Answer:
-176.0 kJ/mol
Step-by-step explanation:
Let's consider the following balanced reaction.
NH₃(g) + HCl(g) → NH₄Cl(s)
We can calculate the standard enthalpy change for the reaction (ΔH°rxn) using the following expression.
ΔH°rxn = 1 mol × ΔH°f(NH₄Cl(s)) - 1 mol × ΔH°f(NH₃(g)) - 1 mol × ΔH°f(HCl(g))
ΔH°rxn = 1 mol × (-314.4 kJ/mol) - 1 mol × (-46.1 kJ/mol) - 1 mol × (-92.3 kJ/mol)
ΔH°rxn = -176.0 kJ/mol