Calculate the vapour pressure of a solution from mole fraction and pure component pressures.
Each component contributes its pure vapour pressure scaled by its mole fraction. The vapour is always richer in the more volatile component than the liquid, which is exactly what makes distillation work. The difference between liquid and vapour composition is the driving force of every separation column, and Raoult’s law is the ideal-case starting point.
Raoult's Law
P_total = x_A P°_A + x_B P°_B for an ideal solution
P_total = x_A P°_A + x_B P°_B for an ideal solution Each component contributes its pure vapour pressure scaled by its mole fraction. The vapour is always richer in the more volatile component than the liquid, which is exactly what makes distillation work.
The difference between liquid and vapour composition is the driving force of every separation column, and Raoult’s law is the ideal-case starting point.
This calculator takes 4 inputs: Mole fraction of solvent, Vapour pressure of the pure solvent, Mole fraction of volatile solute, Vapour pressure of the pure solute. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.