State what happens to the motion of the molecules of a gas in a sealed container when the temperature of the gas is increased.
A quantity of gas is contained in a sealed container of fixed volume. The temperature of the gas is increased. State, in terms of molecules, two reasons why the pressure of the gas increases.
A helium-filled research balloon is released from ground level. The volume of the balloon at the ground is 4500 m34500 \text{ m}^34500 m3 and the pressure of the helium is 100 kPa100 \text{ kPa}100 kPa.
The balloon rises to a high altitude where the volume of the balloon increases to 7500 m37500 \text{ m}^37500 m3.
Calculate the new pressure of the helium. Assume that the temperature remains constant.
Suggest why it may be necessary to release some helium from the balloon if it rises even higher.
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.