What is an important step in determining the empirical formula when given masses of substances?

Using the smallest number of moles as a reference is a crucial step in determining the empirical formula of a compound. The empirical formula is a simplified representation of the ratios of elements within a compound, showing the smallest whole-number ratio of atoms.

To find the empirical formula, you start by converting the masses of each element present in the compound into moles. This involves dividing the mass of each element by its respective atomic mass. After obtaining the number of moles for each element, the next step is to identify the smallest number of moles among them.

By using this smallest value as a reference, you can then divide the number of moles of each element by that smallest value to find the simplest whole-number ratio. This ensures that the ratio accurately reflects the proportion of each element in the compound. The final step is to express these ratios as the subscripts in the empirical formula.

This methodology is essential because it standardizes the results and allows for the determination of the most simplified ratio, which is what the empirical formula represents.