Question

As shown in the figure below, a gas contained within a piston-cylinder assembly, initially at a volume of 0.1 m3, undergoes a constant-pressure expansion at p 2 bar to a final volume of V2 0.2 m3, while being slowly heated through the base. The change in internal energy of the gas is 0.25 kJ. The piston and cylinder walls are fabricated from heat-resistant material, and the piston moves smoothly in the cylinder. The local atmospheric pressure is 1 bar. Piston- Patm 1 bar p, V2 Vi-0.1 m3 Gas (U2-빛=0.25 kJ (a) For the gas as the system, evaluate work and heat transfer, each in k). (b) For the piston as the system, evaluate work and change in potential energy, each in kJ. Part A For the gas as the system, evaluate work and heat transfer, each in kJ. gas k) k)

Answer 1

Work done during expansion is given by, W pdV Pressure is constant and is given as 2 bar W p(V-) 103 1 kJ ра =(2 bar) (0.2 m3-0.1 m2 1 bar 1000 N m -20 kJ Calculate the heat transfer. According to first law of thermodynamics, Q =AU +W Here O is the heat transfer, AU change in energy and W is the work done. Q AU+W -0.25+20 kJ -20.25 kJ