Henry's Law describes the relationship between the pressure of a gas above a liquid and the amount of the gas that will dissolve in the liquid.
Raoult's law gives a method of estimating the composition and pressure of the vapour above a liquid mixture. This article describes the basis of Raoult's law and provides an example of how to apply it.
Dalton's law provides a method by which the total pressure of a gas mixture can be calculated using the partial pressures of the component gases of the mixture.
This article presents the method to convert between pressure and head for several common unit sets. Head relates the pressure of a fluid to the height of a column of that fluid which would produce an equivalent static pressure at its base. It is particularly useful for the specification of pumps as it provides a measure of pressure as it is independent of fluid density.