Maxwell Boltzman Distribution and reactivity

1. Maxwell Boltzman Distribution and reactivity Describes the distribution of gas particles with different kinetic energies.

2. Not all gas particles will have the same amount of energy at the same temperature. Most probable energy Average energy NB as the curve is assymmetric the average > most probable.

3. Collision theory states that a reaction will occur if a collision has the correct orientation and an energy equal to or greater than the activation energy. • The Maxwell-Boltzman distribution can be used to show the numbers of particles that meet this criterion.

4. Activation energy Area under the curve to the RHS is the number of collisions that can result in a reaction.

5. 298 K 498 K 698 K Increasing the temperature flattens the curve and pushes it to the RHS, but the total area remains constant.

6. As temperature increases so does the probability of a collision with a higher energy. 0 oC 25 oC 100 oC As temperature rises there are more collisions with an energy≥ the activation energy, hence rate increases.

7. The Q10 Rule A 100C rise in temperature results in a doubling of the metabolic rate.

8. Effect of decreasing activation energy. If activation energy is lowered the area under the curve to the RHS of the activation energy increases. There will be more collisions with an energy ≥ activation energy, so the rate increases. Catalysed activation energy Uncatalysed activation energy