Thermal Physics and Ideal Gas

Water of depth 10 m exerts a pressure equal to atmospheric pressure.

An air bubble rises to the surface of a lake which is 20 m deep. When the bubble reaches the surface, its volume is 6.0 cm³.

What is the volume of the air bubble at the bottom of the lake?

• 2.0 cm³

• 3.0 cm³

• 12 cm³

• 18 cm³

A gas in a container of fixed volume is heated.

What happens to the molecules of the gas?

• They collide less frequently.

• They expand.

• They move faster.

• They move further apart.

A fixed mass of gas undergoes a change of volume at constant temperature.

Which diagram shows the relationship between the volume and the pressure of the gas?

• A

• B

• C

• D

A substance consists of particles that are close together and moving past each other at random. The average speed of the particles is gradually increasing.

What best describes the substance?

• a gas being heated

• a liquid being heated

• a liquid undergoing solidification

• a solid being heated

The table shows the melting points and the boiling points of some elements.

Which element is a liquid over the largest range of temperature?

• A

• B

• C

• D

Some ice cubes are taken from a freezer and heated in a container. The readings of temperature and time are recorded on the graph.

Which temperature is 0 °C?

• A

• B

• C

• D

The mercury-in-glass thermometer shown has a linear scale.

At a temperature of 100 °C, h has a value of 28 cm. At 80°C, h has a value of 24 cm.

What is the value of h when the temperature is 0 °C?

• 0.0 cm

• 2.8 cm

• 4.0 cm

• 8.0 cm

A fixed mass of gas is enclosed in a cylinder with a movable piston.

The gas is initially at pressure p₁ and has a volume V₁.

The temperature is kept constant. The piston is moved so that the pressure becomes p₂ and the volume becomes V₂.

Which equation is correct?

• p₁/V₁ = p₂/V₂

• p₁/p₂ = V₁/V₂

• p₁V₁ = p₂V₂

• p₁V₂ = p₂V₁

A tray for making ice cubes holds 30 g of water. The specific latent heat of fusion of ice is 3.3 × 10⁵ J/kg.

How much thermal energy is removed from the water at 0 °C to change it into ice at 0 °C?

• 9.9 × 10³ J

• 1.1 × 10⁴ J

• 9.9 × 10⁶ J

• 1.1 × 10⁷ J

A sealed container of gas is heated and the pressure inside increases.

What happens to the molecules of the gas to cause this increase in pressure?

• Their kinetic energy decreases.

• They become heavier.

• They expand.

• They hit the container more frequently.