Question #9e97b

1 Answer
Mar 22, 2017

Here's what I got.

Explanation:

Start by writing out the chemical formulas for these two ionic compounds

Fe(OH)2 iron(II) hydroxide

CaSO4 calcium sulfate

Next, you're dealing with insoluble ionic compounds, so you must write a dissociation equilibrium that is established when these salts are dissolved in water.

For iron(II) hydroxide, you will have

Fe(OH)2(s)Fe2+(aq)+2OH(aq)

By definition, the solubility product constant for this equilibrium will be

Ksp=[Fe2+][OH]2

Notice that the stoichiometric coefficients present in the dissociation equilibrium become exponents in the expression for Ksp and that the equilibrium concentration of the undissolved solid is not included.

Do the same for calcium sulfate.

CaSO4(s)Ca2+(aq)+SO2+4(aq)

This time, the solubility product constant will be

Ksp=[Ca2+][SO24]

Once again, the stoichiometric coefficients become exponents and the equilibrium concentration of the undissolved solid is not included.