1. The problem statement, all variables and given/known data Which of the following changes during the free adiabatic expansion of a real gas? (I) internal energy (II) temperature (III) pressure 2. Relevant equations PV=nRT; ΔU= q + w 3. The attempt at a solution For ideal gases under adiabatic conditions, we know that there is no heat transfer. Thus, the only change is pressure. However, what can be concluded about real gases? Ideal gas law assumes no volume or attraction between molecules but real gases do not act this way, thus under high pressures, there is an increase in attraction due to intermolecular forces. So, if the real gas expands, volume changes but what can be said about internal energy and temperature? The correct answer states II and III but I do not see how temperature is affected under adiabatic conditions. Help please!