# Alkenes are unsaturated hydrocarbons that can undergo addition polymerisation. Explain how monomers of ethene form poly(ethene) and describe one property of poly(ethene) that makes it suitable for use as a plastic packaging material.

> Edexcel A-Level Chemistry (9CH0) — Topic 5 Organic chemistry II · Explain · 5 marks

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

## Mark scheme (5 marks)

1. Ethene molecules contain a C=C double bond
2. The double bond opens/breaks during addition polymerisation
3. Many ethene monomers join together to form a long polymer chain
4. No other product/by-product is formed (addition polymerisation produces only the polymer)
5. A named property of poly(ethene) that makes it suitable for packaging, e.g. it is flexible / lightweight / does not react with food / waterproof / can be moulded into different shapes

## Key terms

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

## Related

- [Revision notes for Edexcel A-Level Chemistry (9CH0)](https://www.gradenine.co.uk/learn)
- [How to answer "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/alkenes-are-unsaturated-hydrocarbons-that-can-7876a98f) · Published by Druglandscape Ltd.