How Do You Calculate the Solubility Product for Copper(I) Sulfide?

[Winning]

Homework Statement

What is the solubility product for copper(I) sulfide, Cu2S, given that the solubility of Cu2S is 8.5 × 10^-17 M?

Homework Equations

$$Cu_{2}S \leftrightarrow 2Cu^{+} + S^{2-}$$

The Attempt at a Solution

Set up the equilibrium constant expression:
$$K_{sp} = [Cu^{+}]^{2}[S^{2-}]$$

Replaced values:
$$K_{sp} = (2*8.5 × 10^{-17})^{2}(8.5 × 10^{-17})$$
$$K_{sp} = 2.5 * 10^{-48}$$

A double-check on this would be wonderful please.

 

[Borek]

Looks OK to me.