1. Catalysts, Endothermic vs. Exothermic Reactions

2. Evaluation/Assessment:
Objective:
Today I will be able to:
Interpret a potential energy diagram including activation energy and enthalpy change.
Explain the role of activation energy in chemical reactions and its change with the addition of a catalyst.
Apply understanding of exothermic and endothermic reactions to understanding the mechanism for hot and cold packs
Evaluation/Assessment:
Informal assessment: monitoring student questions and discussions as they complete the practice and the article questions
Formal assessment: analyzing responses to the practice and the exit ticket
Common Core Connection
Value Evidence
Make sense of problem and persevere in solving them
Use appropriate tools strategically
Attend to precision

3. Lesson Sequence Evaluate: Warm – Up Evaluate: Review HW
Explain: Reaction Rates Notes
Elaborate: Reaction Rates Practice
Evaluate: Exit Ticket

4. Warm - Up
What is the difference between an endothermic and an exothermic reaction?
What is a catalyst? (Think back to Biology!)

5. Objective Today I will be able to:
Interpret a potential energy diagram including activation energy and enthalpy change.
Explain the role of activation energy in chemical reactions and its change with the addition of a catalyst.
Apply understanding of exothermic and endothermic reactions to understanding the mechanism for hot and cold packs

6. Homework
Study for ICE Table and Energy Diagram Quiz Thursday, June 5

7. Agenda Warm – Up Review HW Reaction Rate Notes Reaction Rate Practice
Exit Ticket

8. Review Acid Base ICE Tables
What questions do you have about ICE tables?

9. Acid Base ICE Tables We will complete the one problem together
1st one from the worksheet you will receive tomorrow
The other 5 will be saved for later!
Problem #1
What is the pH of a M solution of benzoic acid, C6H5CO2H? Ka = 6.3 x 10-5

10. Reaction Rate Notes

11. Q: What factors affect the rate of a reaction?
Concentration
Surface Area
Temperature
Stirring
Pressure
Catalyst
We need to think on the microscale

12. Q: Why do Chemical Reactions Occur?
Ans: Collision Theory
Molecules or atoms must collide with other molecules or atoms in order for reactions to occur

13. Collision Theory Explained
When particles collide there is a transfer in kinetic energy
In order for reaction rates to increase their must be an “effective collision”
Enough kinetic energy
Proper orientation of colliding particles

14. Q: How do reactions begin?
Ans: All reactions need to absorb energy to begin
After the reaction occurs:
Energy can be released = Exothermic Reaction
More energy can be absorbed = Endothermic Reactions

15. Energy Diagrams
Used to determine if reactions are exothermic or endothermic
Symbols on diagrams
ΔH = Enthalpy Change (heat of reaction) - energy absorbed or released
EA = Activation Energy - amount of energy required to start a reaction
Other Vocabulary
Activated Complex – unstable intermediate compound formed right before the reaction occurs (located at highest peak)
Potential energy – energy that the reactants have before the reaction and the products have after the reacton

16. Exothermic Reaction
Energy is released

17. Endothermic Reaction
Energy is absorbed

18. Q: What is a catalyst? Substance or element
Ex: Palladium (Pd), Platinum (Pt)
Speeds up the rate of a reaction by lowering the activation energy
Catalysts provide the surface and the orientation that help the reaction to take place

19. Catalyzed vs. Uncatalyzed Reactons
Sketch the diagram
Discuss with a partner
What do you notice about the activation energy in a catalyzed and an uncatalyzed reaction?
What do you notice about the amount of energy produced (ΔH) ?

20. Final Exam 50 multiple choice questions 2nd semester topics ONLY
Still must know the basics spanning from the whole year
i.e. polyatomic ions, naming, periodic table basics, etc.
Topics will be handed out later this week with the final review project

21. Exit Ticket
Explain why the quantity of reactant and product of a reaction does not change when a catalyst is added.
Why does adding a catalyst to a reaction cause the activation energy to decrease?