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
