Alkanes: past paper questions

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• Question 25May/June 2026, paper 12Multiple choice1 mark

  What is the least number of carbon atoms in a non-cyclic alkane molecule that has a chiral centre?

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• Question 28Oct/Nov 2025, paper 11Multiple choice1 markHas a diagram

  Two hydrocarbons, ${\text{R–CH}}_3$ and ${\text{R’–CH}}_3$, react separately with bromine in the presence of ultraviolet light. One of these hydrocarbons is unsaturated. In each case, free radical substitution reactions occur.

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• Question 31Oct/Nov 2024, paper 11Multiple choice1 mark

  The reaction of chlorine with methane is carried out in the presence of light. What is the function of the light?

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• Question 28Oct/Nov 2023, paper 11Multiple choice1 mark

  The hydrocarbon ${\mathrm{C}}_{17}{\mathrm{H}}_{36}$ can be cracked. Which compound is the least likely to be produced in this reaction?

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• Question 26May/June 2026, paper 12Multiple choice1 mark

  The first propagation step in the reaction between methane and chlorine is shown. $${\text{CH}}_4+{\text{Cl}}^{\bullet }\to {\text{CH}}_3^{\bullet }+\text{HCl}$$ How many different first propagation steps are possible in the reaction between pentane and chlorine?

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• Question 29Oct/Nov 2025, paper 11Multiple choice1 mark

  The fumes from the exhausts of petrol-burning cars contain the following pollutants. 1 unburnt hydrocarbons 2 nitrogen dioxide 3 carbon monoxide Which pollutants are removed by oxidation in a catalytic converter?

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• Question 30Oct/Nov 2024, paper 13Multiple choice1 markHas a diagram

  The structure of limonene is shown. [Diagram of limonene] What are the number of moles of carbon dioxide and water produced when a sample of limonene is completely combusted in oxygen?

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• Question 32Oct/Nov 2023, paper 12Multiple choice1 mark

  Which list contains a compound that is not made during the free radical substitution of methane with chlorine?

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• Question 28May/June 2026, paper 13Multiple choice1 mark

  Ethane reacts with bromine by a free-radical substitution mechanism. The mechanism for this reaction has three steps: initiation, propagation and termination. Which species is a possible product in one of the steps?

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• Question 5May/June 2026, paper 22Structured9 marks

  Hexane, $\mathrm{C}{\mathrm{H}}_3(\mathrm{C}{\mathrm{H}}_2{)}_4\mathrm{C}{\mathrm{H}}_3$, reacts with $\mathrm{C}{\mathrm{l}}_2(\mathrm{g})$ in the presence of ultraviolet light to produce different organic products, including those shown in Table 5.1. Complete Table 5.1.

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• Question 2Oct/Nov 2024, paper 21Structured13 marks

  Chlorine is one of the elements in Group 17 of the Periodic Table. Describe the colours of the Group 17 elements, chlorine to iodine, at room temperature.

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• Question 27May/June 2023, paper 11Multiple choice1 mark

  Which equation represents a reaction that proceeds through initiation, propagation and termination steps?

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• Question 5May/June 2026, paper 23Structured12 marksHas a diagram

  Propane, ${\mathrm{C}\mathrm{H}}_3{\mathrm{C}\mathrm{H}}_2{\mathrm{C}\mathrm{H}}_3$, reacts with ${\mathrm{C}\mathrm{l}}_2(\mathrm{g})$ in the presence of ultraviolet light to produce different organic products, including those shown in Table 5.1.

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• Question 3Oct/Nov 2025, paper 21Structured13 marksHas a diagram

  Cycloalkanes show similar chemical properties to alkanes but have the same empirical formula as alkenes.

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• Question 4May/June 2023, paper 12Multiple choice1 mark

  If 1 mole of hexane combusts in an excess of oxygen, how many moles of products are formed?

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• Question 3Oct/Nov 2025, paper 22Structured14 marksHas a diagram

  The alkanes are a homologous series of organic molecules. Alkanes are generally unreactive and are commonly used as fuels. Define homologous series.

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• Question 24May/June 2023, paper 12Multiple choice1 mark

  The equation shows a reaction that occurs between carbon monoxide and nitrogen monoxide in a catalytic converter. $$2\text{CO(g)}+2\text{NO(g)}\to 2{\text{CO}}_2(\text{g})+{\text{N}}_2(\text{g})$$ Which statement is correct?

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• Question 28May/June 2024, paper 11Multiple choice1 mark

  Which reaction occurs when ethane and chlorine are mixed in diffused sunlight?

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• Question 28May/June 2023, paper 12Multiple choice1 mark

  Ethane reacts with an excess of chlorine in the presence of ultraviolet light to form a mixture of products. How many of these products contain two carbon atoms and one or more chlorine atoms?

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• Question 37May/June 2025, paper 11Multiple choice1 mark

  Three substances are listed. 1 butane 2 hydrogen 3 hydrogen bromide Which substances are possible products of the free-radical substitution reaction between ethane and bromine?

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• Question 27May/June 2024, paper 13Multiple choice1 mark

  The alkane $\mathrm{C}{\mathrm{H}}_3\mathrm{C}{\mathrm{H}}_2\mathrm{C}\mathrm{H}(\mathrm{C}{\mathrm{H}}_3{)}_2$ undergoes free radical substitution with chlorine. No C–C bonds are broken in this reaction. How many isomeric products, including positional and optical isomers, of molecular formula ${\mathrm{C}}_5{\mathrm{H}}_{11}\mathrm{C}\mathrm{l}$ can be formed?

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• Question 35May/June 2025, paper 12Multiple choice1 mark

  Samples of the gases $\mathrm{C}{\mathrm{H}}_3\mathrm{C}\mathrm{l}$ and $\mathrm{C}{\mathrm{l}}_2$ are mixed together and irradiated with ultraviolet light. Which compound is produced by a termination step in the reaction?

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• Question 3May/June 2023, paper 21Structured15 marks

  Chlorine is a very reactive element. Chlorine reacts with silicon to form silicon(IV) chloride. Describe the appearance of silicon(IV) chloride at room temperature and pressure.

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• Question 5May/June 2023, paper 21Structured15 marksHas a diagram

  Molecule $\mathbf{M}$ is present in petrol, a fuel used in cars. $\mathbf{M}$ is a saturated, non-cyclic hydrocarbon. $\mathbf{M}$ contains eight carbon atoms.

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• Question 36May/June 2025, paper 13Multiple choice1 mark

  Two steps in the free-radical substitution reaction between methane and chlorine are shown.

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