Chemistry Paper 2 November 2017

1. AThe movement of particles from a region of higher concentration to a region of lower concentration.
2. BThe net movement of water molecules from a region of high water potential to a region of low water potential across a partially permeable membrane.
3. CThe escape of a gas through a small hole into a vacuum.
4. DThe process by which a solid changes directly into a gas without passing through the liquid state.

1. Aammonia reacts with the glass tube before it can reach the centre, so the fumes form nearer the hydrochloric acid end.
2. Bhydrogen chloride is denser than air and sinks within the tube, so the fumes form nearer the hydrochloric acid end.
3. Chydrogen chloride has a smaller molar mass than ammonia, so it diffuses more quickly; the fumes therefore form closer to the hydrochloric acid end.
4. Dhydrogen chloride has a larger molar mass than ammonia, so it diffuses more slowly; the fumes therefore form closer to the hydrochloric acid end.

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1. Ametallic bonding.
2. Bionic bonding.
3. Chydrogen bonding.
4. Dcovalent bonding.

1. AIt is a good conductor of electricity in the solid state.
2. BIt is a liquid at room temperature and pressure.
3. CIt is a strong-smelling gas at room temperature.
4. DIt is soluble in water.

1. ABubbles of a colourless gas are given off.
2. BA brown gas is given off.
3. CA pale green gas with a sharp smell is given off.
4. DA black solid is deposited.

1. A3.17 mol/dm3
2. B0.32 mol/dm3
3. C1.59 mol/dm3
4. D15.9 mol/dm3

1. AThe litmus paper is bleached white, because chlorine gas is produced at the anode.
2. BThe litmus paper is unaffected, because no gas reaches it.
3. CThe litmus paper turns red, because an acidic gas is produced at the anode.
4. DThe litmus paper turns a darker blue, because an alkaline gas is produced at the anode.

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1. AIt raises the pH, because carbonic acid is formed.
2. BIt has no effect on the pH, because carbon dioxide does not react with water.
3. CIt lowers the pH, because carbon dioxide gas is alkaline.
4. DIt lowers the pH, because carbonic acid is formed.

1. A-3
2. B0
3. C+3
4. D+5

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1. AEsterification.
2. BOxidation.
3. CNeutralisation.
4. DAddition.

1. Ait is a strong oxidising agent that kills bacteria by oxidising them.
2. Bit is acidic, and the resulting low pH prevents the growth of bacteria that could spoil the feed.
3. Cit has a sweet taste that improves the palatability of the feed.
4. Dit is alkaline, and neutralises acidic spoilage products in the feed.

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1. AZn2+
2. BCa2+
3. CCu2+
4. DFe3+

1. AAdd aqueous barium chloride; a white precipitate forms that is insoluble in excess hydrochloric acid.
2. BAdd aqueous sodium hydroxide and warm gently; ammonia gas is produced, turning damp red litmus paper blue.
3. CAdd aqueous sodium hydroxide and warm gently; ammonia gas is produced, turning damp blue litmus paper red.
4. DAdd dilute hydrochloric acid; a colourless gas is produced that turns limewater milky.

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1. AMagnesium reacts faster than iron because magnesium is more reactive.
2. BMagnesium and iron react at the same rate because they form the same gas.
3. CIron reacts faster than magnesium because iron has a larger relative atomic mass.
4. DIron reacts faster than magnesium because iron is more reactive.

1. AThe same as magnesium, because zinc and magnesium are in the same group of the periodic table.
2. BFaster than magnesium, because zinc is the most reactive of the three metals.
3. CSlower than iron, because zinc is the least reactive of the three metals.
4. DBetween magnesium and iron, because zinc is more reactive than iron but less reactive than magnesium.

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1. A0.00018 mol
2. B0.018 mol
3. C0.0018 mol
4. D1.8 mol

1. A0.605 g
2. B0.101 g
3. C0.702 g
4. D1.21 g

1. ACompounds with different molecular formulae and different structural formulae but the same relative molecular mass.
2. BCompounds with the same structural formula but different molecular formulae.
3. CCompounds with the same molecular formula but different structural formulae.
4. DCompounds with the same molecular formula and the same structural formula but different physical states.

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1. AHydrogen, in the presence of a nickel catalyst.
2. BBromine water (or liquid bromine).
3. CAcidified potassium manganate(VII).
4. DSteam, in the presence of a catalyst.