2. (36 pts) 50g of H2O (18g/mol) is depressurized and cooled from 645 K and 1x107 Pa to 373 K and 5x104 Pa (ideal gas in the final state). There is no phase change.

The following data is provided and you are required to use it to solve the problem (do not use residual properties):

Van der Waals EOS coefficients: a: 0.5536 J.m3.mol-2 b: 3.049 x 10-5 m3.mol-1

(a) What is the molar volume in the initial conditions

b) Evaluate the total entropy change for this process. Use a precise correlation for heat capacity and you can use Cp = Cv + R.