Pressure (OCR GCSE Combined Science A (Gateway): Physics)

The particles in a gas are said to move in constant random motion.

i) State the name given to this type of particle motion.

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ii) What quantity is related to the average speed of the gas molecules?

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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?

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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.

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ii) As a result, the frequency of the collisions increases / decreases.

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iii) This leads to a larger / smaller change in momentum in each collision.

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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.

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v) Since pressure is directly / inversely proportional to the force, this leads to an increase / decrease in the pressure of the gas.

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