Answer to Question #35901 in Engineering for Kevin

Question

Oxygen is placed in a well-insulated tank of volume 0.2 m3 at an initial temperature of 180K and a pressure of 110 bar. Using the van der Waals equation of state, calculate the final temperature and pressure after half of the original amount of oxygen is removed from the tank.
The problems tells me to assume that the heat capacity for oxygen in the ideal gas state is given by CP* [J/mol-K] = 25.46 + 1.52 x 10-2 T[K]. The parameters for oxygen for the van der Waals equation of state are: a=0.1381 [Pa m6/mol2] and b = 3.184 [(m3/mol) x 10 5]. (Hint: this is solved with an entropy balance).