Final answer:
To calculate the Ksp for iron(II) hydroxide, convert the given solubility from grams to moles to find molar solubility, then plug into the expression Ksp = 4s³ where 's' is the molar solubility.
Step-by-step explanation:
The solubility of iron(II) hydroxide at 18.0°C is given, and the task is to calculate the solubility product constant (Ksp) of the substance at this temperature. The solubility provided is 3.25 x 10⁻³ g in 3.80 liters.
First, we convert the solubility in grams into moles using the molar mass of Fe(OH)₂. Once we have the molar solubility (s), which is moles per liter, we can use the dissolution equation:
Fe(OH)₂ (s) → Fe²⁺ (aq) + 2OH⁻ (aq)
And the Ksp expression:
Ksp = [Fe²⁺][OH⁻]²
Substituting 's' for [Fe²⁺] and '2s' for [OH⁻], we arrive at the expression Ksp = s(2s)², which simplifies to Ksp = 4s³. Knowing the solubility (s), we can calculate the Ksp for iron(II) hydroxide.