1. LecturePLUS Timberlake1 Chapter 9 Acids and Bases Ionization of Water The pH Scale

2. LecturePLUS Timberlake2 Ionization of Water Occasionally, in water, a H + is transferred between H 2 O molecules........ H : O : + : O : H H : O : H + + : O : H -........ H H H water molecules hydronium hydroxide ion (+) ion (-)

3. LecturePLUS Timberlake3 Pure Water is Neutral Pure water contains small, but equal amounts of ions: H 3 O + and OH - H 2 O + H 2 O H 3 O + + OH - hydronium hydroxide ion ion 1 x 10 -7 M H3O+H3O+ OH -

4. LecturePLUS Timberlake4 Ion Product of Water K w [ ] = Molar concentration K w = [ H 3 O + ] [ OH - ] = [ 1 x 10 -7 ][ 1 x 10 -7 ] = 1 x 10 -14

5. LecturePLUS Timberlake5 Acids Increase H + HCl (g) + H 2 O (l) H 3 O + (aq) + Cl - (aq) More [H 3 O + ] than water > 1 x 10 -7 M As H 3 O + increases, OH - decreases [H 3 O + ] > [OH - ] H3O+H3O+ OH -

6. LecturePLUS Timberlake6 Bases Increase the hydroxide ions (OH - ) H 2 O NaOH (s) Na + (aq) + OH - (aq) More [OH - ] than water, [OH - ] > 1 x 10 -7 M When OH - increases, H 3 O + decreases [OH  ] > [H 3 O + ] H3O+H3O+ OH -

7. LecturePLUS Timberlake7 Using K w The [OH - ] of a solution is 1.0 x 10 - 3 M. What is the [H 3 O + ]? K w = [H 3 O + ] [OH - ]= 1.0 x 10 -14 [H 3 O + ] =1.0 x 10 -14 [OH - ] [H 3 O + ] = 1.0 x 10 -14 = 1.0 x 10 -11 M 1.0 x 10 - 3

8. LecturePLUS Timberlake8 Learning Check pH1 The [H 3 O + ] of lemon juice is 1.0 x 10 -3 M. What is the [OH - ] of the solution? 1) 1.0 x 10 3 M 2) 1.0 x 10 -11 M 3) 1.0 x 10 11 M

9. LecturePLUS Timberlake9 Solution pH1 The [H 3 O + ] 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

10. LecturePLUS Timberlake10 Using the Calculator 1.0 x 10 -14 4.0 x 10 -5 Enter 1.0 EE +/- 14  4.0 EE +/- 5 = 2.5 x 10 -10

11. LecturePLUS Timberlake11 Learning Check pH2 The [OH-] of a solution is 5 x 10 -5 M. What is the [H 3 O + ] of the solution? 1) 2 x 10 - 5 M 2) 1 x 10 10 M 3) 2 x 10 -10 M

12. LecturePLUS Timberlake12 Solution pH2 The [OH - ] of a water solution is 5 x 10 -5 M. What is the [H 3 O + ] in the solution? [ H 3 O + ] = 1.0 x 10 -14 5 x 10 - 5 On some calculators: 1.0 EE +/- 14  5 EE +/- 5 = 2 x 10 -10 M

13. LecturePLUS Timberlake13 Learning Check pH3 A.The [OH - ] when [H 3 O + ] 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 [H 3 O + ] 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

14. LecturePLUS Timberlake14 Solution pH3 K w = [H 3 O + ][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) [H 3 O + ] = 1.0 x 10 -14 = 2 x 10 - 6 5 x 10 - 9

15. LecturePLUS Timberlake15 pH Indicates the acidity [H 3 O + ] of the solution pH = - log [H 3 O + ] From the French pouvoir hydrogene (“hydrogen power” or power of hydrogen)

16. LecturePLUS Timberlake16 In the expression for [H 3 O + ] 1 x 10 -exponent the exponent = pH [H 3 O + ] = 1 x 10 -pH M pH

17. LecturePLUS Timberlake17 pH Range 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Neutral [H + ] > [OH - ] [H + ] = [OH - ] [OH - ] > [H + ] Acidic Basic

18. LecturePLUS Timberlake18 Some [H 3 O + ] and pH [H 3 O + ] pH 1 x 10 -5 M 5 1 x 10 -9 M 9 1 x 10 -11 M 11

19. LecturePLUS Timberlake19 pH of Some Common Acids gastric juice1.0 lemon juice2.3 vinegar2.8 orange juice3.5 coffee5.0 milk6.6

20. LecturePLUS Timberlake20 pH of Some Common Bases blood 7.4 tears 7.4 seawater 8.4 milk of magnesia10.6 household ammonia11.0

21. LecturePLUS Timberlake21 Learning Check pH4 A. The [H 3 O + ] of tomato juice is 1 x 10 -4 M. What is the pH of the solution? 1) - 42)43)8 B. The [OH - ] of an ammonia solution is 1 x 10 -3 M. What is the pH of the solution? 1) 32)113)-11

22. LecturePLUS Timberlake22 Solution pH4 A. pH = - log [ 1 x 10 -4 ] = -(- 4) = 4 B. [H 3 O + ] = 1 x 10 -11 pH = - log [ 1 x 10 - 11 ] = -(- 11) = 11

23. LecturePLUS Timberlake23 Learning Check pH5 The pH of a soap is 10. What is the [H 3 O + ] of the soap solution? 1) 1 x 10 - 4 M 2) 1 x 10 10 M 3) 1 x 10 - 10 M

24. LecturePLUS Timberlake24 Solution pH5 The pH of a soap is 10. What is the [H 3 O + ] of the soap solution? [H 3 O + ] = 1 x 10 -pH M = 1 x 10 -10 M

25. LecturePLUS Timberlake25 pH on the Calculator [H 3 O + ] is 4.5 x 10 -6 M pH = 4.5 x EXP(or EE) 6+/- LOG +/- = 5.35

26. LecturePLUS Timberlake26 Learning Check pH6 A soap solution has a [H 3 O + ] = 2 x 10 -8 M. What is the pH of the solution? 1)8 2) 7.7 3)6

27. LecturePLUS Timberlake27 Solution pH6 A soap solution has a [H 3 O + ] = 2.0 x 10 -8 M. What is the pH of the solution? B) 2.0 EE 8 +/- LOG +/- = 7.7

28. LecturePLUS Timberlake28 Learning Check pH7 Identify each solution as 1. acidic 2. basic3. 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

29. LecturePLUS Timberlake29 Solution pH7 Identify each solution as 1. acidic 2. basic3. 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

30. LecturePLUS Timberlake30 Acid Rain Unpolluted rain has a pH of 5.6 Rain with a pH below 5.6 is “acid rain“ CO 2 in the air forms carbonic acid CO 2 + H 2 O H 2 CO 3 Adds to H + of rain H 2 CO 3 H + (aq) + HCO 3 -(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 N 2 SO 2 26 million tons in 1980 NO and NO 2 22 million tons in 1980 Mt. St Helens (1980) 400,000 tons SO 2 2. Reactions in the atmosphere form SO 3 2SO 2 + O 2  2 SO 3 3. Reactions with atmosphere water form acids SO 3 + H 2 O  H 2 SO 4 sulfuric acid NO + H 2 O  HNO 2 nitrous acid HNO 2 + H 2 O  HNO 3 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

31. LecturePLUS Timberlake31 Sources of Acid Rain Power stations Oil refineries Coal with high S content Car and truck emissions Bacterial decomposition, and lighting hitting N 2

32. LecturePLUS Timberlake32 SO 2 26 million tons in 1980 NO and NO 2 22 million tons in 1980 Mt. St Helens (1980) 400,000 tons SO 2 Reactions with oxygen in air form SO 3 2SO 2 + O 2 2 SO 3 Reactions with water in air form acids SO 3 + H 2 O H 2 SO 4 sulfuric acid NO + H 2 O HNO 2 nitrous acid HNO 2 + H 2 O HNO 3 nitric acid

33. LecturePLUS Timberlake33 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