What does an empirical formula represent?

An empirical formula represents the simplest whole number ratio of the different types of atoms present in a compound. It provides a concise way to show the composition of a compound without detailing the specific arrangement of the atoms or the total number of each type of atom in an individual molecule. For instance, the empirical formula of hydrogen peroxide (H₂O₂) simplifies to HO, indicating that the ratio of hydrogen to oxygen atoms is 1:1, even though the actual molecule contains two hydrogen and two oxygen atoms. Thus, the empirical formula is crucial for understanding the basic stoichiometric relationships in chemical reactions, allowing chemists to utilize recipes for reactants and products based on ratios rather than absolute quantities.

The total number of atoms in a molecule refers to the molecular formula, while the arrangement of atoms relates more to structural formulas. The average mass of a compound is represented by molar mass, not the empirical formula.