Problem 5.16: 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?
Problem 5.17: The steam tables are calculated with reference state the saturated liquid at the triple point (Ptriple = 0.006117 bar, Ttriple = 0.01 °C). Suppose we want to retabulate the properties of steam using a different reference state. Show how this can be done by calculating V, U, H, and S at 1 bar, 200 °C using the following reference states:
a) the saturated vapor at 10 bar;
b) the saturated vapor in the hypothetical ideal-gas state at 10 bar.
Additional data: The ideal-gas heat capacity of water is given by the following equation with T in kelvin.
