Pressure and volume of gases: Particle model of matter: Physics: GCSE (9:1)

• Effect of pressure changes on the volume of a gas

  The gas will expand or compress
• Expand


  When the space between particles increases so they occupy a greater volume

  
• Compress


  When the space between particles decreases so they occupy a smaller volume

  
• Effect of increasing the volume on the pressure of a gas

  Increasing the volume causes the pressure to decrease providing the mass and the temperature of the gas stay the same

  
• Relationship between gas pressure and volume


  The pressure and volume of a gas are inversely proportional

  
• Inversely proportional


  The relationship between two variables whose product is a constant

  
• pV = constant


  The equation linking pressure, volume and a constant

  
• p


  The symbol for pressure
• V

  The symbol for volume
• Pascals (Pa)


  The SI unit for pressure
• Cubic metres (m³)


  The SI unit for volume

  
• p(1)V(1) = p(2)V(2)


  The equation for the change in volume or pressure for gas at a constant temperature

  
• p(1) and V(1)

  The pressure and volume before either one is changed

  
• p(2) and V(2)


  The pressure and volume after either one is changed