Poly(propene) is an addition polymer. Polyesters and nylon are condensation polymers.
State two differences between addition polymerisation and condensation polymerisation.
The polyester used to make plastic drinks bottles is made from two monomers:
ethane-1,2-diol, HO−CH2−CH2−OH\mathrm{HO-CH_{2}-CH_{2}-OH}HO−CH2−CH2−OH
benzene-1,4-dicarboxylic acid, HOOC−C6H4−COOH\mathrm{HOOC-C_{6}H_{4}-COOH}HOOC−C6H4−COOH
Explain how these monomers join together to make a polyester.
One chain of this polyester contains 2000 ester links.
How many molecules of water are made when this chain forms?
Poly(lactic acid) is a polyester made from only one monomer, lactic acid.
The structural formula of lactic acid is CH3CH(OH)COOH\mathrm{CH_{3}CH(OH)COOH}CH3CH(OH)COOH.
Explain how a single monomer can form a condensation polymer.
A student tries to make nylon in the laboratory. This is the student's method.
Step 1: Pour 10 cm3\mathrm{cm^{3}}cm3 of a solution of a monomer with two −NH2\mathrm{-NH_{2}}−NH2 groups, dissolved in water, into a small beaker.
Step 2: Add 10 cm3\mathrm{cm^{3}}cm3 of a solution of a monomer with two −COCl\mathrm{-COCl}−COCl groups, dissolved in cyclohexane, to the beaker.
Step 3: Stir the mixture quickly with a glass rod.
Cyclohexane does not mix with water and is less dense than water.
The student gets small lumps of solid instead of a long thread of nylon.
Explain why the student's method does not make a long thread of nylon, and describe how the method should be changed.
The reaction makes nylon and a small molecule.
Name the small molecule.
63 exam-style questions on OCR GCSE Chemistry 6.2 Organic chemistry, covering 6.2.1 Crude oil and fractional distillation, 6.2.2 Cracking and dependence on hydrocarbons, 6.2.3 Functional groups and homologous series, 6.2.4 Reactions of alkanes, alkenes and alcohols, 6.2.5 Addition polymerisation and repeat units, 6.2.6 Naturally occurring polymers, 6.2.7 Chemical cells and fuel cells, and 6.2.8 Condensation polymerisation and how to make one. Each one has a worked solution and a mark scheme showing where the marks go.