How many grams of SrSO4 must be dissolved in water to produce 1 L saturated solution?

2017-02-28 2:00 am

The solubility constant of strontium sulfate, SrSO4, is 2.8x10^-7. How many grams of SrSO4 must be dissolved in water to produce 1 L saturated solution?
a. 0.00005 g
b. 0.1 g
c. 0.0005 g
d. 2 g

更新1:

Kindly show the step by step solution for me to have an understanding on this. Thanks!

回答 (1)

胡雪8°

2017-02-28 2:18 am

✔ 最佳答案

________ SrSO₄(s) ⇌ Sr²⁺(aq) + SO₄²⁻(aq) …. Ksp = 2.8 × 10⁻⁷
At eqm: __ ---- _____ y mol/L ___ y mol/L

Ksp = [Sr²⁺] [SO₄²⁻]
y² = 2.8 × 10⁻⁷
y = √(2.8 × 10⁻⁷) = 5.29 × 10⁻⁴
Solubility of SrSO₄ in mol/L = 5.3 × 10⁻⁴ mol/L

Molar mass of SrSO₄ = (87.6 + 32.1 + 16.0×4) g/mol = 183.7 g/mol
Solubility of SrSO₄ in g/L = (5.3 × 10⁻⁴ mol/L) × (183.7 g/mol) = 0.097 g/L ≈ 0.1 g/L
Mass of SrSO₄ in 1 L of solution = 0.1 g

The answer: b. 0.1 g

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