chermistry.com
Practice paper written from an analysis of every
O-Level Chemistry paper, 2009–2026
Paper 1 Multiple Choice
FORECAST PAPER · SET 4 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 16.
The use of an approved scientific calculator is expected, where appropriate.
A student prepares hydrogen chloride gas in the laboratory.
Hydrogen chloride is an acidic gas that is denser than air and very soluble in water.
Which apparatus can be used to dry the gas and collect a dry sample of it?
Iodine is used as an antiseptic for cuts.
A sample of iodine is mixed with sand.
Iodine changes directly from a solid to a gas when it is warmed gently.
Sand does not change when it is warmed gently.
Which method can be used to obtain pure iodine from the mixture?
Sugars are colourless.
A food scientist separates the sugars in apple juice by paper chromatography.
When the solvent has risen up the paper, the paper is dried and sprayed with a locating agent.
Which statements about the locating agent are correct?
Which statement explains why the skin feels cooler when sweat evaporates?
Which statement explains why the smell of a durian can be detected a few metres away?
Hydrogen chloride, HCl, is a covalent compound.
Which row shows the number of electrons around each atom, counting the shared pair, in a molecule of hydrogen chloride?
| hydrogen atom | chlorine atom | |
|---|---|---|
| A | 1 | 7 |
| B | 1 | 8 |
| C | 2 | 7 |
| D | 2 | 8 |
Pure gold is too soft to be used for most jewellery.
Jewellers mix gold with copper to make an alloy that is harder.
Which statement explains why the alloy is harder than pure gold?
Which row gives the correct formulae of the three compounds?
| ammonia | calcium hydroxide | carbon monoxide | |
|---|---|---|---|
| A | NH3 | Ca(OH)2 | CO2 |
| B | NH3 | CaOH2 | CO |
| C | NH3 | Ca(OH)2 | CO |
| D | NH4 | Ca(OH)2 | CO |
In a self-heating food can, calcium oxide reacts with water and produces heat.
Which statement about the reaction is correct?
Dilute hydrochloric acid is added separately to four solids.
Which solids react with the acid to form a gas?
Many crops grow poorly in soil that is too acidic.
A farmer adds calcium hydroxide to an acidic soil.
Which row describes the changes in the soil?
| pH of the soil | concentration of hydrogen ions in the soil | |
|---|---|---|
| A | decreases | decreases |
| B | decreases | increases |
| C | increases | decreases |
| D | increases | increases |
Which row classifies the three oxides correctly?
| aluminium oxide | carbon monoxide | sulfur dioxide | |
|---|---|---|---|
| A | amphoteric | acidic | acidic |
| B | amphoteric | neutral | neutral |
| C | basic | neutral | acidic |
| D | amphoteric | neutral | acidic |
Calcium carbonate is insoluble in water.
It is used in some toothpastes to help to clean the teeth.
Which pair of aqueous solutions can be mixed to prepare calcium carbonate?
Nitrogen and hydrogen are sealed in a container in the exact ratio needed to make ammonia.
After a long time, the amounts of nitrogen, hydrogen and ammonia no longer change.
Which statement explains why nitrogen and hydrogen are still present?
Water from a pond contains two different anions.
Three tests are done on separate samples of the water.
Which two anions are present?
Three reactions are shown.
In which reactions is the underlined substance oxidised?
Sea water is electrolysed using inert electrodes.
Which statement about the electrolysis is correct?
Table salt is sodium chloride.
Molten sodium chloride is electrolysed using inert electrodes.
Which row describes what happens at the positive electrode?
| ions attracted to the positive electrode | product at the positive electrode | |
|---|---|---|
| A | Cl− | chlorine |
| B | Cl− | sodium |
| C | Na+ | chlorine |
| D | Na+ | sodium |
Which statement about a bus powered by a hydrogen fuel cell is correct?
Atoms of element X have a proton number of 13.
Atoms of element Y have a proton number of 16.
The letters are not the chemical symbols.
Which pair gives the charges on the ions formed by X and Y?
Four statements about the elements in Period 3 of the Periodic Table, from sodium to chlorine, are listed.
Which statements are correct?
A colourless solution of iodide ions is made from seaweed.
Chlorine gas is bubbled through the solution.
Which row is correct?
| observation | explanation | |
|---|---|---|
| A | the solution turns brown | chlorine is more reactive than iodine |
| B | the solution turns brown | chlorine is less reactive than iodine |
| C | there is no change | chlorine is more reactive than iodine |
| D | there is no change | chlorine is less reactive than iodine |
Which metal reacts with dilute hydrochloric acid but has an oxide that is not reduced when heated with carbon?
Five metals are listed in order of decreasing reactivity: magnesium, zinc, iron, lead and copper.
Metal Q is tested.
Where is Q in the reactivity series?
Calcium and iron are both obtained from their ores.
Which row is correct?
| extracted by electrolysis | extracted by heating with carbon | |
|---|---|---|
| A | iron | iron |
| B | iron | calcium |
| C | calcium | iron |
| D | calcium | calcium |
The steel legs of an offshore platform are protected from rusting by blocks of metal M attached to them below the water line.
Which statement about metal M is correct?
Excess crushed indigestion tablets, which contain calcium carbonate, are added to 50 cm3 of dilute hydrochloric acid in experiment X and to 100 cm3 of the same acid in experiment Y.
The volume of carbon dioxide formed is measured over time. The results are shown.
Which statement about the results is correct?
Which row describes natural gas?
| main compound | type of energy source | |
|---|---|---|
| A | butane | non-renewable |
| B | butane | renewable |
| C | methane | non-renewable |
| D | methane | renewable |
Which structure shows a branched alkane?
But-1-ene has the structure CH2=CHCH2CH3.
Four hydrocarbons are shown.
Which hydrocarbons are isomers of but-1-ene?
Crude oil is separated into four fractions, P, Q, R and S, by fractional distillation.
The table shows the percentage of each fraction obtained from the crude oil and the percentage of each fraction that is needed.
| fraction | carbon atoms in each molecule | obtained from crude oil / % | needed / % |
|---|---|---|---|
| P | 1 to 4 | 3 | 10 |
| Q | 5 to 10 | 17 | 40 |
| R | 11 to 20 | 38 | 30 |
| S | more than 20 | 42 | 20 |
Which fractions should be cracked to match the demand?
Margarine is made from vegetable oils.
Three statements about the manufacture of margarine are listed.
Which statements are correct?
Methanol is used as a fuel in some camping stoves.
A stove burns 3.2 g of methanol completely in air.
What mass of oxygen is used?
Propanoic acid is added to bread to stop mould growing.
Which structure shows propanoic acid?
An ester with the smell of pears is made by warming ethanoic acid with propan-1-ol and a few drops of concentrated sulfuric acid.
What is the relative molecular mass of the ester?
Part of a molecule of poly(ethene) is shown.
How many ethene molecules joined together to form this part of the molecule?
Poly(ethene) is a typical plastic.
Which two items are made from poly(ethene)?
Four statements about recycling plastics are listed.
Which statements are correct?
After nitrogen and oxygen, which gas is the most abundant in dry air?
Which pollutant is removed by reduction in the catalytic converter of a car?
Group | |||||||||||||||||
1 | 2 |
| 13 | 14 | 15 | 16 | 17 | 18 | |||||||||
|
|
| Key |
| 1 H hydrogen 1 |
|
|
|
|
|
|
|
|
| 2 He helium 4 | ||
3 Li lithium 7 | 4 Be beryllium 9 |
| proton (atomic) number atomic symbol name relative atomic mass |
|
|
|
|
|
| 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 – |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
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 |
| |
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 – |
| |
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