Which of the following fuels will have the highest calorific value $(kJ/kg)$?

Calculate the standard enthalpy of combustion of carbon monoxide $(CO)$ given that $\Delta_f H^{\circ}(CO) = -110 \text{ kJ mol}^{-1}$ and $\Delta_f H^{\circ}(CO_2) = -393 \text{ kJ mol}^{-1}$.

One mole of acetone requires less heat to vaporise than $1$ mol of water. Which of the two liquids has higher enthalpy of vaporisation?

Consider the following data:
$\Delta_{f}H^{\Theta}(CH_{4}, g) = -X \ kJ \ mol^{-1}$
Enthalpy of sublimation of graphite = $Y \ kJ \ mol^{-1}$
Dissociation enthalpy of $H_{2} = Z \ kJ \ mol^{-1}$
The bond enthalpy of $C-H$ bond is given by:

Calculate the enthalpy change of vaporisation of benzene if $13 \ g$ of benzene vaporised by supplying $5.1 \ kJ$ of heat.

The bond dissociation energies of $XY$,$X_2$,and $Y_2$ (all diatomic molecules) are in the ratio $1 : 1 : 0.5$. If the enthalpy of formation of $XY$ is $\Delta_fH = -200 \ kJ \ mol^{-1}$,find the bond dissociation energy of $X_2$ in $kJ \ mol^{-1}$.