Enthalpy of formation of $CO_{(g)}$ and $CO_{2(g)}$ are $-110 \ kJ \ mol^{-1}$ and $-393 \ kJ \ mol^{-1}$ respectively. The enthalpy of combustion of $CO$ (in $kJ \ mol^{-1}$) is:

With the help of the following data,find out the change in heat content for the reaction in $kJ$:
$C_2H_{4(g)} + H_{2(g)} \to C_2H_{6(g)}$

Bond	Bond energy $(kJ \ mol^{-1})$
$C-H$	$413$
$C-C$	$348$
$C=C$	$610$
$H-H$	$436$

If the ratio of the enthalpy of formation of $CO_2$ and $SO_2$ is $4:3$ and the enthalpy of formation of $CS_2$ is $26 \ kcal/mol$,then what will be the enthalpy of formation of $SO_2(g)$ based on the following reaction?
$CS_2(l) + 3O_2(g) \to CO_2(g) + 2SO_2(g)$

The oxidizing power of chlorine in an aqueous solution can be determined by the parameters given below. What is the total energy change in $kJ \ mol^{-1}$ for the conversion of $\frac{1}{2} Cl_{2(g)}$ to $Cl^-_{(aq)}$?
$\frac{1}{2} Cl_{2(g)}$ $\xrightarrow{\frac{1}{2} \Delta_{diss} H^\Theta} Cl_{(g)}$ $\xrightarrow{\Delta_{eg} H^\Theta} Cl^-_{(g)}$ $\xrightarrow{\Delta_{hyd} H^\Theta} Cl^-_{(aq)}$
(Given: $\Delta_{diss} H_{Cl_2}^\Theta = 240 \ kJ \ mol^{-1}$,$\Delta_{eg} H_{Cl}^\Theta = -349 \ kJ \ mol^{-1}$,$\Delta_{hyd} H_{Cl^-}^\Theta = -381 \ kJ \ mol^{-1}$)

Given the thermochemical reactions:
$C(\text{graphite}) + \frac{1}{2} O_{2(g)} \to CO_{(g)}; \Delta H = -110.5 \ kJ$
$CO_{(g)} + \frac{1}{2} O_{2(g)} \to CO_{2(g)}; \Delta H = -283.2 \ kJ$
Calculate the heat of reaction for $C(\text{graphite}) + O_{2(g)} \to CO_{2(g)}$ in $kJ$.

The bond dissociation energies of gaseous $H_2$,$Cl_2$ and $HCl$ are $104$,$58$ and $103 \ kcal$ respectively. The enthalpy of formation of $HCl$ gas would be $... \ kcal$.