sentence: Hydrocarbons are molecules containing only the elements carbon and hydrogen in the form of chains.
sentences_before: The study of hydrocarbons is a very large part of organic chemistry.
sentences_after: Hydrocarbons can be classified into two categories based on the presence of a benzene ring, a circular type of hydrocarbon. Aliphatic hydrocarbons do not contain a benzene ring and aromatic hydrocarbons do.
concept_name: hydrocarbon
headings: Organic chemistry Hydrocarbons
categories: Chemistry