Question

If an ideal gas starts out at a pressure of 103 kPa and a volume of 0.0330 m3 and then ends at a pressure of 248 kPa and volume of 0.0890 m3, how much work is done if it follows an isochoric process up to the final pressure, then an isobaric expansion to the final volume?

If instead it had an isobaric expansion to the final volume, followed by an isochoric process to the final pressure, how much work is done?

Answer 1

(a)

When gas follows an isochoric process up to the final pressure, then an isobaric expansion to the final volume,

Work done = W_isochoric + W_isobaric

We know that in isochoric process volume is constant. so, work done is 0.

W = 0 + PfV

W = 248 * (0.089 - 0.033)

W = 13.88 kJ

(b)

When gas follows an isobaric expansion to the final volume, followed by an isochoric process to the final pressure,

W =  W_isobaric +  W_isochoric

W = PiV + 0

W = 103 * (0.089 - 0.033)

W = 5.768 kJ