Theorem of corresponding states

According to van der Waals, the theorem of corresponding states (or principle/law of corresponding states) indicates that all fluids, when compared at the same reduced temperature and reduced pressure, have approximately the same compressibility factor and all deviate from ideal gas behavior to about the same degree. Material constants that vary for each type of material are eliminated, in a recast reduced form of a constitutive equation.

Source: Wikipedia — Theorem of corresponding states (CC BY-SA 4.0)