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Practice paper written from an analysis of every
O-Level Chemistry paper, 2009–2026
Paper 1 Multiple Choice
FORECAST PAPER · SET 7 Medium
For practice before the 2026 examination
1 hour
Additional Materials: Paper for your answers, numbered 1 to 40
Write in soft pencil.
Do not use staples, paper clips, glue or correction fluid.
There are forty questions on this paper. Answer all questions. For each question there are four possible answers A, B, C and D.
Choose the one you consider correct and record your choice on a separate sheet of paper, numbered 1 to 40.
Each correct answer will score one mark. A mark will not be deducted for a wrong answer.
Any rough working should be done in this booklet.
A copy of the Periodic Table is printed on page 18.
The use of an approved scientific calculator is expected, where appropriate.
Three waste mixtures from an electronics factory are to be separated.
Which row gives a suitable method of separating each mixture?
| mixture 1 | mixture 2 | mixture 3 | |
|---|---|---|---|
| A | sublimation | fractional distillation | use a separating funnel |
| B | add water, filter, then crystallise the filtrate | fractional distillation | use a separating funnel |
| C | add water, filter, then crystallise the filtrate | fractional distillation | filtration |
| D | add water, filter, then crystallise the filtrate | use a separating funnel | fractional distillation |
A technician identifies the dye in the plastic coating of a cable by paper chromatography.
The dye is run in two different solvents. The chromatograms are shown.
The table shows the Rf values of four known dyes in the two solvents.
| dye | Rf in solvent 1 | Rf in solvent 2 |
|---|---|---|
| P | 0.40 | 0.30 |
| Q | 0.40 | 0.65 |
| R | 0.72 | 0.65 |
| S | 0.72 | 0.30 |
Rf = distance moved by the dye ÷ distance moved by the solvent
Which dye is in the coating?
Bromine compounds are added to some plastics used in electronic equipment. Bromine is a brown vapour that is denser than air.
A gas jar of bromine vapour has a gas jar of air placed upside down on top of it, with a glass cover between them.
The glass cover is removed. The time taken for the brown colour to become the same throughout both jars is measured at three temperatures.
| temperature / °C | time for the colour to become the same / s |
|---|---|
| 20 | 280 |
| 40 | 170 |
| 60 | 100 |
Which statements are correct?
Silicon, aluminium and phosphorus are used to make electronic components.
Which pair of atoms are isotopes of the same element?
Mineral-insulated cables used in buildings contain solid magnesium oxide, MgO. Part of its structure is shown.
The mass of magnesium oxide is described by its relative formula mass, 40, and not by a relative molecular mass.
Which statement explains this?
Ethanol is a covalent liquid used to clean circuit boards. It does not conduct electricity.
Molten sodium chloride conducts electricity.
Which statement explains the difference?
Copper is used in the heat sinks that remove heat from computer processors.
Which statements about copper are correct?
Which row classifies the three substances correctly?
| concrete | silicon(IV) oxide | copper | |
|---|---|---|---|
| A | compound | compound | element |
| B | compound | mixture | element |
| C | mixture | compound | compound |
| D | mixture | compound | element |
X and Y are two forms of carbon. The letters are not the chemical symbols.
The table shows some properties of X and Y.
| property | X | Y |
|---|---|---|
| hardness | soft | very hard |
| conducts electricity | yes | no |
| melting point | very high | very high |
Which statements are correct?
Limestone, which is mainly calcium carbonate, is heated in a kiln in the first stage of making cement.
Which statement about the reaction is correct?
A metal oxide used as a red pigment in coloured concrete has the formula M2O3. Its relative formula mass is 160.
The letter M is not the chemical symbol.
What is the relative atomic mass of M?
Silicon nitride is a hard ceramic used to insulate the layers in microchips.
A sample of silicon nitride contains 8.4 g of silicon and 5.6 g of nitrogen only.
What is the empirical formula of silicon nitride?
A cleaning acid for brickwork contains hydrochloric acid. 20.0 cm3 of the cleaning acid is neutralised by 25.0 cm3 of aqueous sodium hydroxide of concentration 0.80 mol / dm3.
What is the concentration of hydrochloric acid in the cleaning acid, in g / dm3?
Two solutions are used to remove limescale from the metal parts of a cooling system.
Which statement is correct?
Which pair of oxides both react with aqueous sodium hydroxide?
Three salts are made in a materials laboratory.
Which row gives a suitable method of preparing each salt?
| lead(II) iodide | potassium nitrate | calcium nitrate | |
|---|---|---|---|
| A | titration with an indicator, then repeat without it and crystallise | precipitation: mix two solutions, then filter off the solid formed | add the excess of an insoluble solid to dilute acid, filter, then crystallise |
| B | add the excess of an insoluble solid to dilute acid, filter, then crystallise | titration with an indicator, then repeat without it and crystallise | precipitation: mix two solutions, then filter off the solid formed |
| C | precipitation: mix two solutions, then filter off the solid formed | titration with an indicator, then repeat without it and crystallise | add the excess of an insoluble solid to dilute acid, filter, then crystallise |
| D | precipitation: mix two solutions, then filter off the solid formed | add the excess of an insoluble solid to dilute acid, filter, then crystallise | titration with an indicator, then repeat without it and crystallise |
Nitrogen from the air and hydrogen from the cracking of hydrocarbons are used to manufacture ammonia.
Which equation represents a hydrocarbon being cracked to produce hydrogen?
Water from an excavation on a building site is tested for nitrate ions.
Aluminium foil and aqueous sodium hydroxide are added to a sample of the water and the mixture is warmed.
Which row shows the gas that indicates the presence of nitrate ions and the result of the test on this gas?
| gas | result of test | |
|---|---|---|
| A | ammonia | turns damp blue litmus paper red |
| B | ammonia | turns damp red litmus paper blue |
| C | hydrogen | makes a ‘pop’ with a burning splint |
| D | nitrogen dioxide | turns damp blue litmus paper red |
Iron(II) ions in waste water from a building site are removed by adding magnesium powder.
Which half-equation shows oxidation?
Solid lead(II) bromide does not conduct electricity. When it is melted, the lamp lights.
Molten lead(II) bromide is electrolysed. Silvery lead forms at the negative electrode and red-brown bromine forms at the positive electrode.
Which statement about lead(II) bromide do these results support?
A technician electrolyses four aqueous solutions, one at a time, using inert electrodes.
Four statements about the products are listed.
Which statements are correct?
A technician in a materials laboratory electrolyses aqueous magnesium sulfate using inert electrodes.
Which row shows the equations for the reactions at the electrodes?
| reaction at the anode | reaction at the cathode | |
|---|---|---|
| A | 4OH− → O2 + 2H2O + 4e− | 2H+ + 2e− → H2 |
| B | 4OH− → O2 + 2H2O + 4e− | Mg2+ + 2e− → Mg |
| C | 4OH− → O2 + 2H2O + 2e− | 2H+ + 2e− → H2 |
| D | 2H+ + 2e− → H2 | 4OH− → O2 + 2H2O + 4e− |
Elements R and S are both among the first twenty elements of the Periodic Table.
Atoms of R form ions with a charge of 2+. Atoms of S form ions with a charge of 3−.
The letters are not the chemical symbols.
How many outer electrons are there in atoms of R and S?
| outer electrons in an atom of R | outer electrons in an atom of S | |
|---|---|---|
| A | 2 | 3 |
| B | 2 | 5 |
| C | 6 | 3 |
| D | 6 | 5 |
An atom of element X has the electronic configuration 2,6.
The letter is not the chemical symbol.
Which proton number is that of an element with similar chemical properties to X?
Bromine water is added separately to aqueous potassium chloride and to aqueous potassium iodide.
Which row shows whether a displacement reaction takes place?
| aqueous potassium chloride | aqueous potassium iodide | |
|---|---|---|
| A | no reaction | no reaction |
| B | reaction | no reaction |
| C | reaction | reaction |
| D | no reaction | reaction |
Which oxide is reduced when it is heated in a stream of hydrogen?
Which metal is the most difficult to obtain from its ore?
The energy profile diagram for a reaction is shown.
Which statement about the reaction is correct?
A biological washing powder contains an enzyme that breaks down proteins in food stains.
Which row describes the effect of the enzyme?
| rate of the reaction | enzyme at the end of the reaction | |
|---|---|---|
| A | decreases | partly used up |
| B | decreases | unchanged |
| C | increases | partly used up |
| D | increases | unchanged |
Catalyst P and catalyst Q are used to speed up the decomposition of hydrogen peroxide. One of them is manganese(IV) oxide and the other is an enzyme from liver.
The time taken to collect 20 cm3 of oxygen is measured at four temperatures.
| temperature / °C | time taken with catalyst P / s | time taken with catalyst Q / s |
|---|---|---|
| 20 | 160 | 90 |
| 40 | 80 | 30 |
| 60 | 40 | 120 |
| 80 | 20 | more than 600 |
Which statement identifies the enzyme and gives a correct reason?
Natural gas, which is mainly methane, and crude oil are non-renewable sources of energy.
Four statements about why they are described as non-renewable are listed.
Which statements are correct?
The first four alcohols form a homologous series. The table shows their boiling points.
| alcohol | formula | boiling point / °C |
|---|---|---|
| methanol | CH3OH | 65 |
| ethanol | C2H5OH | 78 |
| propan-1-ol | C3H7OH | 97 |
| butan-1-ol | C4H9OH | 118 |
What is the most likely boiling point of pentan-1-ol, C5H11OH?
Four statements about reactions of ethane, C2H6, are listed.
Which statements are correct?
A molecule of an alkene contains 24 atoms in total.
How many hydrogen atoms are in the molecule?
Ethene is the raw material for the poly(ethene) used to insulate electric cables.
A mixture of 30 cm3 of ethene and 50 cm3 of hydrogen is passed over a heated nickel catalyst. All gas volumes are measured at the same temperature and pressure.
Assume that all of the ethene reacts. What is the volume of gas at the end?
The first two members of a homologous series are methanoic acid, HCO2H, and ethanoic acid, CH3CO2H.
What is the molecular formula of the fifth member of the series?
In experiment X, 50 cm3 of 0.20 mol / dm3 hydrochloric acid is added to 0.50 g of magnesium ribbon.
In experiment Y, 50 cm3 of 0.20 mol / dm3 ethanoic acid is added to 0.50 g of magnesium ribbon.
The volume of hydrogen formed is measured over time. Which graph shows the results?
Part of a polymer used to make cable ties is shown. The rectangles represent parts of the structure that are not shown.
Which pair of monomers forms this polymer?
Which list contains only common atmospheric pollutants?
Powdered calcium carbonate is added to a lake that has been damaged by acid rain.
What is the purpose of the calcium carbonate?
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