09.08 - Calculation of Fugacity (Liquids)

Liquid fugacity relative to vapor fugacity. (LearnChemE, 5 min) This screencast shows a sample derivation and sample calculation for the vapor equation of state given by: Z = 1-0.01P, solve for: (a) the vapor fugacity at 500K and 30 bar (b) the liquid fugacity in equilibrium with the same vapor at 500K and 30bar (c) the liquid fugacity at 500K and 60 bar. Data: V^L = 25 cm³/mol.

Comprehension Questions:

1. How much did raising the pressure to 60 bar change the liquid fugacity (bars) (+/- 1%)?
2. Estimate the fugacity (bars) of the vapor at 500 K and 60 bar and compare it to the liquid. Which is smaller? Which state do you think best characterizes the fluid (ie. V or L)?
3. Estimate the fugacity (bars) of n-pentane vapor at 30 bar and 460 K by Eqn. 7.5.
4. Assuming V^L=229cm³/mol, estimate the fugacity of liquid n-pentane at 460K and 600bar.
5. Compare your answers for 3 and 4 to the PREOS.