1. CHEMICAL ENERGY CHAPTER 6.5

2. NOVEMBER 28, 2011 HW: 6.5 CTG P. 475 #1-7 DUE WED LO: Differentiate between endothermic and exothermic reactions using chemical thermodynamics SC: Make hot packs and cold packs. Observe energy changes when matter undergoes a change. Determine whether energy changes are endothermic or exothermic from a particular point of reference. Do Now: Copy Down LO and SC WDYS; WDYT p. 468 Read through Investigation # 1-5 and set up notebooks Agenda: Do Now Investigation Chem Talk Summary

3. INVESTIGATION You have 10 minutes to do numbers 1, 2, and 4 Make sure you make your observations Be sure that your lab station is clean by the end of the time! Be careful with the sodium hydroxide! If you are finished with the lab before everyone else, please read through the Chem Talk on p. 470

4. INVESTIGATION The teacher will now demonstrate number 3. Is this endothermic or exothermic? How do you know? Does this mean that bonds are breaking or forming?

5. DATE: HW: CTG P. 475 #1-7 LO: Differentiate between endothermic and exothermic reactions using chemical thermodynamics SC: Make hot packs and cold packs. Observe energy changes when matter undergoes a change. Determine whether energy changes are endothermic or exothermic from a particular point of reference. Do Now: Read through the Chem Talk on p. 470 Agenda: Chem Talk Summary

6. CHEM TALK Please Read the Chem Talk for this chapter—take 10 minutes silently to read through it!

7. What does ‘endothermic’ mean? Give an example. CHEM NOTES

8. What does ‘endothermic’ mean? Give an example. A change in which energy in the form of heat is absorbed from the surrounding environment resulting in an increase in energy of a system. General form: Reactants + energy  Products Example: Cold Packs! CHEM NOTES

9. REACTION COORDINATE:

10. What does ‘exothermic’ mean? Give an example. CHEM NOTES

11. What does ‘exothermic’ mean? Give an example. A reaction where heat is released from a system resulting in a decrease in the internal energy of the system. General Form: Reactants  products + heat Example: Hot Pack CHEM NOTES

12. REACTION COORDINATE:

13. What causes a chemical reaction? What is the ‘activation energy’? CHEM NOTES

14. What causes a chemical reaction? What is the ‘activation energy’? The collision of molecules! They must have a higher Kinetic Energy than the Activation Energy. The minimum energy required to cause the bonds to break in a reaction. Exothermic—bonds are breaking Endothermic—bonds are forming CHEM NOTES

15. Every reaction has both bonds forming and bonds breaking 1.As the reactants collide, they break eachother’s bonds— energy must be added to the system. 2.Once these bonds are broken (activation energy), the individual components form bonds to form the products— energy must be given off! 3.The difference between the energy needed for bond breaking and released by bond formation determines whether endo or exo

16. DO NOT COPY…BUT EXPLAIN.

17. CHEM TALK Read through the rest of the chem talk and do the checking up questions These should be pretty easy—we saw this in chapter 2!

18. DO NOW—AS A GROUP Everybody puts gasoline in their cars to go places every day. Gasoline is a mixed form of hydrocarbons, though it is primarily made of octane. As octane passes through the car, it burns and powers the pistons in the car to move forward. Is this an endothermic or exothermic reaction? Explain. Draw a reaction coordinate that describes the energy changes of this reaction!

19. SUMMARY Essential Questions, p. 474 --How do you know? --Why do you believe --Why should you care LO and SC reflection