Multiple choice Which chemical element or compound is commonly present in propellants and explosives? CO2 O2 H2 N2 H2O Reveal answer Fill a bubble to check yourself D Correct answer Explanation Nitrogen is a chemical element with symbol N and atomic number 7. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.09% by volume of Earth's atmosphere.