Air- Chemistry and the Atmosphere

Air: Chemistry and the Atmosphere : Air: Chemistry and the Atmosphere 5C Acids in the Atmosphere

Acid Rain : Acid Rain 1. Where did acid rain start? in Scandinavia then in NE U.S. 2. What are some of the environmental effects of acid rain? fish disappear from lakes, surfaces of limestone and concrete buildings and marble statues crumble, crops grow slowly and forests begin to die out

Acid Rain : Acid Rain 3. Why is normal rain acidic? Carbon dioxide mixes with water to form carbonic acid H20 + CO2 --> H2CO3 4. What are some other gases that cause acid rain? H20 + SO2 --> H2SO3 H20 + SO3 --> H2SO4 H20 +2 NO2 --> HNO3 + HNO2

Slide6 : 5. What produces these acid rain gases? Combustion of fossil fuels Sulfur oxides and nitrogen oxides are produced by coal fired power plants like Bull Run 6. What other problems does acid rain create? Damages our building materials like concrete Many ancient building like the Parthenon have been irrepairably damaged

Slide7 : 7. Give an equation that explains how limestone(or concrete is damaged)? CaCO3(s) + H2SO4(aq) --> CaSO4(s) + CO2(g) + HOH(l) 8. What is the problem with CaSO4 replacing CaCO3? CaSO4 is more soluble in water-it washes away

Slide8 : 9. What is the biggest geopolitical problem with acid rain? The country or state that produces the pollution are often not the one that gets hit with the acid rain Wind carries the gases to other parts of the continent

Slide9 : 10. According to the graph on the screen, what is the number one producer of SO2?

Slide10 : 11. Who regulates how much SO2 gases these plants can emit? EPA-Environmental Protection Agency 12. What Law gives them the right to do this? Clean Air Act of the 1990’s

Slide11 : 13. Was there any progress in the 90’s? Yes in the late 90’s 14. What were the reasons for the decline in emissions? Using more expensive, lower sulfur coal Use of scrubbers in smokestacks to filter out the SO2

Slide12 : 15. What is the problem with reducing NOx gases? Produced by automobiles 16. How has this been reduced? Auto industries have installed more efficient exhaust systems

Making Acid Rain : Making Acid Rain

Read Chemistry at Work on page 303 for quiz : Read Chemistry at Work on page 303 for quiz

Do Making Decisions on page 304 : Do Making Decisions on page 304

Acids and Bases: Structure determines Function : Acids and Bases: Structure determines Function 17. Who first defined acids and bases? Svante Arrhenius 18. What is the Arrhenius definition of acids and bases? anything that gives a H+ = acid anything that gives a OH- = base

Slide18 : 19. Give 2 examples each of acids and bases? Acids: Ascorbic acid(vitamin C) , Acetic Acid(vinegar), Hydrochloric acid(Muriatic acid) Bases: Sodium Hydroxide(Lye), Calcium carbonate(limestone), Sodium bicarbonate(baking soda)

Slide19 : 20. What exactly happens when an acid dissolves in water? breaks down into ions HCl--> H+ + Cl- HNO3 --> H+ + NO3- H2SO4 --> H+ + HSO4- 21. What happens when an acid meets a base? they neutralize each other

Slide20 : 22. Give 2 examples of neutralization reactions? NaOH(aq) + HCl(aq) --> NaCl(aq) + HOH(l) H+ + OH- --> HOH 23. What are spectator ions? ions that do not change their phase, they do nothing, they just “look” on...

Slide21 : 24. What is a net ionic equation? equation who has had all the spectator ions eliminated

Do Building Skills 10 form Homework : Do Building Skills 10 form Homework

Acid and Base Strength : Acid and Base Strength 25. What is the difference between a weak acid and a strong acid? Strong acid 100% divorce rate will always give a H+ if given a chance Weak acid 5% divorce rate will sometimes give a H+ if forced to

Slide24 : 26. Give examples of strong and weak acids HCl --> H+ + Cl- HC2H3O2 <--> C2H3O2- + H+ (vinegar)

HCl in water : HCl in water

Slide26 : 27. What is the difference between a weak base and a strong base? Strong base 100% divorce rate Definitely wants to grab a H+ anytime, anywhere Weak base 5% divorce rate, sometimes will grab H+ if it is forced to

Slide27 : 28. Give examples of strong and weak bases. NaOH --> Na+ + OH- NH3 + HOH <--> NH4+ + OH-

Slide28 : 29. There are three types of acid base reactions. What are they? Strong Acid + Strong Base --> complete neutralization-forms water and a neutral salt Strong acid + weak base --> incomplete neutralization-forms water and an acidic salt Weak Acid + strong base --> incomplete neutralization-forms water and a basic salt

Slide29 : 30. What is a conjugate base? What is a conjugate acid? what the acid becomes when it gives up the H+ what the base becomes when it accepts the H+

Slide30 : 31. In the following examples, label each compound as an acid, base, conjugate acid, conjugate base a. acetic acid solution reacts with ammonia b. Nitrous acid solution reacts with water c. Ammonia solution reacts with water

Slide31 : 32. From the examples above, you can tell that water can act as an acid and a base. What do we call these types of molecules that can “go both ways”? amphoteric 33. Give another example of an amphoteric substance and 2 reactions demonstrating it?

Amphoteric Nature of water : Amphoteric Nature of water

pH : pH 34. Water is amphoteric, what weird thing can it do as related to acids and bases? it can break up, self ionize, to form H+ and OH- HOH --> H+ and OH- 35. If a substance is added and it messes up the balance, what do we say has occurred? pH has been changed

Slide34 : 36. What is pH? power of Hydrogen, measures how acidic some solution is 37. How is it measured? What equation do we use? pH units, pH = -log[H+]

Slide35 : 38. What calculator steps are involved? 1. [-] 2. [log] 3. [Hydrogen concentration] (ex. 3.06 x 10-3 = [3] [.] [0] [6] [2nd] [,] [-] [3] 39. What is the pH range for an acid? What is the pH range for a base? 0-6.9 7.1-14

Slide36 : 40. Determine the pH of the following H+ ion concentrations and determine whether the solution is acid or base? a. 2.55 x 10-6 b. 5.33 x 10-10 c. 2.19 x 10-8 d. 9.55 x 10-2 e. 6.42 x 10-4

Slide37 : 41. Following are listed some common aqueous solutions with their typical pH values. Classify each as either acidic, basic, or neutral. Arrange them in order of increasing H+ ion concentration a. Stomach acid, 1 b. A solution of baking soda, 9 c. A cola drink, 3 d. A solution of household soap, 13 e. Milk, drinking water, 6 f. Sugar dissolved in pure water, 7 g. Household ammonia, 11

Slide38 : 42. How many more times acidic is cola than milk? 1000x 43. Why such a large number? every step is based on the power of 10 so since 6 is 3 away from 3 then it is 10x10x10 time more acidic

Slide39 : 44. Which of the following would you recognize as acids? As bases? a. NaOH b. HNO3 c. CH4 d. C12H22O11(table sugar) e. H2SO3

Slide40 : 45. Which of the following solutions has the lowest pH? The highest pH? a. Lemon juice b. Stomach juice c. Drain Cleaner(NaOH) 46. Technology to prevent acid rain is available. Why, then, is acid rain still a problem?

Do BS 11 on page 308 for homework : Do BS 11 on page 308 for homework

Acids, Bases, and Buffers : Acids, Bases, and Buffers 47. What was one of the early mysteries concerning acid rain? Why some lakes and streams were affected while others were not 48. What two things did the affected bodies of water have in common? Down wind from a pollution source Surrounded by soils unable to absorb acids

Slide43 : 49. How is that soils heavy can help prevent acid rain damage 50. In essence, what did the lakes and streams naturally have? A buffer

Slide44 : 51. What is a buffer? A solution that resists changes in pH 52. How does a buffer form? When you have the presence of a weak acid and its conjugate base in roughly equal amounts

Slide45 : 53. Where does the medicine Bufferin get its name? Aspirin is an acid and can upset the stomach of some people Bufferin contains the conjugate base of the aspirin acid so that it does not irritate the stomach

Slide46 : 54. Explain how a body buffer works to prevent hyperventilation?

Lab: Buffers : Lab: Buffers