These compounds are not equal in terms of chemical composition. Each compound has a different chemical formula and properties:

Na2O is sodium oxide, composed of sodium and oxygen ions.Na2SO4 is sodium sulfate, composed of sodium, sulfur, and oxygen ions.NaOH is sodium hydroxide, composed of sodium, hydrogen, and oxygen ions.NaNO3 is sodium nitrate, composed of sodium, nitrogen, and oxygen ions.

Therefore, these compounds are not equal to each other and have different compositions.