Collision Theory

[Nora 1F]

How do mean relative speeds and activation energy relate to the collision theory? How is collision theory used to determine a rate constant?

[Ashin_Jose_1H]

In a chemical reaction, we need to break or form bonds. If we look at the gases, we need molecules to meet (or collide) in order to break/ form new bonds. Hense, we have the collision theory. Two factors that affect the whether bonds are broken or formed within a collision are relative speed and kinetic energy.

As the relative speed of the molecules increase, there is a higher probability that the molecules will collide.

The activation energy is the minimum kinetic energy required for a collision to result in the forming or breaking of a bond.

[Lily Guo 1D]

The higher the speed, the more likely particles are to collide and break/form bonds. Activation energy is the energy required to break/form bonds, so the higher the activation energy, the more difficult it will be to break/form bonds because the reaction requires a large input of energy before the products can form.

[Guangyu Li 2J]

The collision theory believes that chemical reactions are led by the molecular collisions. Only those with high enough energy and appropriate direction, or called activated molecules, can collide with each other and proceed chemical reactions. Based on the molecular knowledge in 14A, we know that only those molecules with kinetic energy higher than the activation energy can make effective collisions and proceed chemical reactions.

As a result, we can conclude that the activation energy is the lowest energy level of molecules to make effective collision with others. In addition, the faster molecules move, the higher kinetic energy they obtain in the chemical reactions, the more likely molecules collide with each other.

Hope this helps!