A rigid, perfectly insulating container is divided into two equal chambers by a thin…
PHYSICS · Single correct · A Level · Physics · Further mechanics and thermal physics · Further mechanics and thermal physics
Problem
A rigid, perfectly insulating container is divided into two equal chambers by a thin removable partition. Each chamber initially contains an ideal gas at the same temperature and pressure. The partition is suddenly removed, allowing the gases to mix until equilibrium is reached. Which statement best describes the energy transfer between the container and its surroundings during the mixing process?
(a) Work occurs but no heating, because each gas expands into the other chamber and pushes on the rigid walls.
(b) Neither heating nor work occurs across the container’s boundary because its walls prevent any transfer of energy.
(c) Both heating and work occur, because the temperature of the gas mixture must change as the gases mix.
(d) Heating occurs into the system, because ideal gases cool during free expansion and must absorb heat from the surroundings to return to the initial temperature.