1. The problem statement, all variables and given/known data A gas sample heated in a cylinder used 650 kJ of heat. A piston that compresses the gas does 800 kJ of work. What is the change in internal energy, ΔE, of the gas during this process 2. Relevant equations ΔE = q + w 3. The attempt at a solution ΔE = q + w ΔE = (650kJ) + (800 kJ) ΔE = 1450 kJ a result of the gas being heated and compressed, the energy of the gas increases by 1450 kJ. Is this at all correct? Or should it be -650 kJ??? Thank you for your help.