2.1 Rates of Reaction

• Activation energy: minimum amount of energy required for a reaction to occur
• The effect on the rate of reaction can be explained by…

  • Frequency of collisions
  • Activation Energy
  • Kinetic energy of colliding particles 
  • Orientation of colliding particles
• At first, the rate of reaction is fast as seen from the steep slope. But as time goes by, the rate is slower, as there are less reactants, they have been used up, as seen from the flatter slope. Hence, this displays chemical equilibrium; when the concentration of all chemicals are constant, or flat on the graph 
• As the concentration of reactants increases, the frequency of collisions increases, which could lead to an increase in the frequency of successful collisions, thus an increase in the rate of reaction. 
• A higher temperature will increase the number of reactant particles with energies equal or greater than the activation energy due to an increased kinetic energy. That increases the average speed of reactant particles, hence increasing the frequency of successful collisions.
• An increase in pressure will decrease the volume thereby increasing the concentration of all substances. As the concentration of reactants increases, the frequency of collisions increases, which could lead to an increase in the frequency of successful collisions, thus an increase in the rate of reaction. 
• Increasing the surface area of the reactant particles increases the frequency of successful collisions, thereby increasing the rate of reaction 
• Including a catalyst provides an alternative pathway with lower activation energy which is not consumed but can be used again. The lower activation energy will increase the number of reactant particles with energies equal or greater than the activation energy increasing the frequency of successful collisions.