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Practice paper written from an analysis of every
O-Level Science (Chemistry) paper, 2010–2025
Paper 1 Multiple Choice (Chemistry section)
FORECAST PAPER
For practice before the 2026 examination
30 minutes
Additional Materials: Paper for your answers, numbered 1 to 20
Write in soft pencil.
Do not use staples, paper clips, glue or correction fluid.
There are twenty 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 20.
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 Data Sheet is printed on page 11.
A copy of the Periodic Table is printed on page 12.
The use of an approved scientific calculator is expected, where appropriate.
A gas is made in a flask.
The gas is collected in a gas jar that is held upside down, as shown.
A gas that is less dense than air can be collected using this apparatus.
Which gas is it?
Sulfur is a solid at room temperature.
Solid sulfur is heated until it melts.
Which row describes what happens to the particles when the sulfur melts?
| arrangement of the particles | energy of the particles | |
|---|---|---|
| A | regular to random | decreases |
| B | regular to random | increases |
| C | random to regular | decreases |
| D | random to regular | increases |
The nuclide notation of an ion of phosphorus is shown.
How many protons, neutrons and electrons are in one of these ions?
| protons | neutrons | electrons | |
|---|---|---|---|
| A | 15 | 16 | 12 |
| B | 15 | 31 | 18 |
| C | 16 | 15 | 18 |
| D | 15 | 16 | 18 |
The 'dot-and-cross' diagram shows only the outer shell electrons of the ions in an ionic compound of the elements X and Y.
The letters are not the chemical symbols.
Which row shows the Group of the Periodic Table in which each element is found?
| element X | element Y | |
|---|---|---|
| A | Group 1 | Group 16 |
| B | Group 1 | Group 17 |
| C | Group 2 | Group 16 |
| D | Group 2 | Group 17 |
The properties of four substances P, Q, R and S are shown.
The letters are not the chemical symbols.
| substance | melting point / °C | conducts electricity when solid | conducts electricity when molten |
|---|---|---|---|
| P | 801 | no | yes |
| Q | 420 | yes | yes |
| R | 115 | no | no |
| S | 1085 | yes | yes |
Which substance has a simple molecular structure?
A sample contains 0.10 mol of methane molecules, CH4.
How many atoms are there in the sample?
Magnesium reacts with dilute hydrochloric acid.
A student adds 0.48 g of magnesium to 20 cm3 of 0.50 mol / dm3 hydrochloric acid.
What volume of hydrogen is formed at r.t.p.?
A solution of hydrochloric acid has a pH of 2.
Water is added to the solution.
Which row describes the changes?
| pH of the solution | concentration of H+ ions | |
|---|---|---|
| A | decreases | decreases |
| B | decreases | increases |
| C | increases | increases |
| D | increases | decreases |
Oxide R reacts with dilute hydrochloric acid to form a salt and water.
Oxide R also reacts with aqueous sodium hydroxide to form a salt and water.
Which oxide could R be?
Aqueous solution W contains one cation and one anion.
The results of two tests on W are shown.
| test | method | observation |
|---|---|---|
| 1 | add aqueous sodium hydroxide and warm | the gas given off turns damp red litmus paper blue |
| 2 | add dilute nitric acid, then aqueous barium nitrate | white precipitate |
What is W?
Aqueous iron(II) sulfate is added to acidified potassium manganate(VII).
The purple colour of the manganate(VII) disappears.
Which row describes the iron(II) ions in this reaction?
| role of the iron(II) ions | what happens to the iron(II) ions | |
|---|---|---|
| A | oxidising agent | oxidised |
| B | oxidising agent | reduced |
| C | reducing agent | oxidised |
| D | reducing agent | reduced |
Sodium and potassium are both in Group 1.
Both metals react with water in a similar way.
Which statement explains why?
Lithium, sodium and potassium are in Group 1.
Each metal is added to a separate trough of cold water.
Which statement is correct?
Four metals P, Q, R and S are added separately to cold water and to dilute hydrochloric acid.
The same mass of each metal is used and all other conditions are the same.
The letters are not the chemical symbols.
| metal | cold water | dilute hydrochloric acid |
|---|---|---|
| P | no reaction | bubbles slowly |
| Q | bubbles rapidly | bubbles very rapidly |
| R | no reaction | bubbles rapidly |
| S | no reaction | no reaction |
What is the order of reactivity, from most reactive to least reactive?
Solid potassium nitrate is added to water in a polystyrene cup.
The solid dissolves and the temperature of the mixture falls from 25 °C to 19 °C.
Which row describes the process?
| type of process | direction of energy transfer | |
|---|---|---|
| A | exothermic | from the mixture to the surroundings |
| B | exothermic | from the surroundings to the mixture |
| C | endothermic | from the mixture to the surroundings |
| D | endothermic | from the surroundings to the mixture |
Excess magnesium reacts with 40 cm3 of 1.0 mol / dm3 hydrochloric acid at 25 °C.
The dotted line shows how the volume of hydrogen formed changes with time.
The experiment is repeated at 35 °C. All other conditions stay the same.
Each graph also shows the dotted line.
Which graph shows the results at 35 °C as a solid line?
Bioethanol is made from sugarcane.
Which statement explains why bioethanol is more environmentally sustainable than petrol?
A large alkane, C12H26, is cracked.
Three products form.
Two of the products are ethene, C2H4, and a hydrocarbon of formula C4H8.
The third product is hydrocarbon X.
What is the formula of X?
Monomer Z is used to make a polymer by addition polymerisation.
Which structure shows part of the polymer formed from Z?
Several gases are air pollutants.
Which statement about air pollutants is correct?
| 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