Metals below carbon in the reactivity series
2 marks · HardState what is meant by 'reduction' in the extraction of metals from metal oxides. Give your answer in terms of both oxygen and electrons.
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Reduction is the removal of oxygen from a substance, or the gain of electrons by a substance.
Also accept: Reduction is when a substance loses oxygen, or when it gains electrons.; It means loss of oxygen or gain of electrons.
Common mistakes: Only giving one definition (e.g. just loss of oxygen).; Stating reduction is loss of electrons.
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Marking points
B1 · 1 mark · States reduction is the removal (or loss) of oxygen from a substance.
B2 · 1 mark · States reduction is the gain of electrons by a substance.
Worked solution
Reduction in the extraction of metals means either:
- Removal of oxygen from a substance (e.g., iron(III) oxide loses oxygen to form iron).
- Gain of electrons by a substance (e.g., Fe^{3+} ions in iron(III) oxide gain electrons to become Fe atoms).