We isolate n moles of an ideal gas with heat capacity CPm and then heat the gas and allow it to expand from a state P1 ,V1 ,T1 to a inal state P2 ,V2 ,T2 . Find a general formula for the S of this process by treating the process as having two steps: an isothermal expansion step and a separate isobaric heating step. Show that the solution does not depend on which step (the expansion or the heating) is carried out First.