Ball-and-stick representations of benzene, a colorless liquid often used in organic chemistry reactions, and acetylene, a gas used as a fuel for high-temperature welding, are shown below. (a) Determine the molecular formula of each.

Key Concepts

Molecular Formula

The molecular formula of a compound indicates the number and types of atoms present in a molecule. It is expressed as a series of chemical symbols with subscripts denoting the quantity of each type of atom. For example, benzene has the molecular formula C6H6, indicating it contains six carbon atoms and six hydrogen atoms.

Structural Representation

Ball-and-stick models are a common way to represent molecular structures, where balls represent atoms and sticks represent bonds between them. This representation helps visualize the geometry and connectivity of atoms in a molecule, which is crucial for understanding chemical properties and reactions. For instance, the structure of toluene shows a benzene ring with a methyl group attached.

Hydrocarbons

Hydrocarbons are organic compounds composed solely of carbon and hydrogen atoms. They can be classified into aliphatic (like pentane) and aromatic (like benzene and toluene) compounds. Understanding the classification and structure of hydrocarbons is essential for predicting their chemical behavior and reactivity in organic chemistry.