1. Reaction Rates and Equilibrium Rates of Reaction

2. Think about it… What are some ways the rate of a reaction can be increased? What is a Rate?? A rate tells you how much something changes in a specified amount of time. Examples could be your speed or growth

3. Reaction Rates Some reactions occur very quickly, almost instantaneously i.e. striking a match Others can occur very, very slowly i.e. coal forming from dead organic matter Rates of reaction vary greatly and depend on several characteristics.

4. Collision Theory Rates of chemical reactions are related to the properties of atoms, ions, and molecules The collision theory states that when these particles react they must come into contact and collide with enough kinetic energy. If they do not have enough K.E., they bounce off and no rxn occurs (unsuccessful collision)

5. Collision Theory Its not enough that they collide, they must have enough force (kinetic energy) to “stick” and react

6. How Much Kinetic Energy?? The amount of force or Kinetic Energy required is known as the Activation Energy, denoted (E a ). This is the minimum amount to have in order for a reaction to take place. Without it, the particles bounce off and nothing happens. This is essentially just a barrier the particles must cross in order to form products.

7. Activation Energy, (E a ) As stated, this is the minimum amount of energy needed during a collision for a rxn to occur.

8. Activation Energy, (E a ) (∆G)

9. During this change… During a chemical reaction, particles are not considered reactants OR products They are “half-done” and are still transitioning to their final product states. This Activated Complex or otherwise known at the Transition State

10. The Transition State At the peak of the activation energy barrier, the “Activated Complex” can go either way It can roll back to the reactants side or continue on to the product side It is a different thing all together (Activated Complex)

11. Heat ‘em up ……… The Collision Theory explains why some reactions are very, very slow or even non- occurring at room temperature “Thermodynamically” Speaking these reactions are said to be _________________ at room temp. However, if you increase their kinetic energy (or in other words _____________________) they collide more frequently with higher energy This, in turn, results in a higher quantity of successful (and unsuccessful) collisions.

12. Factors Affecting Reaction Rates You can modify the rate of almost any reaction by changing the conditions Such conditions can be Temperature, Concentration, and Particle Size. You could also add a catalyst… what is a catalyst?? Think about Collision Theory. The question you should ask is: What can I do to INCREASE THE NUMBER OF COLLISIONS??

13. Temperature Usually, raising the temperature will speed up a reaction. At higher temperatures, the motion of the particles is __________________. With this increase in motion also comes an increase of average _______________, thereby giving the particles enough energy to overcome the Activation Energy (E a )

14. Concentration The number of reacting particles in a given volume also plays a huge role in the speed. By sticking in more particles you increase the concentration, which then increases the number of collisions, which thennnn increases the reaction rate (speed)

15. Particle Size The smaller the sample, the more surface area there is for contact The more surface area, the more collisions One way to increase the surface area is to dissolve them in solution or crush them up Crushing or grinding reactants up will greatly increase the speed of reaction.

16. Catalysts What is a catalyst?? The catalyst itself is NOT used up or altered in any way in a chemical reaction It speeds up a reaction by _______________ the activation energy, making it a smaller, easier hump to get over.

17. Catalyzed Reaction 2H 2(g) + O 2(g)  2H 2 O (l) Pt Because catalysts are not consumed or changed in a reaction, they are not written as reactants OR products.

18. Biological Catalysts Catalysts in our bodies are VERY important. Many necessary reactions do not occur at body temperature (37⁰C) and we cannot simply jack up the temp… Why not?? In order to help speed up these needed reactions, we add have biological catalysts, or enzymes.

19. Enzymes Without enzymes, digestion of proteins would takes years!!! We need to obviously speed this reaction up! An inhibitor is a substance that interferes with a catalysts’ job. Reactions will slow or even stop when an inhibitor is introduced. They stop the catalyst from doing its job (which is to speed it all up!)

20. Vocab Sheets Will Be Due Next Thursday