Collision Theory and Reaction Rate

1. Collision Theory and Reaction Rate Notes

2. Rates of Chemical Reactions • The amount of time it takes for a chemical reaction to come to completion is called the reaction rate • Reaction rates are different for different reactions • They can range from a fraction of a second to days or even years

3. Why do different reactions have different rates? • The rates of reaction are related to the properties of particles through a model called collision theory • Particles will only react if there is an effective or successful collision between them

4. In order for particles to react, • They must collide

5. 2. They must collide in the correct orientation to form the activated complex

6. The activated complex is a temporary, unstable arrangement of atoms that may lead to products • It can be thought of as a transition state between reactants and products

7. 3. They must collide with a specific minimum amount of energy (activation energy) to form the activated complex

8. Collision theory and rate of reaction • The rate of a reaction can be increased by changing certain factors in a reaction like temperature or concentration of reactants • These factors will increase the reaction rate if they produce a greater number of effective collisions

9. A greater number of effective collisions can be achieved by anything that • Increases the energy of the reactants • Lowers the activation energy • Produces more collisions per unit of time