# A student adds magnesium ribbon to a solution of copper sulfate. The magnesium ribbon gradually disappears and a reddish-brown solid forms on the surface of the metal. The student also notices that the test tube becomes warm to the touch. Explain why this reaction is classified as both an oxidation reaction and an exothermic reaction.

> OCR GCSE Chemistry A: Gateway Science (J248) — C3.3 Types of chemical reactions · Explain · 4 marks

> Magnesium is more reactive than copper and displaces it from copper sulfate solution. During the reaction, magnesium atoms lose electrons and copper ions gain electrons.

## Mark scheme (4 marks)

1. Oxidation involves the loss of electrons (by magnesium)
2. Magnesium is oxidised / the oxidising agent is the copper ion which gains electrons
3. The reaction is exothermic because energy is transferred to the surroundings
4. The temperature of the surroundings increases, shown by the test tube becoming warm

## Key terms

- [oxidation](https://www.gradenine.co.uk/glossary/oxidation)
- [exothermic reaction](https://www.gradenine.co.uk/glossary/exothermic-reaction)

## Related

- [Revision notes for OCR GCSE Chemistry A: Gateway Science (J248)](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/a-student-adds-magnesium-ribbon-to-bea82248) · Published by Druglandscape Ltd.