argon enters a turbine at a rate of 800 kg/min, a temp of 800C and a pressure of 1.5MPa. It expands adiabatically as it pushes on the turbine blades and exits at a pressure 300KPa. Calculate its temperature at exit. The equations I am working with are PV^(gamma)=constant and TV^(gamma-1)=constant. In this case gamma=1.67. If I could figure out how the second of these equations was derived from the first (I'm assuming it involves PV=nRT) I have a feeling I could solve the problem by deriving a similar expression involving P and T but I not sure how and my brain is tired. :yuck: Help would be appreciated. By the way I have the answer - it is 564K.