1. Kinetics Lesson 3 Collision Theory

2. The Collision Theory Link to Simulation of Molecular Motion 1.Matter is moving particles. 2.Temperature increases- particles move faster -more collisions -more collision energy. 3.Chemical reactions -bonds break -new bonds form 4.Collisions provide the energy.

3. Collision Theory Most collisions are not successful Collisions provide the energy required to break bonds. You need a collision to have a reaction.

4. Collision Theory products no products 1.Favourable Geometry A successful collision requires: Poor Geometry

5. 2.Sufficient Energy to break the chemical bonds Activation energy is the minimum amount of energy required for a successful collision.

6. The Collision Theory can be used to explain how the rate of a reaction can be changed. And that’s it! 3.Lower activation energy or Ea- low energy collisions are more effective. 2.Harder collisions- greater collision energy 1.More collisions Reaction rates can increase due to

7. The Collision Theory can be used to explain how the rate of a reaction can be changed. Harder collisions More collisions 1.Increasing the temperature increases the rate because there are:

8. 2.Increasing the reactant concentration increases the rate because there are: More frequent collisions

9. The Collision Theory can be used to explain how the rate of a reaction can be changed. The catalyst KI is added to H 2 O 2, food colouring, and dishwashing detergent. The O 2 produced makes foam. Lowers the activation energy or Ea- allowing low energy collisions to be successful 3.Adding a catalyst Movie

10. The Collision Theory can be used to explain how the rate of a reaction can be changed. Lower activation energy or Ea- allowing low energy collisions to be successful 4.Changing the nature of the reactant for a more reactive chemical increases the rate

11. The Collision Theory can be used to explain how the rate of a reaction can be changed. More frequent collisions 5.Increasing the surface area of a solid reactant increases the rate because:

12. Explain each Scenario Using the Collision Theory The spark provides the Ea and it explodes because it is exothermic A small spark ignites causes an explosion. Ea is too high for the room temperature collisions 1.A balloon full of H 2 and O 2 do not react at room temperature.

13. Explain each Scenario Using the Collision Theory It burns because it is exothermic The candle continues to burn The match provides the Ea A match causes the candle to burn Ea is too high for the room temperature collisions 2.A candle does not burn at room temperature

14. Explain each Scenario Using the Collision Theory 3.H 2 O 2 decomposes very slowly at room temperature. 2H 2 O 2(aq) → O 2(g) + 2H 2 O (l) KI increases the reaction rate dramatically. Lowers the Ea- allows low energy collisions to be successful KI is a catalyst as it is not a reactant and it speeds up the rate.

15. Describe and Graph the Relationship between the Following Ea and the rate Ea Rate Decreasing the Ea increases the rate- inverse.

16. Describe and Graph the Relationship between the Following Temperature and the rate Temp Rate Increasing the temperature increases the rate- direct.

17. Describe and Graph the Relationship between the Following Concentration and the rate Conc Rate Increasing the concentration increases the rate- direct.

18. Describe and Graph the Relationship between the Following Ea and the temperature Ea Temp No relationship! The only way to change the Ea is by adding a catalyst!

19. Which factors increase the percentage of successful collisions? I.Increasing temperature II.Increasing concentration III.Increasing surface area IV.Adding a catalyst