Poly(ethene) is a polymer made from ethene monomers. Describe how poly(ethene) is formed from ethene monomers and state one use of poly(ethene).

Cambridge International IGCSE Chemistry (0620) — 11.8 Polymers · Describe · 4 marks · View as Markdown

Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).

Ethene, CH₂=CH₂, is a small molecule that can be joined together in a chemical reaction to form a polymer called poly(ethene).

Model answer (4 marks)

Many ethene molecules join together to form a long chain.
The double bond in each ethene opens, allowing the carbon atoms to bond.
This process is called addition polymerisation.
Poly(ethene) is used to make plastic bags.

Examiner tips

Use the term "addition polymerisation". Explain the opening of the double bond. Mention that many monomers join. Give a specific use such as plastic bags.

Common mistakes

Saying "polymerisation" without specifying addition. Forgetting to mention the double bond opening. Giving a non‑specific or incorrect use of poly(ethene).

Mark scheme (4 marks)

Many/thousands of ethene monomers join together
The double bond in ethene opens/breaks to allow bonding
The process is called addition polymerisation
A correct use of poly(ethene) stated

Key terms in this question

monomer · polymer