SC23a Ethanol Production

Question 1

what is needed for fermentation to take place?

Answer 1

enzymes from yeast

Question 2

why is fermentation anaerobic?

Answer 2

yeast respires without oxygen

Question 3

fermentation reaction, word and symbol equation.

Answer 3

Glucose → Ethanol + Carbon dioxide​

C₆H₁₂O₆(aq) → 2C₂H₅OH(l) + 2CO₂(g)​

​

Question 4

what needs to happen to seeds to produce glucose?

Answer 4

need to be germinated first to convert the stored starch into glucose

Question 5

sources of glucose? 2

Answer 5

~fruits
~seeds

Question 6

why is temperature and pH controlled?

Answer 6

to maintain optimum conditions for the enzymes

Question 7

what happens to the fermentation when alcohol concentrations reach 15% and why?

Answer 7

fermentation stops as these concentrations kill the yeast

Question 8

how are more concentrated solutions of ethanol produced?

Answer 8

through fractional distillation

Question 9

Burning glucose completely in oxygen produces carbon dioxide and water. Compare and contrast the combustion and fermentation of glucose. 2 marks

Answer 9

Both produce carbon dioxide (and energy) (1)​

Combustion uses up oxygen and produces water, while fermentation cannot occur if oxygen is present and does not produce water (1).​