# A student wants to make a polymer from but-1-ene (CH₂=CHCH₂CH₃) using addition polymerisation. Explain what happens during addition polymerisation and describe the structure of the repeat unit that would be produced from this monomer.

> AQA A-Level Chemistry (7405) — 3.3.12 Polymers (A-Level only) · Explain · 5 marks

> But-1-ene is an alkene with the molecular formula C₄H₈. It can be used as a monomer in addition polymerisation.

## Mark scheme (5 marks)

1. Many small molecules (monomers) join together to form a polymer / large long-chain molecule
2. The double bond in but-1-ene opens / breaks during the reaction
3. The opened double bond allows covalent bonds to form between monomer units / monomers link together via covalent bonds
4. No other product / no small molecule is lost / nothing is released
5. The repeat unit contains four carbon atoms / a chain of four carbons with only single bonds between them and hydrogen atoms attached, with no double bond present

## 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)
- [repeat unit](https://www.gradenine.co.uk/glossary/repeat-unit)

## Related

- [Revision notes for AQA A-Level Chemistry (7405)](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/a-student-wants-to-make-a-bf1d3029) · Published by Druglandscape Ltd.