conservation of mass vs law of conservation of matter

conservation of mass and law of conservation of matter both are nouns.

Word	Noun	Adjective	Verb	Adverb
conservation of mass	Yes	No	No	No
law of conservation of matter	Yes	No	No	No

As nouns, conservation of mass and law of conservation of matter are synonyms defined as:

conservation of mass and law of conservation of matter: a fundamental principle of classical physics that matter cannot be created or destroyed in an isolated system

Other synonyms of conservation of mass include conservation of matter, law of conservation of mass.

conservation of mass (noun)	law of conservation of matter (noun)
a fundamental principle of classical physics that matter cannot be created or destroyed in an isolated system	a fundamental principle of classical physics that matter cannot be created or destroyed in an isolated system