In chemistry, Raoult's law states that the vapor pressure of mixed liquids is dependent on the vapor pressures of the individual liquids and the molar vulgar fraction of each present in solution. // Introduction Chemistry is a large field encompassing many subdisciplines that often overlap with significant portions of other sciences. ... The vapor pressure is the pressure (if the vapor is mixed with other gases, the partial pressure) of a vapor(this vapour being formed from molecules/atoms escaping from a liquid/solid). ... A liquid will assume the shape of its container. ... Concentration is a very common concept used in chemistry and related fields. ... It has been suggested that this article or section be merged with fraction (mathematics). ...

Once equilibrium has been reached,

P_Total = P₁x₁ + P₂x₂

where P₁and P₂ are the vapor pressures of two liquids, and x₁ and x₂ are their molar fractions in solution.

This law is strictly valid only under the assumption that the bonding between the two liquids is equal to the bonding within the liquids. Therefore, comparing actual measured vapor pressures to predicted values from Raoult's law allows information about the relative strength of bonding between liquids to be obtained. If the measured value of vapor pressure is less than the predicted value, fewer molecules have left the solution than expected. This is put down to the strength of bonding between the liquids being greater than the bonding within the individual liquids, so fewer molecules have enough energy to leave the solution. Conversely, if the vapor pressure is greater than the predicted value more molecules have left the solution than expected, due to the bonding between the liquids being less strong than the bonding within each. A chemical bond is the phenomenon of atoms being held together in molecules or crystals. ... A molecule is the smallest particle of a pure chemical substance that still retains its chemical composition and properties. ...

See also: Henry's law In chemistry, Henrys law is one of the gas laws. ...