Making ethanol by fermentation
2 marks · NormalState two conditions required for the fermentation of glucose to produce ethanol.
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Two of: (i) Temperature around 30°C (ii) Absence of air (anaerobic conditions) (iii) Presence of yeast
Also accept: Warm temperature around 30°C; No oxygen/no air; Yeast present
Common mistakes: Stating high temperature >40°C; Stating presence of air
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Marking points
B1 · 1 mark · States one correct condition for fermentation.
B2 · 1 mark · States a second correct condition for fermentation.
Worked solution
The fermentation requires (1) a temperature of about 30°C and (2) absence of air (anaerobic conditions).