posted by Melissa .
The formula for epson salts is MgSO4*7H2O. If 1.250 g of the compound is dissolved in water, calculate the number of milliliters of 0.200 M Ba(NO3)2 that would be required to precipitate all of the sulfate ions as barium sulfate. Make the same determination for 1.000 g of alum.
I don't understand where to even start with this problem. Please help me.
I figured out the first part but don't understand the second part still. I looked at the response you had for someone else, but still couldn't get the right answer.