Question

Ethylenediaminetetraacetic acid EDTA is 41.09% C, 5.53% H, 9.58%N, and 43.8% O. What is the empirical formula of EDTA?

Answer 1

Assume you have 100g of EDTA

Going by the percentages, you have 41.09%C or 41.09g C in our case. Divide this by the molar mass of C to get moles C.

Repeat with the other elements.

You should now have the relative amounts of moles per element. If you have ~whole numbers (or very close to whole numbers) you can write the formula based on those numbers. If you have fractions like 1/2 or 1/3, multiply all moles by the lowest whole number that eliminates the fractions.