boltzmann distribution

• Collision theory

  Two reacting particles must collide for a reaction to occur, and must be in the correct orientation and have sufficient energy to overcome the activation energy of the reaction
• x-axis is energy
• y-axis is number of molecules
• the area under the curve is equal to the total number of molecules
• at higher temperature the peak of the curve is lower and shifted to the right
• at higher temperature a greater proportion of molecules can overcome the activation energy
• at high temp:

  • more molecules have an energy greater than or equal to the activation energy
  • therefore a greater proportion will lead to a reaction, increasing the rate of reaction
  • collisions will also be more frequent as the molecules are moving faster (increased energy is more important than increased frequency of collisions)
• in the presence of a catalyst a greater proportion of molecules exceeds the new lower activation energy
• a catalyst provides an alternative reaction route with lower activation energy
• on the graph

  • activation energy with catalyst is Ec
  • activation energy without catalyst is Ea
• on the graph

  • higher temp is T2
  • lower temp is T1