A chemist monitors the thermal decomposition of a gaseous oxide of nitrogen, NxOy\text{N}_x\text{O}_yNxOy, at a constant temperature of 400 ∘C400\ ^\circ\text{C}400 ∘C and a constant pressure.
Under these conditions, complete decomposition of 120 cm3 of the gaseous oxide yields 120 cm3 of nitrogen gas (N2\text{N}_2N2) and 240 cm3 of oxygen gas (O2\text{O}_2O2).
What is the empirical formula of this oxide of nitrogen?
NO\text{NO}NO
N2O4\text{N}_2\text{O}_4N2O4
NO2\text{NO}_2NO2
N2O\text{N}_2\text{O}N2O