The question asked... Calculate the solubility of calcium sulfate in grams solute per 100 grams solvent. Assume that the volume occupied by the solute in the solution in negligibly small. I solved and got 4.9 x 10 ^-3 mol/L... how do I put this in grams solute per 100 grams solvent?

3 answers

M = moles/L.
moles = g/molar mass. You know molar mass and you know moles, solve for grams. That, of course, will be grams/L and you take 1/10 of that to obtain g/100 mL of solution which is g/100 mL solvent IF the mass solute is very small.
I came up with 6.67 x 10^-3 g solute/ 100g solvent. Based on the information in the problem, does this seem about right?
I don't know what you used for Ksp; however, based on your answer of 4.9 x 10^-3 moles/L, I think it should be more like 0.0667.
0.0049 x 136 something = 0.666 g/L and 1/10 that is 0.0667.