Single-Component Fugacity
This Demonstration plots fugacity of a hypothetical single component as a function of temperature or pressure. Use the dropdown menu to select the plot. The saturation point is where liquid and vapor have equal fugacities. Above or below the saturation point, the phase with the lower fugacity is the stable phase. The fugacity-versus-pressure plot is for low pressure, where the vapor phase is ideal and the fugacity versus pressure for the gas phase is linear. When the "high pressure" box is checked, the vapor is assumed to be a real gas and the fugacity versus pressure for the vapor phase is not linear.

Download the CDF file to view the simulation using the free Wolfram CDF player.