Cambridge IGCSE Chemistry

6.4Redox

Redox in Cambridge IGCSE Chemistry: what the syllabus expects you to know, the learning objectives and how to practise.

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Learning objectives

What the syllabus expects you to be able to do.

6.4.1Use a Roman numeral to show the oxidation number of an element in a compound, for example iron(III) chloride.
6.4.2Define a redox reaction as one in which oxidation and reduction take place at the same time.
6.4.3Define oxidation as the gain of oxygen and reduction as the loss of oxygen.
6.4.4Identify redox reactions as reactions in which oxygen is gained by one substance and lost by another.
6.4.5Identify which substance is oxidised and which is reduced in a redox reaction.
6.4.6Supplement: define oxidation as the loss of electrons and as an increase in oxidation number.
6.4.7Supplement: define reduction as the gain of electrons and as a decrease in oxidation number.
6.4.8Supplement: identify redox reactions as reactions involving the gain and loss of electrons.
6.4.9Supplement: identify redox reactions from changes in oxidation number, using the rules that an uncombined element has oxidation number zero, a monatomic ion has an oxidation number equal to its charge, the oxidation numbers in a compound add up to zero and those in an ion add up to its charge.
6.4.10Supplement: identify redox reactions from the colour changes seen with acidified aqueous potassium manganate(VII) or aqueous potassium iodide.
6.4.11Supplement: define an oxidising agent as a substance that oxidises another substance and is itself reduced.
6.4.12Supplement: define a reducing agent as a substance that reduces another substance and is itself oxidised.
6.4.13Supplement: identify the oxidising agent and the reducing agent in a redox reaction.

Lessons

Half-equations and redox equations
35 min
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Oxidation and reduction
35 min
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