Organic chemistry/How are organic molecules represented?

The empirical formula of a chemical compound is the simplest positive integer ratio of atoms present in a compound. For example, the empirical formula of hydrogen peroxide, H2O2, is H1O1. It shows the ratio of each atom in a molecule.
 * Empirical Formula
 * Molecular Formula

Molecular formula are a way of describing a chemical structure in letters and numbers.
 * Structural formula
 * Lewis Structures
 * Line-Angle Drawings
 * Naming conventions