Final answer:
The Ksp for Ca(OH)2, the mass of the dissolved compound is first converted to moles and then to molarity. The stoichiometry of the dissolution reaction is used to find the concentration of Ca2+ and OH- ions, which are then plugged into the expression for Ksp to find its value, which is 4.034×10^-5.
Step-by-step explanation:
To calculate the Ksp (solubility product constant) for Ca(OH)2, we'll start by converting the mass of Ca(OH)2 that dissolves in water into molar solubility. Molar mass of Ca(OH)2 is approximately 74.1 g/mol, so 0.160 g translates into 0.160 g / 74.1 g/mol = 0.00216 mol.
This amount of substance is in 0.100 L of water, hence the molarity of Ca2+ is 0.00216 mol / 0.100 L = 0.0216 M.
For Ca(OH)2, the dissolution can be represented as:
Ca(OH)2 (s) ↔ Ca2+ (aq) + 2 OH- (aq)
The stoichiometry of the reaction tells us that for every 1 mole of Ca(OH)2 that dissolves, we get 1 mole of Ca2+ and 2 moles of OH-. Thus, the concentration of OH- will be twice that of Ca2+, which is 2 * 0.0216 M = 0.0432 M. Then, we can use these concentrations to calculate the Ksp:
Ksp = [Ca2+][OH-]2
Ksp = (0.0216)(0.0432)2
Ksp = (0.0216)(0.001867)
Ksp = 4.034×10-5
Therefore, the Ksp for Ca(OH)2 at the given temperature is 4.034×10-5.