0654.C6.3.04 — Identify oxidation and reduction in redox reactions. (Oxidation number limited to its use to name ions, e.g. iron(II), iron(III), copper(II): past paper questions
Real questions on 0654.c6.3.04 — identify oxidation and reduction in redox reactions. (oxidation number limited to its use to name ions, e.g. iron(ii), iron(iii), copper(ii)
The newest 5 of 5 written questions. Open one to see it on the real paper.
- 0973/31 · May/June 2025 · Q7a(i)[1]
Explain what is meant by reduction. (i)
See it on the paper → - 0973/41 · May/June 2025 · Q7b[1]
In the second stage, carbon reacts with carbon dioxide to make carbon monoxide. C + CO 2 2CO State what happens to the carbon dioxide in this reaction. Choose from the list. combustion oxidation reduction thermal decomposition
See it on the paper → - 0973/32 · May/June 2024 · Q11c[1]
Iron is extracted from iron oxide using carbon monoxide. iron oxide + carbon monoxide iron + carbon dioxide State the substance that is reduced in this reaction.
See it on the paper → - 0973/31 · May/June 2020 · Q8b(ii)[2]
Identify which substance is reduced in this reaction. Explain your answer. substance explanation
See it on the paper → - 0973/42 · May/June 2019 · Q8a(ii)[2]
During the reaction Fe 3+ ions become Fe atoms and Al atoms become Al 3+ ions. Identify the oxidising agent and the reducing agent. Explain your answer in terms of electron transfer. oxidising agent reducing agent explanation
See it on the paper →
What examiners said
Many candidates gave vague answers around the idea of having less of something and did not understand that reduction was used in a technical sense. Candidates should be familiar with these technical terms. Others repeated the sentence from the stem of the question, describing the process in a blast furnace. Some who attempted an explanation in terms of electrons got the change the wrong way around...
— Examiner report, May/June 2025, 0973/31 Q7(a)(i) (Cambridge)
The strongest candidates were more successful in recognising that the carbon dioxide was reduced.
— Examiner report, May/June 2025, 0973/41 Q7(b) (Cambridge)
This proved challenging for most candidates. Candidates need to ensure that they understand what is meant by oxidation and reduction and by the terms oxidising and reducing agents. Those candidates that did identify aluminium as the reducing agent often stated that the oxidising agent was iron rather than iron oxide or Fe3+ ions.
— Examiner report, May/June 2019, 0973/42 Q8(a)(ii) (Cambridge)
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