The ksp of cobalt(ii) hydroxide, co(oh)2, is 5.92 × 10-15. calculate the solubility of this compound in g/l.

When cobalt (II) hydroxide dissolves, it dissociates into the following ions,
Co(OH)₂ --> Co²⁺  + 2OH⁻
molar solubility is the number of moles that are dissolved in 1 L of solution. 
If molar solubility of Co(OH)₂ is X, then molar solubility of Co²⁺ is X and molar solubility of OH⁻ is 2X.
the formula for solubility product constant - ksp is as follows;
ksp = [Co²⁺][OH⁻]²
ksp = (X) * (2X)²
ksp = 4X³
ksp = 5.92 x 10⁻¹⁵ 
4X³ = 5.92 x 10⁻¹⁵
X = 1.14 x 10⁻⁵ M
molar solubility of Co(OH)₂ is 1.14 x 10⁻⁵ M
solubility of compound - 1.14 x 10⁻⁵ mol/L x 93 g/mol = 1.06 x 10⁻³ g/L

60.0 - there are 3 significant numbers