Chemistry / Unit 8 Chem 1555 short lesson, about 20 seconds
Raoult's Law and Vapor Pressure Lowering
Captions available
The idea
Raoult's law states a solution's vapor pressure equals the pure solvent's vapor pressure times the solvent's mole fraction, so a nonvolatile solute lowers it.
In practice
Dissolving glycerin, a nonvolatile solute, in ethanol lowers the solution's vapor pressure below that of pure ethanol.
Where people slip
This form covers a nonvolatile solute — a volatile second component would add its own partial pressure instead.
Your place on the trail
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