1. Solubility
Lesson 3
Calculating
Ksp

2. The Molar Solubility is the molarity required to saturate or fill the solution at any given temperature.
1. The solubility (s) of BaCO3 is 5.1 x C. Calculate the solubility product or Ksp.

3. The Molar Solubility is the molarity required to saturate of fill the solution at any given temperature.
1. The solubility (s) of BaCO3 is 5.1 x C. Calculate the solubility product or Ksp.
BaCO3(s) ⇌ Ba CO32-
Ba2+
CO32-
BaCO3(s)
s s s
Ksp = [Ba2+][CO32-]
Ksp = [s][s]
Ksp = s2
Ksp = (5.1 x 10-5)2
Ksp = x 10-9

4. Ksp
Solubility Product
Saturated solutions- at equilibrium
No Units
Increasing Temperature increases the Ksp

5. 2. The solubility of PbBr2 is 0.012 M @ 25 0C. Calculate the Ksp.
dissociation equation
PbBr2(s) ⇌ Pb Br-
solubility
s s 2s
equilibrium expression
Ksp = [Pb2+][Br-]2
substitute & solve
Ksp = [s][2s]2
Ksp = 4s3
Ksp = 4(0.012)3
Ksp = 6.9 x 10-6
Note that the Br- is doubled and then squared!

6. 3. If 0. 00243 g of Fe2(CO3)3 is required to saturate 100
3. If g of Fe2(CO3)3 is required to saturate mL of solution. What is the solubility product?
Fe2(CO3)3 ⇌ 2Fe CO32-
s s s
Ksp = [Fe3+]2[CO32-]3
s = g
x 1 mole
291.6 g
Ksp = [2s]2[3s]3
0.100 L
Ksp = 108s5
= x 10-5 M
Ksp = 108(8.333 x 10-5)5
Ksp = x

7. 4. A 200. 0 mL sample of a saturated solution of Mg(OH)2 weighs 222
4. A mL sample of a saturated solution of Mg(OH)2 weighs g. When the beaker containing the solution is evaporated to dryness it weighs g. The mass of the empty beaker is g. Calculate the Ksp.
Mass of Beaker + Mg(OH) g
note sig figs- 4th decimal
-Mass of Beaker g
Mass of Mg(OH) g
Mg(OH)2⇌ Mg OH-
s s s g
x 1 mole
Ksp = [Mg2+][OH-]2
s =
58.3 g
= [s][2s]2 = 4s3 L
= 4( x 10-4)3
= x M
= 5.5 x

8. mL of a saturated Ba(OH)2 solution is neutralized by adding mL of M HCl. Calculate the Ksp for Ba(OH)2.
Titration 2HCl Ba(OH)2 L L
0.300 M
? M
L HCl
x moles
x mole Ba(OH)2
1 L
2 moles HCl
[Ba(OH)2] = L
s = M

9. Ksp
Ba(OH)2 ⇌ Ba2+ + 2OH-
s s 2s
Ksp = [Ba2+][OH-]2
= [s][2s]2
= 4s3
= 4(0.1091)3
= x 10-3