chemical science vs relative molecular mass

chemical science and relative molecular mass both are nouns.

Word	Noun	Adjective	Verb	Adverb
chemical science	Yes	No	No	No
relative molecular mass	Yes	No	No	No

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