Which of the following statements is true?

Question

A. Heat capacity is not a state function.
B. Monatomic gases can always be considered ideal gases.
C. If you compress a gas isothermally, it will condense to a liquid.
D. Heat capacity is an intensive property.
E. None of the above are true.

Answer 1

A. Incorrect. Heat capacity is a state function. CV is a derivative of U with respect to T (holding V constant) and CP is a derivative of H with respect to T (holding P constant). U, H, T, P and V are all themselves state functions.
B. Incorrect. Even species like helium and neon, which we think of as being almost completely inert, will show significant departures from ideal gas behavior when the pressure is high enough.
C. Incorrect. A gas is a compound above its critical temperature; it won’t condense no matter how much you compress it. The statement would be true if it used the word vapor instead of gas.
D. Correct. The heat capacity of a compound is a function of temperature and pressure, but it’s not dependent upon how much of the material is present.
E. Incorrect. One of the statements is true.