Posted by NICOLE on .
what is solubility, in mol/L, of MgCO3 in a 0.65 mol/L solution of MgCL2 if the ksp of MgCO3 is 2.5*10^5

CHEMITRY 
DrBob222,
MgCO3 ==> Mg^2+ + CO3^2
....x......x........x
where x = solubility in mols/L.
........MgCl2 > Mg^2+ + 2Cl^
I........0.65.....0..........0
C.......0.65....0.65.....2*0.65
E .......0.........0.65....1.30
Substitute from the above ICE charts into Ksp for MgCO3 and solve for x.
(Mg^2+) = x+0.65 (that's x from MgCO3 and 0.65 from MgCl2.)
(CO3^2) = x