Enthalpy Reaction from Enthalpy Formation

Question

Using standard heats of formation, calculate the standard enthalpy change for the following reaction.

H₂(g) + Cl₂(g)2HCl(g)

Answer 1

∆H_rxn = ∑n∆H_f HCl(g) - [ ∑n∆H_fH₂(g) + n∆H_fCl₂(g) ]

∆Hf HCl(g) = -92.30 kJ/mol

∆Hf H₂(g) = 0

∆Hf Cl₂(g) = 0

∆Hrxn = 2 mol x -92.30 kJ/mol - 0 = - 184.6 kJ