To calculate enthalpy change, what we do is to use the following formula:
[tex]\Delta H^o_{Rxn}=\sum ^{}_{}(B.E,Reactants)-\sum ^{}_{}(B.E,Products)[/tex]Where B.E represents the bonds energy.
Replacing, we got:
[tex]\begin{gathered} \Delta H^o_{Rxn}=\sum ^{}_{}(B.E,Reactants)-\sum ^{}_{}(B.E,Products) \\ \Delta H^o_{Rxn}=(H-H)+(I-I)-2(H-I) \\ \Delta H^o_{Rxn}=436+151-2(297) \\ \Delta H^o_{Rxn}=-\frac{7KJ}{mol} \end{gathered}[/tex]So that's the enthalpy change.
