Details

The saturation pressures are calculated using the Antoine equation:

,

where is the saturation pressure (bar) of component ; , and are Antoine constants; and is temperature (K).

Raoult's law for a binary mixture is used to calculate the bubble and dew pressures:

,

,

where and are the liquid mole fractions of each component and and are the vapor mole fractions .

The overall mole fraction of component 1 is , where and are the total moles of each component.

When only vapor is present,

,

,

where is pressure (bar), is the gas constant ([L bar]/[mol K]), is volume (L) and are moles of vapor.

The following five equations are solved for , , , , and liquid moles when both liquid and vapor are present.

From Raoult's law:

,

.

From overall and species mole balances:

,

.

From a volume balance:

,

where is the molar density of the mixture (mol/L).

The screencast video at [1] explains how to use this Demonstration.

Reference

[1] Adding a Second Component to a Fixed-Volume Container [Video]. (Aug 31, 2016) www.colorado.edu/learncheme/thermodynamics/AddingSecondComponentFixedVolume.xhtml.