Explain why an empirical formula alone cannot be used to derive the actual molecular formula for a given compound. Provide one or more examples.

Molecular formulas indicate how many atoms there are of each element in a compound, while empirical formulas indicate the reduced proportion of elements in a given compound. The molecular formula can be achieved through the empirical formula if the molecular weight of the compound is known, therefore the empirical formula alone cannot be used to obtain the molecular formula.

Explanation:

An empirical formula expresses the relative relationships of the different atoms in a given compound. For example, H2O is made up of two hydrogen atoms and 1 oxygen atom. In the same way, 1.0 mol of H2O is made up of 2.0 mol of hydrogen and 1.0 mol of oxygen ...

The molecular formula for a compound is always the empirical formula. The molecular formula can be obtained from the empirical formula if the molecular weight of the compound is known.