How to Calculate Raoult's Law
What is Raoult's Law?
Raoult's Law states that the partial vapour pressure of a volatile component in an ideal solution is proportional to its mole fraction and pure component vapour pressure. P_solution = x_solvent × P°_solvent.
Step-by-Step Guide
- 1P_solution = x_solvent × P°_pure
- 2x_solvent = moles solvent / total moles
- 3Vapour pressure lowering: ΔP = x_solute × P°_pure
- 4Basis for boiling point elevation and freezing point depression
Worked Examples
Input
Benzene P°=96 mmHg · xbenzene=0.7 in toluene solution
Result
P_benzene = 0.7 × 96 = 67.2 mmHg
Raoult's law for ideal mixtures
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