Use the average bond enthalpies below to calculate the enthalpy change, in kJ, for the following reaction.

$${{\text{H}}_2}{\text{(g)}} + {{\text{I}}_2}{\text{(g)}} \to {\text{2HI(g)}}$$

A.     +290

B.     +10

C.     –10

D.     –290

C

One G2 comment stated that the question should have asked for the enthalpy change in the reaction in units of ${\text{kJ}}\,{\text{mo}}{{\text{l}}^{ - 1}}$ instead of kJ. This aspect of units has been discussed in detail in several previous subject reports and teachers are referred to these reports for further reference.