# Hand warmers contain iron powder. When a hand warmer is activated, iron reacts with oxygen in the air. The hand warmer becomes hot to the touch. Explain why the hand warmer becomes hot, and describe what this tells us about whether bonds are broken or formed during the reaction.

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

> Hand warmers are single-use packets used by hikers and skiers to keep their hands warm in cold conditions. Inside each packet is iron powder that reacts when exposed to air.

## Mark scheme (4 marks)

1. The reaction is exothermic
2. Energy is transferred to the surroundings, causing the temperature to increase
3. In an exothermic reaction, more energy is released making bonds than is taken in breaking bonds
4. Bond making releases energy / bond making is an exothermic process

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