Particle Motion in Gases

• The molecules of a gas are in constant random motion
• The temperature of the gas is related to the average kinetic energy of the molecules
• Changing the temperature of a gas, held at constant volume, changes the pressure exerted by the gas
• A gas can be compressed or expanded by pressure changes. The pressure produces a net force at right angles to the wall of the gas container (or any surface)
• $pressure \times volume =$$constant$ $pV=$$constan t$

  • Pressure (p) in pascals (Pa)
  • Volume (V) in metres cubed (m3)
• Pressure and volume are inversely proportional to each other
• In a sealed container the outward gas pressure is the total force excerted by all particles in the gas per unit area of the container walls
• Increasing the temperature of a gas increases the kinetic energy of the particles meaning more frequent collisions and an increase in gas pressure
• Work is the transfer of energy by a force
• Doing work on a gas increases the internal energy of the gas and can cause an increase in the temperature of the gas