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Practice paper written from an analysis of every
O-Level Science (Chemistry) paper, 2010–2025
Paper 3 Chemistry
FORECAST PAPER · PAPER 3.2
For practice before the 2026 examination
1 hour 15 minutes
Candidates answer on the Question Paper.
No Additional Materials are required.
Write your name, centre number and index number in the boxes above.
You may use an HB pencil for any diagrams, graphs or rough working.
Write in dark blue or black pen.
Do not use staples, paper clips, glue or correction fluid.
The use of an approved scientific calculator is expected, where appropriate.
You may lose marks if you do not show your working or if you do not use appropriate units.
Section A
Answer all questions.
Write your answers in the spaces provided on the question paper.
Section B
Answer one question.
Write your answers in the spaces provided on the question paper.
A copy of the Data Sheet is printed on page 16.
A copy of the Periodic Table is printed on page 17.
The number of marks is given in brackets [ ] at the end of each question or part question.
The total mark for this paper is 65.
Fig. 1.1 shows the scales of a thermometer, a measuring cylinder and a burette. The burette is shown twice: before and after a student adds dilute hydrochloric acid to an alkali.
Record the temperature shown on the thermometer.
Calculate the volume of acid that the student adds from the burette.
Compare the scales of the measuring cylinder and the burette in Fig. 1.1.
State which piece of apparatus measures a volume more precisely.
Boron is added to glass to make borosilicate glass, which is used for laboratory apparatus. Fig. 2.1 shows the nuclei of five different atoms, P, S, U, X and Z. The letters are not the chemical symbols.
Use the Periodic Table to answer the questions. Each nucleus can be used once, more than once or not at all.
Identify the nucleus that has a proton number of 5.
Identify the nucleus that has a nucleon number of 11.
Identify the nucleus of a Group 1 atom.
Identify the nucleus of the atom that has three electron shells.
Lithium batteries are made using metals, ionic compounds and simple molecular substances. Table 3.1 gives clues about five substances that are used in or with them.
Complete Table 3.1 by writing ionic, metallic or simple molecular in each row to show the type of bonding.
| substance | clue | type of bonding |
|---|---|---|
| aluminium | a shiny solid that conducts electricity when it is solid | |
| lithium chloride | a white solid that melts at 605 °C; it does not conduct electricity when solid but conducts when it is molten | |
| dimethyl carbonate | a colourless liquid that boils at 90 °C and does not conduct electricity | |
| copper | a reddish-brown solid that melts at 1085 °C and conducts electricity when solid and when molten | |
| ethanol | a colourless liquid that boils at 78 °C and does not conduct electricity |
Complete Table 3.1.
Lithium atoms form lithium ions in the battery.
Describe, in terms of electrons, what happens when a lithium atom forms a lithium ion.
State two physical properties of metals that are not mentioned in Table 3.1.
Limescale forms inside kettles in areas with hard water. It is mainly calcium carbonate. A descaler contains dilute hydrochloric acid, which removes the limescale. Fig. 4.1 shows two reactions of the descaler.
Name gas Y.
Name salt X.
Name the type of reaction that happens when the spilled descaler reacts with calcium hydroxide.
The descaler has a pH of 1.5 before use. After the limescale has been removed, the pH of the liquid in the kettle is 4.0.
Explain why the pH has increased.
Magnesium carbonate reacts with dilute hydrochloric acid.
In experiment 1, an excess of magnesium carbonate is added to 25.0 cm3 of dilute hydrochloric acid of concentration 0.50 mol / dm3. The carbon dioxide is collected in a gas syringe. In experiment 2, the experiment is repeated using 25.0 cm3 of acid of an increased concentration, 1.00 mol / dm3. The temperature of the acid is the same in both experiments.
Three students make statements about the experiments.
Amy says: “The rate of reaction is higher in experiment 2 because the particles in the acid move faster.”
Put a tick in one box to show whether Amy is correct or incorrect.
| correct | incorrect |
|---|---|
Ben says: “The final volume of gas is the same in both experiments because magnesium carbonate is in excess in both.”
Put a tick in one box to show whether Ben is correct or incorrect.
| correct | incorrect |
|---|---|
In a separate experiment, the temperature of the mixture rises from 20.0 °C to 22.5 °C.
Chen says: “This shows that the reaction is exothermic.”
Put a tick in one box to show whether Chen is correct or incorrect.
| correct | incorrect |
|---|---|
Write a correct explanation of why the rate of reaction is higher in experiment 2, to replace Amy’s reason.
Use ideas about particles in your answer.
A forest fire burns trees and releases gases into the atmosphere.
The fire releases carbon dioxide.
Name the process by which growing trees remove carbon dioxide from the atmosphere.
The trees burn in a limited supply of air, so carbon monoxide forms.
Name one other pollutant that forms when the trees burn in a limited supply of air.
Methane is a greenhouse gas that is released by farming.
State one source of methane on farms.
Methane is also the main compound in natural gas, a fuel that is found underground. Natural gas was formed from the remains of sea animals over millions of years.
Explain why natural gas is described as a non-renewable energy source.
Crude oil, found with natural gas, is a mixture of hydrocarbons.
State what is meant by the term hydrocarbon.
Fig. 7.1 shows some reactions of two white or silvery solids, R and U.
Identify each of R, S, T, U, V, W and X.
You may give the name or the formula of each.
Write a balanced chemical equation, including state symbols, for any one of the reactions shown in Fig. 7.1.
Hydrogen peroxide, H2O2, is used to clean contact lenses. It decomposes to form water and oxygen.
A solution of hydrogen peroxide has a concentration of 68 g / dm3. A sample of 50.0 cm3 of the solution is allowed to decompose completely.
State what is meant by the term relative molecular mass.
Calculate the relative molecular mass, Mr, of hydrogen peroxide.
Use your answer to (b) to calculate the concentration of the hydrogen peroxide solution in mol / dm3.
Calculate the amount, in moles, of hydrogen peroxide in the 50.0 cm3 sample.
Use your answer to (d) and the equation to calculate the volume of oxygen formed, at room temperature and pressure.
Calculate the mass of water formed in the reaction.
Fig. 9.1 shows the displayed formulae of four hydrocarbons, A, B, C and D. The letters are not the chemical symbols.
Identify the two unsaturated hydrocarbons. Give a reason for your answer.
State the molecular formula of hydrocarbon C.
Name hydrocarbon D.
Hydrocarbons A and D are in the same homologous series.
State the general formula of the series that contains A and D.
Hydrocarbon B is made by cracking.
State one reason why cracking is essential.
Hydrocarbon A reacts with chlorine in ultraviolet light.
Fig. 9.2 shows part of a molecule of a polymer that is used to coat pipes.
Draw the displayed formula of the monomer from which this polymer is made.
State the name of the type of polymerisation that forms this polymer.
The elements in Group 1 of the Periodic Table are called the alkali metals.
A student adds a small piece of each of three Group 1 metals, each of mass 0.05 g, to separate beakers containing 100 cm3 of cold water. The beakers are behind a safety screen. The student measures the time taken for each piece of metal to react completely. Table 10.1 shows the results.
| metal | proton number | time for the metal to react completely / s |
|---|---|---|
| lithium | 3 | 150 |
| sodium | 11 | 40 |
| potassium | 19 | 8 |
Use data from Table 10.1 to answer the questions.
Describe how the reactivity of Group 1 metals with water changes down the group.
Rubidium is below potassium in Group 1. Predict the time taken for 0.05 g of rubidium to react completely in the same experiment.
State one physical property in which Group 1 metals are different from a typical metal such as iron.
Magnesium is a metal and sulfur is a non-metal. Both elements are in Period 3 of the Periodic Table. State how the character of the elements changes across a period. Give one property of magnesium and one property of sulfur that contrast with each other.
Rubidium, Rb, reacts with oxygen to form rubidium oxide. Predict the formula of rubidium oxide.
A small piece of potassium is added to cold water. State one observation that shows that potassium is more reactive than sodium.
Lithium reacts with chlorine to form lithium chloride, an ionic compound. Draw a 'dot-and-cross' diagram to show the bonding in lithium chloride. Show only the outer shell electrons. Include the charge on each ion.
The equation for the reaction between lithium and chlorine is shown.
A student investigates the reactivity of four metals, zinc, lead, copper and silver. The student adds a small piece of each metal to dilute hydrochloric acid and heats a separate piece of each metal strongly in air. The pieces of metal are the same size and the acid has the same concentration in each test. Table 11.1 shows the observations.
| metal | added to dilute hydrochloric acid | heated strongly in air |
|---|---|---|
| zinc | steady stream of bubbles; the metal dissolves | |
| lead | a few bubbles form very slowly | the surface slowly becomes covered with a dull grey layer |
| copper | no bubbles | the surface turns black very slowly |
| silver | no change |
The four metals are listed in Table 11.1 in order of reactivity, with the most reactive metal first. Two observations are missing from the table. Complete Table 11.1.
Magnesium is more reactive than zinc. Predict how the reaction of magnesium with dilute hydrochloric acid compares with the reaction of zinc with dilute hydrochloric acid.
Zinc reacts with dilute hydrochloric acid but copper and silver do not.
Zinc reacts with dilute hydrochloric acid to form hydrogen and one other product. Name the other product.
Explain why copper and silver do not react with dilute hydrochloric acid.
Zinc and lead can each be obtained from their oxides by heating the oxide with carbon. State which of these two metals is easier to obtain from its oxide. Use Table 11.1 to explain your answer.
Which metal would you expect to react more vigorously with cold water, calcium or silver? Give a reason for your answer.
Hydrogen reacts with oxygen to form water, a covalent compound. Draw a 'dot-and-cross' diagram to show the bonding in a molecule of water. Show only the outer shell electrons.
Zinc burns in air to form zinc oxide. The equation for the reaction is shown.
Oxygen atoms ........................ electrons, so oxygen is ........................ .
| aluminium hydroxide | white |
| calcium hydroxide | white |
| copper(II) hydroxide | light blue |
| iron(II) hydroxide | green |
| iron(III) hydroxide | red-brown |
| zinc hydroxide | white |
Group | |||||||||||||||||
1 | 2 |
| 13 | 14 | 15 | 16 | 17 | 18 | |||||||||
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| 1 H hydrogen 1 |
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| 2 He helium 4 | ||
3 Li lithium 7 | 4 Be beryllium 9 |
| proton (atomic) number atomic symbol name relative atomic mass |
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| 5 B boron 11 | 6 C carbon 12 | 7 N nitrogen 14 | 8 O oxygen 16 | 9 F fluorine 19 | 10 Ne neon 20 | ||
11 Na sodium 23 | 12 Mg magnesium 24 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 Al aluminium 27 | 14 Si silicon 28 | 15 P phosphorus 31 | 16 S sulfur 32 | 17 Cl chlorine 35.5 | 18 Ar argon 40 |
19 K potassium 39 | 20 Ca calcium 40 | 21 Sc scandium 45 | 22 Ti titanium 48 | 23 V vanadium 51 | 24 Cr chromium 52 | 25 Mn manganese 55 | 26 Fe iron 56 | 27 Co cobalt 59 | 28 Ni nickel 59 | 29 Cu copper 64 | 30 Zn zinc 65 | 31 Ga gallium 70 | 32 Ge germanium 73 | 33 As arsenic 75 | 34 Se selenium 79 | 35 Br bromine 80 | 36 Kr krypton 84 |
37 Rb rubidium 85 | 38 Sr strontium 88 | 39 Y yttrium 89 | 40 Zr zirconium 91 | 41 Nb niobium 93 | 42 Mo molybdenum 96 | 43 Tc technetium – | 44 Ru ruthenium 101 | 45 Rh rhodium 103 | 46 Pd palladium 106 | 47 Ag silver 108 | 48 Cd cadmium 112 | 49 In indium 115 | 50 Sn tin 119 | 51 Sb antimony 122 | 52 Te tellurium 128 | 53 I iodine 127 | 54 Xe xenon 131 |
55 Cs caesium 133 | 56 Ba barium 137 | 57–71 lanthanoids
| 72 Hf hafnium 178 | 73 Ta tantalum 181 | 74 W tungsten 184 | 75 Re rhenium 186 | 76 Os osmium 190 | 77 Ir iridium 192 | 78 Pt platinum 195 | 79 Au gold 197 | 80 Hg mercury 201 | 81 Tl thallium 204 | 82 Pb lead 207 | 83 Bi bismuth 209 | 84 Po polonium – | 85 At astatine – | 86 Rn radon – |
87 Fr francium – | 88 Ra radium – | 89–103 actinoids
| 104 Rf rutherfordium – | 105 Db dubnium – | 106 Sg seaborgium – | 107 Bh bohrium – | 108 Hs hassium – | 109 Mt meitnerium – | 110 Ds darmstadtium – | 111 Rg roentgenium – | 112 Cn copernicium – | 113 Nh nihonium – | 114 Fl flerovium – | 115 Mc moscovium – | 116 Lv livermorium – | 117 Ts tennessine – | 118 Og oganesson – |
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lanthanoids | 57 La lanthanum 139 | 58 Ce cerium 140 | 59 Pr praseodymium 141 | 60 Nd neodymium 144 | 61 Pm promethium – | 62 Sm samarium 150 | 63 Eu europium 152 | 64 Gd gadolinium 157 | 65 Tb terbium 159 | 66 Dy dysprosium 163 | 67 Ho holmium 165 | 68 Er erbium 167 | 69 Tm thulium 169 | 70 Yb ytterbium 173 | 71 Lu lutetium 175 |
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actinoids | 89 Ac actinium – | 90 Th thorium 232 | 91 Pa protactinium 231 | 92 U uranium 238 | 93 Np neptunium – | 94 Pu plutonium – | 95 Am americium – | 96 Cm curium – | 97 Bk berkelium – | 98 Cf californium – | 99 Es einsteinium – | 100 Fm fermium – | 101 Md mendelevium – | 102 No nobelium – | 103 Lr lawrencium – |
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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