The percentage of the elements in the compound is determined by suitable methods and from the data collected;
The empirical formula is determined by the following steps:
1. Divide the percentage of each element by its atomic mass. This will give the relative number of moles of various elements present in the compound.
2. Divide the quotients obtained in step 1 by the smallest of them so as to get a simple ratio of moles of various elements. This maintains the molar ratio and bases all the molar amounts on one mole of the least abundant element.
3. If results of step 2 are not integers, multiply all of them with a smallest common factor to convert all molar amounts to integers or near integers.
4. Round off all the molar amounts to the nearest integers.
5. Finally write down the symbols of the various elements side by side and put the above number as the subscripts to the lower right hand corner of each symbol. This will represent the empirical formula of the compound.