24.01 Determining Solubility from Ksp The qualitative analysis scheme depends on

Question

24.01 Determining Solubility from Ksp
The qualitative analysis scheme depends on the relative solubilities of the salts of the cations with various anions. The aqueous solubility of a salt can be estimated from Ksp, the solubility product constant, describing the equilibrium reaction between the solid salt and the ions in solution:

MxAy(s) xMy+(aq) + yAx-(aq)
Ksp = [My+]x[Ax-]y

The actual solubility may differ slightly from the calculated value, though, if the undissociated salt itself is slightly soluble, and if there are intermediate ion-pair structures formed in solution. Nevertheless, the calculated value is still very useful in comparing solubility relationships of various ions and predicting whether or not a precipitate will form when two ionic solutions are mixed.
Part A
For the salt   , Ksp = 2.5

Explanation / Answer

ForCaSO4-
Ksp= [Ca+2][SO4-2] = 4.9x10^-5
[Ca+2] = [SO4-2] = 0.0070 M

0.0070 mole/liter x 136.14 g/mol = 0.953 g/L
Solubility = 0.095 g/dL

Ksp = [Ca+2][SO4-2] = 4.9x10^-5
[Ca+2] = Ka/ [SO4-2] = 4.9x10^-5 / 0.05 M = 0.00098 M

For SeF2-
This is the same problem as the CaSO4 problem witrh new numbers. You should be able to do it now.

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