# Ethene is an alkene produced by the cracking of crude oil fractions. Ethene can be used as a monomer to produce poly(ethene). Explain how the structure of ethene allows it to undergo addition polymerisation to form a long chain polymer.

> OCR GCSE Chemistry A: Gateway Science (J248) — C6.2 Organic chemistry · Explain · 4 marks

> Poly(ethene) is one of the most widely used plastics in the world. It is produced from ethene, a small molecule obtained from cracking crude oil fractions.

## Mark scheme (4 marks)

1. Ethene contains a carbon–carbon double bond, making it unsaturated
2. The double bond opens / breaks during the reaction
3. Many ethene monomers join together to form a long chain
4. No other molecules / small molecules are produced in addition polymerisation (no by-products lost)

## Key terms

- [addition polymerisation](https://www.gradenine.co.uk/glossary/addition-polymerisation)
- [monomer](https://www.gradenine.co.uk/glossary/monomer)
- [alkene](https://www.gradenine.co.uk/glossary/alkene)
- [long chain polymer](https://www.gradenine.co.uk/glossary/long-chain-polymer)

## Related

- [Revision notes for OCR GCSE Chemistry A: Gateway Science (J248)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
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Source: [GradeNine](https://www.gradenine.co.uk/q/ethene-is-an-alkene-produced-by-604b3366) · Published by Druglandscape Ltd.