Since linear dimensions are not given, it means that the change of internal energy of the gas due to the pressure and volume change are not considered (are negligible). Then the change of mechanical energy of the system is delta(P) = mgh = 1.9 kg * 9.81 m/s^2 * 0.24 m = 4.473 joules. This amount of energy transforms to the heat energy and goes from the ideal gas to the heat reservoir. Answer. 4.473 joules of heat energy go from the ideal gas to the heat reservoir.