Molarity question?

Question

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Can somebody explain to me the solubility constant is and how to use it? Thanks

Answer 1

Solubility constant is defined for the equilibrium between a solid precipitate of a compound and the compound's ions in solution. If the compound is AxCy (A=anion,C=cation), the constant indicates the upper limit for the conc of the compound in solution. The general formula is
that if have M moles/liter of the compound at equilibrium with precipitate, and this is the ONLY compound in solution.
(xM)^x (yM)^y = Ksp

If you have multiple compounds of an anion A with
different cations, each compound's Ksp will indicate the conc of ions. Moreover, if you have multiple compounds of different anions with the same cation, this also will be true.

In the lab, adding the more soluble lithium floride to a solution with cadmium floride adds more floride ion in solution. To compensate for this, CdF2 precipitates out until the Ksp limit is again attained, but the ratio of F to Cd will be much greater than 2 to 1.

Answer 2

You may know that different compounds will dissolve (in water) at different amounts before the solution is saturated and nothing else can dissolve. For example, compare how much salt can dissolve in water compared to sugar (much more salt).

The reason is based on the bonding. But the amount that can dissolve is usually strongly influenced by temperature. In most cases, higher temperature means more can be dissolved.

The solubility constant is a factor which tells you how much of a substance will dissolve at a given temperature. For comparison purposes, many solubility constants are defined at 25 oC. The moles of dissolved product or ions are compared to the undissolved portion and a constant (k) is derived. If the k is greater than 1, than much is dissolved. The reverse is also true.

Answer 3

nope