Vapor pressure

Vapor pressure is defined as the pressure exerted by a vapor when it’s in thermodynamic equilibrium with its condensed phase – whether that phase is a solid or a liquid – within a closed container at a specific temperature. This pressure represents the inherent tendency of a substance to evaporate or sublime, driven by the kinetic energy of its molecules. Critically, vapor pressure increases with temperature; as temperature rises, molecules gain more kinetic energy and are more likely to escape from the condensed phase, leading to a higher vapor pressure. Understanding vapor pressure is fundamental to many chemical processes, including distillation and phase diagrams.