Acrylic fibres used in jumpers are made from an addition polymer. A section of the polymer chain is shown as a condensed formula:
−CH2−CH(CN)−CH2−CH(CN)−CH2−CH(CN)−\mathrm{-CH_{2}-CH(CN)-CH_{2}-CH(CN)-CH_{2}-CH(CN)-}−CH2−CH(CN)−CH2−CH(CN)−CH2−CH(CN)−
Deduce the repeat unit of this polymer and the structure of its monomer.
Poly(phenylethene), used in packaging, is made from the monomer phenylethene, C6H5CH=CH2(Mr=104)\mathrm{C_{6}H_{5}CH=CH_{2}} (M_{r} = 104)C6H5CH=CH2(Mr=104). A sample of poly(phenylethene) has an average MrM_{r}Mr of 520 000.
Calculate the average number of monomer units in each polymer chain.
A packaging tray contains 2.6 g of this poly(phenylethene). Calculate the number of polymer molecules in the tray. The Avogadro constant is 6.02 × 1023 per mole.
Phenylethene decolourises bromine water, but poly(phenylethene) does not. Explain why.
Write an equation, using condensed formulae and n, for the formation of poly(phenylethene) from phenylethene.
37 exam-style questions on Edexcel GCSE Chemistry 10.3 Polymers, covering 10.3.1 Addition polymerisation of alkenes, 10.3.2 Uses and properties of polymers, 10.3.3 Condensation polymers and polyesters, 10.3.4 Problems with polymers and recycling, and 10.3.5 Natural polymers: DNA, starch and proteins. Each one has a worked solution and a mark scheme showing where the marks go.