You haven't shown the structural formula but it's either an Alkene(double bond c=b between 2 carbons) or an alkane If there is 1 carbon it is methane (methene is not possible as a carbon cannot double bond with itself) If there are 2 carbons it could be ethane or ethene If there are 3 carbons it could be propane or propene If there are 4 carbons it could be butane or butene If there are 5 carbons it could be pentane or pentene Etc.
E.g ethane E.g. Ethene H H H H | | | | H---C---C---H C = C | | | | H H H H
