Do Now #33…

1. Do Now #33… • Which units are used for the following: • q= • m= • Cp= • T= LecturePLUS Timberlake

2. Objective…. • I will be able to determine if a substance (liquid) is either a base or an acid based upon its pH. LecturePLUS Timberlake

3. Agenda… • Learn something today…. LecturePLUS Timberlake

4. Chapter 9Acids and Bases Ionization of Water The pH Scale LecturePLUS Timberlake

5. Ionization of Water Occasionally, in water, a H+ is transferred between H2O molecules . . . . . . . . H:O: + :O:H H:O:H + + :O:H- . . . . . . . . HH H water molecules hydronium hydroxide ion (+)ion (-) LecturePLUS Timberlake

6. Pure Water is Neutral Pure water contains small, but equal amounts of ions: H3O+ and OH- H2O + H2O H3O+ + OH- hydronium hydroxide ion ion 1 x 10-7 M1 x 10-7 M H3O+ OH- LecturePLUS Timberlake

7. Ion Product of Water Kw [ ] = Molar concentration Kw = [ H3O+ ] [ OH- ] = [ 1 x 10-7 ][ 1 x 10-7 ] = 1 x 10-14 LecturePLUS Timberlake

8. Acids • Increase H+ • HCl (g) + H2O (l)H3O+(aq) + Cl-(aq) • More [H3O+] than water > 1 x 10-7M • As H3O+ increases, OH- decreases [H3O+] > [OH-] H3O+ OH- LecturePLUS Timberlake

9. Bases • Increase the hydroxide ions (OH-) H2O • NaOH (s) Na+(aq) + OH- (aq) • More [OH-] than water, [OH-] > 1 x 10-7M • When OH- increases, H3O+ decreases [OH] > [H3O+] OH- H3O+ LecturePLUS Timberlake

10. Using Kw The [OH- ] of a solution is 1.0 x 10- 3M. What is the [H3O+]? Kw = [H3O+ ] [OH- ] = 1.0 x 10-14 [H3O+] = 1.0 x 10-14 [OH-] [H3O+] = 1.0 x 10-14= 1.0 x 10-11 M 1.0 x 10- 3 LecturePLUS Timberlake

11. Learning Check pH1 The [H3O+] of lemon juice is 1.0 x 10-3 M. What is the [OH-] of the solution? 1) 1.0 x 103 M 2) 1.0 x 10-11 M 3) 1.0 x 1011 M LecturePLUS Timberlake

12. Do Now #34… • What does the water equilibrium Kw (H20Keq) actually mean? What does the number represent? LecturePLUS Timberlake

13. Objective… • I will be able to correctly calculate the pH values of 3 out of 4 reactions correctly and tell if the final pH of the solution is a Acid or Base. LecturePLUS Timberlake

14. Solution pH1 The [H3O+] of lemon juice is 1.0 x 10- 3 M. What is the [OH-]? [OH- ] =1.0 x 10 -14 = 1.0 x 10-11 M 1.0 x 10 - 3 LecturePLUS Timberlake

15. Learning Check pH2 The [OH-] of a solution is 5 x 10 -5 M. What is the [H3O+ ] of the solution? 1) 2 x 10- 5 M 2) 1 x 1010 M 3) 2 x 10-10 M LecturePLUS Timberlake

16. Solution pH2 The [OH-] of a water solution is 5 x 10-5 M. What is the [H3O+] in the solution? [ H3O+] =1.0 x 10 -14 5 x 10- 5 LecturePLUS Timberlake

17. Learning Check pH3 A.The [OH-] when [H3O+ ] of 1 x 10- 4 M 1) 1 x 10-6 M 2) 1 x 10-8 M 3) 1 x 10-10 M B.The [H3O+] when [OH- ] of 5 x 10-9 M 1) 1 x 10- 6 M 2) 2 x 10- 6 M 3) 2 x 10-7 M LecturePLUS Timberlake

18. Solution pH3 Kw = [H3O+ ][OH-] = 1.0 x 10 14 A. (3) [OH- ] = 1.0 x 10 -14 = 1.0 x 10 -10 1.0 x 10- 4 B.(2) [H3O+] = 1.0 x 10 -14 = 2 x 10 - 6 5 x 10- 9 LecturePLUS Timberlake

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

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

21. Do Now #35… • A substance with a pH of 2.0 is considered to be a ________. Write the pH as a denomination of a power of 10. LecturePLUS Timberlake

22. Objective… • I will be able to determine the difference between Arrhenius Acids and Bronstead- Lowry acids and bases.

23. pH Range 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

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27. 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

28. 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

29. 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

30. Learning Check pH4 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

31. Solution pH4 A. pH = - log [ 1 x 10-4] = -(- 4) = 4 B. [H3O+] = 1 x 10-11 pH = - log [ 1 x 10- 11] = -(- 11) = 11 LecturePLUS Timberlake

32. Learning Check pH5 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

33. Solution pH5 The pH of a soap is 10. What is the [H3O+] of the soap solution? [H3O+] = 1 x 10-pH M = 1 x 10-10 M LecturePLUS Timberlake

34. pH on the Calculator [H3O+] is 4.5 x 10-6 M pH = 4.5 x EXP(or EE) 6+/- LOG +/- = 5.35 LecturePLUS Timberlake

35. Learning Check pH6 A soap solution has a [H3O+] = 2 x 10-8 M. What is the pH of the solution? 1) 8 2) 7.7 3) 6 LecturePLUS Timberlake

36. Solution pH6 A soap solution has a [H3O+] = 2.0 x 10-8 M. What is the pH of the solution? B) 2.0 EE 8 +/- LOG +/- = 7.7 LecturePLUS Timberlake

37. Learning Check pH7 Identify each solution as 1. acidic 2. basic 3. neutral A. _____ HCl with a pH = 1.5 B. _____ Pancreatic fluid [H+] = 1 x 10-8 M C. _____ Sprite soft drink pH = 3.0 D. _____ pH = 7.0 E. _____ [OH- ] = 3 x 10-10 M F. _____ [H+ ] = 5 x 10-12 LecturePLUS Timberlake

38. Solution pH7 Identify each solution as 1. acidic 2. basic 3. neutral A. _1__ HCl with a pH = 1.5 B. _2__ Pancreatic fluid [H+] = 1 x 10-8 M C. _1__ Sprite soft drink pH = 3.0 D. _3__ pH = 7.0 E. _1__ [OH-] = 3 x 10-10 M F. _2__ [H+] = 5 x 10-12 LecturePLUS Timberlake

39. 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) Formation of acid rain: 1. Emission of sulfur and nitrogen oxides from the burning of fuels expecially coal with high S content, power stations, oil refineries, vehicles as well as bacterial decomposition, and lighting hitting N2 SO2 26 million tons in 1980 NO and NO2 22 million tons in 1980 Mt. St Helens (1980) 400,000 tons SO2 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  HNO2 nitrous acid HNO2 + H2O  HNO3 nitric acid 4. Effects of Acid Rain Decline in fish populations in rivers and lasts due to toxic effect of Al leached from soil by acid rain Extensive fish kills in spring from runoff due to accumulation of large amounts of acid on the snow Dissolves minerals Mg, Ca, and K from the soil and waxy coatings that protect leaves from bacteria Corrodes metals, textiles, paper and leather LecturePLUS Timberlake

40. 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

41. SO2 26 million tons in 1980 NO and NO2 22 million tons in 1980 Mt. St Helens (1980) 400,000 tons SO2 • Reactions with oxygen in air form SO3 2SO2 + O2 2 SO3 • Reactions with water in air form acids SO3 + H2O H2SO4 sulfuric acid NO + H2O HNO2 nitrous acid HNO2 + H2O HNO3 nitric acid LecturePLUS Timberlake

42. 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

43. Modern Theories of Acids & Bases The Arrhenius and Bronsted-Lowry Theories

44. Acids & Bases • Acids and bases are special kinds of electrolytes. Like all electrolytes they break up into charged particles. • What sets them apart from each other, and other electrolytes is the way that they break up.

45. Arrhenius Acids Svente Arrhenius (who first proposed the theory of ionization) identified acids as substances that ionize in water to produce hydronium ion. For example: HCl + H2O  H3O+ + Cl- Any substance that ionizes in water to produce hydronium ion can be classified as an acid.

46. H3O+ (aka H+) • The hydronium ion is also known as a hydrogen ion. • This allows us to shorten the ionization reactions for acids. The following equations represent the same chemical change: HCl + H2O  H3O+ + Cl- and HCl  H+ + Cl- However, it should be understood that H+ is an abbreviation for the hydronium ion. H+ ions DO NOT exist in water solution but are snatched up by water molecules to form hydronium ions.

47. Arrhenius Base Svente Arrhenius also identified bases as substances that ionize in water to produce hydroxide ion. For example: NaOH  Na+ + OH- Any substance that ionizes in water to produce hydroxide ion can be classified as a base.

48. Properties of Acids All acids have the following properties: Neutralize bases to form a salt and water Have a sour taste (example: citric acid, vinegar) React with metals to produce a salt plus hydrogen gas. Have pH’s less than 7 / Affect indicators Why? Because all acids have H3O+ ions present!

49. Properties of Bases All bases have the following properties: Neutralize acids to form a salt and water Have a bitter taste (example: unsweetened chocolate, heroin) Are slippery. React with fats/oils to form soap (saponification) Have pH’s greater than 7 / Affect indicators Why? Because all bases have OH- ions present!

50. Salts Ionic substances that break up in solution to produce ions other than hydronium and hydroxide ions. NaCl (s)  Na+(aq) + Cl- (aq) KNO3(s)  K+ (aq) + NO3- (aq) Li2SO4 (s)  2 Li+ (aq) + SO42-(aq) Salts are made up of positive (metal) and negative (non-metallic or polyatomic) ions. The more familiar you become with Table E, the easier it will be for you to identify salts.