1. The problem statement, all variables and given/known data http://img846.imageshack.us/img846/5678/problemem.jpg [Broken] 2. Relevant equations Pv= nRT U = Q-W dS = dQ/T (entropy transferred) + σ (entropy created) 3. The attempt at a solution Part A. Assuming that as the gas expands Volume increases and Pressure decreases, thus the Temperature will stay constant. Part B. Entropy will increase as the gas expands. Assuming the system is isolated, there will be no entropy transfered in or out. For entropy created: Because T is constant internal energy U will stay constant, which means that Q = -W = -dPV so dS = -dPV. But the pressure in the problem is not given so I am stuck. So I was wondering, are my assumptions correct? V and P change but T stays the same no entropy is transfered because the system is isolated How do I go about solving part b?