The heat of combustion of $CH_{4(g)}$,$C_{(graphite)}$ and $H_{2(g)}$ are $-20 \ kcal$,$-40 \ kcal$ and $-10 \ kcal$ respectively. The heat of formation of methane is.......$kcal$.

Calculate the enthalpy change when $12 \ g$ of carbon reacts with sufficient hydrogen to form methane. If the enthalpy of formation of methane is $-75 \ kJ \ mol^{-1}$. (in $kJ$)

Given the following thermochemical equations:
$C_{(s)} + O_{2_{(g)}} \to CO_{2_{(g)}} + 94.2 \, kcal$
$H_{2_{(g)}} + \frac{1}{2} O_{2_{(g)}} \to H_2O_{(l)} + 68.3 \, kcal$
$CH_{4_{(g)}} + 2O_{2_{(g)}} \to CO_{2_{(g)}} + 2H_2O_{(l)} + 210.8 \, kcal$
Calculate the heat of formation of methane in $kcal$.

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.....$kcal$.

On the basis of the following reactions,which one is correct?
$C_{(gr)} + O_{2_{(g)}} \to CO_{2_{(g)}}, \Delta H = x \ kJ/mol$
$C_{(gr)} + \frac{1}{2} O_{2_{(g)}} \to CO_{(g)}, \Delta H = y \ kJ/mol$
$CO_{(g)} + \frac{1}{2} O_{2_{(g)}} \to CO_{2_{(g)}}, \Delta H = z \ kJ/mol$

The enthalpy of formation $(\Delta H_f)$ of methanol,formaldehyde and water are $-239, -116$ and $-286 \ kJ \ mol^{-1}$ respectively. The enthalpy change for the oxidation of methanol to formaldehyde and water in $kJ$ is