How do I find the emperical formula of
16.9% Fe3+
39.7% C2O42-
43.4% H2O
Take a 100 g sample which means you are starting with
16.9 g Fe^+3
39.7 g C2O4^-2
43.4 g H2O
Convert each gram above to moles by dividing by molar mass.
Then find the ratio (in small whole numbers) to each other. You want the smallest number to be one; the easy way to do that is to divide the smallest number by itself to make it 1.0000, then divide all the other numbers by that same small number. You want to round them to whole numbers BUT don't round a number like 0.5. Instead. if one of the numbers is something and a 1/2, multiply everything by 2 (to get rid of the half) and those numbers then should be rounded to whole numbers. Trust me, it works.