Problem: What is the solubility in mole/liter for copper(II) sulfide at 25 °C given a Ksp value of 1.3 x 10-36. Write using scientific notation and use 1 or 2 decimal places (even though this is strictly incorrect!) 

For this problem, we’re being asked to calculate the  solubility in mole/liter for copper(II) sulfide at 25 °C given a Ksp value of 1.3 x 10^-36

Since the copper(II) sulfide (CuS) is an ionic compound, it forms ions when dissociating in water. The dissociation of CuS in water is as follows:

The hydroxide ion, OH^–, has a charge of –1. Nickel then has a charge of +2:

CuS(s) ⇌ Cu²⁺(aq) + S^2-(aq)

We can construct an ICE table for the dissociation of CuS. 

Remember that solids are ignored in the ICE table and K_sp expression.