Explain why gold is used to make jewellery and why titanium is used to make replacement hip joints. Give two reasons for each use.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Model answer (4 marks)
Gold is used for jewellery because it does not corrode or tarnish, so it retains its appearance over time.
Gold is used for jewellery because it is highly malleable, allowing it to be shaped into intricate designs.
Titanium is used for replacement hip joints because it does not corrode in the body, resisting reaction with body fluids.
Titanium is used for replacement hip joints because it has a high strength‑to‑density ratio, making it strong yet lightweight.
Gold is used for jewellery because it is highly malleable, allowing it to be shaped into intricate designs.
Titanium is used for replacement hip joints because it does not corrode in the body, resisting reaction with body fluids.
Titanium is used for replacement hip joints because it has a high strength‑to‑density ratio, making it strong yet lightweight.
Examiner tips
- Use the exact phrases from the mark scheme (e.g. "does not corrode" and "malleable").
- Separate each reason with a new line or bullet for clarity.
- Mention both reasons for each metal to earn full marks.
Common mistakes
- Confusing gold with silver or stating it is a good conductor – not relevant to corrosion.
- Omitting the high strength‑to‑density ratio for titanium or using vague terms like "strong" without context.
Mark scheme (4 marks)
- Gold is used for jewellery because it does not corrode / does not react / is resistant to tarnishing
- Gold is used for jewellery because it is malleable / can be shaped / worked into intricate designs
- Titanium is used for replacement hip joints because it does not corrode / is resistant to corrosion inside the body / does not react with body fluids
- Titanium is used for replacement hip joints because it is strong / hard-wearing / has a high strength-to-density ratio / is low density yet strong
Related
- All Cambridge International IGCSE Chemistry (0620) revision notes →
- How to answer a "Explain" question →
- Decode the mark scheme abbreviations →
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