20.1.3—Monomer(s) present
- Syllabus
- 9701–2028–2029
- Objective
- 20.1.3
- Level
- AS
Identify an addition-polymer monomer by restoring the C=C at the repeat-unit ends
To find the monomer, cut the polymer backbone at a repeat-unit boundary and replace the single bond between the two backbone carbons with a C=C. Preserve all substituents.
Check that the reconstructed monomer has the correct valency and that repeating it would reproduce the polymer. This is a structure-reversal task, not a naming guess.
[–CH₂–CH(CH₃)–]ₙ comes from propene, CH₂=CHCH₃. [–CH₂–CHCl–]ₙ comes from chloroethene.
The brackets do not represent a separate molecule to be hydrolysed; they indicate a repeating section of a chain.
ConceptA-Level CAIE Chemistry AS