Collision Theory.

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Presentation transcript:

Collision Theory

Reaction Coordinate Diagrams

Multistep Reactions

Rates, Temperature and Ea Boltzmann Plots and k: Temperature: Activation Energy:

Arrhenius Equation: Temperature and Ea Dependence

What about A?

Example 1. Use the data below to find Ea.

Example 2. A reaction has Ea = 75 kJ/mol. If k = 1.50 x 10-3 at 25 oC, what is k at 50 oC?

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

The reaction is a series of elementary steps. 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.

Rate Laws for Elementary Steps

Overall Reaction: Intermediates: Catalysts: