A rigid, sealed metal tank contains an ideal gas at room temperature. The tank is…
PHYSICS · Single correct · AP · Physics 2: Algebra-based · Thermodynamics · Thermodynamics
Problem
A rigid, sealed metal tank contains an ideal gas at room temperature. The tank is slowly heated while its volume remains constant. The internal pressure rises.
Which of the following provides the best microscopic explanation for the pressure increase?
(a) Heating the gas decreases its density, so molecules have more space and the pressure drops.
(b) Gas molecules move faster at higher temperature, so they strike the walls more often and with greater momentum change, increasing the pressure.
(c) Because the volume is fixed, the number of wall collisions per second cannot change, so the pressure stays the same regardless of temperature.
(d) The pressure rises because each molecule’s mass increases slightly at higher temperature, producing larger momentum changes during collisions.