Internal Energy & Energy Transfers (AQA GCSE Physics)

Exam Questions

2 hours11 questions
1a2 marks

Define specific heat capacity.

1b3 marks

Figure 1 shows some equipment used to determine the specific heat capacity of aluminium.

Figure 1

3-2-e-1b-specific-heat-capacity-experiment

Complete the missing labels using words or phrases from the box below. Each option is used once.

Electric heater Insulating container Thermometer

1c3 marks

Figure 2 shows the reading before the heater was switched on. Figure 3 shows the reading at the end of the investigation.

Figure 2

3-2-e-1c-thermometer-1-for-specific-heat-capacity

Figure 3

3-2-e-1cthermometer-2-for-specific-heat-capacity

Calculate the change in temperature.

 

change in temperature = ....................................°C  

1d4 marks

Calculate the specific heat capacity of aluminium.

The following information may be useful:

  • Mass of block  = 0.796 kg 
  • Energy supplied  = 18 792 J 

State the correct unit.

specific heat capacity = .................................... unit.............

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2a2 marks

The particles in the different states of matter behave differently. 

Draw a straight line linking each state of matter with the description of its particles. 

screenshot-2022-09-27-at-13-01-13

2b3 marks

Define internal energy.

2c2 marks

State the two forms of energy the molecules within a substance can possess.

2d4 marks

Figure 1 shows hot water from a power station being sprayed into a cooling tower. As it falls through the air, some of the hot water evaporates.

The rest of the water is collected and returned as cold water to the power station.

Figure 1

3-2-e-2d-cooling-tower

Complete the sentences by choosing the correct words:

The temperature of the particles is directly / inversely proportional to their average kinetic / potential energy.

Energetic particles turn into liquid / gas as they leave the surface of the liquid / gas.

Gas particles have a higher / lower average kinetic / potential energy than the particles in the liquid, therefore, they move faster / slower.

The average kinetic / potential energy, and therefore temperature, of the remaining particles in the liquid increases / decreases.

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3a1 mark

A substance is cooled. Figure 1 shows how the temperature changes with time.

Figure 1

5-2-q5a-e-cooling-curve

State the physical change happening between X and Y on the graph.

3b1 mark

A solid substance is heated at a constant rate. Figure 2 shows how its temperature changes with time.

Figure 2

5-2-q5b-e-changes-of-state-heating-graph

Identify the region of the graph which represents the time when the substance is partially a liquid and partially a gas.

3c3 marks

A student pours 0.20 kg of water into a beaker. A thermometer placed in the water has a reading of 25 °C.

The temperature is monitored as ice is added to the beaker until the thermometer reads 0 °C.

Calculate the amount of energy transferred by the water as it cools from 25 °C to 0 °C.

The specific heat capacity of water is 4200 J/kg °C.  

 
 
energy transferred = .............................. J

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1a2 marks

A student decides to compare two different methods for recording how the temperature of H2O changes over a 30 minute period as it turns from ice to water.

Figure 1 shows the two sets of apparatus used by the student.

Figure 1

fig-1-3-2-medium-aqa-gcse-physics

State two advantages of using the digital thermometer rather than the analogue thermometer.

1b1 mark

The results obtained by the student are shown in Figure 2.

Figure 2
fig-2-3-2-medium-aqa-gcse-physics

What was the change in temperature between 0 and 80 seconds?

1c1 mark

Using Figure 2, determine how long it took for the water to change from a solid to a liquid. 

Time = ______________ seconds

1d3 marks

Calculate the energy transferred to the ice as 0.25 kg of ice was heated from -15°C to C.

The specific heat capacity of ice is 2050 J / kg °C.

1e3 marks

83 500 J of energy was transferred to the ice as it changed from solid to liquid.

Calculate the latent heat of fusion of ice.

1f2 marks

After 1760 seconds the temperature of the water began to increase again.

Explain why.

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2a4 marks

A thermos flask, as shown in Figure 3, is designed to minimise the transfer of thermal energy between the contents and the surroundings. 

The claim made by the manufacturer is that the thermos can keep hot water warm for up to 6 hours.

Figure 3

fig-3-3-2-medium-aqa-gcse-physics

14 800 J of energy are transferred from the thermos to the surroundings in 6 hours.

The mass of water in the flask is 360 g

The specific heat capacity of water is 4200 J / kg°C

The initial temperature of the water is 95 °C

Calculate the temperature of water in the flask after 6 hours, and state whether or not you agree with the manufacturer’s claim.

2b1 mark

By how much has the internal energy of the water in the flask changed?

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3a2 marks

What is meant by ‘specific latent heat of vaporisation’?

3b2 marks

When the water in a saucepan boils, 0.074 kg of water changes to steam.

Calculate the amount of energy required for this change.

Specific latent heat of vaporisation of water = 2.3 cross times 106 J / kg.

3c4 marks

The graph in Figure 4 shows how the temperature of a substance changes as it is heated.

Figure 4

fig-4-3-2-medium-aqa-gcse-physics

Explain what is happening to the substance in sections XY and YZ of the graph.

3d1 mark

State what change of state is taking place from point Z onwards.

3e2 marks

Explain whether the specific heat capacity of the substance in Figure 1 is greater for its solid or liquid form.

3f5 marks

The heater used to heat the substance in Figure 1 outputs a power of 1.2 kW  mass of substance being heated = 0.060 kg

Use information from Figure 1 to calculate the specific latent heat of fusion of the substance.

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4a2 marks

Figure 5 shows how an old-fashioned storage heater is constructed.

There are ceramic bricks inside, which are heated by the heating element during the night. 

During the daytime, the heating element is switched off and the blocks transfer their stored internal energy to the room.

Figure 5

fig-5-3-2-medium-aqa-gcse-physics

The reason for heating the room in this way is that electricity can be bought at a lower price between midnight and 7am.

The heating elements in the storage heater have a power output of 2.1 kW.

Calculate the amount of energy that will be transferred to the blocks between the hours of midnight and 7am.

4b3 marks

By 7am the temperature of the blocks has risen from 20 °C to 750 °C.

Calculate the total mass of the blocks inside the heater.

Specific heat capacity of the blocks = 800 J / kg °C.

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5a3 marks

A student wants to carry out an investigation to calculate the specific latent heat of fusion of water. 

She uses a 250 ml beaker to hold the water.

Suggest what other apparatus she would need to carry out the investigation.

5b3 marks

Describe the measurements the student would have to take to determine the specific latent heat of fusion of water, and explain how she would determine its value.

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1a4 marks

A student wants to determine the specific heat capacity of water using the apparatus shown in Figure 1:

Figure 1

5-2-q5a-h-immersion-heater-practical

State the variables which need to be measured to calculate the specific heat capacity of water.

Explain how the student should measure one of these variables.

1b4 marks

Table 1 shows the student's results. The temperature of the water was recorded every minute for 6 minutes.

Table 1

Time (mins) Temperature (°C)
0 20
1 31
2 39
3 40
4 61
5 70
6 82

 

Plot a graph of these results.

graph-paper
1c3 marks

Circle the anomalous point on the graph.

State what the student should do with the anonymous reading.

1d2 marks

Predict the temperature at 8 and 9 minutes. 

Temperature at 9 minutes = .................................... °C

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2a3 marks

A lidded beaker contains water vapour.

Describe the movement of the particles that make up the lidded beaker and the movement of the particles of water vapour.

2b4 marks

The water vapour is allowed to cool and the temperature is taken at regular intervals.

Sketch a graph to show the change in temperature with time.

2c2 marks

Explain what is meant by the specific heat capacity of a substance.

2d3 marks

A mass of 170 g of water is needed to make a cup of instant hot chocolate for which the optimum temperature is 80 ºC. The water is heated in a kettle from a temperature of 55 ºC.

The specific heat capacity of water = 4200 J kg–1 K–1.

Calculate the energy required to heat the water to the optimum temperature.

 

Energy required = ....................................... J

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3a3 marks

Define and state the differences between latent heat of fusion and latent heat of vaporisation.

3b3 marks

The energy needed to boil 530 g of a liquid is 0.6 MJ.

Calculate the specific latent heat of the liquid and state whether it is the latent heat of vaporisation or fusion.

3c2 marks

The group of students doing this experiment used the equipment shown in Figure 1 to determine the energy transferred to the liquid.

Figure 1

latent-heat-equipment

The students were provided with the liquid, an electric water bath, and were allowed to use water from the tap.

Suggest why the students were given an electric water bath rather than a Bunsen burner.

3d3 marks

The calculation of specific latent heat using this method may give a value that is different to the true answer.

Explain why.

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