Condensation
Definition and meaning of Condensation in chemistry.
Condensation is the phase transition in which a substance changes from a gas (vapor) into a liquid, most often triggered by cooling or increased pressure.
In more detail
As vapor molecules lose kinetic energy, intermolecular attractive forces (such as hydrogen bonding or van der Waals forces) overcome the molecules' motion and pull them together into the more ordered liquid state. Condensation is the reverse of vaporization and is exothermic, releasing the same amount of heat per mole that vaporization absorbs. It occurs at the same temperature as the liquid's boiling point for a given pressure, and it drives everyday phenomena like cloud, fog, and dew formation, as well as industrial separations such as distillation.
Key facts
| Field | Physical Chemistry |
|---|---|
| Process type | Exothermic phase transition (gas to liquid) |
| Reverse process | Vaporization (evaporation/boiling) |
| Energy relation | ΔH(condensation) = −ΔH(vaporization) |
Water vapor in humid air condenses into liquid droplets on the outside of a glass of ice water, because the cold glass cools the nearby air below its dew point.
Frequently asked questions
Is condensation exothermic or endothermic?
Condensation is exothermic. Forming intermolecular attractions as gas molecules become a liquid releases energy to the surroundings, the mirror image of the energy absorbed during vaporization.
How is condensation different from a condensation reaction?
Physical condensation is a phase change with no chemical bonds broken or formed. A condensation reaction is a distinct chemical process in which two molecules join and release a small byproduct molecule, often water.