topic 9 kinetics

• How does a catalyst work?

  1. Gas diffuses onto the metal catalyst surface
  2. The reactant molecules are adsorbed on to the solid catalyst surface by forming bonds between the catalyst and reactant atoms
• Why is a solid heterogeneous catalyst suitable for a reaction in the gas phase? [1]


  It provides a surface area for the reaction.
• How to find the decrease of activation energy for a forward reaction when a catalyst is added?

  Lowered. Therefore, find the difference in the peaks when the reaction was uncatalysed and then catalysed.
• Activation energy of a reaction

  The minimum energy required for a reaction to occur
• What does a catalyst provide a reaction

  Increases the rate. Provides an alternative reaction pathway that had a lower activation energy -> a greater proportion of molecules in the reaction mixture that would have the activation energy
• how do heterogeneous catalysts work?


  1. Reactants ADsorb on to the surface of the catalyst, which has active sites on it. 2. Reactant bonds are weakened & a chemical reaction occurs. 3. The products DEsorb from the active site on the catalyst surface