Problem 1: Use the Lee-Kesler method to do the following:
a) Calculate the entropy of propane at its critical point. The reference state is the ideal-gas state at the critical point.
b) Calculate ΔS of propane for an isothermal process that takes the substance from its critical point to pressure 1 Pa.
c) A member of our engineering team objects that the reference state is not valid because a substance is not ideal at the critical point. What is your response?