Kinetic Particle Model of Matter (Cambridge (CIE) IGCSE Physics): Exam Questions

Exam code: 0625 & 0972

3 hours40 questions
11 mark

A popular demonstration of kinetic theory is to view smoke particles through a microscope, while illuminating them with a bright light.

The diagram shows the view of the smoke particles through a microscope. They are moving about randomly.

q1-easy-mcq-2-1-simple-kinetic-cie-igcse-physics

What causes the motion of the smoke particles?

  • The smoke particles are attracted to each other.

  • The smoke particles vibrate because they are warm.

  • Smaller air particles are colliding with the smoke particles.

  • The microscope is vibrating slightly, making the smoke particles appear to move.

21 mark

A sealed piston is used to expand a gas. No gas escapes during the process.

q3-easy-mcq-2-1-simple-kinetic-cie-igcse-physics

What happens to both the density of the gas and to its pressure when it is expanded in this way?

 

Density

Pressure

A

stays the same

stays the same

B

increases

decreases

C

decreases

stays the same

D

decreases

decreases

    31 mark

    Descriptions of two different states of matter are shown below. 

    To which state of matter do each of the descriptions fit?

    X: the molecules are very close together, in fixed positions. They vibrate around these fixed positions.

    Y: the molecules move rapidly and randomly in straight lines until they collide with something. The molecules are spaced apart very far.

       

     

    State X

    State Y

    A

    solid

    liquid

    B

    solid

    gas

    C

    liquid

    gas

    D

    gas

    liquid

      41 mark

      The diagrams represent the molecules in two different states of matter. The arrows show the motion of the molecules.

      2-1-5-e-molecules-states-of-matter

      Which state represents a solid?

      • state 1

      • neither

      • both

      • state 2

      51 mark

      The diagram represents particles of a gas inside a closed container of constant volume. 

      A rectangle contains multiple arrows pointing in different directions, with dots at their tails, arranged randomly against a white background.

      The gas is heated. 

      What happens to the particles of the gas? 

      • They expand.

      • They get closer together.

      • They hit the container walls with less force.

      • They move faster

      61 mark

      When using a microscope to look at smoke particles in air, Brownian motion is observed.

      What causes the smoke particles to move at random?

      • Smoke particles are hit by air particles.

      • Smoke particles are moved by convection currents in the air.

      • Smoke particles have different weights and fall at different speeds.

      • Smoke particles hit the walls of the container.

      71 mark

       The list gives three properties of different states of matter. 

      1. They cannot be compressed significantly. 

      2. They can flow. 

      3. They always completely fill their container. 

      Which properties are correct for liquids? 

      • 1 and 2 only

      • 2 and 3 only

      • 1 and 3 only

      • 1, 2 and 3

      8
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      1 mark

      Gases, liquids and solids are made up of small particles.

      Which row gives the relative separation of the particles?

      gas

      liquid

      solid

      A

      far apart

      far apart

      far apart

      B

      far apart

      far apart

      close together

      C

      far apart

      close together

      close together

      D

      close together

      close together

      far apart

        11 mark

        Air is trapped inside a cylinder. The volume of the cylinder cannot change.

        The temperature of the air is increased.

        Which of the graphs below shows the correct relationship between pressure and temperature?

        q2-medium-mcq-2-1-simple-kinetic-cie-igcse-physics
          21 mark

          A beaker of water, at its boiling point of 100 oC, is heated so that the liquid starts to become a gas, also at 100 oC.

          Which row of the table correctly compares the liquid phase with the gas phase under these conditions?

           

          Average distance between the particles

          Average speed of the particles

          A

          the same in the liquid and the gas

          the same in the liquid and the gas

          B

          greater in the liquid

          greater in the gas

          C

          greater in the gas

          greater in the liquid

          D

          greater in the gas

          the same in the liquid and the gas

            31 mark

            A sealed yet empty (except for air) plastic drinks bottle is left outside in the sunshine on a warm day.

            Which row of the table correctly describes what happens to the average speed of the air molecules, and to the pressure inside the bottle?

             

            Average speed of particles

            Pressure inside bottle

            A

            increases

            increases

            B

            increases

            decreases

            C

            decreases

            increases

            D

            decreases

            decreases

              41 mark

              A car tyre is inflated with air.

              As the car drives, the temperature of the tyre increases, which also causes the temperature of the air inside the tyre to increase. This increases the pressure of the air inside the tyre.

              Which of the following is a correct explanation as to why?

              • The mass of air inside the tyre has increased.

              • The area of the tyre has decreased, thus increasing the pressure.

              • The air molecules collide with each other less frequently.

              • The average kinetic energy of the air molecules has increased.

              51 mark

              A substance can exist in three different states: solid, liquid or gas. 

              Each of the two statements below describes a change of state. 

              Change 1: Particles move much closer together but continue to travel throughout the substance.

              Change 2: Particles stop travelling throughout the substance and just vibrate about fixed positions. 

              Which changes of state do these statements describe? 

               

              change 1

              change 2

              A

              condensation

              melting

              B

              condensation

              solidification

              C

              solidification

                      condensation

              D

              solidification

              melting

                61 mark

                Extended Tier Only

                When particles of a gas collide with a wall of a container, the wall experiences a pressure.

                What is the cause of this pressure?

                • the change in energy of the particles

                •  the change in momentum of the particles

                •  the change in power of the particles

                •   the change in speed of the particles

                71 mark

                A sealed rigid container has a fixed volume. The container is filled with air. 

                The container is placed in a freezer cabinet and the temperature of the air in the container decreases. 

                Which row correctly describes what happens to the air in the container?  

                 

                average distance between air particles

                average speed of air particles

                A

                decreases

                increases

                B

                decreases

                decreases

                C

                no change

                increases

                D

                no change

                decreases

                  81 mark

                  A student uses a microscope to observe pollen moving on the surface of water.

                   Which statement describes the reason for this movement?

                  • Water molecules are moved by microscopic pollen particles.

                  • Water molecules are moved by pollen molecules.

                  • Microscopic pollen particles are moved by water molecules.

                  • Pollen molecules are moved by water molecules.

                  11 mark

                  Extended tier only

                  A whale takes a breath at the surface of the ocean, where the pressure is 1.00 x 105 Pa. It then dives to a depth where the pressure is 1.21 x 105 Pa. The temperature is the same at this depth as it is at the surface.

                  q1-hard-mcq-2-1-simple-kinetic-cie-igcse-physics

                  The whale lets out a bubble of air of volume 50 cm3. This bubble rises to the surface of the ocean.

                  What is the volume of the bubble when it reaches the surface?

                  • 41.3 cm3

                  • 60.5 cm3

                  • 50.0 cm3

                  • 21.0 cm3

                  21 mark

                  Extended tier only

                  In an experiment to determine the nature of liquids, some very tiny pollen grains are suspended in water. They are illuminated by a bright light, and observed under a microscope.

                  q4-hard-mcq-2-1-simple-kinetic-cie-igcse-physics

                  The view through the microscope is of small, bright dots, which move about at random, rapidly and they frequently change direction.

                  Which of the following would be the correct explanation for the observation through the microscope?

                  • The bright dots are water molecules, being hit by other water molecules.

                  • The bright dots are water molecules, which are vibrating due to their thermal kinetic energy.

                  • The bright dots are pollen grains, which are being hit many times per second by water molecules.

                  • The bright dots are pollen grains, which are vibrating due to their thermal kinetic energy.

                  31 mark

                  A syringe is half filled with air and sealed. The plunger is then pulled outwards, causing the volume of the gas to increase.

                  This is done slowly, so that the expansion happens at a constant temperature.

                  What happens to the pressure of the gas, and to the speed of the air molecules?

                   

                  Pressure inside syringe

                  Speed of air molecules

                  A

                  stays the same

                  stays the same

                  B

                  increases

                  decreases

                  C

                  decreases

                  stays the same

                  D

                  decreases

                  decreases