P1.3.1 - Gas pressure and temperature

• Q1. What happens when you blow up a balloon and it gets bigger?

  You are increasing the number of air particles in it and the particles collide with the inside surface of the balloon like so.

  
• Q2. Each collision produces a very small force making many collisions each producing an outward force over a certain area. What does this produce?

  Gas pressure
• Q3.

  The force on the rubber makes the balloon get bigger
• Q4. What happens if you add more air particles to a container that cannot expand?

  The pressure increases
• Q5. How does temperature affect the gas pressure?

  If the temperature of a gas increases , the gas particles have a higher average speed meaning they collide more frequently with the sides of the container. The collisions produce a bigger force over a certain area creating a bigger pressure
• Q6. What can you use to measure the pressure of air that is trapped in a bottle?

  A pressure gauge

  
• Q7. What is the pressure of the gauge measured in?

  Pascals (Pa)

  One pascal equals one newton per square metre

  you will sometimes see the unit kilopascal (kPa) which is equal to 1000Pa
• Q8. If you measure the pressure or volume of a gas as its temp increases you can draw a graph like:

  These graphs show how the pressure or volume of a gas varies with temperature

  
• Q9. What did the graphs previously shown tell us?

  That as you decrease the temp the pressure also decreases.
• Q10.

  The dotted line shows what would happen if you carried on cooling the gas. This is when the pressure 'would' reach the absolute zero. We cannot actually hit the absolute zero but we can work out the value of it by extrapolating.

  
• Q11. What is an extrapolation

  Its the dotted line on the graph which shows what you estimate would happen if you continue to change the independent variable
• Q12. What is the theory which you are using when using the idea that the particles in a gas produce pressure?

  Kinetic theory
• Q13. What do scientists use the kinetic theory for

  To explain and predict the behaviour of gases
• Q14. What is the tool you can use to measure the pressure of a gas?

  Manometer