Barium is a nonessential element in the human body, but some organisms build exoskeletons using barium sulfate, which has a K_sp of 1.1 * 10^-¹⁰ at 25°C. What is the mass of barium in 1.0 L of a saturated solution of barium sulfate at 25°C?

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Quizplus · Accepted Answer

The solubility product (Ksp) of barium sulfate is used to calculate the concentration of barium ions in a saturated solution. The Ksp expression for BaSO4 is [Ba²⁺][SO₄²⁻] = 1.1 * 10⁻¹⁰. Since the solution is saturated, [Ba²⁺] = [SO₄²⁻] = s, where s is the solubility. Solving for s gives s = √(1.1 * 10⁻¹⁰) = 1.05 * 10⁻⁵ M. The molar mass of Ba is 137.33 g/mol, so the mass of Ba in 1.0 L is 1.05 * 10⁻⁵ mol/L * 137.33 g/mol = 1.44 mg.

Barium Is a Nonessential Element in the Human Body, but Some