If $C + O_2 \to CO_2 + 94.2 \ kcal$,$H_2 + \frac{1}{2} O_2 \to H_2O + 68.3 \ kcal$,and $CH_4 + 2O_2 \to CO_2 + 2H_2O + 210.8 \ kcal$,then the possible heat of formation of methane will be $...... \ kcal$.

The enthalpy change for a reaction does not depend on:

The enthalpy of formation of ethane $(C_2H_6)$ from ethylene $(C_2H_4)$ by the addition of hydrogen,where the bond energies of $C-H$,$C-C$,$C=C$,and $H-H$ are $414 \ kJ/mol$,$347 \ kJ/mol$,$615 \ kJ/mol$,and $435 \ kJ/mol$ respectively,is $........$ $kJ/mol$.

Given $\Delta H_f^{\circ}$ for $CO_{2(g)}$, $CO_{(g)}$ and $H_2 O_{(g)}$ are $-393.5$, $-110.5$ and $-241.8 \ kJ \ mol^{-1}$, respectively. The $\Delta H_r^{\circ}$ [in $kJ \ mol^{-1}$] for the reaction $CO_{2(g)} + H_{2(g)} \longrightarrow CO_{(g)} + H_2 O_{(g)}$ is

What is the heat of formation of $HCl_{(g)}$ from the following equation (in $kJ$)?
$H_{2(g)} + Cl_{2(g)} \rightarrow 2HCl_{(g)} \quad \Delta_{r}H = -194 \ kJ$

Given that,$C_{(s)} + O_{2(g)} \longrightarrow CO_{2(g)} ; \Delta H^{\circ} = -x \ kJ \ mol^{-1}$ and $2CO_{(g)} + O_{2(g)} \longrightarrow 2CO_{2(g)} ; \Delta H^{\circ} = -y \ kJ \ mol^{-1}$. The enthalpy of formation of $CO$ will be: