1. The problem statement, all variables and given/known data Consider the adiabatic expansion of .553mol of an ideal monatomic gas with CV,m = 3R/2. The initial state is described by P = 6.25bar and T = 306K. Calculate the final temperature if the same gas undergoes an adiabatic expansion against an external pressure of P = 1.25bar to a final pressure P = 1.25bar. 2. Relevant equations CVΔT = -PextΔV 3. The attempt at a solution I need to find ΔT. P, V, and T are all variables, though, so I can't find ΔT because I don't know ΔV. What do I do?