critical vs chemical science

critical is not a noun while chemical science is a noun.

Word	Noun	Adjective	Verb	Adverb
critical	No	Yes	No	No
chemical science	Yes	No	No	No

critical (noun)	chemical science (noun)
	the science of matter; the branch of the natural sciences dealing with the composition of substances and their properties and reactions

critical (adjective)	chemical science (adjective)
marked by a tendency to find and call attention to errors and flaws
characterized by careful evaluation and judgment
being in or verging on a state of crisis or emergency
at or of a point at which a property or phenomenon suffers an abrupt change especially having enough mass to sustain a chain reaction
of or involving or characteristic of critics or criticism
forming or having the nature of a turning point or crisis
urgently needed; absolutely necessary