# Hand warmers contain chemicals that undergo a reaction when activated. When a hand warmer is used, the temperature of the surroundings increases. State the type of reaction occurring in the hand warmer and explain, in terms of energy transfer, why the temperature of the surroundings increases.

> Pearson Edexcel International GCSE Chemistry (4CH1) — 3.1 Energetics · Explain · 4 marks

## Mark scheme (4 marks)

1. The reaction is exothermic
2. Energy is transferred from the reaction/chemicals to the surroundings
3. Because more energy is released when bonds are formed in the products than is needed to break bonds in the reactants
4. This causes the temperature of the surroundings to increase / rise

## Key terms

- [energy transfer](https://www.gradenine.co.uk/glossary/energy-transfer)
- [surroundings](https://www.gradenine.co.uk/glossary/surroundings)

## Related

- [Revision notes for Pearson Edexcel International GCSE Chemistry (4CH1)](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/hand-warmers-contain-chemicals-that-undergo-c61624d6) · Published by Druglandscape Ltd.