The simplest organic compounds are hydrocarbons and are composed of carbon and hydrogen. Hydrocarbons can be aliphatic or aromatic; aliphatic hydrocarbons are divided into alkanes, alkenes, and alkyne...The simplest organic compounds are hydrocarbons and are composed of carbon and hydrogen. Hydrocarbons can be aliphatic or aromatic; aliphatic hydrocarbons are divided into alkanes, alkenes, and alkynes. The combustion of hydrocarbons is a primary source of energy for our society.