How do you differentiate between molecular and structural formulas?

Molecular formulas show the types and numbers of atoms in a molecule, while structural formulas also show their arrangement.

Molecular and structural formulas are both ways of representing the composition of a molecule. However, they provide different levels of information. A molecular formula simply tells you which atoms are present in a molecule and in what quantities. For example, the molecular formula of water is H2O, which tells you that each molecule of water contains two hydrogen atoms and one oxygen atom.

On the other hand, a structural formula also gives you information about how these atoms are arranged or bonded together. For example, the structural formula of water shows that the two hydrogen atoms are bonded to the oxygen atom. This is important because the structure of a molecule can greatly affect its properties. For instance, although ethanol (C2H5OH) and dimethyl ether (CH3OCH3) have the same molecular formula (C2H6O), they have different structures and therefore different properties.

Structural formulas can be represented in several ways. The simplest is the Lewis structure, which shows the arrangement of atoms and the bonds between them. More complex representations include the ball-and-stick model, which shows the spatial arrangement of atoms, and the space-filling model, which shows the relative sizes of atoms.

In summary, while molecular formulas provide a basic overview of a molecule's composition, structural formulas provide a more detailed picture, showing the arrangement of atoms and the bonds between them. This additional information can be crucial for understanding a molecule's properties and behaviour.