Example 5.11b: Evaluating an Enthalpy of Formation

Hydrogen gas, \(\ce{H2}\), reacts explosively with gaseous chlorine, \(\ce{Cl2}\), to form hydrogen chloride, \(\ce{HCl(g)}\). What is the enthalpy change for the reaction of 1 mole of \(\ce{H2(g)}\) with 1 mole of \(\ce{Cl2(g)}\) if both the reactants and products are at standard state conditions? The standard enthalpy of formation of \(\ce{HCl(g)}\) is -92.3 kJ/mol.