Which statement about the use of Peng-Robinson and Soave EOSs is incorrect?

Question

A. A P-V-T relationship graph can be created for any compound if you have Pc, Psat|Tr = 0.7 and Tc.
B. The Peng-Robinson and Soave equations can be used to model both liquid and vapor molar volumes, but not supercritical fluids.
C. The Peng-Robinson equation of state is slightly more complex, but does not require any additional physical properties.
D. The attraction variable is dependent on the temperature of the substance, but the repulsion variable is not.
E. Both equations have identical repulsion pressure terms.

Answer 1

A. Incorrect. This is true. You can find the acentric factor using the vapor pressure and critical pressure, and then the critical pressure, critical temperature and acentric factor are all that is needed to make the plot.
B. Correct. These equations are designed to model liquid, vapor, gas and supercritical phases.
C. Incorrect. This statement is true. PR EOS uses an extra term in the denominator of the second term (Compare Equations 7.12 and 7.14), but requires the same three physical properties: Pc, Tc, and ?.
D. Incorrect. This statement is true. The a (attraction) variable is temperature dependent. The b (repulsion, or excluded volume) variable is a constant.
E. Incorrect. This statement is true, the “repulsion” term RT/(V-b) is identical in both equations.