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How many grams of Zn(CN)₂(s) (117.44 g/mol) would be soluble in 100 mL of H₂O? Include the balanced reaction and the expression for Ksp in your answer. The Ksp value for Zn(CN)₂(s) is 3.0 × 10⁻¹⁶.

a) 0.0054 g
b) 0.0108 g
c) 0.0216 g
d) 0.0432 g

1 Answer

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Final answer:

To determine the grams of Zn(CN)₂(s) soluble in 100 mL of H₂O, we can use the balanced reaction and Ksp expression. However, the concentration of CN⁻ in the solution is needed to complete the calculation.

Step-by-step explanation:

To determine the number of grams of Zn(CN)₂(s) that would be soluble in 100 mL of H₂O, we can use the balanced reaction and the expression for Ksp.

The balanced reaction for the dissolution of Zn(CN)₂(s) in water is:

Zn(CN)₂(s) → Zn²⁺(aq) + 2CN⁻(aq)

The expression for Ksp is:

Ksp = [Zn²⁺][CN⁻]²

Given that the Ksp value for Zn(CN)₂(s) is 3.0 × 10⁻¹⁶, we can calculate the number of moles of Zn²⁺ and CN⁻ ions in 100 mL (0.1 L) of water:

Moles of Zn²⁺ = Ksp / [CN⁻]² = (3.0 × 10⁻¹⁶) / ([CN⁻]²)

Since Zn(CN)₂ is a 1:2 electrolyte, the moles of CN⁻ is twice the moles of Zn(CN)₂. Therefore, moles of Zn(CN)₂ = 0.5 * Moles of Zn²⁺.

Finally, we can calculate the number of grams of Zn(CN)₂(s) using the molar mass of Zn(CN)₂:

Grams of Zn(CN)₂ = Moles of Zn(CN)₂ * Molar mass of Zn(CN)₂

Plugging in the values, we get:

Grams of Zn(CN)₂ = 0.5 * (3.0 × 10⁻¹⁶) / ([CN⁻]²) * 117.44 g/mol

To solve for [CN⁻]², we need to know the concentration of CN⁻ in the solution. Without that information, we cannot calculate the grams of Zn(CN)₂ that would be soluble in 100 mL of H₂O.

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