A frictionless piston-cylinder device contains 0.15 kg of air at 350 C and 315 kPa. The ace is first compressed isothermally to a pressure of 1500 kPa. It is then expanded slowly according to the relation PV" - constant, where n = 1.2, until it reaches the initial pressure. Compute the boundary work (in kJ) done for each process. (8 marks)