Determine the amount of iron in a dietary supplement, a random sample of 15 tablets weighing a total of 23. 58 g was ground into a fine powder. A 3. 1289 -g sample of the powdered tablets was dissolved and treated to precipitate the iron as Fe(OH)3. The precipitate was collected, rinsed, and ignited to constant weight as Fe2O3, yielding 0. 3691 g. Calculate the iron content of the dietary supplement as g FeSO4. 7H2O per tablet