The number of covalent bonds in an alkane depends on the number of carbon atoms in the molecule. Each carbon atom in an alkane has four valence electrons, and each carbon atom forms four covalent bonds with other atoms. For example, ethane (C2H6) has two carbon atoms, and each carbon atom forms four covalent bonds, two with hydrogen atoms and two with the other carbon atom. Therefore, ethane has a total of eight covalent bonds. In general, the formula for the number of covalent bonds in an alkane is 2n + 2, where n is the number of carbon atoms in the molecule. So, for example, propane (C3H8) has three carbon atoms and a total of ten covalent bonds, and butane (C4H10) has four carbon atoms and a total of twelve covalent bonds.