alkyl vs chemical group

alkyl and chemical group both are nouns.

Word	Noun	Adjective	Verb	Adverb
alkyl	Yes	No	No	No
chemical group	Yes	No	No	No

As nouns, chemical group is a hypernym of alkyl; that is, chemical group is a word with a broader meaning than alkyl:

alkyl: any of a series of univalent groups of the general formula CnH2n+1 derived from aliphatic hydrocarbons
chemical group: (chemistry) two or more atoms bound together as a single unit and forming part of a molecule

Other hypernyms of alkyl include group, radical.

alkyl (noun)	chemical group (noun)
any of a series of univalent groups of the general formula CnH2n+1 derived from aliphatic hydrocarbons	(chemistry) two or more atoms bound together as a single unit and forming part of a molecule