I only need part B. I found Part A to be 312.5 kJ/kg.
Your piston-cylinder assembly executes a Carnot heat pump cycle, as shown in the figure below. The magnitude of heat per kg of air is 625 k. The pressure at the start of the isothermal expansion is 325 kPa at 600K and 300K. The energy directed by the transfer diagram for a Carnot gas refrigeration or heat pump cycle.
Find the magnitude of the net work input, in kJ per kg of air.