Imagine that we have two identical pistons of ideal gas in the same initial states at room temperature. Piston 1 is free to move up or down. Piston 2 is fixed so it maintains a constant volume. We put both systems into a reservoir of hot water and let them come to equilibrium. Which statement about this situation is true?

1. Both the heat Q and the change in internal energy will be the same for the two pistons
2. The heat is the same for the two pistons but piston 1 has a larger change in internal energy.
3. The heat is the same for the two pistons but piston 2 has a larger change in internal energy.
4. The changes in internal energy are the same for the two pistons but piston 1 has more heat.
5. The changes in internal energy are the same for the two pistons but piston 2 has more heat.
6. None of the above