Steam in a cylinder-piston arrangement expands from an initial condition of 5 bar, 80% dry to a final state of 2 bar, dry saturated steam.

Question

The initial volume of steam is 0.8 m3.
The process of expansion can be represented by a straight line on the p–Vdiagram.

5B. What is the mass of steam in the system, in kg?

5C. What is the work done by the system, in kJ?

5D. What is the change in energy of the system, in kJ?

5E. What is the heat absorbed by the system, in kJ?

5F. Which of the following assumptions did you have to make

The process is adiabatic.

The process is reversible.

All work interaction is of the expansion type.

Only thermal energy change is significant.

The behaviour of the contents of the system is like that of an ideal gas.

Answer 1

for 5f -

All work interaction is of the expansion type.

Only thermal energy change is significant.

these two apply. becoz the process itself is expansion only as stated in problem and only significant change which we can notice is temperature which lowers as expansion gets done

Answer 2

50kg