What is the difference between Molar solubility and solubility product?

[wolverine1]

^. This is one of the concepts tested on one of the practice exams and I can't differentiate the two.

Help!

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[boaz]

^. This is one of the concepts tested on one of the practice exams and I can't differentiate the two.

Help!

Solubility product is just an equilibrium constant. Molar solubility is the maximum number of moles that can be solvated before the solution becomes saturated. The latter can be calculated from Ksp and stiochiometry... If you have a specific example I can show you.

 

[wolverine1]

Solubility product is just an equilibrium constant. Molar solubility is the maximum number of moles that can be solvated before the solution becomes saturated. The latter can be calculated from Ksp and stiochiometry... If you have a specific example I can show you.

For example, AgCl, The ksp would be the equilibrium concentrations between Ag and Cl that can dissolve. The molar solubility would be the maximum amount of AgCl that can dissolve before the solution becomes saturated.

Do i have the right?

 

[boaz]

To put it more concretely:

Let's say Ksp of AgCl was 12 (I know, it's far from that; just for argument's sake). I dissolve 6 mols of AgNO3 in 1 L of water, then I add NaCl. AgCl will start precipitating once I add more than 2 mols of NaCl. Ksp=[Ag][Cl]=12=6*2. If instead of having dissolved 6 mols of AgNO3 I only dissolved 4, then I may add 3 mols of NaCl without seeing any precipitate. Ksp is the solubility product.

The "molar solubility" is just the maximum number of mols of AgCl that I can put into water without seeing precipitate. In this case, we have equal numbers of mols of Ag and Cl. Since Ksp of AgCl is 12, then [Ag]=[Cl]=(12)^.5 This is your molar solubility.