A system consisting of 3 lb of water vapor in a piston- cylinder assembly, initially at 350°F and a volume of 71.7 ft3, is expanded in a constant-pressure process to a volume of 85.38 ft3. The system then is compressed isothermally to a final volume of 28.2 ft3. During the isothermal compression, energy transfer by work into the system is 72 Btu. Kinetic and potential energy effects are negligible. Determine the heat transfer, in Btu, for each process.