chemical science vs law of constant proportion

chemical science and law of constant proportion both are nouns.

Word	Noun	Adjective	Verb	Adverb
chemical science	Yes	No	No	No
law of constant proportion	Yes	No	No	No

chemical science (noun)	law of constant proportion (noun)
the science of matter; the branch of the natural sciences dealing with the composition of substances and their properties and reactions	(chemistry) law stating that every pure substance always contains the same elements combined in the same proportions by weight