1. The problem statement, all variables and given/known data Rigid tank volume .5m^3 initially evacuated. Tiny hole develops, air seeps in @ 1 bar and 21 degrees C. Pressure in tank reaches 1 bar, slow leak so temp remains 21 deg C inside tank. What's amount of heat transfer? 2. Relevant equations Q=T[S(2)-S(1)] Pv=nRT 3. The attempt at a solution Ok, I understand this is a reversible isothermal process but it seems that I am not given enough information to solve the problem. Please help to send me in the right direction! Thanks!