gassing vs chemical change

gassing and chemical change both are nouns.

Word	Noun	Adjective	Verb	Adverb
gassing	Yes	No	No	No
chemical change	Yes	No	No	No

As nouns, chemical change is a hypernym of gassing; that is, chemical change is a word with a broader meaning than gassing:

gassing: the process of interacting with gas
chemical change: (chemistry) any process determined by the atomic and molecular composition and structure of the substances involved

Other hypernyms of gassing include chemical action, chemical process.

gassing (noun)	chemical change (noun)
the deliberate act of poisoning some person or animal with gas	(chemistry) any process determined by the atomic and molecular composition and structure of the substances involved
the process of interacting with gas