chemical science vs make pure

chemical science is a noun but make pure is not a noun.

Word	Noun	Adjective	Verb	Adverb
chemical science	Yes	No	No	No
make pure	No	No	Yes	No

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

chemical science (verb)	make pure (verb)
	remove impurities from, increase the concentration of, and separate through the process of distillation