A gas is kept at a constant temperature in a closed container of fixed volume. The pressure exerted by the gas is due to the molecules colliding with the container walls.
Which statement correctly describes what happens to the gas molecules when they collide with the walls?
Their average kinetic energy decreases during the collisions.
Their average speed decreases as they bounce off the walls.
The momentum of the molecules changes during the collisions.
The molecules undergo inelastic collisions with the walls.
321 exam-style questions on CIE IGCSE Physics 2.1 Kinetic particle model of matter, covering 2.1.1 States of matter and changes of state, 2.1.2a Particle structure and motion in solids, liquids and gases, 2.1.2b Gas pressure and particle collisions, 2.1.2c Brownian motion, 2.1.3a The absolute scale of temperature, and 2.1.3b Pressure, volume and temperature of a gas. Each one has a worked solution and a mark scheme showing where the marks go.