A sealed, rigid canister contains a constant volume of gas. When the canister is placed in a freezer, the gas cools down and its pressure decreases. What explains this decrease in pressure in terms of the motion of gas molecules?
Number of gas molecules in canister: decreased; Average force exerted during a collision with the canister wall: decreased; Number of collisions per second with the canister wall: increased
Number of gas molecules in canister: decreased; Average force exerted during a collision with the canister wall: unchanged; Number of collisions per second with the canister wall: increased
Number of gas molecules in canister: unchanged; Average force exerted during a collision with the canister wall: decreased; Number of collisions per second with the canister wall: decreased
Number of gas molecules in canister: unchanged; Average force exerted during a collision with the canister wall: unchanged; Number of collisions per second with the canister wall: decreased
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.