3.3.2 Pressure in Gases

• What is the formula for a fixed mass of gas held at a constant temperature?

  Constant = pressure x volume.
• What is pressure measured in?

  Pascals (Pa).
• What is volume measured in?

  Metres cubed (m3).
• What does Boyle’s law state?

  Pressure and volume of a gas are inversely proportional at constant temperature.
• For a gas at a constant temperature, which two statements can be made?

  When volume decreases, pressure increases and when volume increases, pressure decreases.
• p1​V1​=p2​V2​

  This is where…?

  p1 is the initial pressure, V1 is the initial volume, p2 is the pressure after a change occurs and V2 is the volume after a change occurs.
• A gas occupies a volume of 0.5 m3 at a pressure of 150 Pa. Calculate the pressure exerted by the gas if the volume is compressed to 0.2 m3? (Assume constant temperature)

  375Pa.
• A gas occupies a volume of 0.3 m3 at a pressure of 50 Pa. The pressure increased to 150 Pa, what is the new volume? (Assume constant temperature)

  0.1m3.
• A gas initially occupied a volume of 10 L at an unknown pressure. The gas was then compressed to 2 L, and measured as having a pressure of 20 kPa. Calculate the original pressure before the gas was compressed. (Assume constant temperature)

  4kPa.