1. The problem statement, all variables and given/known data 1) A quantity of propane is contained in a piston-cylinder assembly. This working fluid undergoes a process starting from an initial state of 2.0 MPa and 60oC. At the end of the process the pressure of the propane is 1.0 MPa and the specific entropy is 0.089 kJ/kgK higher than at the start of the process. Determine the temperature of the propane at the end of the process. 2. Relevant equations For the first question I am using the propane tables found here, ( http://www.engr.mun.ca/muzychka/ThermodynamicPropertiesTables.PDF ) I think this equation may be useful, s2 - s1 = so(T2) - so(T1) - (R/M)(ln(p2/p1)) 3. The attempt at a solution For the first question I am pretty sure all I have to do is just interpolate to find what so(T1) is, then would I just rearrange the equation to find so(T2) and then interpolate to determine T2? I just don't quite understand interpolating but I think what I have said above is correct.