Given, N 2 ( g ) + 3 H 2 ( g ) → 2 NH 3 ( g ) ; Δ r H ∘ = - 9 2 · 4 kJ mol - 1 What is the magnitude of standard enthalpy of formation of NH 3 gas?

Step-by-step solution

Given, N 2 g + 3 H 2 g → 2 NH 3 g ; Δ r H ∘ = - 9 2 · 4 kJ mol - 1 Chemical reaction for the enthalpy of formation of NH 3 (g) is as follows: 1 2 N 2 g + 3 2 H 2 g → NH 3 g Therefore, Δ f H ∘ = - 9 2 · 4 2 = + 4 6 · 2 kJ mol - 1