Condensation: definition in chemistry
Condensation: The change of a gas or vapor into a liquid, usually when it cools. In chemistry the word also names reactions in which two molecules join and release a small molecule such as water.
When vapor particles lose energy, the attractions between them pull them together into droplets, releasing heat to the surroundings, so condensation is exothermic. It is the reverse of evaporation and the key step in distillation, where vapor is cooled in a condenser to collect a purified liquid. Condensation reactions build many large molecules, including proteins from amino acids and polyesters from smaller units.
Examples
- Water droplets forming on a cold glass of soda
- Fog on a bathroom mirror after a hot shower
- Dew forming on grass overnight
- Two amino acids joining and releasing H₂O to form a peptide bond