Question #9e97b
1 Answer
Here's what I got.
Explanation:
Start by writing out the chemical formulas for these two ionic compounds
#"Fe"("OH")_2 -># iron(II) hydroxide
#"CaSO"_4 -># 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")_ (color(red)(2)(s)) rightleftharpoons "Fe"_ ((aq))^(2+) + color(red)(2)"OH"_ ((aq))^(-)#
By definition, the solubility product constant for this equilibrium will be
#K_(sp) = ["Fe"^(2+)] * ["OH"^(-)]^color(red)(2)#
Notice that the stoichiometric coefficients present in the dissociation equilibrium become exponents in the expression for
Do the same for calcium sulfate.
#"CaSO"_ (4(s)) rightleftharpoons "Ca"_ ((aq))^(2+) + "SO"_ (4(aq))^(2+)#
This time, the solubility product constant will be
#K_(sp) = ["Ca"^(2+)] * ["SO"_4^(2-)]#
Once again, the stoichiometric coefficients become exponents and the equilibrium concentration of the undissolved solid is not included.