Ethanol is made by fermentation of a carbohydrate dissolved in water, in the presence of yeast - Edexcel - GCSE Chemistry - Question 4 - 2019 - Paper 1
Question 4
Ethanol is made by fermentation of a carbohydrate dissolved in water, in the presence of yeast.
The reaction is carried out at 30°C.
Explain why the reaction is ca... show full transcript
Worked Solution & Example Answer:Ethanol is made by fermentation of a carbohydrate dissolved in water, in the presence of yeast - Edexcel - GCSE Chemistry - Question 4 - 2019 - Paper 1
Step 1
Explain why the reaction is carried out at a temperature of 30°C rather than at a temperature of 80°C.
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Answer
The fermentation process is carried out at 30°C because this temperature is optimal for yeast activity. At 30°C, yeast enzymes function effectively and promote fermentation. However, at temperatures around 80°C, the enzymes become denatured, losing their functionality and thus halting the fermentation process. Therefore, to sustain yeast activity and increase ethanol production, maintaining a temperature around 30°C is crucial.
Step 2
In this reaction ethanol is
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Answer
B oxidised.
Step 3
Draw the structure of a molecule of ethanoic acid, CH₃COOH, showing all covalent bonds.
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Answer
The structure of ethanoic acid can be represented as follows:
H O H
\ ||
C--C
/ \
H O
/
H
In this structure, all covalent bonds are depicted. Each line represents a bond between atoms.
