1. The problem statement, all variables and given/known data There are two insulated air containers, first with a volume V1 and second with V2. In the first there is a pressure p1 and in the second p2. The temperatures are the same in both, thus T. Then both containers are connected with a hose so that pressure equalizes, but no heat is transferred between them. What are the final temperatures and final pressure? 2. Relevant equations ... 3. The attempt at a solution If there was heat transfer between containers, the final temperature would be the same in both and even the same as the temperature T in the beginning and because of that I could calculate the final pressure using pV = mRT (R = gas constant for air), where I'd get mass for one container from specific volumes. But this case with no heat transfer is a bit confusing. I can't get final pressure with the equation used above because I don't know the final temperatures. The book says the final pressure is the same as above, but I don't know why is it so.