chemistry vs open-chain

chemistry is a noun but open-chain is not a noun.

Word	Noun	Adjective	Verb	Adverb
chemistry	Yes	No	No	No
open-chain	No	Yes	No	No

chemistry (noun)	open-chain (noun)
the science of matter; the branch of the natural sciences dealing with the composition of substances and their properties and reactions
the way two individuals relate to each other
the chemical composition and properties of a substance or object

chemistry (adjective)	open-chain (adjective)
	having an open chain structure