P1.3.2 - Pressure and volume

• How are pressure and volume related

  In a syringe if you seal the of it and press the plunger the volume of the gas decreases and the pressure has doubled.

  
• Key things to remember

  
  

  Volume and pressure are inversely proportional to each other, In other words:

  • As the volume doubles the pressure halves
  • As the volume halves the pressure doubles
• Why is pressure and volume inversely proportional?

  The collisions of the gas particles produce a force that is at right angles to the surface. If you half the volume , you double the number of gas particles colliding per second against the container
• How do you calculate with pressure and volume?

  Using the formula

  Pressure(Pascals) x Volume(m³) = constant
• You have a large syringe of air. When the pressure is 2x10^5Pa the volume of the gas is 4x10^-6(0.000004)m³. Calculate the volume when the pressure is 5 x10^5Pa

  The formula you must use is : Pressure x volume = constant (rearranged)

  Answer = 1.6x10^-6m³ (2 sig fig)

  
• This can measure pressure and volume

  apparatus

  
• How does doing work on a gas affect the temperature?

  When using a bike pump you may notice that the vale gets hot. You can increase the internal energy of a gas by:

  • heating it
  • doing work on it