Vapor pressure of an ideal solvent from mole fraction and the pure-solvent vapor pressure.
| Partial pressure | – |
Use this calculator for a non-volatile solute problem when you know x_solvent and p* and want the lowered vapor pressure.
The calculation is p = x × p*. Mole fraction is 0–1. The same pressure unit comes out as p* in.
This is Raoult’s law for an ideal solution. It does not include a Henry’s-law solute, activity coefficients, or a second volatile component unless that is already in x.
Mole fraction x: Mole fraction of the solvent, 0 to 1. 0.95 if the solute is 5 mol %.
Pure vapor pressure p*: Vapor pressure of the pure solvent, any unit, for example 2.3 kPa for water at 20 °C.
Partial pressure: Solvent vapor pressure in the same unit as p*.
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