Kinetic Particle Model of Matter

The strength of the forces between the particles of a solid determines how much the solid expands when heated.

Which statement about these forces is correct?

Options

A   The forces are strong so solids expand less than liquids and gases.
B   The forces are strong so solids expand more than liquids and gases.
C   The forces are weak so solids expand less than liquids and gases.
D   The forces are weak so solids expand more than liquids and gases.

Air is heated in a sealed container with constant volume.

Why does the air pressure increase when the temperature increases?

Options

A   The air molecules expand.
B   The air molecules bounce off each other more frequently.
C   The air molecules bounce off the walls more frequently.
D   The number of air molecules increases.

The diagram shows a cylinder containing air.

The piston is free to move inside the cylinder and atmospheric pressure acts outside the cylinder.

As the air inside the cylinder is heated, the piston moves to the right.

Which quantity decreases?

Options

A   the average force exerted on the piston each time that one air particle hits the piston
B   the average speed of the air particles
C   the mass of air inside the cylinder
D   the number of collisions made by air particles with the piston in one second

A fixed mass of air has a volume of $150\ \text{cm}^3$ and a pressure of $120\ \text{kPa}$.

The volume of the air is now changed to $100\ \text{cm}^3$. The temperature of the air remains constant.

What is the new pressure of the air?

Options

A   $80\ \text{kPa}$
B   $180\ \text{kPa}$
C   $80\,000\ \text{kPa}$
D   $180\,000\ \text{kPa}$

The pressure and volume of a sample of gas at constant temperature are measured and plotted on a graph.

The pressure is decreased to $12.5\ \text{kPa}$.

What is the new volume of this sample of gas?

Options

A   $1.2 \times 10^{-4}\ \text{m}^3$
B   $4.8 \times 10^{-4}\ \text{m}^3$
C   $1.2 \times 10^{-2}\ \text{m}^3$
D   $4.8 \times 10^{4}\ \text{m}^3$

A student heats a substance in which the particles are in fixed positions and vibrate.

After a short period of heating, the particles start to flow past each other, but the forces between the particles remain strong.

What has happened to the substance?

Options

A   It has condensed.
B   It has evaporated.
C   It has frozen.
D   It has melted.

A student investigates how changing the temperature of a gas affects the volume of the gas.

The gas is kept at a constant pressure.

Which graph shows the relationship between the temperature and the volume of a sample of gas at constant pressure?

Options

A student compares the properties of the three states of matter.

The partially completed table in the student's notebook for one of the states is shown.

Which words complete the table?

Options

Air is trapped in a glass tube by a liquid.

When the tube is horizontal, the length of the trapped air is $50\ \text{mm}$ and its pressure is $1.0 \times 10^5\ \text{Pa}$.

When the tube is vertical, with the closed end downwards, the length of the trapped air is $45\ \text{mm}$.

The temperature of the air remains constant.

What is the pressure of the trapped air when the tube is vertical?

Options

A   $0.50 \times 10^5\ \text{Pa}$
B   $0.90 \times 10^5\ \text{Pa}$
C   $1.1 \times 10^5\ \text{Pa}$
D   $1.9 \times 10^5\ \text{Pa}$

In which example are the particles in fixed positions?

Options

A   ice in an ice cube
B   water in a lake
C   air in an air bubble
D   water vapour in the atmosphere