Acids, Bases, Buffers and Acid Rain

1. Acids, Bases, Buffers and Acid Rain

2. VOCABULARY TERMS: • IONIZATION • Atoms can gain or lose electrons in order to form ions • DISSOCIATION • When ionic compounds dissolve in water, their ions separate from one another

3. Steve Spangler Acids and Bases Youtube

5. Ionization of Water youtube (29 secs) H+ will quickly attach to another water molecule

6. What determines if it is becoming an acid or a base?

9. reversible • Dissociation of Water Podcast (2:37) –southern accent

12. Equilibrium constant

13. What is Kw? • Kw is essentially just an equilibrium constant for the reactions shown. You may meet it in two forms: • Based on the fully written equilibrium . . . • . . . or on the simplified equilibrium:

14. FYI • A hydrogen ion is also just a proton.

15. Nice Nerdy Explanation Nice Nerdy Explanation • Dissociation of Water (youtube 4:33)

18. pH • Indicates the acidity [H3O+] of the solution • pH = - log [H3O+] • From the French pouvoir hydrogene (“hydrogen power” or power of hydrogen) LecturePLUS Timberlake

19. pH In the expression for [H3O+] 1 x 10-exponent the exponent = pH [H3O+] = 1 x 10-pH M LecturePLUS Timberlake

20. pH Range: each number is 10 times more concentrated H+ than the number above it 0 1 2 3 4 5 6 7 8 910 11 12 13 14 Neutral [H+]>[OH-][H+] = [OH-][OH-]>[H+] Acidic Basic LecturePLUS Timberlake

21. Some [H3O+] and pH [H3O+] pH 1 x 10-5 M 5 1 x 10-9 M 9 1 x 10-11M 11 LecturePLUS Timberlake

22. pH of Some Common Acids gastric juice 1.0 lemon juice 2.3 vinegar 2.8 orange juice 3.5 coffee 5.0 milk 6.6 LecturePLUS Timberlake

23. pH of Some Common Bases blood 7.4 tears 7.4 seawater 8.4 milk of magnesia 10.6 household ammonia 11.0 LecturePLUS Timberlake

24. Learning Check A. The [H3O+] of tomato juice is 1 x 10-4 M. What is the pH of the solution? 1) - 4 2) 4 3) 8 B. The [OH-] of an ammonia solution is 1 x 10-3 M. What is the pH of the solution? 1) 3 2) 11 3) -11 LecturePLUS Timberlake

25. Learning Check A. The [H3O+] of tomato juice is 1 x 10-4 M. What is the pH of the solution? 1) - 4 2) 4 3) 8 B. The [OH-] of an ammonia solution is 1 x 10-3 M. What is the pH of the solution? 1) 3 2) 11 3) -11 LecturePLUS Timberlake

26. Learning Check The pH of a soap is 10. What is the [H3O+] of the soap solution? 1) 1 x 10 - 4 M 2) 1 x 1010 M 3) 1 x 10 - 10 M LecturePLUS Timberlake

27. Solution Kw = [H3O+ ][OH-] = 1.0 x 10 14 A. [H3O+] = 1.0 x 10 -14 1.0 x 10-10 [OH- ] = 10-4 or pH 4 LecturePLUS Timberlake

28. Buffers • solution in which the pH of the solution is "resistant" to small additions of either a strong acid or strong base.

29. Buffer Animation Carbonic acid is a good blood buffer

30. Buffer exampls

31. Where are buffers used? • chemical research, • biological research • industry • Your body uses buffers to maintain a blood pH of 7.35-7.45, • massive number of biochemical reactions involving enzymes.

32. Acid Rain • Unpolluted rain has a pH of 5.6 • Rain with a pH below 5.6 is “acid rain“ • CO2 in the air forms carbonic acid CO2 + H2O H2CO3 • Adds to H+ of rain H2CO3 H+ (aq) + HCO3-(aq) LecturePLUS Timberlake

33. Formation of acid rain: • 1. Emission of sulfur and nitrogen oxides • SO2 26 million tons in 1980 • NO and NO2 22 million tons in 1980 • Mt. St Helens (1980) 400,000 tons SO2

34. Sources of Acid Rain • Power stations • Oil refineries • Coal with high S content • Car and truck emissions • Bacterial decomposition, and lighting hitting N2 LecturePLUS Timberlake

36. 2. Reactions in the atmosphere form SO3 • 2SO2 + O2 2 SO3 • 3. Reactions with atmosphere water form acids • SO3 + H2O H2SO4 sulfuric acid • NO + H2O NO2 nitrous acid • HNO2 + H2O HNO3 nitric acid

37. Effects of Acid Rain • Leaches Al from soil, which kills fish • Fish kills in spring from runoff due to accumulation of large amounts of acid in snow • Dissolves waxy coatings that protect leaves from bacteria • Corrodes metals, textiles, paper and leather LecturePLUS Timberlake

38. Criteria Air Pollutants: NOx and SOx • 200+ now-fishless lakes in Adirondacks • Little Echo Pond, Franklin, NY pH = 4.2 • Thousands of lakes in Canada (Ontario, Quebec, New Brunswick) now-fishless http://www.elmhurst.edu/~chm/vchembook/194acidraineffects.html

39. pH Scale Matching • Quia - The pH Scale • Write the order you think these are from pH 1-14.

40. 1Stomach Fluids • 7Pure Water • 11Rolaids, Tums • 13Bleach • 2Lemon Juice • 5Coffee • 3Vinegar • 8Blood • 10Borax • 14Lye • 4Tomatoes • 6Milk • 9Baking Soda • 12Household Ammonia

42. ACID RAIN MOVIE • Acid Rain - Our Changing Planet – UMAC • When precipitation goes below pH 5.6. • Comes from burning of fossil fuels (cars, factories, airplanes). Sulfur and nitric oxides form sulfuric acid and nitric acid.

43. Main Pollutant of Acid Rain

44. Forest Destroyed by Acid Rain

45. Canada U.S.

46. Not just in US. • China Guangzhou Shajiao on the Pearl River • India Korba England

47. Effects on WildlifeGenerally, the young of most species are more sensitive to environmental conditions than adults. At pH 5, most fish eggs cannot hatch. At lower pH levels, some adult fish die. Some acid lakes have no fish.

48. Young fish Wuhan dead fish (China)