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1 It is Wednesday. The first homework is due. Place it on the bench in front.

2 Acids and bases of varying strengths.

3 Acids and bases of varying strengths.
Strong acid = 100% ionization Strong acid = 100% donation of acidic proton.

4 HCl(aq) + H2O(l) H3O+(aq) + Cl-(aq)

5 HCl(aq) + H2O(l) H3O+(aq) + Cl-(aq)
[H3O+][Cl-] K = [HCl]

6 HCl(aq) + H2O(l) H3O+(aq) + Cl-(aq)
[H3O+][Cl-] large K = = [HCl]

7 Generic acid HA(aq) + H2O(l) H3O+(aq) + A-(aq)

8 Generic acid HA(aq) + H2O(l) H3O+(aq) + A-(aq) [H3O+][A-] = acidity constant = Ka [HA]

9 Generic acid HA(aq) + H2O(l) H3O+(aq) + A-(aq) [H3O+][A-] = acidity constant = Ka [HA] -log10 Ka = pKa

10 Acid Ka pKa HI  -11 HCl   -7 H2SO   -2 CH3COOH x Table page 332

11 Base strength

12 Base strength Inversely related to strength of conjugate acid.

13 Base strength Inversely related to strength of conjugate acid. H2O(l) + B(aq) HB+(aq) + OH-(aq) conjugate acid

14 H2O(l) + B(aq) HB+(aq) + OH-(aq)
[HB+][OH-] = Kb = basicity constant [B]

15 [HB+][OH-] = Kb = basicity constant [B] [H3O+][B] = acidity constant = Ka [HB+] [H3O+][OH-] = Kw

16 [HB+][OH-] = Kb = basicity constant [B] [H3O+][B] = acidity constant = Ka [HB+] Conjugate acid [H3O+][OH-] = Kw KbKa = Kw

17 [HB+][OH-] = Kb = basicity constant [B] [H3O+][B] = acidity constant = Ka [HB+] [H3O+][OH-] = Kw KbKa = Kw pKb + pKa = pKw

18 KbKa = Kw pKb + pKa = pKw Expressions can be used for any conjugate acid-base pair in water.

19 Indicators : Usually a weak organic acid that has a color different from its conjugate base.

20 Indicators : Usually a weak organic acid that has a color different from its conjugate base. HA + H2O H3O+ + A-

21 phenolphthalein

22 Indicators : Usually a weak organic acid that has a color different from its conjugate base. + H2O H3O+ + A-

23 phenolphthalein

24 Equilibria with weak acids
and weak bases.

25 Equilibria with weak acids
and weak bases. Weak acid:

26 Equilibria with weak acids
and weak bases. Weak acid: Ka < 1

27 Equilibria with weak acids
and weak bases. Weak acid: Ka < 1 [H3O+][A-] Ka = [HA]

28 Equilibria with weak acids
and weak bases. Weak acid: Ka < 1 Ka (H3O+) = 1

29 Equilibria with weak acids
and weak bases. Weak acid: Ka < 1 Ka (H3O+) = 1 Why is a weak acid weak?

30 HCl Ka  strong HF Ka = 6.6 x weak

31 HCl Ka  strong HF Ka = 6.6 x weak HF more ionic than HCl

32 HCl Ka  strong HF Ka = 6.6 x weak HF more ionic than HCl Relative Kas show that HF holds proton more strongly than HCl

33 HCl Ka  strong HF Ka = 6.6 x weak HF more ionic than HCl Relative Kas show that HF holds proton more strongly than HCl Electrostatic attraction for H+ stronger for F- than for Cl-.

34 Organic acids Ka CH3COOH x 10-5 CH3CH2COOH x 10-5 CCl3COOH x 10-1

35 Organic acids Ka CH3COOH x 10-5 CH3CH2COOH x 10-5 CCl3COOH x 10-1

36 Ka CH3COOH x 10-5 CH3CH2COOH x 10-5 CCl3COOH x 10-1 The more stable the conjugate base, the stronger the acid.

37 Ka CH3COOH x 10-5 CH3CH2COOH x 10-5 CCl3COOH x 10-1

38 Ka CH3COOH x 10-5 CH3CH2COOH x 10-5 CCl3COOH x 10-1

39 Ka CH3COOH x 10-5 CH3CH2COOH x 10-5 CCl3COOH x 10-1

40 Ka CH3COOH x 10-5 CH3CH2COOH x 10-5 CCl3COOH x 10-1

41 Ka CH3COOH x 10-5 CH3CH2COOH x 10-5 CCl3COOH x 10-1

42 Equilibria with weak acids
and weak bases. HA(aq) + H2O(l) H3O+(aq) + A-(aq) [H3O+][A-] = Ka [HA]

43 HA(aq) + H2O(l) H3O+(aq) + A-(aq)
= Ka [HA]

44 HA(aq) + H2O(l) H3O+(aq) + A-(aq)
= Ka [HA] CH3COOH(aq) + H2O(l) H3O+(aq) + CH3COO-(aq)

45 HA(aq) + H2O(l) H3O+(aq) + A-(aq)
= Ka [HA] CH3COOH(aq) + H2O(l) H3O+(aq) + CH3COO-(aq) Ka = 1.8 x 10-5

46 CH3COOH(aq) + H2O(l) H3O+(aq) + CH3COO-(aq) Ka = 1.8 x 10-5 1 mol CH3COOH 1 L water solution

47 CH3COOH(aq) + H2O(l) H3O+(aq) + CH3COO-(aq) Ka = 1.8 x 10-5 1 mol CH3COOH Calculate pH 1 L water solution

48 [M] [CH3COOH] [H3O+] [CH3COO-] initial change Eq.

49 [M] [CH3COOH] [H3O+] [CH3COO-] initial change -y y y Eq.

50 [M] [CH3COOH] [H3O+] [CH3COO-] initial change -y y y Eq. 1.0 -y y y

51 [M] [CH3COOH] [H3O+] [CH3COO-] initial change -y y y Eq. 1.0 -y y y [H3O+][A-] = Ka [HA]

52 [M] [CH3COOH] [H3O+] [CH3COO-] initial change -y y y Eq. 1.0 -y y y [H3O+][A-] [H3O+][CH3COO-] = Ka [HA] [CH3COOH]

53 [M] [CH3COOH] [H3O+] [CH3COO-] initial change -y y y Eq. 1.0 -y y y [H3O+][CH3COO-] = 1.8 x 10-5 [CH3COOH]

54 [M] [CH3COOH] [H3O+] [CH3COO-] initial change -y y y Eq. 1.0 -y y y (y)(y) [H3O+][CH3COO-] = 1.8 x 10-5 = (1-y) [CH3COOH]

55 [M] [CH3COOH] [H3O+] [CH3COO-] initial change -y y y Eq. 1.0 -y y y (y)(y) (y2) 1.8 x 10-5 = = (1-y) (1-y)

56 [M] [CH3COOH] [H3O+] [CH3COO-] initial change -y y y Eq. 1.0 -y y y (y)(y) (y2) 1.8 x 10-5 = = (1-y) (1-y) y << 1

57 [M] [CH3COOH] [H3O+] [CH3COO-] initial change -y y y Eq. 1.0 -y y y (y)(y) (y2) 1.8 x 10-5 = = (1-y) (1-y) y << 1 1-y  1

58 [M] [CH3COOH] [H3O+] [CH3COO-] initial change -y y y Eq. 1.0 -y y y (y)(y) (y2) 1.8 x 10-5 = = = y2 (1-y) (1-y) y << 1 1-y  1

59 [M] [CH3COOH] [H3O+] [CH3COO-] initial change -y y y Eq. 1.0 -y y y 1.8 x 10-5 = y2 y = 4.24 x 10-3

60 [M] [CH3COOH] [H3O+] [CH3COO-] initial change -y y y Eq. 1.0 -y y y 1.8 x 10-5 = y2 y = 4.24 x 10-3 -log x 10-3 =

61 [M] [CH3COOH] [H3O+] [CH3COO-] initial change -y y y Eq. 1.0 -y y y 1.8 x 10-5 = y2 y = 4.24 x 10-3 -log x 10-3 = 2.37 = pH

62 [M] [CH3COOH] [H3O+] [CH3COO-] initial change -y y y Eq. 1.0 -y y y y = 4.24 x 10-3 What is the fraction of acid ionized?

63 [M] [CH3COOH] [H3O+] [CH3COO-] initial change -y y y Eq. 1.0 -y y y y = 4.24 x 10-3 What is the fraction of acid ionized? [A-] [HA]

64 [M] [CH3COOH] [H3O+] [CH3COO-] initial change -y y y Eq. 1.0 -y y y y = 4.24 x 10-3 What is the fraction of acid ionized? [A-] 4.24 x 10-3 = [HA] 1.0

65 [M] [CH3COOH] [H3O+] [CH3COO-] initial change -y y y Eq. 1.0 -y y y y = 4.24 x 10-3 What is the percent of acid ionized? [A-] 4.24 x 10-3 X 100% = 0.42% = [HA] 1.0

66 [M] [CH3COOH] [H3O+] [CH3COO-] initial change -y y y Eq. y y y Calculate % ionization for M

67 [M] [CH3COOH] [H3O+] [CH3COO-] initial change -y y y Eq. y y y (y2) (y)(y) = 1.8 x 10-5 = ( y) ( y) [A-] [HA]

68 [M] [CH3COOH] [H3O+] [CH3COO-] initial change -y y y Eq. y y y (y2) (y)(y) = 1.8 x 10-5 = (0.0001) (0.0001) [A-] [HA]

69 [M] [CH3COOH] [H3O+] [CH3COO-] initial change -y y y Eq. y y y (y2) (y)(y) = 1.8 x 10-5 = (0.0001) (0.0001) [A-] y2 = 1.8 x 10-9 [HA]

70 [M] [CH3COOH] [H3O+] [CH3COO-] initial change -y y y Eq. y y y (y2) (y)(y) = 1.8 x 10-5 = (0.0001) (0.0001) [A-] y2 = 1.8 x 10-9 [HA] y = 4.2 x 10-5

71 [M] [CH3COOH] [H3O+] [CH3COO-] initial change -y y y Eq. y y y (y2) (y)(y) = 1.8 x 10-5 = (0.0001) (0.0001) [A-] 4.2 x 10-5 y = 4.2 x 10-5 = 1 x 10-4 42% [HA]

72 1 x 10-4 and 4.2 x 10-5 do not differ enough to ignore y.

73 [M] [CH3COOH] [H3O+] [CH3COO-] initial change -y y y Eq. y y y (y2) (y)(y) 1.8 x 10-5 = = ( y) ( y) 34% Full solution: pg 342

74 1.0 M CH3COOH % ionized M CH3COOH % ionized

75 1.0 M CH3COOH % ionized M CH3COOH % ionized [A-] = [HA]

76 1.0 M CH3COOH % ionized [A-] = 4.2 x 10-3 M M CH3COOH % ionized [A-] = 3.4 x 10-5 M [A-] = [HA]

77 1.0 M CH3COOH % ionized [A-] = 4.2 x 10-3 M M CH3COOH % ionized [A-] = 3.4 x 10-5 M [A-] [A-]  10-2 = [HA] [HA]  10-4

78 Problem 29: Calculate pH of 0.35 M solution of propionic acid.

79 Problem 29: Calculate pH of 0.35 M solution of propionic acid. Ka = 1.3 x 10-5 Table 8-2

80 Problem 29: Calculate pH of 0.35 M solution of propionic acid. Ka = 1.3 x 10-5 Table 8-2 HA(aq) + H2O(l) H3O+(aq) + A-(aq)

81 Problem 29: Calculate pH of 0.35 M solution of propionic acid. Ka = 1.3 x 10-5 Table 8-2 HA(aq) + H2O(l) H3O+(aq) + A-(aq) [HA] = 0.35 M

82 Calculate pH of 0.35 M solution of propionic
acid. Ka = 1.3 x 10-5 Table 8-2 HA(aq) + H2O(l) H3O+(aq) + A-(aq) [HA] = 0.35 M [H3O+][A-] = Ka [HA]

83 Calculate pH of 0.35 M solution of propionic
acid. Ka = 1.3 x 10-5 Table 8-2 HA(aq) + H2O(l) H3O+(aq) + A-(aq) [HA] = 0.35 M [H3O+][A-] (x2) = Ka = [HA] [HA]

84 Calculate pH of 0.35 M solution of propionic
acid. Ka = 1.3 x 10-5 Table 8-2 HA(aq) + H2O(l) H3O+(aq) + A-(aq) [HA] = 0.35 M x2 = [HA] Ka

85 Calculate pH of 0.35 M solution of propionic
acid. Ka = 1.3 x 10-5 Table 8-2 HA(aq) + H2O(l) H3O+(aq) + A-(aq) [HA] = 0.35 M x2 = [HA] Ka = 0.35 x 1.3 x 10-5 =

86 Calculate pH of 0.35 M solution of propionic
acid. Ka = 1.3 x 10-5 Table 8-2 HA(aq) + H2O(l) H3O+(aq) + A-(aq) [HA] = 0.35 M x2 = [HA] Ka = 0.35 x 1.3 x 10-5 = 4.55 x 10-4

87 Calculate pH of 0.35 M solution of propionic
acid. Ka = 1.3 x 10-5 Table 8-2 HA(aq) + H2O(l) H3O+(aq) + A-(aq) x2 = [HA] Ka = 0.35 x 1.3 x 10-5 = 4.55 x 10-4 x = 4.55 x 10-4

88 Calculate pH of 0.35 M solution of propionic
acid. Ka = 1.3 x 10-5 Table 8-2 HA(aq) + H2O(l) H3O+(aq) + A-(aq) x2 = [HA] Ka = 0.35 x 1.3 x 10-5 = 4.55 x 10-4 x = 4.55 x 10-4 = 2.13 x 10-3

89 Calculate pH of 0.35 M solution of propionic
acid. Ka = 1.3 x 10-5 Table 8-2 HA(aq) + H2O(l) H3O+(aq) + A-(aq) x2 = [HA] Ka = 0.35 x 1.3 x 10-5 = 4.55 x 10-4 4.55 x 10-4 = 2.13 x 10-3 x = -log x 10-3 =

90 Calculate pH of 0.35 M solution of propionic
acid. Ka = 1.3 x 10-5 Table 8-2 HA(aq) + H2O(l) H3O+(aq) + A-(aq) x2 = [HA] Ka = 0.35 x 1.3 x 10-5 = 4.55 x 10-4 4.55 x 10-4 = 2.13 x 10-3 x = -log x 10-3 = 2.67

91 Equilibria involving weak bases

92 Equilibria involving weak bases
H2O(l) + B(aq) OH-(aq) + HB+(aq)

93 Equilibria involving weak bases
H2O(l) + B(aq) OH-(aq) + HB+(aq) Acid base base acid2

94 Equilibria involving weak bases
H2O(l) + B(aq) OH-(aq) + HB+(aq) Acid base base acid2 [OH-][HB+] = Kb [B]

95 Equilibria involving weak bases
H2O(l) + B(aq) OH-(aq) + HB+(aq) Acid base base acid2 [OH-][HB+] = Kb [B] Weak base: Kb < 1

96 Equilibria involving weak bases
H2O(l) + NH3(aq) OH-(aq) + NH4+(aq) Acid base base acid2 Kb = ?

97 Equilibria involving weak bases
H2O(l) + NH3(aq) OH-(aq) + NH4+(aq) Acid base base acid2 Kb = ? KaKb = Kw

98 Equilibria involving weak bases
H2O(l) + NH3(aq) OH-(aq) + NH4+(aq) Acid base base acid2 Kw Kb = Ka

99 Equilibria involving weak bases
H2O(l) + NH3(aq) OH-(aq) + NH4+(aq) Acid base base acid2 Kw Kb = Ka

100 Equilibria involving weak bases
H2O(l) + NH3(aq) OH-(aq) + NH4+(aq) Acid base base acid2 Kw Kb = Ka Table page 332: Ka = 5.6 x 10-10

101 Equilibria involving weak bases
H2O(l) + NH3(aq) OH-(aq) + NH4+(aq) Acid base base acid2 1 x 10-14 Kw Kb = = 5.6 x 10-10 Ka

102 Equilibria involving weak bases
H2O(l) + NH3(aq) OH-(aq) + NH4+(aq) Acid base base acid2 1 x 10-14 Kw Kb = = = 1.8 x 10-5 5.6 x 10-10 Ka

103 Hydrolysis

104 Hydrolysis The reaction of water with an ion resulting in a change in the [H3O+]- [OH-] balance.

105 Hydrolysis The reaction of water with an ion resulting in a change in the [H3O+]- [OH-] balance. Hydrolysis of anions raises pH.

106 Hydrolysis The reaction of water with an ion resulting in a change in the [H3O+]- [OH-] balance. Hydrolysis of anions raises pH. Hydrolysis of cations lowers pH.

107 Hydrolysis H2O(l) + F-(aq) HF(aq) + OH-(aq)

108 Hydrolysis H2O(l) + F-(aq) HF(aq) + OH-(aq) Ka (HF) = 6.6 x 10-4

109 Hydrolysis H2O(l) + F-(aq) HF(aq) + OH-(aq) Ka (HF) = 6.6 x 10-4 [HF][OH-] Kb = [F-]

110 Hydrolysis H2O(l) + F-(aq) HF(aq) + OH-(aq) Ka (HF) = 6.6 x 10-4 [HF][OH-] Kb = [F-] pH M NaF

111 Hydrolysis H2O(l) + F-(aq) HF(aq) + OH-(aq) Ka (HF) = 6.6 x 10-4 [HF][OH-] Kw = Kb = [F-] Ka pH M NaF

112 Hydrolysis H2O(l) + F-(aq) HF(aq) + OH-(aq) Ka (HF) = 6.6 x 10-4 [HF][OH-] Kw [F-]Kw = [OH-]2 = [F-] Ka Ka pH M NaF

113 Hydrolysis H2O(l) + F-(aq) HF(aq) + OH-(aq) Ka (HF) = 6.6 x 10-4 [F-]Kw (0.095)(1 x 10-14) [OH-]2 = = (6.6 x 10-4) Ka pH M NaF

114 Hydrolysis H2O(l) + F-(aq) HF(aq) + OH-(aq) [F-]Kw (0.095)(1 x 10-14) = = = [OH-]2 (6.6 x 10-4) Ka

115 Hydrolysis H2O(l) + F-(aq) HF(aq) + OH-(aq) [F-]Kw (0.095)(1 x 10-14) = [OH-]2 = = (6.6 x 10-4) Ka 1.44 x 10-12 [OH-]2 =

116 Hydrolysis H2O(l) + F-(aq) HF(aq) + OH-(aq) [F-]Kw (0.095)(1 x 10-14) = [OH-]2 = = (6.6 x 10-4) Ka 1.44 x 10-12 [OH-]2 = [OH-] = 1.2 x 10-6

117 Hydrolysis H2O(l) + F-(aq) HF(aq) + OH-(aq) [OH-] = 1.2 x 10-6 1 x 10-14 [H3O+] = = 1.2 x 10-6

118 Hydrolysis H2O(l) + F-(aq) HF(aq) + OH-(aq) [OH-] = 1.2 x 10-6 1 x 10-14 8.34 x 10-9 [H3O+] = = 1.2 x 10-6

119 Hydrolysis H2O(l) + F-(aq) HF(aq) + OH-(aq) [OH-] = 1.2 x 10-6 1 x 10-14 8.34 x 10-9 [H3O+] = = 1.2 x 10-6 -log10 (8.34 x 10-9) = 8.08

120 Hydrolysis H2O(l) + F-(aq) HF(aq) + OH-(aq) pH = 8.08

121 It is Wednesday. The first homework is due. Place it on the bench in front.


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