Solubility product

Saturated solution

Formed when a solvent has dissolved as much of a solute as it can. Any more solid that is added will not dissolve.

Solubility

The maximum amount of solid that will dissolve in a certain solvent

What is solubility usually measured in

gdm^-3

What affects solubility

Temperature

Sparingly soluble salt

A salt that does not fully dissolve in water

What occurs when a sparingly soluble salt is dissolved in water to give a saturated solution

An equilibrium is established.

What is the equilibrium constant of a sparingly soluble salt called

Solubility product (K_sp)

Why are solids not included in K_sp (all K_c) expressions

Their concentration doesn’t change

What are the techniques and procedures for determining the solubility product of Ca(OH)₂

• Add Ca(OH)₂ to distilled water and leave to equilibrate for 48 hours.

• Filter the solution into a conical flask.

• Pipette 25cm³ portions into separate conical flasks

• Titrate against HCl

• Calculations can be performed to determine the solubility of the salt and then work out the solubility product.

What are the 3 uses of the solubility product

1. Indicate solubility

2. Calculate solubility

3. Predict precipitation

What does a greater K_sp vale indicate

A more soluble compound

When does precipitation occur and why

When the ionic product > solubility product as in this case a saturated solution is reached

What is the ionic product

Has the same formula as K_sp but uses the actual concentrations of ions in solution