CAIE A Level Chemistry 9701 · Polymerisation
Poly(alkenes) such as poly(ethene) are widely used but persist in the environment for many years. In contrast, polyesters and polyamides can be broken down under certain conditions. Some polymers are also degraded by exposure to light. Explain why poly(alkenes) are difficult to biodegrade, why polyesters and polyamides are biodegradable, and how light can degrade some polymers.
4 marks, so the mark scheme is looking for about 4 separate creditworthy points. Making the same point twice in different words earns it once.
Explain means: Give the reasons or the mechanism: why or how something happens. Link each point to the next with because, so or which means. A list of facts with no links usually loses the reasoning marks.
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