A gas within a piston–cylinder assembly undergoes a thermodynamic cycle consisting of three processes in series, beginning at state 1 where m = 0.5 kg, p1 = 1 bar, V1 = 1.5 m3, as follows:
Process 1–2: Compression with pV = constant, W12 = -102 kJ, u1 = 424 kJ/kg, u2 = 780 kJ/kg.
Process 2–3: W23 = 0, Q23 = -150 kJ.
Process 3–1: W31 = 48 kJ.
There are no changes in kinetic or potential energy. Determine Q12 and Q31, each in kJ.