Question Constellation Sign up for free AQA · GCSE · Combined Science · Higher
Oil layer on a reaction-mixture surface
Suggest why a layer of oil was needed on the surface of the mixture.
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Marking points
- 1 Explain that the oil keeps oxygen/air out.
- 2 Link this to fermentation being anaerobic or preventing aerobic respiration.
Full-mark answer
The oil keeps oxygen out, because fermentation is anaerobic and oxygen would allow aerobic respiration.