AP Chemistry: Student Notes
Objectives
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Definition of Acids-Bases
Acid Strength
Base Strength
pH-pOH Scale
Calculating pH of Strong Acids-Bases
Calculating pH of Weak Acids-Bases
Calculating Ka from percent dissociation
Polyprotic Acids
Acid-Base Properties of Salts
Calculating with salts
Effect of Structure on Acid-Base Properties
Acid-Base Properties of Oxides
Definition of Acids-Bases
Properties of Acids-Bases
Acids
Bases
Arrhenius
Acid
Base
Bronstead-Lowry
Acid
Base
-1-
Lewis
Acid
Base
Conjugate Acid-Base Concept
Acid-Dissociation Constant
-2-
Acid Strength
Definitions:
Strong Acid
Weak Acid (Discuss Diagram)
List of Strong Acids
Base Strength
Definitions:
Strong Base
Weak Base
Amines
List of Strong Bases
-3-
pH-pOH Scale
Autoionization of Water
Definitions
pH =
pOH =
pH + pOH =
10-pH =
10-pH =
pH
2.3
pOH
[OH-]
[H+]
4.5
3.4x10-5
4.6 x 10-9
7
-4-
Acid-Base?
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Calculating pH of Strong Acids-Bases
Sample Problems
a. Calculate the pH of a 0.10 M HNO3 solution
b. Calculate the pH of a 1 x 10-10 M HClO4 solution
c. 54 mL of 0.00125-M HNO3 is mixed with 25.0-mL of 0.025-M HCl. What is the
pH of the resulting solution?
d. What is the pH of a 25.0 mL of a 0.25-M solution of NaOH
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Calculating pH of Weak Acids-Bases
Sample Problems
a. What is the pH of 25.0 mL of a 0.250M solution of acetic acid?
b. What the percent dissociation of a 0.325-M solution of formic acid?
c. Calculate the pH of a solution that contains 1.00 M HCN and 5.00 M HNO2.
Also calculate the concentration of CN- ion in this solution at equilibrium.
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d. What is the pH of a solution where 25.0-mL of 0.25 M HNO3 is mixed with 25.0mL of 0.25-M HNO2
e. What is the pH of a 0.25-M solution of NH3?
f. What is the pH of a mixture of 25.0 mL of 0.25M KOH and 25.0 mL of 0.25 M
CH3NH2
Values of Kb for Some Common Weak Bases
Formula
Conjugate
Kb
Acid
Ammonia
NH3
NH4+
1.8 x 10-5
+
Methylamine
CH3NH2
CH3NH2
4.38 x 10-4
Ethylamine
C2H5NH2
C2H5NH3+
5.6 x 10-4
Diethylamine
(C2H5)2NH2 (C2H5)2NH2+ 1.3 x 10-3
Triethylamine
(C2H5)3N
(C2H5)3NH+
4.0 x 10-4
Hydroxylamine NONH2
NONH3+
1.1 x 10-8
+
Hydrazine
H2NNH2
H2NNH3
3.0 x 10-6
Aniline
C6H5NH2
C6H5NH3+
3.8 x 10-10
+
Pyridine
C5H5N
C5H5NH
1.7 x 10-9
Name
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Calculating Ka from percent dissociation
Sample 1:
Lactic Acid (HC3H5O3) is a waste product that accumulates in muscle during exertion,
leading to pain and a feeling of fatigue. In a 0.100 M aqueous solution, lactic acid is
3.7% dissociated. Calculate the value of Ka for this reaction.
Polyprotic Acids
Definition of
Polyprotic Acids
Monoprotic Definition and dissociation
Diprotic Definition and dissociation
Triprotic Definition and dissociation
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The Value of Ka1 vs Ka2 vs Ka3
Polyprotic Acid Problem 1
Calculate the pH and concentration of all species of a 3.0-M solution of phosphoric acid
(H3PO4)
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Acid-Base Properties of Salts
Salts that Produce Basic Solutions: Examples—Salts of weak acids
Ka x Kb = Kw
Salts that Produces Acid Solutions: Examples—Salts of weak bases
Calculating with salts
Sample 1: What is the pH of a 0.140 M solution of sodium acetate?
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Sample 2: What is the pH of a 0.140 M solution of diethyl amine?
Sample 3: Predict whether an aqueous solution o feach of the following salts will be
basic, acidic, or neutral
a. NH4C2H3O2
b. NH4CN
c. Al2(SO4)3
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Effect of Structure on Acid-Base Properties
Discussion of the polarity of the hydrogen halides
Discussion of the Oxyacids
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Acid-Base Properties of Oxides
Metal Oxides + Water 
Non-Metal Oxides + Water 
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