Calculate Δ H ∘ in kilojoules for the reaction of ammonia (Δ H ∘ f =−46.1 kJ/mol) with O 2 to yield nitric oxide NO (Δ H ∘ f =91.3 kJ/mol) and H 2 O(g) (Δ H ∘ f =−241.8 kJ/mol) , a step in the Ostwald process for the commercial production of nitric acid.