Explain why addition polymers, such as poly(ethene), cannot be broken down by chemical reactions in the environment, and suggest one problem this causes.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Model answer (4 marks)
Addition polymers such as poly(ethene) have very strong covalent C–C bonds along the chain, making them chemically inert and unreactive to most environmental conditions.
Because of this inertness, microorganisms and bacteria cannot digest or break down the polymer chains.
Consequently, addition polymers are non‑biodegradable and persist in the environment for a very long time.
One problem this causes is the accumulation of plastic waste in landfills or oceans, which harms wildlife and pollutes ecosystems.
Because of this inertness, microorganisms and bacteria cannot digest or break down the polymer chains.
Consequently, addition polymers are non‑biodegradable and persist in the environment for a very long time.
One problem this causes is the accumulation of plastic waste in landfills or oceans, which harms wildlife and pollutes ecosystems.
Examiner tips
- Use the term ‘covalent C–C bonds’ and ‘chemically inert’ to show understanding of the structure. Explain why microbes cannot digest the polymer. State the environmental consequence clearly. Keep the answer concise – 4 marks only.
Common mistakes
- Using ‘weak bonds’ instead of ‘strong covalent bonds’. Failing to mention that the polymer is chemically inert. Giving a non‑specific or irrelevant environmental problem.
Mark scheme (4 marks)
- Addition polymers have very strong covalent bonds (within the polymer chain) / are chemically inert / unreactive
- Microorganisms / bacteria cannot break down / digest the polymer chains
- This means addition polymers are non-biodegradable / persist in the environment for a very long time
- One named problem: e.g. plastic waste accumulates in landfill / oceans / harms wildlife / pollutes ecosystems (any one valid environmental problem)
Key terms in this question
Related
- All Edexcel GCSE Chemistry (1CH0) revision notes →
- How to answer a "Explain" question →
- Decode the mark scheme abbreviations →
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