P5 - Conservation of Momentum & Pressure

Question 1

What does kinetic theory state, 4 points?

Answer 1

• Kinetic theory states that gases consist of very small particles. which they do, oxygen consists of oxygen molecules, neon consists of neon atoms.
• These particles are constantly moving in completely random directions
• They constantly collide with each and with the walls of their container, when they collide they bounce off each other, or off the walls
• The particles hardly take up any space, most of the gas is empty space.

Question 2

What happens as gas particles move about?

Answer 2

• As gas particles move about, they bang into each other and whatever else happens to get in the way.

Question 3

Why do gas particles exert force when they collide?

Answer 3

• When gas particles collide with something, they exert force onto it.
• Because gas particles have some mass, they will exert force onto something when they collide with it.

Question 4

What happens to gas inside a sealed container?

Answer 4

• In a sealed container, gas particles smash against the containers walls, creating an outwards pressure.

Question 5

What happens if you take gas and place it in a bigger container than the volume of the gas?

Answer 5

• If you put a volume of gas in a container that has a larger volume than the gas, the pressure will decrease.
• This is because there will be fewer collisions between the gas particles and container walls.

Question 6

What happens to pressure when the volume is reduced?

Answer 6

• When the volume is reduced, the particles get more squashed up, and so they hit the walls more often, hence the pressure increases.

Question 7

What does the pressure of a gas depend upon?

Answer 7

• The pressure of a gas depends upon the how fast the particles are moving and how often they hit the walls of a container they are in.

Question 8

How is pressure affected by increased heat?

Answer 8

• If you heat a gas, the particles move faster and have more kinetic energy.
• This increase in kinetic energy means the particles hit the container walls harder and more often, creating more pressure.

Question 9

How is pressure affected by decreased heat?

Answer 9

• If a gas is cooled, the particles have less kinetic energy.
• The particles hit the walls with less force and less often, so the pressure is reduced.

Question 10

How does colliding particles change momentum?

Answer 10

• Gas particle are moving and have mass, so they have momentum.
• When gas particles collide with the walls of a container their velocity changes.
• A change in velocity also means a change in momentum.
• So as particles collide with a container, they experience a change of momentum and exert a force on the walls of the container, this creates pressure.
• Hotter particles collide more often, so there are more particles exerting a force on the container and the pressure increases.