1. The problem statement, all variables and given/known data n = 1.46 moles of ideal gas are heated isobarically (at constant pressure) from temperature To = 431 oC to temperature Tf = 1227 oC. Find: change in Energy, Q, W. 2. Relevant equations Change in IE = Q + W W (isobaric process) = P(vf-v1) 3. The attempt at a solution change in IE = change in KE (because it is an ideal gas) = (3/2)nRT. So, (3/2)(1.46)(8.314 x 10^-3)(1227-431) = 14.5 kJ (no issue here) W = P(Vf-Vi), since it is an isobaric process. However, how are you supposed to get the volumes of the initial and final state? I tried pv = nRT, but am stuck with two unknowns. (Both Pressure, and Volume). Any suggestions? Many thanks in advance !