chemistry vs break down

chemistry is a noun but break down is not a noun.

Word	Noun	Adjective	Verb	Adverb
chemistry	Yes	No	No	No
break down	No	No	Yes	No

chemistry (noun)	break down (noun)
the science of matter; the branch of the natural sciences dealing with the composition of substances and their properties and reactions
the way two individuals relate to each other
the chemical composition and properties of a substance or object

chemistry (verb)	break down (verb)
	collapse due to fatigue, an illness, or a sudden attack
	stop operating or functioning
	separate (substances) into constituent elements or parts
	make a mathematical, chemical, or grammatical analysis of; break down into components or essential features
	make ineffective
	cause to fall or collapse
	lose control of one's emotions
	fall apart