The empirical formula of a chemical compound gives the ratio of elements using subscripts to indicate the number of each atom. Determine Mass of Each Element. Assume a 100 g sample of the compound so that the given percentages can be directly converted into grams.
Calculate Number of Moles.
The molecular formula gives the actual whole number ratio between elements in a compound. Converting mass of carbon dioxide to mass of carbon. The empirical formula gives the smallest whole number ratio between elements in a compound. If you hit a problem that just doesnt seem to be working out go back and re-calculate with more precise atomic weights.