Which of the following is true about partial molar properties?

Question

A. When evaluating a partial molar property of a component in a mixture, you keep temperature, molar volume and the mole fraction of all but one of the components constant.
B. The partial molar enthalpy of a component in a mixture is equal to the pure component molar enthalpy of that component (at the same T and P) if the system is modeled as an ideal solution.
C. The partial molar entropy of a component in a mixture is equal to the pure component molar entropy of that component (at the same T and P) if the system is modeled as an ideal solution.
D. The partial molar enthalpy of a component in a mixture is equal to the pure component molar enthalpy (at the same T and P) if the system is modeled as an ideal solution or an ideal gas.
E. None of the above are true.

Answer 1

A. Incorrect. Temperature, pressure and the molar amounts of all other components are fixed when calculating a partial molar property.
B. Correct. If the solution is ideal, Equations 9.27 and 9.25 are equal and the properties are identical.
C. Incorrect. Entropy and Gibbs free energy are more complex than enthalpy, volume and internal energy. Review Table 9-2 and its development.
D. Incorrect. Be careful to keep all the different “ideal” conditions straight. An ideal solution is NOT the same as an ideal gas.
E. Incorrect. One statement is accurate.