New
New
Year 10
•
OCR
•
Foundation
Changes of pressure
I can explain the effect of a temperature change on the pressure of a gas.
New
New
Year 10
•
OCR
•
Foundation
Changes of pressure
I can explain the effect of a temperature change on the pressure of a gas.
Lesson details
Key learning points
- The pressure of a gas in a container increases if the temperature or the mass of gas increases, or the volume decreases.
- Increasing the temperature increases the average speed of the particles in a gas.
- Increasing the speed of the particles in a gas at a fixed volume increases its pressure.
Keywords
Particle model - a scientific model using the idea of moving particles to explain the behaviour of matter
Pressure - caused by a force acting over an area on a surface; it can be calculated using: pressure = force ÷ area
Common misconception
Pressure is a weight or a force; pressure has a preferred downwards direction in a liquid or gas.
Use the particle model to provide opportunities for pupils to explain the causes of pressure in a gas that is in a container, and to explain how the difference in pressure between inside and outside causes an outward force.
Particles in a gas or liquid exert pressure. Don't say: A gas or liquid has pressure.
Teacher tip
Equipment
None required.
Licence
This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).
Lesson video
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Starter quiz
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6 Questions
Q1.
Which of the following can be used to describe the motion of particles in a gas?
Correct answer: random
random
constant speed
Correct answer: typically faster than in liquids
typically faster than in liquids
typically the same speed as in liquids
Q2.
Which of the following show a definition of pressure or a unit of pressure?
a type of force
Correct answer: force per unit area
force per unit area
force per unit volume
N
Correct answer: N/m$$^2$$
N/m$$^2$$
Q3.
Which of the following are equal to 1 kN?
0.001 N
Correct answer: 0.001 MN
0.001 MN
1000 mN
Correct answer: 1000 N
1000 N
1 000 000 N
Q4.
If the particles in a gas are pushed closer together, the pressure of the gas increases. Which of the following explains why?
Correct answer: Particles collide with each other more often.
Particles collide with each other more often.
Some of the particles stick together.
The particles are squashed so they become smaller.
The particles repel each other more strongly all the time.
Q5.
A table of weight 500 N stands on the floor. The area of contact between the table and the floor is 200 cm$$^2$$. The pressure exerted by the table on the floor is __________ N/cm$$^2$$.
0.40
Correct answer: 2.5
2.5
500
700
1000
Q6.
A sealed container in the shape of a cube contains gas. Which of the following statements are correct?
Correct answer: pressure of gas = force on one inner face of cube ÷ area of one face
pressure of gas = force on one inner face of cube ÷ area of one face
pressure of gas = force on one inner face of cube ÷ total area of all faces
The gas exerts pressure because its weight pushes down on the container’s base.
Correct answer: The gas exerts pressure because its particles exert forces on all inner faces.
The gas exerts pressure because its particles exert forces on all inner faces.
Exit quiz
Download exit quiz
6 Questions
Q1.
Which of the following statements about the particle model are correct?
Correct answer: It can be used to explain how matter behaves.
It can be used to explain how matter behaves.
Correct answer: It can be used to predict how matter will behave.
It can be used to predict how matter will behave.
The model is made of diagrams or animations.
It says that particles move in liquids and gases but not in solids.
Correct answer: It says that particles in solids, liquids and gases are always moving.
It says that particles in solids, liquids and gases are always moving.
Q2.
A sealed container of fixed volume contains gas. Which of the following happen when more gas is added to the container?
Correct answer: The mass of the gas in the container increases.
The mass of the gas in the container increases.
The volume of the gas in the container increases.
Correct answer: The pressure of the gas on the container increases.
The pressure of the gas on the container increases.
Correct answer: The gas exerts a greater average force on the inside of the container.
The gas exerts a greater average force on the inside of the container.
Correct answer: There are more collisions per second between gas particles and container.
There are more collisions per second between gas particles and container.
Q3.
A child blows air into a balloon. Order the statements to describe and explain what happens.
1 - There are more particles inside, so their collisions become more frequent.
1
- There are more particles inside, so their collisions become more frequent.
2 - This increases the outward forces exerted by the air on the balloon.
2
- This increases the outward forces exerted by the air on the balloon.
3 - The outward forces are now greater than the inward forces.
3
- The outward forces are now greater than the inward forces.
4 - This makes the balloon expand, which increases the volume inside it.
4
- This makes the balloon expand, which increases the volume inside it.
5 - The particles inside are now more spread out, so collisions are less frequent.
5
- The particles inside are now more spread out, so collisions are less frequent.
6 - This decreases the pressure on the inside of the balloon.
6
- This decreases the pressure on the inside of the balloon.
7 - Expansion stops when this balances the air pressure outside.
7
- Expansion stops when this balances the air pressure outside.
Q4.
Which of the following happen when a car tyre is under-inflated, so that there less air in it than when it is correctly inflated?
The tyre is too hard.
Correct answer: The tyre wears out unevenly and more quickly.
The tyre wears out unevenly and more quickly.
Correct answer: The air pressure in the tyre is too low.
The air pressure in the tyre is too low.
Correct answer: The tyre changes shape more easily.
The tyre changes shape more easily.
There is less contact area between the tyre and road surface.
Q5.
A driver puts air into their car’s tyres when the car is empty. They check that the pressure is correct. If a lot of heavy luggage is now put into the car, which of the following are correct?
Correct answer: The pressure inside the tyres increases.
The pressure inside the tyres increases.
The pressure inside the tyres stays the same.
The mass of air inside the tyres increases.
Correct answer: The mass of air inside the tyres stays the same.
The mass of air inside the tyres stays the same.
Q6.
Which of the following changes would increase the pressure of a gas in a closed container?
Correct answer: increasing the mass of gas inside
increasing the mass of gas inside
decreasing the mass of gas inside
Correct answer: increasing the temperature of the gas inside
increasing the temperature of the gas inside
decreasing the temperature of the gas inside