Ammonia in a piston-cylinder assembly undergoes two processes in series. Initially, the ammonia is saturated vapor at p1 = 100 lbf/in.2 Process 1-2 involves cooling at constant pressure until x2 = 75%. The second process, from state 2 to state 3, involves heating at constant volume until x3 = 100%. Kinetic and potential energy effects are negligible. For 1.2 lb of ammonia, determine (a) the heat transfer and work for Process 1-2 and (b) the heat transfer for Process 2-3, all in Btu.