chemical decomposition reaction vs chemistry

chemical decomposition reaction and chemistry both are nouns.

Word	Noun	Adjective	Verb	Adverb
chemical decomposition reaction	Yes	No	No	No
chemistry	Yes	No	No	No

chemical decomposition reaction (noun)	chemistry (noun)
(chemistry) separation of a substance into two or more substances that may differ from each other and from the original substance	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