Solubility Product (Ksp), Entropy and Greenhouse effect

What is The Solubility Product, Ksp

• The solubility product, Ksp, gives the maximum concentration that ions can have in a solution

• It is the equilibrium constant for the equilibrium established between a solid and a saturated solution of its ions

• The Ksp just includes aqueous ions as solids don’t have concentrations

• E.g. BaCl2(s) <=> Ba²+ (aq) + 2Cl-

Ksp = [Ba²+(aq)] [Cl-(aq)]²

How can we predict if a precipitate will form using Ksp

• Calculate a hypothetical Ksp, compare the actual

• If hypothetical Ksp is larger than the actual Ksp, a precipitate will form

What is the method for determining Ksp

Part 1 - Preparation of a saturated solution

• Add salt to warm distilled water in conical flask, with thorough stirring, until no more dissolves

• Leaves the mixture to cool to room temperature

• Filter to remove excess salt

Part 2 - Analysis

• Titrate with HCl if we are finding [OH-]

• Use colorimetry if we are finding to concentration of a coloured ion

Part 3 - Calculating

• Use the concentration of the ion to find the concentration of the other ion according to the salt formula

• Put the concentrations in to the Ksp expression

What happens to the solubility of a solid if there is more than one source of an ion (common ion effect)

• Ksp is constant

• If there is more than one source of one of the ions, this will reduce the solubility of the solid