Which of the following statements is false?

Question

A. The “summability” relationship calculates a mixture property by summing the products of the mole fraction of a component in the mixture with its partial molar property.
B. The ideal solution molar enthalpy is equal to the weighted average pure component molar enthalpies.
C. For an ideal solution, the molar volume of mixing is equal to zero.
D. For an ideal gas, the molar enthalpy is not a function of pressure.
E. For an ideal solution, the molar entropy of mixing is equal to zero.

Answer 1

A. Incorrect. This is a true statement. Summability (Equation 9.27) is the reason for the development of partial molar properties. It allows simple calculations that are easily understood.
B. Incorrect. This is a true statement and is the definition of the ideal solution molar enthalpy.
C. Incorrect. This is a true statement. Refer to Table 9-2 to see this. Remember that for ideal solutions, volumes are additive and there is no positive or negative change from ?Vi.
D. Incorrect. This is a true statement. Enthalpy is a function of temperature only in ideal gases.
E. Correct. As Table 9-2 shows, molar entropy and molar Gibbs free energy have mixing properties even when they are ideal solutions.