Understanding Solubility and Ksp
* Solubility: The maximum amount of a solute that can dissolve in a given amount of solvent at a specific temperature. In this case, the solubility of BaCO3 is 1.1 x 10⁻⁴ M.
* Ksp: The solubility-product constant is an equilibrium constant that represents the product of the concentrations of ions in a saturated solution of a sparingly soluble salt. For BaCO3, the dissolution equilibrium is:
BaCO3(s) ⇌ Ba²⁺(aq) + CO₃²⁻(aq)
Calculating Ksp
1. Write the Ksp expression:
Ksp = [Ba²⁺][CO₃²⁻]
2. Relate solubility to ion concentrations:
Since the dissolution of one mole of BaCO3 produces one mole of Ba²⁺ and one mole of CO₃²⁻, the concentration of each ion in a saturated solution is equal to the solubility:
[Ba²⁺] = 1.1 x 10⁻⁴ M
[CO₃²⁻] = 1.1 x 10⁻⁴ M
3. Substitute ion concentrations into the Ksp expression:
Ksp = (1.1 x 10⁻⁴ M) (1.1 x 10⁻⁴ M) = 1.21 x 10⁻⁸
Therefore, the solubility-product constant (Ksp) of barium carbonate (BaCO3) is 1.21 x 10⁻⁸.
