Particle Model & Pressure (Edexcel GCSE Physics)

Exam Questions

2 hours11 questions
1a1 mark

Figure 1 shows air inside a cylinder with a movable piston.


fig-1-paper2h-june2018-edexcel-gcse-physicsFigure 1

The piston is pulled a little way in the direction of the arrow, but stays inside the cylinder.

Which of these increases?

  

        A The mass of the air inside the cylinder.
        B The rate at which air particles collide with the walls of the cylinder.
        C The volume of the air inside the cylinder.
        D The pressure of the air inside the cylinder.

1b6 marks
Figure 2 shows a rubber tube that can be used inside a bicycle tyre.

The tube is inflated with a bicycle pump.

fig-2-paper2h-june2018-edexcel-gcse-physics
Figure 2

(i)
The air inside the tube exerts an outward force on the wall of the tube.
    
State the angle that this outward force makes with the wall of the tube.

[1]

(ii)
It takes 4.8 litres of air from the atmosphere to inflate the empty tube to a pressure of 400 000 Pa.
  
Atmospheric pressure is 100 000 Pa.
   
Calculate the volume of air inside the tube.
   
Assume the temperature of the air inside the tube is the same as the temperature of the air outside the tube.
   
Use an equation selected from the list of equations at the end of this paper.

[3]

volume = ............................................... litres

(iii)
When a bicycle pump is used to inflate the tube, the air in the bicycle pump gets warm.

You should ignore any effects of friction in the pump.

Explain why the air in the bicycle pump gets warm.
[2]

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2a2 marks

Figure 1 shows some gas particles in a container.

The piston can be moved in or out to change the volume of the gas. The temperature remains constant. 

3-3-e-3a-piston

Figure 1

Add arrows to the diagram to show the motion of the gas particles.

2b3 marks

Explain how the motion of the gas particles produces a pressure inside the container. 

2c1 mark

State what would happen to the pressure if you pushed the piston into the container without changing the temperature.

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3a1 mark

The particles of a gas exert pressure on the walls of a container.

Which of the following rows correctly describes the relationship between pressure and the number of particle collisions with the walls of the container every second?

  pressure number of collisions with the walls of the container every second
A increases stays the same
B increases increases
C decreases stays the same
D decreases increases
    3b1 mark

    A digital thermometer gives a temperature reading of 19 °C.

    Convert this temperature to kelvin.

    3c3 marks

    A small container contains helium gas at high pressure. It comes with a label stating the pressure and volume of the helium gas inside.

    5-3-4c-e-helium-gas-container-sq-igcse

    The helium gas from one small container is pumped into a large balloon which fills a final volume of 2200 cm3.

    (i)
    State the equation linking the initial pressure, initial volume, final pressure and final volume of a gas.

    [1]

    (ii)
    Calculate the final pressure of the gas in the large balloon.
    [2]
     
    final pressure = .............................. MPa

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    1a1 mark

    The particles of a gas exert a pressure on the walls of a container.

    Which row of the table is correct when the pressure of the gas changes?

          pressure of gas number of particles colliding with the walls of the container each second
      A increases stays the same
      B increases increases
      C decreases stays the same
      D decreases increases
      1b2 marks

      Figure 3 shows an oxygen cylinder.

      fig-3-paper2f-june2018-edexcel-gcse-physics

      Figure 3

      The volume of the gas in the cylinder is 2100 cm3.

      When the gas is released into the atmosphere the volume of the gas is 8600 cm3.

      The pressure of the atmosphere is 98 kPa.

      Calculate the pressure of the gas when it is in the cylinder.

      Use the equation

                     P subscript 1 equals fraction numerator P subscript 2 cross times V subscript 2 over denominator V subscript 1 end fraction



      pressure of the gas in the cylinder = ............................................... kPa

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      2a2 marks

      Figure 1 shows some gas particles in a container with a piston which can be moved in or out to change the volume of the gas. 

      14-2-m-2a-syringe-pressure

      Figure 1

      Add arrows to the diagram to show the random motion of the gas particles. 

      2b3 marks

      Explain how the movement of the particles of gas produces pressure inside the container. 

      2c1 mark

      State the effect on the pressure if you pushed the piston into the container. Assume the temperature does not change.

      2d3 marks

      When the gas in the container is heated, the piston moves outwards.

      Describe what happens to the gas particles.

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      3a2 marks
      Figure 1 shows a syringe which contains air.

      3-3-e-1a-bicycle-pump-piston

      Figure 1

      When the piston is pushed in, the volume and pressure in the syringe change.

      State how the volume and pressure of the air change when the piston is pushed in.

      3b4 marks
      Use words from the box to complete the following sentences about kinetic theory.
       

      low high molecules temperature outsides
      medium ions pressure volume sides
       

      Molecules in a gas are in constant random motion at ............... speeds.

      Random motion means that the molecules do not travel in a specific path and undergo sudden changes in their motion if they collide with the ............... of its container or with other ................. .

      The ................ of the gas is related to the average kinetic energy of the molecules.

      3c3 marks

      The syringe can be used as a pump to inflate a bicycle tyre where the air inside the tube exerts an outward force on the wall of the tube.

      It takes 3.2 litres (l) of air from the atmosphere to inflate the empty tube to a pressure of 360 000 Pa.

      Atmospheric pressure is 100 000 Pa.

      Calculate the final volume of air inside the tube once inflated.
       
      final volume = ................................... l
      3d4 marks
      The air in the bicycle pump gets warm when a bicycle pump is used to inflate the tube.

      Complete the sentences by circling the correct words:

      When the air in the bicycle pump is compressed, the volume / pressure of the gas decreases and the volume / pressure increases.

      This is because the particles are moving in less space and collide more often / less often / the same amount.

      The increased / decreased pressure leads to an increase in temperature. This is because the temperature is a measure of the average kinetic / potential / thermal energy of particles.

      When the air in the bicycle pump is compressed, this increases / decreases the energy in the kinetic / potential / thermal store of the air particles and contributes to the overall kinetic / potential / thermal energy stored in the system, this is why the bicycle pump gets warm.

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      4a3 marks
      Figure 1 shows a spray-can containing gas particles which are in constant motion.

       14-2-m-4a-gas-bottle

      Figure 1

      Explain how the gas particles cause pressure on the walls of the spray-can.

      4b3 marks
      Liquid leaves the can when the button is pressed.

      Describe and explain what happens to the gas pressure in the spray-can as the liquid leaves.
      4c4 marks
      In order to investigate gas pressure further, two balloons are blown up to the same size. One balloon is put in a freezer.

      After a while, the two balloons are compared, and it is found that the balloon that has been cooled is smaller. 

      Explain why the cooled balloon is smaller using ideas about particles.

      4d2 marks
      A decision is made to investigate the link between temperature and the size of the balloon.

      The researcher writes a plan for this experiment:

      I will change the temperature of the balloon by putting it into a freezer.

      To get a range of different temperatures I will put the balloon into the freezer for different times.

      I will measure the temperature of the balloon using a thermometer.

      To measure the size of the balloon I will take it out of the freezer and line it up next to a ruler.

      To make sure it is a fair test I will repeat the experiment three times.

      I will plot a graph of size against temperature.


      There are several flaws in the plan.


      Identify one of these faults and suggest an improvement to correct it.

      (2)

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      5a5 marks
      Figure 1 shows a fixed mass of gas inside a cylinder with a movable piston.

      fig-1-paper2f-june2018-edexcel-gcse-physicsFigure 1

                                                                            

      (i)
      Describe, in terms of gas particles, how the gas exerts a pressure on the cylinder.
      [3]

      (ii)
      Figure 2 shows the same gas squashed into a smaller volume.

      fig-2-paper2f-june2018-edexcel-gcse-physics

      Figure 2

      State what happens to the pressure the gas exerts on the cylinder when the volume of gas is reduced, as in Figure 2.

      [1]

      (iii)
      State what happens to the gas particles when the volume of the gas is reduced, as in Figure 2.
      [1]
      5b1 mark
      A digital thermometer gives a temperature reading of 23°C.

      Calculate the value of this temperature in kelvin.
      5c4 marks

      A student changes the volume of gas in a container and notes the pressure for different values of the volume.

      The results are shown in Figure 6 and plotted on the graph in Figure 7.


      volume in ml pressure in kPa
      10 260
      12 200
      20 140
      25 150
      30 100
      40 75
      50 65

      Figure 6

      fig-7-paper2f-june2019-edexcel-gcse-physics
      Figure 7

       

      (i)
      Identify the anomalous result plotted on Figure 7 by drawing a circle on Figure 7 around the anomalous point.

      [1]

      (ii)
      Draw the curve of best fit on Figure 7.

      [1]

      (iii)
      Describe how the graph in Figure 7 would change if the student repeated the experiment with the same mass of gas, at a higher constant temperature.
      [2]
      5d3 marks
      Figure 8 shows a small container of carbon dioxide at high pressure.

      The pressure, P1 , in the container is 8.00 MPa.

      The volume, V1 , of the container is 14.5 cm3.
      fig-8-paper2f-june2019-edexcel-gcse-physics
      Figure 8

      The container is pierced and all of the carbon dioxide goes into a large balloon.

      The volume of gas, V2 , in the large balloon is 1160cm3.

      Calculate the pressure, P2 , in the large balloon.

      Use the equation

      P1V1 = P2V2


      pressure in the large balloon = ........................... MPa

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      1a5 marks
      Figure 4 shows a small piece of copper about 3 cm high.

      fig-4-paper2h-june2020-edexcel-gcse-physics

      Figure 4

      A student wants to determine the density of copper.

      The student uses a balance to measure the mass of the piece of copper.

      i)
      Explain how the student could measure the volume of the piece of copper.
      [3]
      ii)
      The mass of the piece of copper is 0.058 kg.

      The volume of the piece of copper is 6.5 × 10–6 m3.

      Calculate the density of copper.

      [2]

      density of copper = .............................................................. kg/m3

      1b4 marks
      A student wants to determine the specific heat capacity of copper.


      Figure 5 shows a piece of copper, with a thread tied around it, in a glass beaker of boiling water.

      fig-5-paper2h-june2020-edexcel-gcse-physics

      Figure 5

      The student leaves the piece of copper in the boiling water so that the copper reaches a temperature of 100°C.

      The student uses the thread to take the piece of copper out of the boiling water.

      The student puts the hot piece of copper into a different beaker of cold water at 20°C.

      The apparatus is shown in Figure 6.

      fig-6-paper2h-june2020-edexcel-gcse-physics

      Figure 6

      The student assumes that the thermal energy gained by the water equals the thermal energy lost by the piece of copper.

      The water and copper both reach a temperature of 22°C.

      The cold water gains 1050 J of energy.

      The mass of the piece of copper is 0.058 kg.

      i)
      Calculate a value for the specific heat capacity of copper, using these results.

      Use the equation


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

      ΔQ = m × c × Δθ

      [2]

      specific heat capacity of copper from these results = ................................ J/kg °C

      ii)
      The value for the specific heat capacity of copper obtained from the student’s results is lower than the correct value.

      State two ways that the experiment could be improved to give a value that is closer to the correct value.

      [2]

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      2a1 mark
      When the pressure in a container of gas increases, the particles of the gas



        A hit the sides of the container less often
        B hit the sides of the container more often
        C move with lower speeds
        D vibrate more energetically about fixed positions
      2b8 marks
      A student investigates the pressure and volume of some trapped gas.

      Figure 4 shows the apparatus used.

      fig-4-paper2f-oct2021-edexcel-gcse-physics

      Figure 4


      Figure 5 shows the student’s table of results.

      P V P × V
      100 28.0 2800
      123 23.0 2829
      140 20.0 2800
      160 18.0 2880
      180 16.5 2970

      Figure 5

      i)
      Suggest what the student should add to the headings of the table in Figure 5.

      [1]
      ii)
      Use Figure 5 to estimate the volume of gas for a pressure reading of ‘170’.

      [2]

      volume of gas = ..............................................................

      iii)
      Suggest two ways the student could improve the investigation.

      [2]


      1.......................................................................................

      2.......................................................................................

      iv)
      Explain whether the values, in the column headed ‘p × V’ in Figure 5, fit the equation

      P1 × V1 = P2 × V2

      [3]

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      3a1 mark

      Figure 16 shows a metal container with a movable piston.

      fig-16-paper2f-june2020-edexcel-gcse-physics

      Figure 16

      Point X is on the inner surface of the container.
      The gas in the container is at a higher pressure than the air outside the container.

      Which of these shows the direction of the force, due to the gas, on the container at point X?

      q7a-paper2f-june2020-edexcel-gcse-physics

      3b2 marks
      The pressure of the gas in Figure 16 (P1) is 120 kPa.

      The volume of the gas in Figure 16 (V1) is 2500 cm3
      The piston is pushed up slowly so that the temperature of the gas does not change.
      The new volume of the gas (V2) is 1600 cm3.
      Calculate the new pressure of the gas, P2.
      Use the equation

      straight P subscript 2 equals fraction numerator straight P subscript 1 space cross times space straight V subscript 1 over denominator straight V subscript 2 end fraction



      new pressure, P2= .............................................................. kPa

      3c3 marks
      Figure 17 shows a bicycle pump with a closed end.

      fig-17-paper2f-june2020-edexcel-gcse-physics

      Figure 17

      The area of the piston is 2 cm2.
      A force of 28 N is applied to the piston.
      Calculate the pressure, in N/cm2, of the piston on the air in the bicycle pump.


      pressure = .............................................................. N/cm2

      3d6 marks
      A container is sealed so that the mass of the gas inside cannot change.
      The volume of the gas is changed and the pressure is measured at different volumes.
      The temperature of the gas does not change.
      Figure 18 is a graph of the results.

      fig-18-paper2f-june2020-edexcel-gcse-physics

      Figure 18

      Explain, in terms of the movement of particles, why there is a pressure on the container and why the pressure changes as shown in Figure 18.

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