At a certain temperature, the solubility of strontium arsenate, sr3 (aso4) 2, is 0.0650 g/l. what is the ksp of this salt at this temperature?

Answer is: Ksp for strontium arsenate is 2.69·10⁻¹⁸.

Balanced chemical reaction (dissociation):

Sr₃ (AsO₄) ₂ (s) → 3Sr²⁺ (aq) + AsO₄³⁻ (aq).

s (Sr₃ (AsO₄) ₂) = 0.0650 g/L.

s (Sr₃ (AsO₄) ₂) = 0.0650 g/L : 540.7 g/mol = 1.2·10⁻⁴ mol/L.

s (Sr²⁺) = 3s (Sr₃ (AsO₄) ₂).

s (AsO₄³⁻) = 2s (Sr₃ (AsO₄) ₂).

Ksp = s (Sr²⁺) ³ · s (AsO₄³⁻) ².

Ksp = (3s) ³ · (2s) ².

Ksp = 108s⁵.

Ksp = 108 · (1.2·10⁻⁴ mol/L) ⁵ = 2.69·10⁻¹⁸.