# Ethene is an important organic compound produced during the cracking of crude oil fractions. Describe what is meant by cracking and explain why ethene is a more useful product than the large hydrocarbon molecules from which it is made.

> WJEC A-Level Chemistry (Wales) — 2.4 Organic compounds · Describe and Explain · 5 marks

## Mark scheme (5 marks)

1. Cracking involves breaking down large hydrocarbon molecules into smaller ones
2. Cracking requires high temperature (and a catalyst or steam)
3. Ethene is an alkene / contains a carbon-carbon double bond
4. Ethene is more reactive / can undergo addition reactions (due to the double bond)
5. Ethene is used to make polymers / plastics (addition polymerisation) OR used as a fuel / in greater demand than large fractions

## Key terms

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

## Related

- [Revision notes for WJEC A-Level Chemistry (Wales)](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/ethene-is-an-important-organic-compound-bf0fb7e3) · Published by Druglandscape Ltd.