The general formula for alkanes is CnH2n+2, where n represents the number of carbon atoms in the molecule/11%3A_Organic_Chemistry/11.02_Alkanes)/12%3A_Organic_Chemistry_-Alkanes_and_Halogenated_Hydrocarbons/12.02%3A_Structures_and_Names_of_Alkanes). This formula applies to both straight and branched-chain alkanes, as well as cyclic alkanes. For example, methane (CH4) is the simplest alkane and has one carbon atom, so n=1 and the formula is C1H4 = CH4. Ethane (C2H6) has two carbon atoms, so n=2 and the formula is C2H6 = C2H6. Propane (C3H8) has three carbon atoms, so n=3 and the formula is C3H8 = C3H8/12%3A_Organic_Chemistry-_Alkanes_and_Halogenated_Hydrocarbons/12.02%3A_Structures_and_Names_of_Alkanes).