Here's my problem: An ideal gas is allowed to expand freely into an evacuated chamber. The gas is at a pressure of 5 bar and a temperature of 45 degrees Celsius. Find the final temperature and pressure of the gas. Find the entropy produced. W=0, Q=0, dU=0, and dT=0. So the final temp. is 45 degrees Celsius. I need pressure at final state though... dU=0 implies that u1=u2. But I don't know what the gas is, so I can't get values for these. Am I missing something obvious? Please help soon! Thanks!