Question

A frictionless piston–cylinder device initially contains 200 L of saturated liquid refrigerant-134a. The piston is free to move, and its mass is such that it maintains a pressure of 900 kPa on the refrigerant. The refrigerant is now heated until its temperature rises to 70°C. Calculate the work done during this process.

A. 0 J
B. 1.5 kJ
C. 2.3 kJ
D. 3.8 kJ

Answer 1

The work done during the process is negative.

Step-by-step explanation:

To calculate the work done, we need to know the initial and final volumes. The final volume is the volume of one of the six cylinders with the piston all the way down: V₁ = 2.40 L/6 = 0.400 L. With a 10:1 compression ratio, the volume of the same cylinder with the piston all the way up is V₁ = 0.400 L/10 = 0.0400 L. Work is done by the system on its surroundings, so work is negative.