chemist vs chemical science

chemist and chemical science both are nouns.

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

chemist (noun)	chemical science (noun)
a scientist who specializes in chemistry	the science of matter; the branch of the natural sciences dealing with the composition of substances and their properties and reactions
a health professional trained in the art of preparing and dispensing drugs