chemical science vs man-made

chemical science is a noun but man-made is not a noun.

Word	Noun	Adjective	Verb	Adverb
chemical science	Yes	No	No	No
man-made	No	Yes	No	No

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

chemical science (adjective)	man-made (adjective)
	not of natural origin; prepared or made artificially