Consider a well-insulated, rigid tank containing 5 kg of water vapor in the same initial state as in Problem 3.52 (540°C, 60 bar). Again, the surroundings are at 1 bar and 25°C, as shown below.
A tiny leak develops, and water slowly escapes until the pressure reaches 20 bar.

Do you expect the fi nal temperature to be higher than, lower than, or the same as that calculated in part (b) of Problem 3.52? Explain your answer.

Problem 3.52

Consider a well-insulated piston–cylinder assembly containing 5 kg of water vapor, initially at 540°C and 60 bar, that undergoes a reversible expansion to 20 bar. The surroundings are at 1 bar and 25°C. Answer the following questions:

(b) What is the fi nal temperature of the water?

Transcribed Image Text:

Very tiny leak hole Pure HO P = 60 bar T = 540C m = 5kg Tsurr = 25C Psurr = 1 bar Well insulated Pure HO P = 20 bar T = ?C