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Q1. Helium, of volume 0.6 m³, is isentropically compressed from a pressure and temperature of 1.2 bar and 20℃ respectively, to a pressure of 12 bar. It is then cooled at constant pressure to the original temperature after which, it expands isothermally to the initial state.

(a) Sketch The sequence of processes on a pressure-Volume and Temperature-specific entropy diagram. (2)

(b) Calculate EACH of the following:

(i) The net heat transfer; (6)

(ii) The network transfer; (6)

(iii) The maximum change in entropy. (2)

Note: for Helium c_p = 5.193 kJ/kg K, Molecular mass = 4.003 kg/kmol K. Universal gas constant R_o = 8.3145 kJ/ kmol K .