Nitrogen trichloride can be prepared directly from its elements according to the following gas-phase reaction at 298 K:
N₂(g) + 3 Cl₂(g) → 2 NCl₃(g)
In a laboratory experiment, 0.0250 mol of N₂ reacted completely with excess Cl₂, absorbing 5.80 kJ of heat from the surroundings.
Average bond energies (kJ mol⁻¹):
N≡N 941
Cl—Cl 243
N—Cl ?
(a) Using the experimental data, determine ΔH°rxn (in kJ mol⁻¹ of reaction as written) for the synthesis of NCl₃.
(b) Identify the total number of each bond type broken and formed per mole of reaction.
(c) Using results from parts (a) and (b), calculate the average bond energy of the N—Cl bond, B(N—Cl), in kJ mol⁻¹.
(d) Compare your calculated B(N—Cl) to the average Cl—Cl bond energy provided. Using bonding concepts, explain why the two values are similar or different.