# Ethanol can be produced by fermentation using yeast and glucose. The ethanol produced can then be separated from the fermentation mixture. Describe the process of fermentation and explain why the conditions used must be carefully controlled.

> Eduqas A-Level Chemistry — 2.4 Organic compounds · Describe and Explain · 5 marks

## Mark scheme (5 marks)

1. Yeast contains enzymes that break down / convert glucose into ethanol and carbon dioxide
2. The process takes place in the absence of oxygen / anaerobic conditions
3. Temperature must be kept at an optimum / warm temperature (around 25–35 °C)
4. If temperature is too high, enzymes are denatured / destroyed and fermentation stops
5. Distillation is used to separate / purify the ethanol from the fermentation mixture

## Key terms

- [fermentation](https://www.gradenine.co.uk/glossary/fermentation)

## Related

- [Revision notes for Eduqas A-Level Chemistry](https://www.gradenine.co.uk/learn)
- [How to answer "Describe and Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

---
Source: [GradeNine](https://www.gradenine.co.uk/q/ethanol-can-be-produced-by-fermentation-8c3bb3c6) · Published by Druglandscape Ltd.