3 marksThe particles in a gas are said to move in constant random motion.
i) State the name given to this type of particle motion.
[1]
ii) What quantity is related to the average speed of the gas molecules?
[1]
Put a ring around the correct option.
volume radius mass temperature
iii) What quantity increases when the particles of a gas collide more with its container walls?
[1]
Put a ring around the correct option.
volume pressure specific heat capacity temperature
The molecules of a gas move around rapidly in a container, as shown in Fig 1.1.
Fig 1.1
Complete the following sentences by putting a ring around the correct words
i) If the temperature of the gas increases, the kinetic energy of the molecules increases / decreases, hence, the average velocity of the molecules increases / decreases.
[1]
ii) As a result, the frequency of the collisions increases / decreases.
[1]
iii) This leads to a larger / smaller change in momentum in each collision.
[1]
iv) Since force is directly / inversely proportional to the change in momentum, a greater change in momentum leads to an increase / decrease in the force exerted by the molecules on / by the walls of the container.
[1]
v) Since pressure is directly / inversely proportional to the force, this leads to an increase / decrease in the pressure of the gas.
[1]
3 marksHigher Tier Only
i) What happens to the volume of a gas when work is done on it?
[1]
ii) What happens to the temperature of a gas when it expands?
[1]
iii) What happens to the volume of a gas when it does work?
[1]
Higher Tier Only
Some gas particles are shown in a container in Fig. 1.2.
The piston can be moved in or out to change the volume of the gas.
Fig. 1.2
i) State what happens to the volume of the gas when the piston is moved in.
[1]
ii) State what happens to the pressure of the gas when the piston is moved in and the temperature remains constant.
[1]
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