At a temperature for which the solubility product constant of calcium carbonate is 4.7 × 10^-9,what mass of the salt will dissolve in 100 mL of water? A)0.69 mg B)0.94 mg C)1.2 mg D)2.4 mg E)4.7 mg

Question

Quizplus · Accepted Answer

To determine the mass of calcium carbonate that will dissolve in 100 mL of water, we need to calculate the concentration of calcium ions and carbonate ions in the solution and use these concentrations to calculate the mass of calcium carbonate that can dissolve.

The solubility product constant expression for calcium carbonate is:

Ksp = [Ca2+][CO32-]

At equilibrium, the concentrations of Ca2+ and CO32- are the same, so we can write:

Ksp = [Ca2+]2 = [CO32-]2

Taking the square root of both sides, we get:

[Ca2+] = [CO32-] = sqrt(Ksp) = sqrt(4.7 × 10-9) = 6.86 × 10-5 M

The mass of calcium carbonate that can dissolve in 100 mL of water is given by:

mass = concentration x volume x molar mass

mass = (6.86 × 10-5 M) x (100 mL/1000) x (100.1 g/mol)

mass = 0.6895 mg

Round this answer to 0.69 mg. Therefore, the best choice is A).

At a Temperature for Which the Solubility Product Constant of Calcium