1. Seminar 7 SC155

2. Icebreaker What types of lightbulbs do you use in your house?

3. Incandescent Light Bulb

4. 1.Run electric current through very thin piece of Tungsten 2.Generates lots of heat along with the light 3.inefficient

5. Compact Fluorescent Bulb http://www.energystar.gov/index.cfm?c=cfls.pr_cfls_about

6. Compact Fluorescent Bulb http://www.energystar.gov/index.cfm?c=cfls.pr_cfls_about 1.Produce less heat and more light 2.Use less energy 3.Use mercury

7. Choosing the right bulb a.Energy star b.How much light you want i. Measured in lumens c.Right shade of light i.Measured in K ii.Lower temps mean yellower light

8. Compact Fluorescent Bulb http://www.energystar.gov/index.cfm?c=cfls.pr_cfls_about 5.How CFL’s work a.Electric current driven though a tube containing argon and mercury vapor. b.Generates ultraviolet light that excites fluorescent coating (phosphor) on the inside if the tube. c.When phosphor electrons relax again, emit visible light d.Take more energy initially

9. CFL’s and mercury 4 milligrams per bulb on average. Mercury only an issue when bulbs are broken or to be disposed of. If the mercury containing powder comes into contact with anything it must be thrown away. Must recycle old bulbs. CFL’s only produce 30% as much mercury waste as power plants produce to electricity for incandescent

10. Seminar Questions Why have some people been reluctant to adopt CFL’s in their homes and workplaces?

11. Seminar Questions Why have some people been reluctant to adopt CFL’s in their homes and workplaces? What are the pros and cons of CFL’s?

12. Seminar Questions Why have some people been reluctant to adopt CFL’s in their homes and workplaces? What are the pros and cons of CFL’s? What are the pros and cons of incandescent bulbs?

13. Seminar Questions Why have some people been reluctant to adopt CFL’s in their homes and workplaces? What are the pros and cons of CFL’s? What are the pros and cons of incandescent bulbs? How are CFL’s disposed of properly? Incandescent?

14. Seminar Questions Why have some people been reluctant to adopt CFL’s in their homes and workplaces? What are the pros and cons of CFL’s? What are the pros and cons of incandescent bulbs? How are CFL’s disposed of properly? Incandescent? Do you believe CFL’s will overtake Incandescent bulbs in popularity?

15. Redox Practice In each of the following equations, indicate the element that has been oxidized and the one that has been reduced. You should also label the oxidation state of each before and after the process: 1)2 Na + FeCl 2  2 NaCl + Fe

16. Redox Practice In each of the following equations, indicate the element that has been oxidized and the one that has been reduced. You should also label the oxidation state of each before and after the process: 1)2 Na + FeCl 2  2 NaCl + Fe Sodium is oxidized, going from a 0 to +1 oxidation state. Iron is reduced, going from a +2 to 0 oxidation state.

17. Redox Practice In each of the following equations, indicate the element that has been oxidized and the one that has been reduced. You should also label the oxidation state of each before and after the process: 1)2 Na + FeCl 2  2 NaCl + Fe 2)2 C 2 H 2 + 5 O 2  4 CO 2 + 2 H 2 O

18. Redox Practice In each of the following equations, indicate the element that has been oxidized and the one that has been reduced. You should also label the oxidation state of each before and after the process: 1)2 Na + FeCl 2  2 NaCl + Fe 2)2 C 2 H 2 + 5 O 2  4 CO 2 + 2 H 2 O Carbon is oxidized, going from a –1 to +4 oxidation state. Oxygen is reduced, going from a 0 to –2 oxidation state.

19. Redox Practice In each of the following equations, indicate the element that has been oxidized and the one that has been reduced. You should also label the oxidation state of each before and after the process: 1)2 Na + FeCl 2  2 NaCl + Fe 2)2 C 2 H 2 + 5 O 2  4 CO 2 + 2 H 2 O 3)2 PbS + 3 O 2  2 SO 2 + 2 PbO

20. Redox Practice In each of the following equations, indicate the element that has been oxidized and the one that has been reduced. You should also label the oxidation state of each before and after the process: 1)2 Na + FeCl 2  2 NaCl + Fe 2)2 C 2 H 2 + 5 O 2  4 CO 2 + 2 H 2 O 3)2 PbS + 3 O 2  2 SO 2 + 2 PbO Sulfur is oxidized, going from a –2 to +4 oxidation state. Oxygen is reduced, going from a 0 to –2 oxidation state.

21. Redox Practice In each of the following equations, indicate the element that has been oxidized and the one that has been reduced. You should also label the oxidation state of each before and after the process: 1)2 Na + FeCl 2  2 NaCl + Fe 2)2 C 2 H 2 + 5 O 2  4 CO 2 + 2 H 2 O 3)2 PbS + 3 O 2  2 SO 2 + 2 PbO 4)2 H 2 + O 2  2 H 2 O

22. Redox Practice In each of the following equations, indicate the element that has been oxidized and the one that has been reduced. You should also label the oxidation state of each before and after the process: 1)2 Na + FeCl 2  2 NaCl + Fe 2)2 C 2 H 2 + 5 O 2  4 CO 2 + 2 H 2 O 3)2 PbS + 3 O 2  2 SO 2 + 2 PbO 4)2 H 2 + O 2  2 H 2 O Hydrogen is oxidized, going from a 0 to +1 oxidation state. Oxygen is reduced, going from a 0 to –2 oxidation state.

23. Redox Practice In each of the following equations, indicate the element that has been oxidized and the one that has been reduced. You should also label the oxidation state of each before and after the process: 1)2 Na + FeCl 2  2 NaCl + Fe 2)2 C 2 H 2 + 5 O 2  4 CO 2 + 2 H 2 O 3)2 PbS + 3 O 2  2 SO 2 + 2 PbO 4)2 H 2 + O 2  2 H 2 O 5)Cu + HNO 3  CuNO 3 + H 2 Copper is oxidized, going from a 0 to +1 oxidation state. Hydrogen is reduced, going from a +1 to 0 oxidation state.

24. Redox Practice In each of the following equations, indicate the element that has been oxidized and the one that has been reduced. You should also label the oxidation state of each before and after the process: 1)2 Na + FeCl 2  2 NaCl + Fe 2)2 C 2 H 2 + 5 O 2  4 CO 2 + 2 H 2 O 3)2 PbS + 3 O 2  2 SO 2 + 2 PbO 4)2 H 2 + O 2  2 H 2 O 5)Cu + HNO 3  CuNO 3 + H 2 6)AgNO 3 + Cu  CuNO 3 + Ag

25. Redox Practice In each of the following equations, indicate the element that has been oxidized and the one that has been reduced. You should also label the oxidation state of each before and after the process: 1)2 Na + FeCl 2  2 NaCl + Fe 2)2 C 2 H 2 + 5 O 2  4 CO 2 + 2 H 2 O 3)2 PbS + 3 O 2  2 SO 2 + 2 PbO 4)2 H 2 + O 2  2 H 2 O 5)Cu + HNO 3  CuNO 3 + H 2 6)AgNO 3 + Cu  CuNO 3 + Ag Copper is oxidized, going from a 0 to +1 oxidation state. Silver is reduced, going from a +1 to 0 oxidation state.

26. Titration Practice Find the requested quantities in the following problems: 1)If it takes 54 mL of 0.1 M NaOH to neutralize 125 mL of an HCl solution, what is the concentration of the HCl?

27. Titration Practice Find the requested quantities in the following problems: 1)If it takes 54 mL of 0.1 M NaOH to neutralize 125 mL of an HCl solution, what is the concentration of the HCl? Because NaOH and HCl are in a 1:1, you can use M 1 V 1 = M 2 V 2­ (54 mL NaOH)(0.1 M NaOH) = (125 mL HCl)(M HCl) M HCl =0.043 M HCl

28. Titration Practice Find the requested quantities in the following problems: 1)If it takes 54 mL of 0.1 M NaOH to neutralize 125 mL of an HCl solution, what is the concentration of the HCl? 2)If it takes 25 mL of 0.05 M HCl to neutralize 345 mL of NaOH solution, what is the concentration of the NaOH solution?

29. Titration Practice Find the requested quantities in the following problems: 1)If it takes 54 mL of 0.1 M NaOH to neutralize 125 mL of an HCl solution, what is the concentration of the HCl? 2)If it takes 25 mL of 0.05 M HCl to neutralize 345 mL of NaOH solution, what is the concentration of the NaOH solution? Because NaOH and HCl are in a 1:1, you can use M 1 V 1 = M 2 V 2­ (25 mL HCl)(0.05 M HCl) = (345 mL NaOH)(M NaOH) M NaOH=0.0036 M NaOH

30. Titration Practice Find the requested quantities in the following problems: 3)If it takes 50 mL of 0.5 M KOH solution to completely neutralize 125 mL of sulfuric acid solution (H 2 SO 4 ), what is the concentration of the H 2 SO 4 solution? KOH + H 2 SO 4  K 2 SO 4 + 2H 2 O

31. Titration Practice Find the requested quantities in the following problems: 3)If it takes 50 mL of 0.5 M KOH solution to completely neutralize 125 mL of sulfuric acid solution (H 2 SO 4 ), what is the concentration of the H 2 SO 4 solution? KOH + H 2 SO 4  K 2 SO 4 + 2H 2 O For problem 3, you need to divide your final answer by two, because H 2 SO 4 is a diprotic acid, meaning that there are two acidic hydrogens that need to be neutralized during the titration. As a result, it takes twice as much base to neutralize it, making the concentration of the acid appear twice as large as it really is. use M 1 V 1 = M 2 V 2­ [(50 mL KOH)(0.5 M KOH)]/2 = (125 mL H 2 SO 4 )(M H 2 SO 4 ) M H 2 SO 4 =0.1 M H 2 SO 4

32. Titration Practice Find the requested quantities in the following problems: 4)Can I titrate a solution of unknown concentration with another solution of unknown concentration and still get a meaningful answer? Explain your answer in a few sentences.

33. Titration Practice Find the requested quantities in the following problems: 4)Can I titrate a solution of unknown concentration with another solution of unknown concentration and still get a meaningful answer? Explain your answer in a few sentences. You cannot do a titration without knowing the molarity of at least one of the substances, because you’d then be solving one equation with two unknowns (the unknowns being M 1 and M 2 ).

34. Titration Practice Find the requested quantities in the following problems: 5)Explain the difference between an endpoint and equivalence point in a titration.

35. Titration Practice Find the requested quantities in the following problems: 5)Explain the difference between an endpoint and equivalence point in a titration. Endpoint: When you actually stop doing the titration (usually, this is determined by a color change in an indicator or an indication of pH=7.0 on an electronic pH probe) Equivalence point: When the solution is exactly neutralized. It’s important to keep in mind that the equivalence point and the endpoint are not exactly the same because indicators don’t change color at exactly 7.0000 pH and pH probes aren’t infinitely accurate. Generally, you can measure the effectiveness of a titration by the closeness of the endpoint to the equivalence point.