Given: $C + O_2 \rightarrow CO_2$ : $\Delta H = -395 \ kJ$,$S + O_2 \rightarrow SO_2$ : $\Delta H = -295 \ kJ$,$CS_2 + 3O_2 \rightarrow CO_2 + 2SO_2$ : $\Delta H = -1110 \ kJ$. Calculate the heat of formation of $CS_2$ in $kJ/mol$.

Which of these species has a standard enthalpy of formation equal to zero?

$18.0 \ g$ of water completely vaporises at $100^{\circ}C$ and $1 \ bar$ pressure and the enthalpy change in the process is $40.79 \ kJ \ mol^{-1}$. What will be the enthalpy change for vaporising two moles of water under the same conditions? What is the standard enthalpy of vaporisation for water?

The standard enthalpy of formation $(\Delta_f H^o_{298})$ for methane,$CH_4$ is $-74.9 \ kJ \ mol^{-1}$. In order to calculate the average energy given out in the formation of a $C-H$ bond from this,it is necessary to know which one of the following?

Which of the following compounds has a standard molar enthalpy of formation equal to zero at $298 \ K$?

Consider the following data:
$\Delta_{f}H^{\Theta}(CH_{4}, g) = -X \ kJ \ mol^{-1}$
Enthalpy of sublimation of graphite = $Y \ kJ \ mol^{-1}$
Dissociation enthalpy of $H_{2} = Z \ kJ \ mol^{-1}$
The bond enthalpy of $C-H$ bond is given by: