# Homework Help: Properties in a closed system Help

1. Nov 2, 2008

### airstrider

Properties in a closed system...Help!!!

1. The problem statement, all variables and given/known data
A cylinder, locked by a plug, contains 1kg of 'wet' steam at a pressure of 5 bar (state point 1). In the locked position, heat is added through the wall of cylinder into the wet steam until the mixtures become dry saturated at 200 degrees(state point 2). The plug is then removed and the pistion is then allowed to expand isothemally(at 200 degrees) until the steam in the cylinder reaches its initial pressure of 5 bar( state point 3). Finally, the piston is returned to the initial state by compression via a heat rejection process. How to determine the properties (P,T,V and U) of the steam at those state points?

2. Relevant equations

3. The attempt at a solution
From the question, we know that P1=P3=5 bar, V1=V2 and T2=T3=200 degrees. I am able to get V3=mRT/P3= (1x287x473)/500000=0.271.
I can't continue from here as there's 2 unknown properties in the other 2 states.
Can anyone help?