Ethane is a hydrocarbon gas made from petroleum. It is the second (first is methane) in a series of simple hydrocarbon petrochemical compounds in a family of related compounds named âAlkanesâ, all of which have the feature of containing only single bonds between carbon atoms. The chemical formula for ethane gas is C 2 H 6. 2  Ethane is a hydrocarbon that exists in nature as an odorless and colorless gas at standard temperature and pressure. 3  It is a stable compound and shows resistance to reactivity. 4  It has a molar mass of 30.07 grams per mole (g/mol).