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Ethanol is made by fermentation of a carbohydrate dissolved in water, in the presence of yeast - Edexcel - GCSE Chemistry - Question 4 - 2019 - Paper 1

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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 this temperature, enzymes produced by yeast function efficiently to catalyze the fermentation reaction. If the temperature were raised to 80°C, the enzymes would become denatured, leading to decreased activity or inactivation. Additionally, yeast cells would be killed at such high temperatures, preventing fermentation from occurring.

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 drawn as follows:

      H   O
      |   ||
  H - C - C - O - H
      |   
      H

In this structure, all covalent bonds between atoms are represented.

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