Chemistry - Thermochemistry Question with Solution | TestHub

$$\begin{array}{rl}& {\mathrm{N}}_2{\mathrm{O}}_{4(g)}+3{\mathrm{CO}}_{(g)}⟶{\mathrm{N}}_2{\mathrm{O}}_{(g)}+3{\mathrm{CO}}_{2(\mathrm{g})}\\ & \Delta H_{\text{reaction }}={\Sigma }_{\text{Heat of formation of products }}\\ & -{\Sigma }_{\text{Heat of formation of reactants }}\end{array}$$ $$\begin{array}{rl}& \Delta H_{\text{reaction }}=\left[\Delta H_f{\mathrm{N}}_2\mathrm{O}+3\times \Delta H_f{\mathrm{CO}}_2\right]-\\ & \left[\Delta H_f{\mathrm{N}}_2{\mathrm{O}}_4+3\times \Delta H_f\mathrm{CO}\right]\\ & \begin{array}{rl}\Delta H_r& =[+811+3(-393)]-[10+3(-110)]\\ & =[811-1179]-[-320]=-368+320\\ & =-48\mathrm{kJ}/\mathrm{mol}\end{array}\end{array}$$