At $298 \ K$,the enthalpy of fusion of a solid $(X)$ is $2.8 \ kJ \ mol^{-1}$ and the enthalpy of vaporisation of the liquid $(X)$ is $98.2 \ kJ \ mol^{-1}$. The enthalpy of sublimation of the substance $(X)$ in $kJ \ mol^{-1}$ is $.....$ (in nearest integer).

The heat of formation of $H_2O_{(l)}$ is $-68.0 \ kcal$. The heat of formation of $H_2O_{(g)}$ is likely to be........$kcal$.

What is enthalpy of reaction?

Calculate the enthalpy of solution of potassium chloride $(KCl)$ if its lattice enthalpy $\Delta_{L} H = 700 \ kJ \ mol^{-1}$ and hydration enthalpy $\Delta_{hyd} H = -680 \ kJ \ mol^{-1}$.

Given $:$
$\Delta H^{\ominus}_{sub}[C(graphite)] = 710 \ kJ \ mol^{-1}$
$\Delta H^{\ominus}_{C-H} = 414 \ kJ \ mol^{-1}$
$\Delta H^{\ominus}_{H-H} = 436 \ kJ \ mol^{-1}$
$\Delta H^{\ominus}_{C=C} = 611 \ kJ \ mol^{-1}$
The $\Delta H^{\ominus}_{f}$ for $CH_2=CH_2$ is $............ \ kJ \ mol^{-1}$ $(nearest \ integer \ value)$

The enthalpies of combustion of cyclohexane $(C_6H_{12})$,cyclohexene $(C_6H_{10})$,and $H_2$ are $-3920, -3800$,and $-241 \, kJ \, mol^{-1}$ respectively. The heat of hydrogenation of cyclohexene is ...... $kJ \, mol^{-1}$.