Collision Theory Reaction Coordinate Diagrams Multistep Reactions Which

Collision Theory

Reaction Coordinate Diagrams

Multistep Reactions

Which reaction is faster? 1. A 2. B 3. The same

Which reaction is faster? 1. A 2. B 3. The same

Arrhenius Equation: Temperature and Ea Dependence Rate = k[A]x[B]y

As Ea increases, k …. 1. Increases 2. Decreases 3. Does not change

As T increases, k …. 1. Increases 2. Decreases 3. Does not change

Arrhenius Equation: Temperature and Ea Dependence

Example 1. Use the data below to find Ea.

Example 2. A reaction has Ea = 75 k. J/mol. If k = 1. 50 x 10 -3 at 25 o. C, what is k at 50 o. C?

Example 3. A reaction doubles its rate when the temperature increases from 25 o. C to 35 o. C. What is the activation energy?

Reaction Mechanisms: The pathway by which a reaction proceeds from reactants to products. • Each discrete chemical event is an “elementary step. ” • The reaction is a series of elementary steps. • Steps are usually unimolecular or bimolecular. • The overall reaction is the sum of the steps. • Each elementary step goes at its own rate. • The rate of the overall reaction is the rate of the slowest (rate determining) step.

Catalysts and Intermediates

Rate Laws for Elementary Steps

Overall Reaction: Intermediates: Catalysts:

Labeling Studies

More about catalysts