1. The problem statement, all variables and given/known data A cylinder contains 0.250mol of carbon dioxide (CO2) gas at a temperature of 27.0∘C. The cylinder is provided with a frictionless piston, which maintains a constant pressure of 1.00atm on the gas. The gas is heated until its temperature increases to 127.0∘C. Assume that the CO2 may be treated as an ideal gas. 2. Relevant equations ΔU = ΔQ -W ΔU = C_v*n*ΔT 3. The attempt at a solution In this case, I thought that ΔU could be set equal to (5/2)nRΔT since we know all of those variables. The value I got for that was ΔU = 520J, but that isn't the correct answer. Any help in explaining where I am going wrong would be appreciated greatly!