Hydrocarbons contain only the elements hydrogen and carbon.
They occur in petroleum and natural gas. Commercial petroleum products, such as gasoline, kerosene, airplane fuel, lubricating oils, and paraffin, are mixtures of hydrocarbons. Some hydrocarbons are found in coal tar and coal gas. Hydrocarbons are starting materials for the petrochemical industry. Petrochemical companies use hydrocarbons from crude oil and natural gas to manufacture solvents, plastics, and synthetic fibers and rubbers.