Saturated refrigerant-134a vapor is expanded reversibly in an insulated piston- cylinder device from an initial state of 0.6 mpa and 0.03 m^3 to a final state of 0.16 mpa. determine a) the reversible work, b) the change in the exergy of the refrigerant during this isentropic process. assume the surroundings to be at 25c and 100 kpa.

An open feedwater heater operates at steady state with liquid entering at inlet 1 with t? = 40°c and pl = 1 .2 mpa. water vapor att2-200°c and p2 = 1.2 mpa enters at inlet 2. saturated liquid water exits with a pressure of pa 1.2 mpa. neglect heat transfer with the surroundings and all kinetic and potential energy effects, determine the mass flow rate of steam at inlet 2 if the mass flow rate of liquid water at inlet 1 is given as 2 kg/s.