Enter the mole fraction of the solvent and the vapor pressure of the solvent (Pa) into the calculator to determine the Saturation Pressure. 

Saturation Pressure Formula

The following formula is used to calculate the Saturation Pressure. 

Psat = Xsolv * Psolv
  • Where Psat is the Saturation Pressure (Pa)
  • Xsolv is the mole fraction of the solvent 
  • Psolv is the vapor pressure of the solvent (Pa) 

To calculate the saturation pressure, multiply the mole fraction of the solvent by the vapor pressure of the solvent.

How to Calculate Saturation Pressure?

The following two example problems outline how to calculate the Saturation Pressure.

Example Problem #1:

  1. First, determine the mole fraction of the solvent. In this example, the mole fraction of the solvent is given as .87.
  2. Next, determine the vapor pressure of the solvent (Pa). For this problem, the vapor pressure of the solvent (Pa) is given as 100.
  3. Finally, calculate the Saturation Pressure using the equation above: 

Psat = Xsolv * Psolv

Inserting the values from above and solving the equation: 

Psat = .87 * 100 = 87 (Pa)

Example Problem #2: 

Using the same process as above, first define the variables required by the formula. In this case, these values are:

mole fraction of the solvent = .75

vapor pressure of the solvent (Pa) = 200

Entering these values yields:

Psat = .75 * 200 = 150(Pa)