Chemistry 0620/13 October/November 2025: question paper and mark scheme

Question

Substances exist as solids, liquids or gases. In which states of matter are the particles a similar distance apart? A solid, liquid and gas B solid and liquid only C solid and gas only D liquid and gas only

Question

A container with a fixed shape is filled with gas and then sealed. The container is then heated. Which changes take place? 1 The volume of gas decreases. 2 The gas molecules move faster. 3 The pressure inside the cylinder increases. A 1 and 2 B 1 only C 2 and 3 D 3 only

Question

A crystal of sodium chloride is dropped into a beaker of water. Over time, the sodium chloride particles become evenly distributed throughout the water. Which processes occur in this experiment? A both dissolving and diffusion B dissolving only C diffusion only D neither dissolving nor diffusion

Question

The electronic structures of two atoms, P and Q, are shown. P Q P and Q combine together to form a compound. What is the type of bonding in the compound, and what is the formula of the compound? type of bonding formula A covalent PQ2 B covalent PQ C ionic PQ D ionic PQ2

Question

The electronic configuration of an ion is 2,8,8. What could this ion be? S2– Ca2+ A key B = yes C = no D

Question

The table shows the nucleon number and the number of neutrons in one atom of isotopes W, X, Y and Z. nucleon number of isotope number neutrons W 35 18 X 37 20 Y 39 20 Z 40 22 Which statement about W, X, Y and Z is correct? A W and X are isotopes of the same element. B X and Y are isotopes of elements in the same group of the Periodic Table. C Y and Z are isotopes of elements in the same period of the Periodic Table. D Z has a higher proton number than Y.

Question

Which statement about an ionic bond is correct? A It is a strong electrostatic attraction between cations and anions. B It is a strong electrostatic attraction between protons and electrons. C It is a weak electrostatic attraction between cations and anions. D It is a weak electrostatic attraction between protons and electrons.

Question

Which row describes simple molecular compounds? electrical melting point conductivity when molten A high good B high poor C low good D low poor

Question

Boron nitride is a compound of the elements boron and nitrogen. It has a similar structure to diamond. What is likely to be a property of boron nitride? A It conducts electricity. B It is soluble in water. C It is used as a lubricant. D It is very hard.

Question

Which statement defines the term molecular formula? A a formula that shows the total number of atoms in a molecule B a formula that shows the total number of elements in a molecule C a formula that shows the arrangement of different atoms in a molecule D a formula that shows the number and type of different atoms in a molecule

Question

What is the relative formula mass, Mr, of calcium hydroxide, Ca(OH)2? A 38 B 58 C 74 D 114

Question

Which statements explain why metal objects are electroplated? 1 Electroplating improves the appearance of the object. 2 Electroplating insulates the metal object. 3 Electroplating makes the metal object more resistant to corrosion. 4 Electroplating makes the metal object softer. A 1 and 2 B 1 and 3 C 2 and 4 D 3 and 4

Question

Three statements about a hydrogen–oxygen fuel cell are listed. 1 The overall equation for the reaction is 2H2 + O2 → 2H2O. 2 The hydrogen required comes from the air. 3 The waste gas causes respiratory problems. Which statements are correct? A 1, 2 and 3 B 1 only C 2 and 3 only D 3 only

Question

Which reaction pathway diagram represents an endothermic reaction? A B energy energy progress of reaction progress of reaction C D energy energy progress of reaction progress of reaction

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Some physical and chemical changes are listed. 1 rusting of iron 2 condensing of steam 3 dissolving of sugar in water 4 cracking of alkanes Which changes are physical changes? A 1 and 3 B 1 and 4 C 2 and 3 D 2 and 4

Question

Blue copper(II) sulfate crystals are heated in air until they turn into a white powder. The powder is allowed to cool and after a few days it starts to turn blue. Why does the white powder start to turn blue? A Carbon dioxide in the air reacts with the powder to form copper(II) carbonate. B The powder reacts with water in the air to form copper(II) hydroxide. C The white copper compound is slowly oxidised. D Water is absorbed from the air and causes the reaction to reverse.

Question

Carbon reacts with silver oxide to form carbon dioxide and silver. Which substance is reduced? A carbon B carbon dioxide C silver D silver oxide

Question

Base Q dissolves in water to make aqueous Q. Aqueous Q is tested with thymolphthalein. Which row gives the colour of thymolphthalein in aqueous Q and the ion responsible for this colour? colour of ion thymolphthalein A blue H+ B colourless H+ C blue OH– D colourless OH–

Question

Solid calcium hydroxide is added to aqueous ammonium chloride and the mixture is warmed. A gas is produced. What is the name of the gas? A hydrogen B chlorine C carbon dioxide D ammonia

Question

Elements L and M are in the same group of the Periodic Table. Why do L and M have similar chemical properties? A They have the same number of electrons in the nucleus. B They have the same number of electrons in the outer shell. C They have the same number of neutrons in the nucleus. D They have the same number of neutrons in the outer shell.

Question

The diagram shows elements W, X, Y and Z in a section of the Periodic Table. W X Z Y Which statement about the reactivity of the elements is correct? A X is more reactive than Y, and W is more reactive than Z. B X is more reactive than Y, and Z is more reactive than W. C Y is more reactive than X, and W is more reactive than Z. D Y is more reactive than X, and Z is more reactive than W.

Question

Which three compounds are all insoluble in water? A ammonium carbonate, silver chloride and sodium sulfate B barium sulfate, calcium chloride and magnesium hydroxide C calcium nitrate, magnesium carbonate and lead(II) hydroxide D calcium sulfate, magnesium hydroxide and silver chloride 23 18 carat gold contains 75% gold and 25% copper by mass. Which statements about 18 carat gold are correct? 1 It is a mixture. 2 It is a compound. 3 It is an alloy. 4 It conducts electricity. A 1, 2 and 4 B 1, 3 and 4 C 1 and 3 only D 2 and 3

Question

In the question paper above.

Question

The properties of four metals, E, F, G and H, are shown. E does not react with cold water, but reacts with steam. F does not react with water or dilute acid, but the oxide of F is reduced by carbon. The oxide of G is not reduced by carbon, but G reacts vigorously with cold water. H does not react with water or steam, but reacts with dilute acid. What is the order of reactivity of the metals starting with the most reactive? most least reactive reactive A F E H G B F H E G C G E H F D G H E F

Question

Four substances, or groups of substances, found in water from a natural source are listed. 1 some metal compounds 2 plastics 3 dissolved oxygen 4 nitrates and phosphates from fertilisers and detergents Which substances found in water from a natural source can be beneficial to aquatic life? A 1 and 3 B 1 and 4 C 2 and 3 D 2 and 4

Question

Which element is used to remove tastes and odours in the treatment of the domestic water supply? A chlorine B carbon C calcium D copper

Question

NPK fertilisers are mixtures of salts used to improve plant growth. Which salt could be used as a component of an NPK fertiliser? A sodium nitrate B aluminium sulfate C magnesium chloride D calcium ethanoate

Question

Plants produce glucose by photosynthesis. What is essential for this process? 1 carbon dioxide 2 oxygen 3 light 4 water A 1 and 2 B 1, 3 and 4 C 1 and 3 only D 2, 3 and 4

Question

Two reactions, M and N, both form carbon dioxide. M N CaCO3 CO2 CH4 Which types of reaction are M and N? M N A thermal decomposition thermal decomposition B thermal decomposition combustion C combustion thermal decomposition D combustion combustion

Question

The molecular formulae of four compounds are shown. C2H2 C3H8 C4H8 C5H10 How many of these compounds are in the alkane homologous series? A 1 B 2 C 3 D 4

Question

Which type of reaction takes place when pentane reacts with chlorine? A polymerisation B addition C substitution D cracking

Question

Which bar chart shows the percentage composition of natural gas? A B 80 80 60 60 % 40 % 40 20 20 key 0 0 gases present gases present = methane = other alkanes = non-hydrocarbons C D 80 80 60 60 % 40 % 40 20 20 0 0 gases present gases present

Question

Which statement about alcohols is correct? A Alcohols have the same functional group as carboxylic acids. B Ethanol is an alcohol that is formed by fermentation at 300 °C. C Ethanol is the alcohol produced in the addition reaction between ethene and hydrogen. D Water is produced from the combustion of alcohols.

Question

The equation shows the reaction between ethanoic acid and solid P to produce Q and hydrogen. ethanoic acid + P → Q + hydrogen Which row identifies P and Q? P Q A sodium ethanol B sodium sodium ethanoate C sodium oxide ethanol D sodium oxide sodium ethanoate

Question

The diagram shows one repeat unit of a polymer. H H C C H H Which row gives the name of the polymer and of the monomer used to make it? name of polymer name of monomer A poly(ethane) ethane B poly(ethane) ethene C poly(ethene) ethane D poly(ethene) ethene

Question

Some properties of a plastic pollutant are listed. 1 It is a poor conductor of electricity. 2 It does not react with water. 3 It is resistant to oxidation. 4 It has low density. Which properties explain why this plastic is difficult to remove from the environment? A 1 and 3 B 1 and 4 C 2 and 3 D 2 and 4

Question

The graph shows the volume of hydrogen produced over time in a chemical reaction. total volume of hydrogen 0 0 time A student uses a stop-watch. Which other item of apparatus is used to take measurements to produce this graph? A beaker B gas syringe C pipette D test-tube

Question

A student uses paper chromatography to identify the food dyes in a coloured sweet, S. The student uses four known food dyes, W, X, Y, and Z, and ethanol as the solvent. The chromatogram obtained is shown. W X Y Z S Which statements are correct? 1 S contains only two dyes. 2 X is insoluble in ethanol. 3 S contains Y and Z. 4 S contains W. A 1, 2 and 4 B 2 and 3 C 2 and 4 only D 4 only

Question

An aqueous cation reacts with aqueous sodium hydroxide to form a white precipitate. The precipitate is insoluble in excess sodium hydroxide. What is the aqueous cation? A aluminium ion B calcium ion C chromium ion D zinc ion

Question

A piece of damp red litmus paper is put into a test-tube of gas. The litmus paper turns white. Which gas is in the test-tube? A ammonia B carbon dioxide C chlorine D oxygen The Periodic Table of Elements Group I II III IV V VI VII VIII 1 2 H He hydrogen helium Key 1 4 3 4 atomic number 5 6 7 8 9 10 Li Be atomic symbol B C N O F Ne lithium beryllium name boron carbon nitrogen oxygen fluorine neon 7 9 relative atomic mass 11 12 14 16 19 20 11 12 13 14 15 16 17 18 Na Mg Al Si P S Cl Ar sodium magnesium aluminium silicon phosphorus sulfur chlorine argon 23 24 27 28 31 32 35.5 40 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr potassium calcium scandium titanium vanadium chromium manganese iron cobalt nickel copper zinc gallium germanium arsenic selenium bromine krypton 39 40 45 48 51 52 55 56 59 59 64 65 70 73 75 79 80 84 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe rubidium strontium yttrium zirconium niobium molybdenum technetium ruthenium rhodium palladium silver cadmium indium tin antimony tellurium iodine xenon 16 85 88 89 91 93 96 – 101 103 106 108 112 115 119 122 128 127 131 55 56 57–71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 lanthanoids Cs Ba Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn caesium barium hafnium tantalum tungsten rhenium osmium iridium platinum gold mercury thallium lead bismuth polonium astatine radon 133 137 178 181 184 186 190 192 195 197 201 204 207 209 – – – 87 88 89–103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 actinoids Fr Ra Rf Db Sg Bh Hs Mt Ds Rg Cn Nh Fl Mc Lv Ts Og francium radium rutherfordium dubnium seaborgium bohrium hassium meitnerium darmstadtium roentgenium copernicium nihonium flerovium moscovium livermorium tennessine oganesson – – – – – – – – – – – – – – – – – 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 lanthanoids La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu lanthanum cerium praseodymium neodymium promethium samarium europium gadolinium terbium dysprosium holmium erbium thulium ytterbium lutetium 139 140 141 144 – 150 152 157 159 163 165 167 169 173 175 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 actinoids Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr actinium thorium protactinium uranium neptunium plutonium americium curium berkelium californium einsteinium fermium mendelevium nobelium lawrencium – 232 231 238 – – – – – – – – – – – The volume of one mole of any gas is 24 dm3 at room temperature and pressure (r.t.p.).