1. Aim: How to represent the energy change in a system?
Do Now:
1.Explain what an effective collision is.
2. How does a catalyst speed up a reaction?

2. Heat of Reaction
*Reminder: Heat of reaction is the amount of heat given off or absorbed in a chemical reaction*
ΔH = H (products) H(reactants)
Heat of Heat content Heat content of
reaction of products reactants

3. Heat of Reaction for Exothermic Process
If the products have less potential energy or heat content than the reactants, heat is given off and its is an exothermic reaction. ΔH = negative

4. Potential Energy Diagram (Exothermic)

5. Heat of Reaction for Endothermic Process
If the products have more potential energy or heat content than the reactants, heat is absorbed and its is an endothermic reaction. ΔH = positive

6. Potential Energy Diagram (Endothermic)

7. 1. The forward reaction above is endothermic or exothermic. 2
1. The forward reaction above is endothermic or exothermic? 2. Which lettered arrow represents the energy of the reactants for the forward reaction? 3. Which lettered arrow represents the energy of the reactants for the reverse reaction? A G

8. 4. Which lettered arrow represents the energy of the products for the forward reaction? 5. Which lettered arrow represents the energy of the products of the reverse reaction? 6. Which lettered arrow represents the ΔH for the forward catalyzed reaction? G A F

9. 7. Which lettered arrow represents ΔH for the forward uncatalyzed reaction? 8. Which lettered arrow represents the ΔH for the reverse catalyzed reaction? 9. Which lettered arrow represents the ΔH for the reverse uncatalyzed reaction? F F F

10. 10. Which lettered arrow represents activation energy for the forward catalyzed reaction? 11. Which lettered arrow represents activation energy for the forward uncatalyzed reaction? 12. Which lettered arrow represents activation energy for the reverse catalyzed reaction? B E I

11. 13. Which lettered arrow represents activation energy for the reverse uncatalyzed reaction? 14. Which lettered arrow represents energy of the activated complex for the catalyzed reaction? 15. Which lettered reaction represents energy of the activated complex for the uncatalyzed reaction? D J C

12. 16. Which lettered arrow represents the difference between the activation energies of the catalyzed and the uncatalyzed reactions? 17. Which lettered arrow represents the difference between the activated complex for the catalyzed and the uncaltyzed reactions? 18. The reverse reaction is (a) endothermic or (b) exothermic. H H

13. Do Now: Fill in the blank spaces.
Word Box:
Catalyzed
Uncatalyzed