2.10 Activation Energy and Collision theory

What determines the rate of a reaction

The rate of a reaction is determined by the number of collisions there are per unit of time between the reactants.

• the greater the number of collision, the faster the rate of reaction

Why must collisions take place for a chemical reaction to occur

A collision must take place between reactant particles to break reactant bonds and form product bonds

What is the activated complex?

The activated complex is the moment during a collision where old bonds are breaking, and new bonds are forming simultaneously

• the activated complex requires the most amount of energy in a reaction

what are the two required conditions to form an activated complex and result in an effective collision

1. Particles must collide in a certain orientation or geometry

2. Particles in the system must possess a certain minimum energy requirement called the activation energy

What are factors that reduce the activation energy requirement, allow for more reactant particles to possess this minimum energy, or increase the number of effective collisions, and why?

• concentration → the greater the concentration, the more collisions can take place in the same unit of time, providing greater odds of an effective collision

• pressure → the greater the pressure, the greater the concentration, which results in a greater number of collisions, which increased the odds of an effective collision

• temperature → increasing the temperature of the reactants provides its particles with greater energy, allowing more particles to exceed the minimum threshold

• a catalyst → a catalyst lowers the requires activation energy requirement by providing an alternate, lower energy path in which an activated complex may form