AP Chemistry Unit 8- Homework Problems Ka and Kb Acid & Base ...

Auto-Ionization of water, pH, and strong acids
1. What is the equation for the auto-ionization of water?
2. What is the equation for K w and what is its value?
3. Because the pH scale is a logarithmic scale, every change in 1 is really a change in how
much?
4. Using the pH square and the equations learned in class, fill in the blank spots in the chart
below:
pH [H 3 O +1 ] [OH -1 ] pOH
3.5
9.2x10 -9 4.7x10 -11 8.2
5. According to the leveling effect:
a. What is the strongest acid species in water?
b. What is the strongest base species in water?
6. What is the % dissociation of strong acids and bases in water?
7. List 6 strong acids.
8. List 6 strong bases.
Weak acids & bases, K a , K b , and pH
1. How are weak acids and bases different from strong ones?
2. What is the general equation for K a ?
3. What is the general equation for K b ?
4. For a 0.25 M solution of HC 2 H 3 O 2 (K a = 1.8x10 -5 ) calculate:
a. pH
b. % dissociation
5. For a 0.75 M solution of C 2 H 5 NH 2 (K b = 5.6x10 -4 ) calculate:
a. pH
b. % dissociation
6. For a 0.055 M solution of HClO (K a = 2.9x10 -8 ) calculate:
a. PH
b. % dissociation
7. For a 0.0034 M solution of C 5 H 5 N (K b = 1.7x10 -9 ) calculate:
a. pH
b. % dissociation
8. For a 0.15 M solution of H 2 C 6 H 6 O 6 (K a1 = 8x10 -5 K a2 = 1.6 x10 -12 ) calculate:
a. pH
b. Equilibrium concentrations of:
i) HC 6 H 6 O 6
-1
ii) C 6 H 6 O 6
-2
9. For a 0.025 M solution of diprotic base, B (K b1 = 4x10 -6 , K b2 = 8x10 -10 ) calculate:
a. pH
b. Equilibrium concentrations of:
i) HB +
ii) H 2 B +2