Describe how the monomers of addition polymers and condensation polymers differ, and state one type of molecule produced as a by-product during condensation polymerisation but not during addition polymerisation.

Edexcel GCSE Chemistry (1CH0) — 10.4 Polymers (Chem only) · Describe · 4 marks · View as Markdown

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

Model answer (4 marks)

Addition polymer monomers contain a carbon–carbon double bond (C=C) and are unsaturated.
Condensation polymer monomers are bifunctional, having two different functional groups, one at each end.
In condensation polymerisation a small molecule is released as a by‑product, whereas no such by‑product is formed in addition polymerisation.
The typical by‑product is water (or hydrogen chloride).

Examiner tips

  • Use the term ‘unsaturated’ for addition monomers. Mention ‘bifunctional’ for condensation monomers. State the by‑product explicitly (water or HCl).

Common mistakes

  • Confusing the double bond with a single bond. Forgetting that condensation monomers have two functional groups. Failing to name the by‑product or giving an incorrect one.

Mark scheme (4 marks)

  1. Addition polymer monomers contain a carbon–carbon double bond (C=C / unsaturated bond)
  2. Condensation polymer monomers have/contain two functional groups (one at each end / bifunctional)
  3. During condensation polymerisation a small molecule is released / produced as a by-product
  4. The by-product is water (or hydrogen chloride)

Key terms in this question

addition polymerisation · condensation polymerisation · monomer · by-product

Related

More Polymers (Chem only) questions

▶ Try answering this question with AI marking (free) →