chemistry vs chemical chain

chemistry and chemical chain both are nouns.

Word	Noun	Adjective	Verb	Adverb
chemistry	Yes	No	No	No
chemical chain	Yes	No	No	No

chemistry (noun)	chemical chain (noun)
the science of matter; the branch of the natural sciences dealing with the composition of substances and their properties and reactions	(chemistry) a series of linked atoms (generally in an organic molecule)
the way two individuals relate to each other
the chemical composition and properties of a substance or object