1. The problem statement, all variables and given/known data 10kg of air is compressed in a closed system from an initial temperature of 30° C to a final temperature of 260° C. Given cv = 710 J/kg.K. Calculate the change in internal energy. 2. Relevant equations ΔU = Q - W W = P ΔV Q = m c ΔT P V = m R ΔT 3. The attempt at a solution Since it is a compression, the work done is -ve. I am able to find the Q which has +ve since the temperature increases. However, how can I get the W?