1. The problem statement, all variables and given/known data If the Helmholtz Free Energy remains constant, estimate the final pressure of 1.0mol of an ideal gas in the following transformation: (1.0atm, 300k) → (pfinal, 600k). Given Sgas = R. 2. Relevant equations A = U - TS dA = -SdT - pdV 3. The attempt at a solution If the Helmholtz Free Energy is constant, then ΔA = 0. So from dA = -SdT - pdV I'd get that S⋅ΔT = -pΔV. But I don't see how that helps me figuring out the final pressure.