[analyticalC]

Hi,

I have a Ksp solubility problem.
I need to calc the weight of precipitate that will dissolve in 400 mL H2O
I am given the formula weight and the Ksp.

I believe I have the problem figured out. But I want to make sure I am on the right course.

I took the Ksp and did the following:

Ksp = [][]
Ksp = s sqrd
s= Molarity in H2O

then I took the Molarity which equals moles/Liters like so:

(mol/L) x (gram weight/1 mol) x (0.4 L) = grams of product dissolved in 400 ml H2O

so my moles cancel out and my Liters cancel out, leaving me with the grams of product dissolved in 400 mL of H2O.... right?

I left out my figures. I don't want someone to solve it for me. I just want to make sure that I am taking the correct steps to solve. Thanks!

[haz658]

By no means am I an expert with respect to solubility product constants and related problems. That said, everything you listed appears to be correct, with my only concern being that you performed the mass calculations for both ions that will form, and summed them. The question asked for the mass of the solid that will dissolve in a solution of this volume, and, therefore, you must sum the masses of both products formed, since both were originally part of the solid.

[Pradeep]

What is the salt you intersting? You can take Ksp = s² if only salt is MCl. If the salt is MCl₂ then Ksp = 4s³. Therefore consider about the salt you have.

[Pradeep]

If your salt is MCl you ar correct.