molecular weight vs chemical science

molecular weight and chemical science both are nouns.

Word	Noun	Adjective	Verb	Adverb
molecular weight	Yes	No	No	No
chemical science	Yes	No	No	No

molecular weight (noun)	chemical science (noun)
(chemistry) the sum of the relative atomic masses of the constituent atoms of a molecule	the science of matter; the branch of the natural sciences dealing with the composition of substances and their properties and reactions