3.1 Particle model of matter - Standard demand – Questions

Q1.Figure 1 shows a model of the particles in a liquid.

Figure 1

(a)     Give one similarity and one difference you would see in Figure 1 if it showed the same substance as a gas.

Similarity ___________________________________________________________

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Difference __________________________________________________________

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(b)     Describe two limitations of the model shown in Figure 1.

1. _________________________________________________________________

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2. _________________________________________________________________

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(c)     Explain why substances have different melting points.

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(d)     Some fire extinguishers contain liquid carbon dioxide.

Suggest how carbon dioxide gas can be changed to liquid carbon dioxide without reducing its temperature.

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Ice was heated at a constant rate.

Eventually all the ice changed to a gas.

Figure 2 shows how the temperature changed over 800 seconds.

Figure 2

(e)     What change of state occurs between 200 seconds and 750 seconds?

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(f)      Explain how Figure 2 shows that the specific latent heat of vaporisation is greater than the specific latent heat of fusion.

Use data from Figure 2.

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(g)     1695 kJ of energy is transferred to water at 100 °C

The specific latent heat of vaporisation of water is 2.260 × 106 J / kg

Calculate the mass of water changed into a gas at 100 °C

Use the Physics Equations Sheet.

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Mass of water = ____________________ kg(3)

(Total 13 marks)

Q2.Students investigated the specific heat capacity of different oils.

The diagram shows the equipment used.

This is the method used.

1.      Put 200 g of an oil in a beaker.2.      Record the temperature of the oil.3.      Switch on the heater.4.      After 5 minutes, record the temperature of the oil and the reading on the joulemeter.5.      Repeat steps 1‒4 with different oils.

(a)     Give one variable the students controlled in the investigation.

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The table shows the students’ results for one oil. 

Temperature at start in °C

Temperature after 5 minutes in °C

21 68

(b)     What is the resolution of the thermometer used in the investigation?

Resolution = ____________________ °C(1)

The students calculated the specific heat capacity of the oil as 2100 J/kg °C

The correct value for the specific heat capacity of the oil is 1630 J/kg °C

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(c)     Calculate the percentage difference between the two values.

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Percentage difference = ____________________ %(2)

(d)     Suggest two improvements the students could make to obtain a more accurate value for the specific heat capacity.

1. _________________________________________________________________

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2. _________________________________________________________________

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(e)     A company is considering what metal to use to make saucepans.

They use data about the:

•        cost of each metal•        specific heat capacity of each metal.

Suggest two other properties the company needs to consider when deciding which metal to use.

1. _________________________________________________________________

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2. _________________________________________________________________

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(Total 8 marks)

Q3.A new design for a kettle is made from two layers of plastic separated by a vacuum.After the water in the kettle has boiled, the water stays hot for at least 2 hours.

The new kettle is shown below.

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(a)     The energy transferred from the water in the kettle to the surroundings in 2 hours is 46 200 J.

The mass of water in the kettle is 0.50 kg.

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

The initial temperature of the water is 100 °C.

Calculate the temperature of the water in the kettle after 2 hours.

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Temperature after 2 hours = ___________ °C(3)

(b)     Calculate the average power output from the water in the kettle to the surroundings in 2 hours.

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Average power output = ______________ W(2)

(Total 5 marks)

Q4.Solid, liquid and gas are three different states of matter.

(a)     Describe the difference between the solid and gas states, in terms of the arrangement and movement of their particles.

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

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(c)     While a kettle boils, 0.018 kg of water changes to steam.

Calculate the amount of energy required for this change.

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

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Energy required = __________________ J(2)

(d)     The graph shows how temperature varies with time for a substance as it is heated.

The graph is not drawn to scale.

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Explain what is happening to the substance in sections AB and BC of the graph.

Section AB _________________________________________________________

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Section BC _________________________________________________________

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(Total 12 marks)

Q5.Figure 1 shows a student making potato soup.

Figure 1

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(a)     The student places 0.5 kg of potato into a pan of water.

During cooking, the temperature of the potato increases from 20 °C to 100 °C

The specific heat capacity of the potato is 3400 J/kg °C

Calculate the change in thermal energy of the potato.

Use the equation:

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

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Change in thermal energy = ____________________ J(3)

(b)     Why is the energy supplied by the cooker greater than that calculated in part (a)?

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(c)     Suggest one way that the student could reduce the time to heat the potato to 100 °C

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Figure 2 shows a food processor.

Figure 2

(d)     The student places the cooked potato into the jug of the food processor.

The food processor contains a motor that spins blades to chop the potato.

The total power input to the motor is 500 W

The useful power output from the motor is 300 W

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Calculate the efficiency of the motor in the food processor.

Use the equation:

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Efficiency = ____________________ (2)

(e)     The jug is made of plastic with a low thermal conductivity.

Explain why this is an advantage.

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(Total 9 marks)

Q6.In this question you will be assessed on using good English, organising information clearly and using specialist terms where appropriate.

The diagram shows the arrangement of particles in a solid, a liquid and a gas.

 

Use the diagram above and your own knowledge to compare solids, liquids and gases in terms of their particles.

You should include information about the arrangement, movement and energy of the particles.

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Q7.The diagram shows a side view of a double-glazed window.

 

(a)     Use each of the terms in the box to explain how heat is lost from inside a house through the window.

 

conduction                 convection                 radiation

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(b)     Besides heat, state one other form of energy that passes through double-glazed windows.

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(c)     Explain why plastic foam cavity wall insulation cuts down energy transfer between warm inner walls and cooler outer walls.

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(d)     When it rains the walls and windows of a house get wet.

Explain how the drying process can increase the cooling of the house.

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(Total 8 marks)

Q8.The drawing shows parts of a house where it is possible to reduce the amount of energy lost.

 

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(a)     Give one way in which the amount of energy lost can be reduced from each of the following parts of the house.

1, 2 and 4 _________________________________________________________

5 ________________________________________________________________

7 ________________________________________________________________(3)

(b)     Energy consumption can be reduced by using a more efficient boiler or more efficient light bulbs.

What is meant by a more efficient light bulb?

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(Total 4 marks)

Q9.(a)     The diagram shows a hot water system.

 

(i)      Explain why the boiler is below the hot water tank.

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(ii)     Why is heat energy transferred from hot water in the tank to the surrounding air?

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(iii)     Name the process by which energy is transferred through the sides of the tank.

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(iv)    How may heat loss from the hot water tank be reduced?

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(b)     One way of reducing heat loss from a house is by cavity wall insulation. Foam is pumped between the inner and outer brick walls as shown in the diagram.

 

How is heat loss from a house reduced by:

(i)      having a cavity wall?

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(ii)     filling the cavity with foam?

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(Total 9 marks)

Q10.The diagram below shows a vacuum flask.

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(a)     Give two features of the flask which reduce heat loss by conduction.

1. _________________________________________________________________

2. _________________________________________________________________(2)

(b)     Give one feature of the flask which reduces heat loss by radiation.

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(Total 3 marks)

Q11.(a)     The diagram shows a section through the walls of a house built in 1930.

 

Explain how the air cavity between the two walls reduces the heat transfer from the house.

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(b)     The table shows the installation costs and yearly savings on energy bills for different methods of insulating a house.

 

Method of insulation

Installation costin £

Yearly saving on energy bills in £

Double glazing 4000 65

Loft insulation 240 60

Cavity wall insulation 600 80

(i)      Give one reason why loft insulation is often fitted to an old house before double glazing or cavity wall insulation.

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(ii)     The time it takes for the saving on energy bills to equal the cost of installing the insulation is called the pay-back time.

Calculate the pay-back time for loft insulation.

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Pay-back time = __________________________ years(1)

(Total 4 marks)

Q12.(a)     In winter, energy is transferred from the warm air inside a house to the air outside.

(i)      What effect will the energy transferred from the house have on the air outside?

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(ii)     What would happen to the energy transfer if the temperature inside the house were reduced? Assume the temperature outside the house does not change.

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(b)     To increase energy efficiency, a householder installs a heat exchanger to an outside wall of the house. The heat exchanger uses heat from the air outside to warm the inside of the house. The diagram shows the idea of the heat exchanger.

 

Physics Through Applications edited by J Jardine et el (OUP, 1989), copyright ©Oxford University Press, reprinted by permission of Oxford University Press.

(i)      Why does the heat exchanger cost money to run?

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(ii)     The heat exchanger is cost effective in reducing energy consumption.Explain why.

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(Total 5 marks)

Q13.(a)     The diagram shows two switches on a room heater. The heater has three power

settings. The power produced by two of the settings is given in the table. 

   

Setting Power in kW

Low 0.5

Medium 1.5

High  

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(i)      When both switches are on, the heater works at the high power setting.

What is the power of the heater, in kilowatts, when it is switched to the high power setting?

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Power = _____________________________ kilowatts(1)

(ii)     The heater is used on the high power setting. It is switched on for 1½ hours.

Calculate the energy transferred from the mains to the heater in 1½ hours.

Show clearly how you work out your answer and give the unit.

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Energy transferred = __________________________(3)

(iii)    This type of heater is a very efficient device.

What is meant by a device being very efficient?

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(b)     The graph shows how the temperature of a room changes during the 1½ hours that the heater is used.

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After 1 hour, the temperature of the room has become constant, even though the heater is still switched on.

Explain why.

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(Total 7 marks)

Q14.Heat exchangers are devices that are used to transfer heat from one place to another.

The diagram shows a simple heat exchanger used by a student in an investigation.Heat is transferred from the hot water inside the pipe to the cold water outside the pipe.

 

(a)     By which process is heat transferred from the hot water inside the pipe to the cold water outside the pipe?

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(b)     The student wanted to find out if the efficiency of a heat exchanger depends on the material used to make the pipe. The student tested three different materials. For each material, the rate of flow of hot water through the pipe was kept the same.

The results obtained by the student are recorded in the table and displayed in the bar chart.

 

Material Temperature of the cold waterat the start in °C

Temperature of the cold waterafter 10 minutes in °C

Copper 20 36

Glass 20 23

Plastic 20 21

 

(i)      The rate of flow of hot water through the pipe was one of the control variables in the investigation.

Give one other control variable in the investigation.

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(ii)     Why did the student draw a bar chart rather than a line graph?

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(iii)    Which one of the three materials made the best heat exchanger?

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Give a reason for your answer.

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(c)     The student finds a picture of a heat exchanger used in an industrial laundry.The heat exchanger uses hot, dirty water to warm cold, clean water.

 

Why does this heat exchanger transfer heat faster than the heat exchanger used by the student in the investigation?

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(Total 6 marks)

Q15.The diagram shows the direction of heat transfer through a single-glazed window.

 

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(a)     (i)      Name the process by which heat is transferred through the glass.

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(ii)     Explain how heat is transferred through the glass.

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(b)     The rate of heat transfer through a window depends on the difference between the inside and outside temperatures.

The graph shows the rate of heat transfer through a 1 m2 single-glazed window for a range of temperature differences.

 

(i)      What is the range of temperature differences shown in the graph?

From ___________________________ to ___________________________(1)

(ii)     A student looks at the graph and concludes:

‘Doubling the temperature difference doubles the rate of heat transfer.’

Use data from the graph to justify the student’s conclusion.

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(iii)    A house has single-glazed windows. The total area of the windows in the house is 15 m2.

On one particular day, the difference between the inside and outside temperatures is 20 °C.

Use the graph to calculate the total rate of heat transfer through all of the windows on this particular day.

Show clearly how you work out your answer.

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Rate of heat transfer = ____________________ J/s(2)

(c)     A homeowner plans to replace the single-glazed windows in his home with double-glazed windows. He knows that double-glazed windows will reduce his annual energy bills.

The table gives information about the double glazing to be installed by the homeowner.

 

Cost to buy and install Estimated yearly savings on energy

bills

Estimated lifetime of the double-glazed

windows

£5280 £160 30 years

Explain, in terms of energy savings, why replacing the single-glazed windows with these double-glazed windows is not cost effective.

To gain full marks you must complete a calculation.

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(2)(Total 10 marks)

Q16.The diagram shows two thermometers. The bulb of each thermometer is covered with a piece of wet cotton wool. One of the thermometers is placed in the draught from a fan.

 

The graph shows how the temperature of each thermometer changes with time.

 

(a)     Which of the graph lines, A or B, shows the temperature of the thermometer placed in the draught?

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Write the correct answer in the box.

Explain, in terms of evaporation, the reason for your answer.

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(b)     A wet towel spread out and hung outside on a day without wind dries faster than an identical wet towel left rolled up in a plastic bag.

Explain why.

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(Total 5 marks)

Q17.The diagram shows how one type of electric storage heater is constructed. The heater has ceramic bricks inside. The electric elements heat the ceramic bricks during the night. Later, during the daytime, the ceramic bricks transfer the stored energy to the room.

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(a)     (i)      Complete the following sentences using words from the box. 

conduction convection evaporation

Energy is transferred through the metal casing by ___________________

The warm air rising from the heater transfers energy to the

room by ________________________(2)

(ii)     The inside of the metal case is insulated.

Which one of the following gives the reason why?

Tick ( ) one box. 

To transfer energy from the ceramic bricks to the room faster 

To stop energy from the room transferring into the heater 

To keep the ceramic bricks hot for a longer time 

(1)

(b)     In winter, the electricity supply to a 2.6 kW storage heater is switched on for seven hours each day.

(i)      Calculate the energy transferred, in kilowatt-hours, from the electricity supply to the heater in seven hours.

Show clearly how you work out your answer.

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Energy transferred = _________________________ kWh(2)

(ii)     The electricity supply to the heater is always switched on between midnight and 7 am. Between these hours, electricity costs 5 p per kilowatt-hour.

Calculate how much it costs to have the heater switched on between midnight and 7 am.

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Cost = _________________________ p(1)

(c)     Between 7 am and 8 am, after the electricity supply is switched off, the temperature of the ceramic bricks falls by 25 °C.

Calculate the energy transferred from the ceramic bricks between 7 am and 8 am.

Total mass of ceramic bricks = 120 kg.Specific heat capacity of the ceramic bricks = 750 J/kg °C.

Show clearly how you work out your answer.

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Energy transferred = _________________________ J(2)

(Total 8 marks)

Q18.Heat exchangers are devices used to transfer heat from one place to another.

The diagram shows a pipe being used as a simple heat exchanger by a student in an investigation.

Heat is transferred from the hot water inside the pipe to the cold water outside the pipe.

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(a)     Complete the following sentence by drawing a ring around the correct word in the box.

Heat is transferred from the hot water inside the pipe 

  conduction.

to the cold water outside the pipe by convection.

  radiation.

(1)

(b)     The student wanted to find out if the efficiency of a heat exchanger depends on the material used to make the pipe. The student tested three different materials. For each material, the rate of flow of hot water through the pipe was kept the same.

The student’s results are recorded in the table. 

Material Temperature of the cold water at the start in °C

Temperature of the cold water after 10 minutes in °C

Copper 20 36

Glass 20 23

Plastic 20 21

(i)      The rate of flow of hot water through the pipe was one of the control variables in the investigation.

Give one other control variable in the investigation.

______________________________________________________________(1)

(ii)     Which one of the three materials made the best heat exchanger?

______________________________________________________________

Give a reason for your answer.

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(c)     The student finds a picture of a heat exchanger used in an industrial laundry.The heat exchanger uses hot, dirty water to heat cold, clean water.

 

This heat exchanger transfers heat faster than the heat exchanger the student used in the investigation.

Explain why.

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(Total 6 marks)

Q19.Diagram 1 shows the energy transferred per second from a badly insulated house on a cold day in winter.

Diagram 1

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(a)     (i)      When the inside of the house is at a constant temperature, the energy transferred from the heating system to the inside of the house equals the energy transferred from the house to the outside.

Calculate, in kilowatts, the power of the heating system used to keep the inside of the house in Diagram 1 at a constant temperature.

1 kilowatt (kW) = 1 kilojoule per second (kJ/s)

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Power of the heating system = ___________________________ kW(1)

(ii)     In the winter, the heating system is switched on for a total of 7 hours each day.

Calculate, in kilowatt-hours, the energy transferred each day from the heating system to the inside of the house.

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Energy transferred each day = ___________________________ kWh(2)

(iii)    Energy costs 15 p per kilowatt-hour.

Calculate the cost of heating the house for one day.

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Cost = _______________(1)

(iv)    The heating system is switched off at midnight.

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The graph shows how the temperature inside the house changes after the heating system has been switched off.

 Time of day

Draw a ring around the correct answer in the box to complete the sentence.

Between midnight and 6 am the rate of energy transfer from 

  decreases.

the house decreases then stays constant.

  increases.

Give the reason for your answer.

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(b)     Diagram 2 shows how the walls of the house are constructed.Diagram 3 shows how the insulation of the house could be improved by filling the air gap between the two brick walls with plastic foam.

 

Diagram 2 Diagram 3

U-value of the wall = 0.7 U-value of the wall = 0.3

The plastic foam reduces energy transfer by convection.

Explain why.

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(Total 8 marks)

Q20.The picture shows a person taking a hot shower.

 

(a)     When a person uses the shower the mirror gets misty.

Why?

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(b)     The homeowner installs an electrically heated mirror into the shower room.

When a person has a shower, the heated mirror does not become misty but stays clear.

Why does the mirror stay clear?

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(Total 5 marks)

Q21.The diagram shows three cups A, B and C.

 

 

Energy is transferred from hot water in the cups to the surroundings.

(a)     Some students investigated how the rate of cooling of water in a cup depends on the surface area of the water in contact with the air.

They used cups A, B and C. They poured the same volume of hot water into each cup and recorded the temperature of the water at regular time intervals.

The results are shown on the graph.

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                Time in minutes

(i)      What was the starting temperature of the water for each cup?

Starting temperature = ____________________ °C(1)

(ii)     Calculate the temperature fall of the water in cup B in the first 9 minutes.

______________________________________________________________

Temperature fall = ____________________ °C(2)

(iii)    Which cup, A, B or C, has the greatest rate of cooling?    

Using the graph, give a reason for your answer.

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(iv)    The investigation was repeated using the bowl shown in the diagram.

The same starting temperature and volume of water were used.

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Draw on the graph in part (b) another line to show the expected result.(1)

(v)     After 4 hours, the temperature of the water in each of the cups and the bowl was 20°C.

Suggest why the temperature does not fall below 20°C.

______________________________________________________________(1)

(b)     (i)      The mass of water in each cup is 200 g.

Calculate the energy, in joules, transferred from the water in a cup when the temperature of the water falls by 8°C.

Specific heat capacity of water = 4200 J / kg°C.

______________________________________________________________

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Energy transferred = ____________________ J(3)

(ii)     Explain, in terms of particles, how evaporation causes the cooling of water.

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(Total 14 marks)

Q22.

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In this question you will be assessed on using good English, organising information clearly and using specialist terms where appropriate.

The information in the box is about the properties of solids and gases. 

Solids:     •        have a fixed shape     •        are difficult to compress (to squash). Gases:     •        will spread and fill the entire container     •        are easy to compress (to squash).

Use your knowledge of kinetic theory to explain the information given in the box.

You should consider: •        the spacing between the particles •        the movement of individual particles •        the forces between the particles.

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