How does an empirical formula differ from a molecular formula?

An empirical formula provides the simplest whole-number ratio of the different types of atoms present in a compound. This means that it gives a basic representation of the composition of the molecule, without specifying the actual number of atoms in a molecule. For instance, the empirical formula for both glucose (C6H12O6) and butene (C4H8) is the same, C2H4, which illustrates that they share the same simplest atomic ratio.

In contrast, a molecular formula details the actual number of each type of atom present in the molecule. In the case of glucose, the molecular formula is C6H12O6, indicating there are six carbon atoms, twelve hydrogen atoms, and six oxygen atoms in each molecule. This distinction is crucial because the molecular formula provides more specific information about the actual composition of the compound than the empirical formula.

The other choices misrepresent the relationship and definitions between empirical and molecular formulas, either by suggesting they are synonymous or by incorrectly describing their characteristics. Understanding this difference is foundational to interpreting chemical compositions accurately.