Exothermic Reactions
Chemistry: Cambridge International GCSE Supplement, topic 5.1.2
Exothermic Reactions
In exothermic reactions, energy from the reacting chemicals is transferred to the surroundings. This often leads to an increase in temperature. Examples include:
Combustion
Neutralisation
Oxidation
Hand warmers
- Disposable hand warmers use the energy released by iron oxidation.
- Reusable hand warmers source their energy from the crystallisation of salt solutions. Boiling the pack re-dissolves the crystals, so that it's ready to be activated once more.
Test yourself on Exothermic Reactions
What type of reaction happens when iron reacts with oxygen to produce heat in a hand warmer?