Two identical rigid tanks are connected by a valve
PHYSICS · Single correct · CBSE · Physics · Kinetic Theory · Kinetic Theory
Problem
Two identical rigid tanks are connected by a valve. Initially the valve is closed, Tank X contains an ideal gas at 100 kPa and Tank Y is evacuated. The tanks are kept at the same temperature. The valve is then opened and the system eventually reaches equilibrium. Which of the following best explains why the final pressures in the two tanks are equal?
(a) Gas molecules are attracted toward the vacuum, so a net outward force permanently lowers the pressure in Tank X.
(b) The gas continues to flow until each tank contains the same number of molecules; because the volumes are equal, this makes the pressures equal.
(c) Gas molecules move randomly in all directions, so they spread out until collisions occur equally often everywhere, producing uniform pressure.
(d) When the valve opens, the gas cools due to free expansion, lowering the pressure in Tank X until it matches Tank Y.