Pressure and volume

• Pressure in gases


  • Caused by gas particles colliding with the walls of the container
  • Can be increased by increasing temperature
  • Can be increased by increasing the number of particles
  • Can be decreased by decreasing the volume
• Pressure and volume


  Inversely related
• PV = constant


  For a given amount of gas at a constant temperature, the pressure times the volume will always be a constant value
• Calculating pressure when volume changes

  1. Given initial pressure and volume

  2. Calculate constant (P1V1)

  3. Use constant to calculate new pressure (P2 = constant/V2)
• Calculating pressure when volume changes (alternative method)

  1. P1V1 = P2V2

  2. Rearrange to find P2
• Atmospheric pressure is 101 kPa