a $.1/2*$ N$\_\{2\}($g$)+$ O$\_\{2\}($g$)->$ N$*$O$\_\{2\}($g$)$ b$.1/2*$ N $*2($g$)+1/2*$ O$\_\{2\}($g$)->$ NO$($g$)$; triangle Ho$=+35$ kj; triangle Ho$=+90\mathrm{.}4$ kj to calculate the AHo of NO$($g$)+1/2*$ O$\_\{2\}($g$)->$ N$*$O$\_\{2\}($g$)$; Ho$=$