Given two processes:
$\frac{1}{2} P_{4(s)} + 3 Cl_{2(g)} \to 2 PCl_{3(l)} \;; \Delta H = -635 \ kJ$
$PCl_{3(l)} + Cl_{2(g)} \to PCl_{5(s)} \;; \Delta H = -137 \ kJ$
The value of the heat of formation of $PCl_{5(s)}$ is ...... $kJ \ mol^{-1}$.

The heat of neutralisation of $NaOH$ and $HCl$ is $-57.46 \, kJ/eq$. What is the heat of ionisation of water in $kJ/mol$?

$AB$,$A_2$,and $B_2$ are diatomic molecules. Enthalpies of dissociation of $AB$,$A_2$,and $B_2$ are in the ratio of $1:1:0.5$. Enthalpy of formation of $AB$,$\Delta_f H = -100 \ kJ \ mol^{-1}$. Find the dissociation enthalpy of $A_2$?
Reaction : $\frac{1}{2} A_2 + \frac{1}{2} B_2 \to AB$

Which of the following values of heat of formation (in $kcal$) indicates that the product is less stable?

The heats of formation of $CO_{2(g)}$,$H_2O_{(l)}$,and $CH_{4(g)}$ are $-94.0$,$-68.4$,and $-17.9 \ kcal$ respectively. The heat of combustion of methane is.....$kcal$.

If the heats of combustion of $C$,$S$,and $CS_2$ are $x$,$y$,and $z \, kJ \, mol^{-1}$ respectively,what will be the heat of formation of $CS_2$?