Using the Energy Balance
As shown in Fig. P2.56, a gas contained within a piston-cylinder assembly, initially at a volume of 0.1 m3, undergoes a constant-pressure expansion at 2 bar to a final volume of 0.12 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.
(a) For the gas as the system, evaluate work and heat transfer, each in kJ.
(b) For the piston as the system, evaluate work and change in potential energy, each in kJ.
Step 1 of 3
We have to evaluate work and heat transfer for the gas as the system.
The work done for the gas as the system can be evaluated using the expression
where, constant pressure = 2 bar = N/m2
= change in volume in m3
The change in volume of the gas is
Thus, the work done for the gas as the system is