Making ethanol by fermentation
3 marks · EasyThe diagram below shows a simple set-up for producing ethanol by fermentation.
Name the microorganism used in this process.
State one condition, other than the absence of air, needed for fermentation to occur efficiently.
What is observed in the boiling tube containing limewater when fermentation takes place?
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
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(a) yeast
(b) temperature around 30°C (or correct temperature range)
(c) limewater turns milky (white/cloudy)
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · Names yeast.
B1 (b) · 1 mark · States temperature around 30°C (accepts range 30–40°C or suitable value).
B1 (c) · 1 mark · States limewater turns milky/white/cloudy.
Worked solution
a) The microorganism is yeast.
b) The temperature should be about 30°C.
c) The limewater turns milky/white/cloudy due to carbon dioxide.