A mass of 1 kg of air at 100 kPa and 20°C is compressed isothermally to a pressure of 400 kPa. 100 kJ of heat are then added at constant pressure and the gas is then expanded adiabatically back to its original pressure. Sketch these processes on a p-V diagram (not to scale) and determine: (a) the work transfer during compression; (b) the temperature after the heat is added; (c) the work transfer during adiabatic expansion; (d) the final volume.