Steam at 400C, 100 bar in an insulated cylinder is rapidly decompressed to 10 bar, by unlocking the piston and permitting the gas to expand, with a constant external pressure of 10 bar applied to the piston. Find the final temperature T2, and the entropy change S.
To solve the problem, ask yourself the following questions:
1) How much work is completed as the steam expands?
2) What does energy conservation tell you in this situation?