The conversion of oxygen to ozone represented by the equation $3O_2 \to 2O_3$ is an endothermic reaction. The enthalpy change $\Delta H$ accompanying the reaction:

If the standard molar enthalpy change for combustion of graphite powder is $-2.48 \times 10^{2} \ kJ \ mol^{-1}$,the amount of heat generated on combustion of $1 \ g$ of graphite powder is $..... \ kJ$.
(Nearest integer)

The enthalpy change for the conversion of $\frac{1}{2} Cl_{2(g)}$ to $Cl^{-}_{(aq)}$ is $......$ $kJ \, mol^{-1}$ (Nearest integer).
Given:
$\Delta_{dis}H^{\circ}_{Cl_{2(g)}} = 240 \, kJ \, mol^{-1}$
$\Delta_{eg}H^{\circ}_{Cl_{(g)}} = -350 \, kJ \, mol^{-1}$
$\Delta_{hyd}H^{\circ}_{Cl^{-(g)}} = -380 \, kJ \, mol^{-1}$

When $1 \, \text{mol}$ of anhydrous salt $AB$ is dissolved in water,$21.0 \, J \, \text{mol}^{-1}$ of heat is released. The enthalpy of hydration of $AB$ is $-29.4 \, J \, \text{mol}^{-1}$. What is the enthalpy of solution of the hydrated salt $AB \cdot 2H_2O_{(s)}$ in $J \, \text{mol}^{-1}$ (in $.4$)?

Hess's law is based on

The $\Delta H_f^o$ for $CO_{2(g)}$,$CO_{(g)}$ and $H_2O_{(g)}$ are $-393.5$,$-110.5$ and $-241.8 \ kJ \ mol^{-1}$ respectively. The standard enthalpy change (in $kJ$) for the reaction $CO_{2(g)} + H_{2(g)} \to CO_{(g)} + H_2O_{(g)}$ is