chem / reactions.mdon commit [chem] activation energy, kinetic energy, catalysts (3ab8fae)
   1# Rates and Equilibria
   2
   3## Energy profile diagrams
   4
   5$$E_A = E_{\text{max}} - E_{\text{initial}}$$
   6
   7- Energy always needed to initiate reaction (break bonds of reactants)
   8- Reactant particles must collide at correct angle, energy etc
   9- Most collisions are not fruitful
  10
  11![](graphics/endothermic-profile.png)
  12![](graphics/exothermic-profile.png)
  13
  14**Ways to increase rate of reaction:**
  15
  161. Increase surface area
  172. Increase concentration/pressure
  183. Increase temperature
  19
  20## Kinetic energy
  21
  22Temperature - measure of _avg_ kinetic energy of particles. Over time each particle will eventually have enough energy to overcome $E_A$.  
  23Note same distribution indicates same temperature.  
  24![](graphics/ke-temperature.png)
  25
  26## Catalysts
  27
  28- alternate reaction pathway, with lower $E_A$
  29- increased rate of reaction
  30- involved in reaction but regenerated at end
  31
  32**Homogenous** catalyst: same state as reactants and products, e.g. Cl* radicals.  
  33**Hetrogenous** catalyst: different state, easily separated. Preferred for manufacturing.
  34![](graphics/catalyst-graph.png)