# When copper carbonate is heated strongly, it decomposes to form copper oxide and carbon dioxide. Explain why this thermal decomposition is a chemical change rather than a physical change.

> Eduqas GCSE Chemistry — C4 Chemical changes · Explain · 4 marks

## Mark scheme (4 marks)

1. A new substance is formed (copper oxide and/or carbon dioxide are new substances not present at the start)
2. The change is irreversible / cannot be reversed by simple physical means
3. The colour change (green to black) indicates a chemical change has occurred, showing the substance has altered chemically
4. In a physical change, no new substances are formed and the change is easily reversible, which is not the case here

## Key terms

- [chemical change](https://www.gradenine.co.uk/glossary/chemical-change)
- [physical change](https://www.gradenine.co.uk/glossary/physical-change)
- [thermal decomposition](https://www.gradenine.co.uk/glossary/thermal-decomposition)

## Related

- [Revision notes for Eduqas GCSE Chemistry](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

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Source: [GradeNine](https://www.gradenine.co.uk/q/when-copper-carbonate-is-heated-strongly-d0707c48) · Published by Druglandscape Ltd.