Question #d71a4

1 Answer

Answer:

#K_(sp) = [Ca^(2+)][F^-]^2#

Explanation:

First consider how the compound will dissolve in water - or rather, how it dissociates into its smaller ionic components due to it being an ionic compound,

#CaF_2 (s) rightleftharpoons Ca^(2+)(aq) + 2F^(-)(aq) #

On the left of the equation is the reactant, and on the right, the products. The reactant is a solid, so it will not be included in the solubility equation.

#K_(sp) = [Ca^(2+)][F^-]^2#

In one mole of #CaF_2#, there is one mole of #Ca^(2+)# ions and two moles of #F^-# ions. Notice in the equation, the coefficient for the fluoride ions becomes an exponent.