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Practice paper written from an analysis of every
O-Level Science (Chemistry) paper, 2010–2026
Paper 1 Multiple Choice (Chemistry section)
FORECAST PAPER · SET 9 Hard
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 9.
A copy of the Periodic Table is printed on page 10.
The use of an approved scientific calculator is expected, where appropriate.
Hydrogen is used as a fuel in space rockets.
A student adds 0.12 g of magnesium ribbon to an excess of dilute sulfuric acid in a flask to make hydrogen. Hydrogen is insoluble in water.
Four ways of collecting the gas are shown.
Which ways can be used to measure the whole volume of hydrogen made?
A rock from a meteorite contains three compounds, X, Y and Z. The melting points and boiling points of the pure compounds are shown.
| compound | melting point / °C | boiling point / °C |
|---|---|---|
| X | 41 | 236 |
| Y | 82 | 286 |
| Z | 41 | 290 |
Four samples from the rock are tested. The results are shown.
| sample | melting point / °C | boiling point / °C |
|---|---|---|
| P | 41 | 236 |
| Q | 78–81 | 291–297 |
| R | 37–40 | 292–298 |
| S | 41 | 290 |
Which sample is impure Z?
Sea water contains dissolved ions of many elements.
One of these ions has 18 electrons, 22 neutrons and a charge of 2+.
Which nuclide notation represents this ion?
Carbon dioxide, CO2, dissolves in sea water.
The atoms in a molecule of carbon dioxide are joined by covalent bonds.
Which molecule has the same number of outer shell electrons that are not shared between atoms (non-bonding electrons) as a molecule of carbon dioxide?
Hydrogen cyanide, HCN, is a molecule found in comets and in clouds of gas in space.
In a molecule of HCN the atoms are joined in the order H, C, N. The hydrogen atom has two electrons in its outer shell and the carbon and nitrogen atoms each have eight.
Which row describes the electrons in the molecule?
| pairs of electrons shared between C and N | pairs of electrons on N that are not shared | |
|---|---|---|
| A | 2 | 1 |
| B | 2 | 2 |
| C | 3 | 0 |
| D | 3 | 1 |
Ammonium phosphate, (NH4)3PO4, and urea, CO(NH2)2, are both used as fertilisers.
How many more atoms, in total, are there in one formula unit of ammonium phosphate than in one molecule of urea?
A farmer treats acidic soil with limewater, which is aqueous calcium hydroxide.
25.0 cm3 of the limewater is neutralised by 20.0 cm3 of 0.050 mol / dm3 hydrochloric acid.
What is the concentration of calcium hydroxide in the limewater?
A student models the treatment of an acidic lake.
25 cm3 of 0.10 mol / dm3 hydrochloric acid is mixed with 25 cm3 of 0.20 mol / dm3 aqueous sodium hydroxide.
Which row describes the mixture after the reaction is complete?
| ion in excess | concentration of the ion in excess in the mixture / mol per dm3 | |
|---|---|---|
| A | H+ | 0.10 |
| B | H+ | 0.050 |
| C | OH− | 0.10 |
| D | OH− | 0.050 |
A gas sample was collected from a volcano.
The sample may contain some or all of the gases listed, but no other gas.
Three tests are done on separate portions of the sample.
Which gases are in the sample?
Uranium, found in some rocks, has 92 protons in each atom.
An element is made in a nuclear reactor. In the Periodic Table it comes immediately after uranium.
How many protons are in each atom of this element?
Chlorine displaces bromine from aqueous potassium bromide. Bromine displaces iodine from aqueous potassium iodide.
Astatine, At, is below iodine in Group 17.
Which mixture will react?
A data book gives some properties of four Group 1 metals.
| metal | melting point / °C | density / g per cm3 |
|---|---|---|
| lithium | 181 | 0.53 |
| sodium | 98 | 0.97 |
| potassium | 63 | 0.86 |
| rubidium | 39 | 1.53 |
Which statement is correct?
Farmers spread limestone, which is mainly calcium carbonate, on acidic soil. Calcium carbonate reacts with acid to form carbon dioxide.
A student adds 2.0 g of limestone lumps to an excess of dilute hydrochloric acid at 25 °C and measures the volume of carbon dioxide made. The results are shown by curve X.
The experiment is repeated using 1.0 g of powdered limestone and the same excess of dilute hydrochloric acid at 25 °C.
Which curve shows the results of the repeated experiment?
A farmer grows sugarcane that is used to make bioethanol.
Which row describes bioethanol?
| bioethanol is made from | bioethanol is | carbon dioxide when bioethanol burns | |
|---|---|---|---|
| A | crude oil | non‑renewable | is formed |
| B | sugarcane | renewable | is not formed |
| C | sugarcane | renewable | is formed |
| D | sugarcane | non‑renewable | is formed |
Crude oil from beneath the sea bed is separated into fractions at a refinery.
The table shows the share of each fraction in the crude oil and the demand for it.
| fraction | share of crude oil / % | demand / % |
|---|---|---|
| petrol | 25 | 40 |
| kerosene | 15 | 15 |
| diesel | 20 | 20 |
| fuel oil | 40 | 25 |
Which statement about cracking at this refinery is correct?
Methanol, ethanol, propanol and butanol are the first four alcohols in a homologous series.
Their formulae are CH3OH, C2H5OH, C3H7OH and C4H9OH.
What is the relative molecular mass of pentanol, the next alcohol in the series?
Poly(ethene) film is used to cover greenhouses.
One molecule of this poly(ethene) has a relative molecular mass of 28 000.
How many carbon atoms are there in this polymer molecule?
Part of a molecule of a polymer is shown.
The polymer is made by addition polymerisation.
Which diagram shows the monomer?
A scientist removes gases from 2.00 dm3 of dry air in two stages.
Stage 1: all of the oxygen is removed.
Stage 2: all of the nitrogen is removed from the gas that is left.
What is the approximate volume of gas that remains?
Which row shows the effect of each process on the amount of carbon dioxide in the atmosphere?
| respiration | photosynthesis | |
|---|---|---|
| A | decreases | decreases |
| B | increases | decreases |
| C | decreases | increases |
| D | increases | increases |
| 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