1. Solubility Product Constant
What is Ksp?
Relationship

3. Go here to visualize salt dissolving in water.

4. Solubility Product Constant (Ksp)
Solubility Product Constant, Ksp is the equilibrium constant for a solid substance dissolving in an aqueous solution.
It represents the level at which a solute dissolves in solution.
The more a substance dissolves, the higher the Ksp value it has.

5. Solubility Products
Consider the equilibrium that exists in a saturated solution of BaSO4 in water:
BaSO4(s)
Ba2+(aq) + SO42−(aq)
The equilibrium constant expression for this equilibrium is
Ksp = [Ba2+] [SO42−]
where the equilibrium constant, Ksp, is called the solubility product.

6. Oh – you mean like solubility?
Ksp is not the same as solubility.
Solubility is generally expressed as:
- mass of solute dissolved in volume (g/mL)
- mol/L (M).

7. PbCl2(s)  Pb2+(aq) + 2 Cl-(aq)
Example 1
Calculate the solubility product constant for lead(II) chloride, if 50.0 mL of a saturated solution was found to contain g of lead (II) chloride dissolved in it.
Write reaction and Ksp expression.
PbCl2(s)  Pb2+(aq) + 2 Cl-(aq)
Ksp = [Pb2+][Cl-]2

8. Example 1
Calculate the solubility product constant for lead(II) chloride, if 50.0 mL of a saturated solution was found to contain g of lead (II) chloride dissolved in it.
Convert to Molarity!
M PbCl2
ICE TABLE!
Ksp = [0.0159][0.0318]2 = 1.61 x 10-5

9. Example 2 (Other Direction)
Estimate the solubility of Ag2CrO4 in pure water if the solubility product constant for silver chromate is 1.1 x 10-12
Write reaction and Ksp expression.
Ag2CrO4(s)  2 Ag+(aq) + CrO42-(aq)
Ksp = [Ag+]2[CrO42-]

10. Example 2 (Other Direction)
Estimate the solubility of Ag2CrO4 in pure water if the solubility product constant for silver chromate is 1.1 x 10-12
Let "x" be the number of moles of silver chromate
that dissolves in every liter of solution
(mol assuming 1 L)
ICE TABLE!
1.1 x = [2x]2[x]
x = 6.50 x 10-5 M