P1.3 Flashcards
Explain why it is dangerous to throw a canister full of pressurised gas in a fire.
This is because the increase in temperature will increase the particles’ kinetic energy so they start colliding with the inside surface of the canister with a larger force which could cause the canister to burst.
How is gas pressure produced?
The particles collide with the inside surface of the container.
Each collision produces a very small force.
There are many collisions, each producing an outward force over a certain area.
This produces a gas pressure.
The net force caused by the particles colliding on the inside surface of the container is the pressure.
The force acting per unit area is the pressure.
What is the pressure of gas measured in?
pascals (Pa)
Convert 1 kPa into Pa
1 kPa = 1000 Pa
Explain what happens to the pressure as you increase the amount of particles in a given volume.
The more particles there are in a given volume, the more often they’ll collide with the walls of the container, and with each other, so the higher the pressure will be.
What happens to the pressure when you heat gas in a sealed container?
If you hold a gas in a sealed container with a fixed volume and heat it, energy is transferred to the kinetic energy stores of the gas particles and they move faster. This means the particles hit the container walls harder and more often, creating more pressure.
How many N/m^2 does one pascal equal to?
One Pa = One N/m^2
What happens when you cool the gas?
If the gas is college, the particles have less energy and move less quickly. The particles hit the walls with less force and less often, so the pressure is reduced.
How does doing work on a gas affect the temperature?
Doing work on a gas can increase its internal energy, which increases it temperature.
The gas exerts pressure on the plunger of the pump, and so exerts a force on it. Work has to be done against this force to push down the plunger.
This transfers energy to the kinetic energy stores of the gas particles, so increases the internal energy and therefore the temperature.
If the pump is connected to e.g. A tyre, some of this energy is transferred from the gas to the thermal energy store of the tyre, and you will feel the tyre getting warmer as you pump it up.
What can you use to measure the pressure of air?
A pressure gauge
What does it mean if a balloon isn’t expanding or contracting?
This means the pressure (and force) of the gas inside the balloon pushing outwards is equal to the pressure (and force) of the air outside the balloon pushing inwards.
What is the equation for a fixed amount of gas at a constant temperature?
pressure (Pa) x volume (m^3) = constant
What does it mean extrapolating a graph?
When you use line on a graph and estimate what would happen if you continue to change the independent value.
Why are pressure and volume inversely proportional?
The collisions of the gas particles produce a force that is at right angles to the surface.
If you halve the volume, you double the number of collisions per second between the gas particles and the container.
Convert 100000N/m^2 to kPa
100 kPa
