Diketahui Ksp CaCO₃ = 4,0 × 10⁻¹⁰ dan Mr CaCO₃ = 100. Kelarutan garam CaCO₃ dalam tiap 200 mL larutan adalah....

Ksp CaCO₃ = 4 × 10⁻¹⁰
CaCO₃ → Ca²⁺ + CO₃²⁻
......s..............s...........s

Ksp CaCO₃ = [Ca²⁺][CO₃²⁻]
Ksp CaCO₃ = s²
s = √Ksp CaCO₃
s = √ 4 × 10⁻¹⁰
s = 2 × 10⁻⁵ mol/L

V = 200 mL = 0,2 L
n = s × V
n = 2 × 10⁻⁵ mol/L × 0,2 L
n = 4 × 10⁻⁶ mol

Mr = 100
m = n × Mr
m = 4 × 10⁻⁶ mol × 100
m = 4 × 10⁻⁴ gram
m = 0,4 mg