# Describe how addition polymers are formed from alkene monomers and explain why the resulting polymer is chemically unreactive compared to the monomer.

> Edexcel A-Level Chemistry (9CH0) — Topic 3 Organic chemistry I · Describe and Explain · 5 marks

> Poly(propene) is an addition polymer widely used to make plastic containers and rope fibres. It is formed from propene monomers.

## Mark scheme (5 marks)

1. Alkene monomers contain a carbon–carbon double bond (C=C)
2. The double bond opens / breaks during polymerisation
3. Monomers join together in a repeat unit to form a long chain polymer
4. The polymer has only carbon–carbon single bonds (C–C) in its backbone / no C=C double bonds remain
5. Carbon–carbon single bonds are strong / do not react easily with other reagents, so the polymer is chemically unreactive / does not undergo addition reactions

## Key terms

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

## Related

- [Revision notes for Edexcel A-Level Chemistry (9CH0)](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/describe-how-addition-polymers-are-formed-de88f195) · Published by Druglandscape Ltd.