Using the average bond energies given below, calculate the approximate enthalpy change, ΔH (in kJ mol⁻¹), for the reaction
H₂(g) + Cl₂(g) → 2 HCl(g) at 298 K.
Bond energy data:
H–H = 436 kJ mol⁻¹
Cl–Cl = 243 kJ mol⁻¹
H–Cl = 431 kJ mol⁻¹
Report ΔH with the correct sign and indicate whether the reaction is endothermic or exothermic.