Vapor pressure facts for kids

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 condensed 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 temperatures is often called a volatile. As the temperature of a liquid increases, the kinetic energy of its 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.

Images for kids

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  If vapor pressure exceeds the thermodynamic equilibrium value, condensation occurs in presence of nucleation sites. This principle is indigenous in cloud chambers, where ionized particles form condensation tracks when passing through.

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  Vapor pressure of liquid and solid benzene

See also

In Spanish: Presión de vapor para niños