a 500 ml portion of .0020 M Na2C2O4 solution is able to dissolve .47g of MgC2O4. What is the Ksp for MgC2O4

Answer 1

The question is a little confusing by not telling us that the MgC2O4 "just" dissolves. My point is that perhaps the 500 mL of the Na2C2O4 could have dissolved more than 0.47 g MgC2O4. At any rate,
MgC2O4 ==> Mg^+ + C2O4^-2

Ksp = (Mg^+2)(C2O4^-2) = ??
You know (Mg^+2) = 0.47/molar mass MgC2O4 and that divided by 0.5 L.
You know C2O4 is the sum of the C2O4 from MgC2O4 and the C2O4 from Na2C2O4. Add those together to obtain the total C2O4, an solve for Ksp. I obtain an answer very close to my text book value for Ksp for MgC2O4.