromatography of a sample of water

In the 1950s, ion chromatography was developed. This technique involves passing a sample
through a chromatography column. Different ions travel through the column at different speeds.
A detector is attached to the end of the column. The results are printed out as a graph.

The retention time is the time it takes each ion to travel through the column. Ions can be identified
by their retention times. The position of the peaks show the retention time of each ion.

The height of each peak (relative intensity) is proportional to the relative amount of each ion in
the sample.

Ion chromatography can be used to identify any ion, even those which contain multiple atoms,
such as the sulfate ion.

The ion chromatography analyses of a sample of water from a natural source are shown in Fig. 8.2
and Fig. 8.3.

Fig. 8.2 shows the ion chromatogram of positive ions in a sample of water.
sodium

1.0
0.9
0.8
calcium

0.7
0.6
relative
intensity 0.5
magnesium

0.4
potassium

0.3
ammonium

0.2
0.1
0
0 10 20
retention time / min

Fig. 8.2

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Fig. 8.3 shows the ion chromatogram of negative ions in a sample of water.

chloride
1.0
0.9
0.8
0.7

sulfate
0.6
relative
intensity 0.5

bromide
0.4
0.3
0.2
0.1
0
0 10 20
retention time / min

Fig. 8.3

(a) Bunsen said that it is difficult to use flame tests to identify elements in mixtures.

Explain why it is difficult to use flame tests to identify which Group 1 elements are in a mixture.

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

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

............................................................................................................................................... [2]

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(b) This is the emission spectrum from a mixture.

400 700
arbitrary scale

Fig. 8.4

(i) What conclusions can you make about which Group 1 elements this mixture does and
does not contain?

Explain your reasoning.

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

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

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

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

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

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

....................................................................................................................................... [3]

(ii) What additional information would you need so that you could use the spectrum to
identify all of the elements in the mixture?

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

....................................................................................................................................... [1]

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(c) Further analysis of the same sample of water that was tested by ion chromatography was
done.

(i) The sample was analysed to find out the concentration of sodium ions.

The first stage was to crystallise solid salts from the water.

Give the formulae of three different sodium salts which could crystallise from the water
sample.

salt 1 ...................................................................................................................................

salt 2 ...................................................................................................................................

salt 3 ...................................................................................................................................
[2]

(ii) The concentration of calcium ions in the water is 0.00420 mol / dm3.

Calculate the concentration of magnesium ions and the concentration of sodium ions in
the water.

[2]

(d) A student comments that the ion chromatograms give more information about mixtures than
the emission spectrum.

Give reasons to support his idea.

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

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

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

............................................................................................................................................... [2]

 [Total: 12]

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Section B

Answer one question from this section.

9 Liquefied Petroleum Gas (LPG) and ethanol can be used as fuels for cars instead of petrol.

LPG contains mainly propane.

This table shows some information about propane and ethanol.

Table 9.1

physical state at enthalpy change

name formula boiling point / °C room temperature of combustion
and pressure / kJ per mol

ethanol C2H5OH 78 –1371

propane C 3H 8 – 42 –2220

(a) Complete Table 9.1 by filling in the boxes. [1]

(b) Give one similarity and one difference between the structures of ethanol and propane.

similarity .....................................................................................................................................

difference ...................................................................................................................................
[2]

(c) When 1 kg of propane burns, 50 450 kJ of energy is given out.

(i) Show by calculation, using data from Table 9.1, that ethanol gives out less energy per kg
than propane.

[3]

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(ii) Suggest a reason why the combustion of 1 kg of ethanol gives out less energy than the
combustion of 1 kg of propane.

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

....................................................................................................................................... [1]

(d) In an ethanol-powered car engine, a spark plug ignites a mixture of air and ethanol. The
spark is needed because the combustion of ethanol needs activation energy.

Complete the energy profile diagram in Fig. 9.1 for the complete combustion of ethanol.

Show the names of the products and label the activation energy for the reaction.

ethanol and oxygen

energy

progress of reaction

Fig. 9.1
[3]

 [Total: 10]

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10 Table 10.1 shows the formulae of the first three members of the alcohol homologous series.

Table 10.1

alcohol formula
methanol CH3OH
ethanol C2H5OH
propanol C3H7OH

(a) Deduce the general formula for the alcohol homologous series.

............................................................................................................................................... [1]

(b) Ethanol can be manufactured from either ethene or glucose.

(i) Write an equation for the production of ethanol from ethene and state the conditions
under which the reaction takes place.

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

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

....................................................................................................................................... [2]

(ii) The fermentation of glucose can be represented by the following equation.

C6H12O6 → 2C2H5OH + 2CO2

Calculate the maximum mass of ethanol that could be made from 36 tonnes of glucose.

1 tonne = 1 x 106 g

[3]
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(iii) Explain why ethanol made from ethene is a non-renewable fuel but that made from
glucose is a renewable fuel.

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

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

....................................................................................................................................... [2]

(c) Propanol reacts in a similar way to ethanol.

(i) Name the organic product of the reaction between propanol and warm, acidified
potassium manganate(VII).

....................................................................................................................................... [1]

(ii) Name the type of product formed when the organic product in (c)(i) reacts with an
alcohol.

....................................................................................................................................... [1]

 [Total: 10]

Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every
reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the
publisher will be pleased to make amends at the earliest possible opportunity.

Cambridge Assessment International Education is part of Cambridge Assessment. Cambridge Assessment is the brand name of the University of Cambridge
Local Examinations Syndicate (UCLES), which is a department of the University of Cambridge.

© UCLES & MOE 2022 6092/02/SP/24

 The Periodic Table of Elements
Group
1 2 13 14 15 16 17 18
1 2

© UCLES & MOE 2022

H He
hydrogen helium
Key 1 4
3 4 proton (atomic) number 5 6 7 8 9 10
Li Be atomic symbol B C N O F Ne
lithium beryllium name boron carbon nitrogen oxygen fluorine neon
7 9 relative atomic mass 11 12 14 16 19 20
11 12 13 14 15 16 17 18
Na Mg Al Si P S Cl Ar
sodium magnesium aluminium silicon phosphorus sulfur chlorine argon
23 24 3 4 5 6 7 8 9 10 11 12 27 28 31 32 35.5 40
19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
potassium calcium scandium titanium vanadium chromium manganese iron cobalt nickel copper zinc gallium germanium arsenic selenium bromine krypton
39 40 45 48 51 52 55 56 59 59 64 65 70 73 75 79 80 84
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
24

Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe
rubidium strontium yttrium zirconium niobium molybdenum technetium ruthenium rhodium palladium silver cadmium indium tin antimony tellurium iodine xenon
85 88 89 91 93 96 – 101 103 106 108 112 115 119 122 128 127 131

6092/02/SP/24
55 56 57 – 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
lanthanoids
Cs Ba Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn
caesium barium hafnium tantalum tungsten rhenium osmium iridium platinum gold mercury thallium lead bismuth polonium astatine radon
133 137 178 181 184 186 190 192 195 197 201 204 207 209 – – –
87 88 89 – 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118
actinoids
Fr Ra Rf Db Sg Bh Hs Mt Ds Rg Cn Nh Fl Mc Lv Ts Og
francium radium rutherfordium dubnium seaborgium bohrium hassium meitnerium darmstadtium roentgenium copernicium nihonium flerovium moscovium livermorium tennessine oganesson
– – – – – – – – – – – – – – – – –

57 58 59 60 61 62 63 64 65 66 67 68 69 70 71
lanthanoids La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu
lanthanum cerium praseodymium neodymium promethium samarium europium gadolinium terbium dysprosium holmium erbium thulium ytterbium lutetium
139 140 141 144 – 150 152 157 159 163 165 167 169 173 175
89 90 91 92 93 94 95 96 97 98 99 100 101 102 103
actinoids Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr
actinium thorium protactinium uranium neptunium plutonium americium curium berkelium californium einsteinium fermium mendelevium nobelium lawrencium
– 232 231 238 – – – – – – – – – – –

The volume of one mole of any gas is 24 dm3 at room temperature and pressure (r.t.p.).
The Avogadro constant, L = 6.02  1023 mol–1.