break down vs chemistry

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

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

break down (noun)	chemistry (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

break down (verb)	chemistry (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