Molecular formulas indicate the types and quantities of atoms present in a molecule, whereas structural formulas also depict the arrangement of these atoms.

Both molecular and structural formulas serve as representations of a molecule’s composition, yet they convey different levels of detail. A molecular formula specifies the types of atoms in a molecule and their respective quantities. For instance, the molecular formula for water is $H_2O$, which indicates that each water molecule consists of two hydrogen atoms and one oxygen atom.

In contrast, a structural formula provides insights into how these atoms are arranged and bonded. For example, the structural formula of water reveals that the two hydrogen atoms are bonded to the oxygen atom. This arrangement is significant because the structure of a molecule can profoundly influence its properties. A notable example is ethanol, with the molecular formula $C_2H_6O$, and dimethyl ether, which shares the same molecular formula $C_2H_6O$. Despite having identical molecular formulas, their distinct structures result in different properties.

Structural formulas can be represented in various formats. The simplest representation is the Lewis structure, which illustrates the arrangement of atoms and the bonds connecting them. More sophisticated representations include the ball-and-stick model, which portrays the spatial arrangement of atoms, and the space-filling model, which illustrates the relative sizes of the atoms.

In conclusion, while molecular formulas provide a fundamental overview of a molecule’s composition, structural formulas offer a more intricate depiction, highlighting the arrangement of atoms and the nature of their bonds. This additional information is essential for understanding the properties and behavior of molecules.