[单选题]
Liquid dinitrogen te
r) -c w30p5drs1ujkgltr
0m 9mfcuc j385dz3g 8-amqwagoxide ($N_2O_4$) is converted to gaseous nitrogen dioxide when heated, as shown in the diagram. No other molecules react or form during this reaction.
The standard enthalpy change of the reaction,ΔH$_r^θ$, is +85.8kJmol$^{-1}$.The standard enthalpy of formation of gaseous $NO_2$ , ΔH$_r^θ$($NO_2$), is +33.1kJmol$^{-1}$.
What is the standard enthalpy of formation of liquid $N_2O_4$,ΔH$_r^θ$($N_2O_4$)?