Exothermic & Endothermic Reactions
Ever wondered why hand warmers get hot or why some chemical reactions make things cold? It's all about energy transfer during chemical reactions.
Exothermic reactions are the energy releasers - they transfer energy from the reacting molecules to their surroundings, making the temperature around them increase. Think of combustion (burning), some oxidation reactions, and neutralisation reactions. In these reactions, the products end up with less energy than the reactants because energy has been given off to the surroundings.
Endothermic reactions work the opposite way - they're energy absorbers that take in energy from their surroundings, causing the temperature to drop. Thermal decomposition is a classic example. Here, the products have more energy than the reactants because they've absorbed energy from around them.
Real-world tip: Hand warmers and self-heating food cans use exothermic reactions to generate heat, whilst some instant cold packs use endothermic reactions to cool down!
