Obtain the experimental mass of each element in the compound
Convert each element’s mass to moles
moles = (mass of element) / (molar mass of element)
Divide all mole values by the smallest number of moles
Round the resulting values to the nearest whole numbers (or simplest whole-number ratio)
Write the empirical formula using those whole-number subscripts
If rounding is ambiguous, multiply all ratios by a whole number to clear fractions and return to the simplest whole-number ratio
Check that the empirical formula matches the simplest ratio of the elements based on the rounded mole values