Calculate $\Delta$G$\degree$for the reaction of ammonia with fluorine.

Question

Quizplus · Accepted Answer

We can use Hess's law to calculate the enthalpy change for the reaction. First, we need to break down the reaction into steps for which we have known enthalpies:
Step 1: F2(g) → 2F(g)     ∆H = +158 kJ/mol
Step 2: NH3(g) + F(g) → NF3(g) + H(g)     ∆H = −990.4 kJ/mol
Step 3: NF3(g) + H2(g) → 3HF(g) + N(g)    ∆H = −271 kJ/mol
Now we can add up the enthalpies for these steps to get the overall enthalpy change:
∆H = ∆H1 + ∆H2 + ∆H3 = (+158 kJ/mol) + (−990.4 kJ/mol) + (−271 kJ/mol)
∆H = −1103.4 kJ/mol
Finally, we need to account for the fact that there are 10 moles of F2 needed in the first step:
∆H = −1103.4 kJ/mol ÷ 10 mol = −110.34 kJ/mol
Therefore, the answer is D.

Calculate Δ\DeltaΔ G °\degree° For the Reaction of Ammonia with Fluorine

Calculate $\Delta$ G $\degree$ For the Reaction of Ammonia with Fluorine