1. The problem statement, all variables and given/known data In a closed system 0.4kg of gas at 374K is expanded isothermally and reversibly from 1MPa pressure to 300kPa. Given that Cv = 718j/kg and R = 287j/kg, determine the work done. 2. Relevant equations Not sure? I guess W = p*V? 3. The attempt at a solution I honestly don't know how to solve this one.