Raoult's Law Calculator
Calculate partial vapor pressure of a solution component: P = mole_fraction x P_pure.
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Enter the mole fraction of the component (between 0 and 1) and its vapor pressure as a pure substance. The calculator multiplies them to give the partial vapor pressure in the solution, following Raoult's law.
About the Raoult's Law Calculator
Raoult's law, formulated by Francois-Marie Raoult in 1887, is the foundation for understanding vapor pressure of solutions. It states that each component's contribution to the total vapor pressure is proportional to its mole fraction. While it applies exactly only to ideal solutions, it serves as the reference point for understanding all solution behavior.
Frequently Asked Questions
What is Raoult's law?
Raoult's law states that the partial vapor pressure of a component in an ideal solution equals its mole fraction times its vapor pressure as a pure substance: P = x * P_pure. It applies to ideal solutions where intermolecular forces between all components are similar.
When does Raoult's law fail?
It fails for non-ideal solutions where solute-solvent interactions differ significantly from solvent-solvent interactions. Positive deviations occur when interactions are weaker (higher vapor pressure than predicted). Negative deviations occur when interactions are stronger.
How does Raoult's law relate to boiling point?
Adding a non-volatile solute reduces the mole fraction of the solvent, lowering its vapor pressure. Since the total vapor pressure is lower, the solution must be heated more to boil, explaining boiling point elevation.