Harris Quantitative Analysis, Quantitative Analysis

1. Aqueous Solution Chemistry
• Review of Chem. I and Chem II
Memorize lists of strong acids-bases
Simple definition
acid – donates a proton
base – accepts a proton
Also know what Lewis acids/bases are,

2. Memorize
Hydroxides of the alkaline
earth metals also considered
to be strong bases
Also note:
Very, very important

3. Acids/Bases
Conjugate Acids and Bases
HAc + H2O = Ac-
+ H3O+
Acid Base C. Base C. Acid
NH3 + H2O = NH4
+
+ OH-
Base Acid C. Acid C. Base
Useful advice: They differ by one and only one proton

4. Is the acetate ion an acid or base?
Is methylamine an acid or base?
Useful advice: Acids have a proton to lose, bases don’t

5. Polyprotic acids/bases

6. Clicker questions
What is the conjugate acid for F-
a. F-2
b. F
c. HF
d. H2F
What is the conjugate base for H2PO4
-
a. HPO4
2-
b. H3PO4
c. PO4
3-
Is H2PO4
-
an acid or a base
a. Acid
b. Base
c. Depends

7. Acids/Bases
Amphiprotic Species
– behave as both an acid and a base
– ex. H2O is an amphiprotic solvent
– ex. H2PO4
-
H2PO4
-
+ H2O = H3PO4 + OH-
H2PO4
-
+ H2O = HPO4
2-
+ H3O+
Useful advice: the pH of an aqueous solution of an
amphiprotic salt is determined by its equilibrium constants

8. Chemical Equilibrium
Reaction:
aA + bB = cC + dD

9. Chemical Equilibrium
Reaction:
aA + bB = cC + dD
K = [C]c
[D]d
/ [A]a
[B]b
Memorize

10. Chemical Equilibrium
Reaction:
aA + bB = cC + dD
K = [C]c
[D]d
/ [A]a
[B]b
Understood,
 [C] = [C]/[C]std
solutes: std state = 1 M
gases: std state = 1 bar
solids. liq = pure solid, pure liquid
Memorize

11. Chemical Equilibrium
Reaction:
aA + bB = cC + dD
K = [C]c
[D]d
/ [A]a
[B]b
Understood,
[C] = [C]/[C]std
solutes: std state = 1 M
gases: std state = 1 bar
solids. liq = pure solid, pure liquid
• Make sure
all concentrations in M
all gases in bar (atm)
pure solids/liquids/solvents are omitted

12. Types of Equilibrium Constants
A. ion product constant for water
2H2O = H3O+
+ OH-

13. Types of Equilibrium Constants
A. Ion product constant for water
2H2O = H3O+
+ OH-
Kw= [H3O+
] [OH-
] = 1.00 x 10-14
pKw =
-log Kw
Memorize

14. Types of Equilibrium Constants
A. ion product constant for water
2H2O = H3O+
+ OH-
K= [H3O+
] [OH-
] / [H2O]2
Kw= [H3O+
] [OH-
] = 1.00 x 10-14
pKw = -log Kw
B. solubility product constant
Ag2CO3(s) = 2Ag+
+ CO3
-2
(temp dependent)

15. Types of Equilibrium Constants
A. ion product constant for water
2H2O = H3O+
+ OH-
K= [H3O+
] [OH-
] / [H2O]2
Kw= [H3O+
] [OH-
] = 1.00 x 10-14
pKw = -log Kw
B. solubility product constant
Ag2CO3(s) = 2Ag+
+ CO3
-2
Ksp = [Ag+
]2
[CO3
-2
] = 8.1 x 10-12
pKsp = -log Ksp

16. Types of Equilibrium Constants
C. Acid Dissociation Constant (Weak Acid)
HNO2 + H2O = H3O+
+ NO2
-

17. Types of Equilibrium Constants
C. Acid Dissociation Constant (Weak Acid)
HNO2 + H2O = H3O+
+ NO2
-
Ka = [H3O+
] [NO2
-
] / [HNO2 ]
pKa = -log Ka

18. Types of Equilibrium Constants
C. Acid Dissociation Constant (Weak Acid)
HNO2 + H2O = H3O+
+ NO2
-
Ka = [H3O+
] [NO2
-
] / [HNO2 ]
pKa = -log Ka
D. Base Dissociation Constant (Weak Base)
NH3 + H2O = OH-
+ NH4
+
Kb = [OH-
] [NH4
+
] / [NH3 ]
pKb = -log Kb

19. Types of Equilibrium Constants
E. Relationship btwn Ka and Kb
conjugate acid base pairs
ex. NH3 and NH4
+
NH3 + H2O = OH-
+ NH4
+
Kb = [OH-
] [NH4
+
] / [NH3 ]
NH4
+
+ H2O = H3O+
+ NH3 Ka = [H3O+
] [NH3 ] / [NH4
+
]
KaKb = Kw Memorize
Useful advice: “a” is for acid, “b” is for base…

20. Clicker Question:
Which one of the following weak acids will be
stronger in water?
a. Acetic acid Ka = 1.75 x 10-5
b. Benzoic acid Ka = 6.28 x 10-5
c. HF Ka = 6.8 x 10-4
d. HCN Ka = 6.2 x 10-10

21. Types of Equilibrium Constants
F. Le Chatelier’s Principle
System will change to relieve the stress
Ex. Ag2CO3(s) = 2Ag+
+ CO3
-2
Ksp = [Ag+
]2
[CO3
-2
] = 8.1 x 10-12
Disturb the system (Add CO3
-2
)
Clicker question
A. Shift right (form more products)
B. Shift left (form more reactants)
“Common ion effect”

22. Types of Equilibrium Constants
F. Le Chatelier’s Principle
System will change to relieve the stress
Ex. Ag+
+ 2NH3 = Ag(NH3)2
+
β2 = K1K2
Disturb the system (Add NH3)
Can also set up the reaction quotient, Q

23. How many grams of barium iodate can be dissolved in
500.0 mL of water at 25 C?
What is the molar solubility of Ag2CO3 in 0.1 M AgNO3
Example Solubility Problems