Internal energy

A scientist poured some liquid nitrogen into a container.

The container was then sealed.

Figure 10 shows the container.

The liquid nitrogen was at its boiling point.

When 9950 J of thermal energy was transferred to the liquid nitrogen, 50 g of the nitrogen turned into a gas.

Calculate the specific latent heat of vaporisation of nitrogen.

Use the Physics Equations Sheet.

Explain how the internal energy of the nitrogen changed as the nitrogen turned from a liquid to a gas.

After the nitrogen had boiled, the temperature of the gas increased.

Explain how the pressure in the container changed as the temperature increased.

Figure 14 shows an electrical circuit used to heat the windscreen of a car.

Each resistor in the circuit represents a heating element.

The 12 V battery supplies direct potential difference.

What is meant by ‘direct potential difference’?

Use the Physics Equations Sheet to answer questions 10.2 and 10.3.

Which equation links charge flow (Q), energy (E) and potential difference (V)?

Tick (✓) one box.

Calculate the charge flow through the 12 V battery when the battery transfers 5010 J of energy.

Ice forms on the windscreen at a temperature of 0 °C.

The electrical circuit transfers 5010 J of energy to the ice.

A mass of 0.015 kg of ice melts.

Calculate the specific latent heat of fusion of water.

Use the Physics Equations Sheet.

The electrical circuit was left switched on while the ice changed from a solid to a liquid and increased in temperature to 5 °C.

Explain the changes in the arrangement and movement of the particles as the ice melted and the temperature increased to 5 °C.

Figure 4 shows an electrical circuit used to heat the windscreen of a car. Each resistor in the circuit represents a heating element.

The 12 V battery supplies direct potential difference. What is meant by ‘direct potential difference’?

Use the Physics Equations Sheet to answer questions 03.2 and 03.3.

Which equation links charge flow (Q), energy (E) and potential difference (V)? Tick (✓) one box.

Calculate the charge flow through the 12 V battery when the battery transfers 5010 J of energy.

Ice forms on the windscreen at a temperature of 0 °C. The electrical circuit transfers 5010 J of energy to the ice. A mass of 0.015 kg of ice melts. Calculate the specific latent heat of fusion of water. Use the Physics Equations Sheet.

The electrical circuit was left switched on while the ice changed from a solid to a liquid and increased in temperature to 5 °C. Explain the changes in the arrangement and movement of the particles as the ice melted and the temperature increased to 5 °C.

Figure 14 shows a Bunsen burner heating some water in a beaker. Eventually the water changes into steam.

Explain how the internal energy of the water changes as it is heated from 20 °C to 25 °C

How is the particle model used to explain the difference in density between a liquid and a gas?

Tick (✓) one box.

A student measured the mass of boiling water that was turned into steam in five minutes.

Explain how the student could use this information to estimate the power output of the Bunsen burner in watts.

Figure 1 shows a cyclist riding along a flat road.

Complete the sentence.

Choose answers from the box.

chemical elastic potential gravitational potential kinetic

the cyclist increases.

The mass of the cyclist is 80 kg. The speed of the cyclist is 12 m/s.

Calculate the kinetic energy of the cyclist.

Use the equation: kinetic energy = 0.5 × mass × (speed)²

When the cyclist uses the brakes, the bicycle slows down.

This causes the temperature of the brake pads to increase by 50 °C. The mass of the brake pads is 0.040 kg. The specific heat capacity of the material of the brake pads is 480 J/kg °C.

Calculate the change in thermal energy of the brake pads.

Use the equation:

change in thermal energy = mass × specific heat capacity × temperature change

How is the internal energy of the particles in the brake pads affected by the increase in temperature?

Tick one box.