# Ethanol can be produced by the fermentation of sugar solutions using yeast. Describe the conditions needed for fermentation and explain why ethanol produced this way is considered a renewable fuel, unlike fuels produced from crude oil.

> AQA A-Level Chemistry (7405) — 3.3.8 Aldehydes and ketones (A-Level only) · Describe and Explain · 5 marks

## Mark scheme (5 marks)

1. Yeast is required (as the organism/catalyst that carries out fermentation)
2. Warm/suitable temperature required (not too hot, not too cold)
3. Absence of oxygen / anaerobic conditions required
4. Crude oil is a finite/non-renewable resource (takes millions of years to form / cannot be replaced)
5. Ethanol from fermentation is renewable because the sugar/crops used to make it can be regrown/replaced

## Key terms

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

## Related

- [Revision notes for AQA A-Level Chemistry (7405)](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)

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Source: [GradeNine](https://www.gradenine.co.uk/q/ethanol-can-be-produced-by-the-19673596) · Published by Druglandscape Ltd.