[SOLVED] volume of gas in a cylindrical vessel on which a piston has been placed 1. The problem statement, all variables and given/known data A cylindrical vessel with a tight but movable piston is placed in a vertical position so that the piston, whose area is 60 cm2, is subject to atmospheric pressure. When the gas in the vessel is heated from 20oC to 80oC, a 0.6 kg mass must be placed on top of the piston to hold it at the position it occupied at lower temperature. What is the volume of 0.3 mol of the gas? 2. Relevant equations Pv=nRT 3. The attempt at a solution Since we were given the moles of gas (.3 mol) and we know R since it's a constant, I assumed that the pv=nRT would be the correct equation. I found the pressure of the cylinder with the weight on to be the pressure by the weight: P=F/A= [(.6 kg * 9.8 m/s^2)]\.6m^2. The temperature I put was 353K - that of the second cylinder. I got a volume of 53.9 m^2 but I know that the volume must be much greater, given the size of the cylinder in the problem. I don't know how else to go about the problem so I would appreciate any help. Thank-you!!