Fugacity from Equation of State for Water
The fugacity f and the fugacity coefficient φ are calculated for water by using the Peng–Robinson equation of state. "Pressure" and "volume" are changed with sliders, and the corresponding state is indicated by the black point on the log pressure versus log volume diagram. The fugacity coefficient indicates how much the fluid deviates from ideal-gas behavior (φ = 1 for an ideal gas). Selecting "isotherms" displays isotherms on the P-V diagram, and the horizontal solid green line represents liquid and vapor in equilibrium. The areas under the curve, which are colored light blue, are equal when viewed on a linear scale.

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