Air is compressed from 100 kPa, 300 K to 1000 kPa in a two-stage compressor with intercooling between stages. The intercooler pressure is 300 kPa. The air is cooled back to 300 K in the intercooler before entering the second compressor stage. Each compressor stage is isentropic. Please calculate the total compressor work per unit of mass flow (kJ/kg). Repeat for a single stage of isentropic compression from the given inlet to the final pressure.