What is Vapor pressure?
[[File:Vapor_pressure.svg|thumb|right|The microscopic process of evaporation and condensation at the surface of a liquid]] '''Vapor pressure''' is the [[pressure]] applied by a [[vapor]] in [[thermodynamic equilibrium]] with its [[Condensation|condensed]] [[States of matter|phases]] at a given temperature in a [[closed system]]. The vapor pressure shows how fast a liquid evaporates. A [[substance]] with a high vapor pressure at normal [[Temperature|temperatures]] is often called a [[Volatiles|volatile]]. As the temperature of a liquid increases, the [[kinetic energy]] of its [[Molecule|molecules]] also increases. As the kinetic energy of the molecules increases, the number of molecules changing into a [[vapor]] also increases, so it increases the vapor pressure. {{Physics-stub}} [[Category:Thermodynamics]]