Exothermic and Endothermic Reactions

Exothermic reactions are like energy donors - they transfer energy to their surroundings, making everything around them warmer. You'll notice the temperature of the surroundings increase because the reaction is essentially giving away heat energy.

Think about lighting a match or a bonfire - these combustion reactions release loads of energy as heat and light. Other common exothermic reactions include neutralisation (when acids and bases react), rusting of metal, respiration in your cells, and oxidation processes.

Endothermic reactions work the opposite way - they're energy takers that absorb energy from their surroundings. This makes the surroundings feel colder as the reaction steals heat energy from the environment.

Quick Check: If you touch a container during a reaction and it feels hot, the reaction inside is exothermic. If it feels cold, it's endothermic!

You might find endothermic reactions in hand warmers and self-heating cans, where the cooling effect is actually useful for the product's function. These reactions need a constant supply of energy to keep going.