Hint: See Example 4.1-1 in Your Handout

ECHE 311/FALL 08

Problem Set #7

FUGACITY

Due Tuesday, October 14th 2008

1. Estimate the fugacity of cyclohexene as a gas at 150oC and 50 bar, 150 bar, 300 bar and 2000 bar. Plot of vs P and vs P for cyclohexene at 150oC.

Hint: See example 4.1-1 in your handout.

2. Estimate the fugacity of liquid n-pentane at its normal-boiling-point temperature and 250 bar.

Hint: Step (1) Calculate the fugacity at the nbp by Eq.

Step (2) Calculate Vsat using Rackett Equation

Step (3) Use Eq.

to calculate the pressure at 250 bar.

3. Prepare a plot of vs P and vs P for chloroform at 180 C for the pressure

range from 0 to 80 bar. At 180 C the vapor pressure of chloroform is 20.27 bar. Assume that Eq. is valid for the vapor phase and that the molar volume of saturated liquid is given by Rackett Eq.

Hint: Use Rackett Eq to calculate Vsat

Calculate fugacity coefficients by Eq

Use Eq. to calculate the fugacity from Psat and Vsat .

4. From data in the steam tables, determine a good estimate for f/fsat for liquid water at 150oC and 150 bar, where fsat is the fugacity of saturated liquid at 150o C.

5. Steam at 9,000 kPa and 400oC undergoes an isothermal change of state to a pressure of 300 kPa. Determine the ratio of fugacity in the final state to that in the initial state.