The answer :ΔH = -67 kJ
Let us consider the following reaction,
[tex] N_{2} + O_{2} --\ \textgreater \ 2NO [/tex] ΔH1 = +180 kJ
[tex]2NO + O_{2} ---\ \textgreater \ 2NO_{2} [/tex] ΔH2 = -113 kJ
Thus, for this decomposition reaction, The enthalpy of reaction is given as
ΔH net = -( - 113) - (+180)
= -67 kJ
