Solubility Equilibria Ksp

Many salts are soluble in water, but others are only slightly soluble. These salts, when placed in water, quickly reach their solubility limit and the ions establish an equilibrium system  

The equilibrium constant expression associated with systems of slightly soluble salts is the solubility product constant, Ksp. It is the product of the ionic concentrations, each one raised to the power of the coefficient in the balanced chemical equation. It contains no denominator since the concentration of a solid is, by convention, 1, and for this reason it does not appear in the equilibrium constant expression. The Ksp expression for the PbS04 system is  

For this particular salt, the value of the Ksp is 1.6 x 10-8 at 25°C. If we know the value of the solubility product constant, then we can determine the concentration of the ions. In addition, if we know one of the ion concentrations, then we can find the Ksp. 

The Ksp of magnesium fluoride in water is 8 X 10 8. How many grams of magnesium fluoride will dissolve in 0.250 L of water  

For every mole of MgF2 that dissolves, 1 mol of Mg2+ and 2 mol of F form  

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