Maxwell-Boltzmann Distribution

• Maxwell - Boltzmann Distribution

  A) Energy

  B) Number of Molecules

  
• What does a Maxwell - Boltzmann graph represent?

  Gas molecules have different kinetic energies so move at different speeds
• What is molecular kinetic energy like in gases?

  • Some molecules have low kinetic energy, so move slower
  • Some molecules have high kinetic energy, so move faster
  • Most molecules have moderate kinetic energies and speeds
  • Only molecules that have energy equal to or more than the activation energy can react when they collide
• Features of a Maxwell-Boltzmann Distribution graph

  A) average energy

  B) Activation energy

  C) most probable energy

  
• Why does the curve start at the origin on the graph?

  No molecules have zero energy
• What does the peak represent?

  The most common kinetic energy
• What does the area under the graph represent?

  The number of molecules
• What effect does increasing temperature have on the distribution?

  • Graph shifts towards the right because more molecules gain energy more than the activation energy
  • The peak becomes lower, because area under the graph is unchanged as well as the number of molecules
  • Distribution broadens
  • There are more successful & frequent collisions
  • A higher proportion of molecules have more energy than the activation energy
• Effect of increasing temperature

  A) Higher temperature

  B) Lower temperature

  C) more

  
• What is the effect of a catalyst?

  The activation energy decreases and shifts to the left
• What effect does temperature have on the rate of reaction?

  Particles gain more energy

  Particles move faster causing more frequent collisions

  There are more successful collisions, so more molecules have the activation energy to cause a chemical reaction