Specific heat capacity

A student investigated the thermal conductivity of different metals.

Figure 2 shows some of the apparatus used.

Each rod was made from a different metal.

The metal rods are joined at the centre.

The size of each metal rod was the same.

This is the method used.

1. Attach a drawing pin to the end of each metal rod using wax.

2. Light the Bunsen burner.

3. Start a stopclock.

4. Record the time taken for the wax to melt and for the drawing pin to fall off each metal rod.

Table 1 shows the results.

Complete Figure 3.

You should:

• label the x-axis

• plot the data from Table 1 as a bar chart.

Which type of metal in Table 1 had the greatest thermal conductivity?

Give a reason for your answer.

Tick () one box.

The thermal energy transferred to the nickel rod was 132 J.

The temperature change of the rod was 20 °C.

mass of the nickel rod = 0.015 kg

Calculate the specific heat capacity of nickel.

Use the equation:

Use the Physics Equations Sheet to answer questions 02.4 and 02.5.

Write down the equation which links energy transferred (E), power (P) and time (t).

At the end of the investigation, the Bunsen burner was turned off.

As the nickel rod cooled to room temperature, the rod transferred 132 J of energy to the room.

The mean power transfer was 0.33 W.

Calculate the time taken for the energy transfer.

A student determined the specific heat capacity of water.

Figure 17 shows the apparatus used.

The joulemeter measures energy transfer.

Give one hazard in the investigation.

Describe how the student could determine the specific heat capacity of water using the apparatus in Figure 17.

One source of error in the experiment was energy loss to the surroundings.

Suggest one change to the apparatus to reduce energy loss to the surroundings.

The student’s value for the specific heat capacity of water was 4410 J/kg °C.

The actual value for the specific heat capacity of water is 4200 J/kg °C.

Calculate the percentage difference between the student’s value and the actual value.

A student determined the specific heat capacity of water.

Figure 4 shows the apparatus used.

The joulemeter measures energy transfer.

Give one hazard in the investigation.

Describe how the student could determine the specific heat capacity of water using the apparatus in Figure 4.

One source of error in the experiment was energy loss to the surroundings.

Suggest one change to the apparatus to reduce energy loss to the surroundings.

The student’s value for the specific heat capacity of water was 4410 J/kg °C.

The actual value for the specific heat capacity of water is 4200 J/kg °C.

Calculate the percentage difference between the student’s value and the actual value.

Scientists have used lasers to start a nuclear fusion reaction.

The scientists used the lasers to heat a small amount of an isotope of hydrogen.

Describe what is meant by ‘isotopes’ of an element.

Explain how nuclear fusion releases energy.

The fusion reaction releases large amounts of energy.

The fusion reaction takes place in a reactor.

Explain why the walls of the reactor should be made from a material with a very high specific heat capacity.

Nuclear fusion is safer than nuclear fission.

Nuclear fission can lead to an uncontrolled chain reaction.

Give one consequence of an uncontrolled chain reaction.

Figure 8 shows a battery-powered hand warmer that contains a heating pad.

The battery transfers energy to increase the temperature of the heating pad.

The heating pad has a mass of 0.20 kg.

When the hand warmer was switched on, the energy transferred to the heating pad was 8000 J.

specific heat capacity of heating pad = 1600 J/kg °C

Calculate the temperature increase of the heating pad.

Use the Physics Equations Sheet.

The hand warmer was powered by a 5.0 V battery.

The battery transferred 180 kJ of energy to the heating pad.

Calculate the charge flow through the battery.

Use the Physics Equations Sheet.

The circuit inside the hand warmer can be connected to a mobile phone to recharge the mobile phone.

Figure 9 shows the circuit diagram when the hand warmer is connected to a mobile phone.

The heating pad of the hand warmer is represented by the resistor symbol.

Explain how closing both switches S₁ and S₂ affects the power output of the battery compared with only closing switch S₁.

A student investigated how the pressure in a fixed mass of air varies with the volume of the air.

Figure 10 shows the equipment used.

When the plunger was pushed slowly into the syringe, the temperature of the air stayed the same.

How did pushing the plunger in affect the volume of air in the syringe?

Tick () one box.

How did pushing the plunger in affect the distance between the air particles in the syringe?

Tick () one box.

How did pushing the plunger in affect the frequency of collisions between the air particles and the syringe walls?

Tick () one box.

How did pushing the plunger in affect the air pressure in the syringe?

Tick () one box.

A fire piston is a special type of syringe that can be used to start fires.

Figure 11 shows a fire piston.

The plunger is pushed quickly downwards and compresses the air.

When the air is compressed quickly, the temperature of the air increases.

How does an increase in temperature affect the mean speed of the air particles inside the syringe?

Tick () one box.

When the air is hot enough, a small piece of cotton wool in the piston catches fire.

The energy transferred to the air in the piston is 0.0130 J.

The mass of air in the piston is 2.60 × 10^–8 kg.

specific heat capacity of air = 1010 J/kg °C

Calculate the temperature change of the air.

Use the Physics Equations Sheet.

A student investigated how the pressure in a fixed mass of air varies with the volume of the air.

Figure 12 shows the equipment used.

When the plunger was pushed slowly into the syringe, the pressure in the syringe increased.

The temperature of the air remained constant.

Explain why the pressure increased.

A fire piston is a special type of syringe that can be used to start fires.

Figure 13 shows a fire piston.

The plunger is pushed quickly downwards and compresses the air.

When the air is compressed quickly, the temperature of the air increases.

How does an increase in temperature affect the air particles inside the piston?

Tick (✓) one box.

When the air is hot enough, a small piece of cotton wool in the piston catches fire.

The energy transferred to the air in the piston is 0.0130 J.

The mass of air in the piston is 2.60 × 10^–8 kg.

specific heat capacity of air = 1.01 kJ/kg °C

Calculate the temperature change of the air.

Use the Physics Equations Sheet.

Figure 12 shows the equipment a student used to determine the specific heat capacity of iron.

The iron block the student used has two holes, one for the heater and one for the thermometer.

Before the power supply was switched on, the thermometer was used to measure the temperature of the iron block.

The student left the thermometer in the iron block for a few minutes before recording the initial temperature.

Suggest why.

Figure 13 shows how the temperature changed after the power supply was switched on.

The energy transferred to the iron block between 5 and 10 minutes was 26 000 J.

The mass of the iron block was 2.0 kg.

Calculate the specific heat capacity of iron.

Use information from Figure 13 and the Physics Equations Sheet.

The student repeated the investigation but wrapped insulation around the iron block.

What effect will adding insulation have had on the investigation?

Tick (✓) two boxes.

Figure 2 shows the equipment a student used to determine the specific heat capacity of iron. The iron block the student used has two holes, one for the heater and one for the thermometer.

Before the power supply was switched on, the thermometer was used to measure the temperature of the iron block. The student left the thermometer in the iron block for a few minutes before recording the initial temperature. Suggest why.

Figure 3 shows how the temperature changed after the power supply was switched on.

The energy transferred to the iron block between 5 and 10 minutes was 26 000 J. The mass of the iron block was 2.0 kg. Calculate the specific heat capacity of iron. Use information from Figure 3 and the Physics Equations Sheet.

The student repeated the investigation but wrapped insulation around the iron block. What effect will adding insulation have had on the investigation? Tick (✓) two boxes.

A student investigated the insulating properties of two different materials.

The same thickness of each material was used.

Figure 9 shows some of the equipment used by the student.

The student used two different types of thermometer to measure the temperature changes.

Figure 10 shows a reading on each thermometer.

What is the resolution of thermometer B ?

Tick (✓) one box.

Complete the sentence.

Choose the answer from the box.

thermometer B.

Figure 11 shows the results.

The mass of water used was 0.12 kg.

specific heat capacity of water = 4200 J/kg °C

Determine the total change in thermal energy of the water when Material X was used.

Use values from Figure 11.

Use the Physics Equations Sheet.

There is an anomalous result on Figure 11.

Draw a ring around the anomalous result.

Give two conclusions that can be made from Figure 11.

Another student investigated how the thickness of the insulation affected the rate of cooling of hot water.

Figure 12 shows some of the equipment used.

How would using thick insulation affect the rate of cooling of hot water compared with using thin insulation?

Tick (✓) one box.

Predict how using thick insulation would affect the temperature of the water after 10 minutes compared with using thin insulation.

Tick (✓) one box.

A student investigated the insulating properties of different materials. Figure 4 shows some of the equipment used by the student.

This is the method used:

1. Wrap insulating material around the can.

2. Put a fixed volume of boiling water in the can.

3. Place the lid on the top of the can.

4. Measure the time taken for the temperature of the water to decrease by a fixed amount.

5. Repeat steps 1–4 using the same thickness of different insulating materials.

Identify the independent variable and the dependent variable in this investigation. Independent variable Dependent variable

The student used two different types of thermometer to measure the temperature changes. Figure 5 shows a reading on each thermometer.

What is the resolution of thermometer B ?

Thermometer A is more likely to be misread. Give one reason why.

For one type of insulating material, the temperature of the water decreased from 85.0 °C to 65.0 °C. The energy transferred from the water was 10.5 kJ. specific heat capacity of water = 4200 J/kg °C Calculate the mass of water in the can. Use the Physics Equations Sheet.

Table 2 shows the results for two insulating materials.

Explain how the results in Table 2 can be used to compare the thermal conductivity of the two materials.

Energy from the Sun is released by nuclear fusion.

Complete the sentences.

Nuclear fusion of deuterium is difficult to achieve on Earth because of the high temperature needed.

Electricity is used to increase the temperature of 4.0 g of deuterium by 50 000 000 °C.

specific heat capacity of deuterium = 5200 J/kg °C

Calculate the energy needed to increase the temperature of the deuterium by 50 000 000 °C.

Use the Physics Equations Sheet.

The idea of obtaining power from nuclear fusion was investigated using models.

The models were tested before starting to build the first commercial nuclear fusion power station.

Suggest two reasons why models were tested.

Generating electricity using nuclear fusion will have fewer environmental effects than generating electricity using fossil fuels.

Explain one environmental effect of generating electricity using fossil fuels.

Energy from the Sun is released by nuclear fusion.

Complete the sentences.

Nuclear fusion of deuterium is difficult to achieve on Earth because of the high temperature needed. Electricity is used to increase the temperature of 4.0 g of deuterium by 50 000 000 °C. specific heat capacity of deuterium = 5200 J/kg °C Calculate the energy needed to increase the temperature of the deuterium by 50 000 000 °C. Use the Physics Equation Sheet.

The idea of obtaining power from nuclear fusion was investigated using models. The models were tested before starting to build the first commercial nuclear fusion power station. Suggest two reasons why models were tested.

Generating electricity using nuclear fusion will have fewer environmental effects than generating electricity using fossil fuels. Explain one environmental effect of generating electricity using fossil fuels.

A student heated water in an electric kettle.

Water has a high specific heat capacity. Complete the sentence. Choose answers from the box.

The specific heat capacity of a substance is the energy needed to raise the

The kettle circuit contains a thermistor which is used to switch the kettle off when the water reaches 100 °C. What is the correct symbol for a thermistor? Tick (✓) one box.

The resistance of the heating element in the kettle is 15 Ω. The current in the heating element is 12 A. Calculate the power of the heating element. Use the equation: power = (current)² resistance

The student investigated how quickly the kettle could increase the temperature of 0.50 kg of water. Figure 10 shows the results of the investigation.

The temperature of the water did not start to increase until 10 seconds after the kettle was switched on. What is the reason for this? Tick (✓) one box.

Describe a method the student could have used to obtain the results shown in Figure 10.

The mass of water in the kettle was 0.50 kg. The temperature of the water increased from 20 °C to 100 °C. specific heat capacity of water = 4200 J/kg °C Calculate the energy transferred to the water. Use the Physics Equations Sheet.

The water in the kettle boiled for a short time before the kettle switched off. During this time 5.0 g of water changed to steam. specific latent heat of vaporisation of water = 2 260 000 J/kg Calculate the energy transferred to change the water to steam. Use the Physics Equations Sheet.

An electric kettle was switched on. Figure 10 shows how the temperature of the water inside the kettle changed.

When the kettle was switched on the temperature of the water did not immediately start to increase. Suggest one reason why.

The energy transferred to the water in 100 seconds was 155 000 J. specific heat capacity of water = 4200 J/kg °C Determine the mass of water in the kettle. Use Figure 10. Give your answer to 2 significant figures.

The straight section of the line in Figure 10 can be used to calculate the useful power output of the kettle. Explain how.

A student carried out an experiment to determine the specific heat capacity of water. Figure 12 shows the equipment the student used to heat the water.

Why did the student insulate the beaker of water?

Tick (✓) one box.

One hazard in this experiment is the hot water. Give one risk to the student caused by this hazard.

Figure 13 shows the thermometer that the student used.

What is the resolution of the thermometer?

Tick (✓) one box.

Figure 14 shows the beaker of water on a balance.

The mass of the water was 0.20 kg What was the mass of the beaker?

Tick (✓) one box.

The energy transferred to the water was 26 400 J The mass of water was 0.20 kg The temperature increase of the water was 30 °C

Calculate the specific heat capacity of water using the data from this experiment. Use the Physics Equations Sheet. Choose the unit from the box.

A student investigated the thermal conductivity of different metals.

This is the method used:

1. Measure the mass of an ice cube.

2. Put the ice cube on a metal block which is at room temperature.

3. Measure the mass of the ice cube after one minute.

4. Repeat with other blocks of the same mass made from different metals.

Table 3 shows the student’s results.

The initial temperature of each ice cube was –15 °C

Why was it important that the initial temperature of each ice cube was the same?

Tick (✓) one box.

Which metal had the highest thermal conductivity?

Give a reason for your answer.

Suggest one source of random error in the student’s investigation.

An ice cube has a temperature of –15.0 °C

The total thermal energy needed to raise the temperature of this ice cube to 0.0 °C and completely melt the ice cube is 5848 J

specific heat capacity of ice = 2100 J/kg °C specific latent heat of fusion of ice = 334 000 J/kg

Calculate the mass of the ice cube.

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.

Figure 15 shows a coffee machine. The coffee machine uses an electric element to heat water.

Figure 15

The coffee machine has a metal case.

Why would it be dangerous for the live wire of the electric cable to touch the metal case?

The power output of the coffee machine is 2.53 kW.

The mains potential difference is 230 V.

Calculate the current in the coffee machine.

The coffee machine heats water from 20 °C to 90 °C.

The power output of the coffee machine is 2.53 kW.

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

Calculate the mass of water that the coffee machine can heat in 14 seconds.