In the industrial production of nitric acid via the Ostwald process, ammonia (NH3\text{NH}_3NH3) is oxidised over a platinum-rhodium catalyst according to the equation:
4NH3+5O2→4NO+6H2O4\text{NH}_3 + 5\text{O}_2 \rightarrow 4\text{NO} + 6\text{H}_2\text{O}4NH3+5O2→4NO+6H2O
Calculate the volume of oxygen gas (O2\text{O}_2O2) needed to react completely with 6.8 kg6.8\text{ kg}6.8 kg of ammonia.
(Relative atomic masses (ArA_rAr): H=1\text{H} = 1H=1, N=14\text{N} = 14N=14; the volume of one mole of gas is 24 dm324\text{ dm}^324 dm3.)