$\Delta H_f^{\circ }(298\text{K})$ of methanol is given by the chemical equation:

The standard enthalpy of formation ($\Delta H_f^{\circ }$) is the enthalpy change for the formation of one mole of a substance from its constituent elements in their standard states.For methanol (${\text{CH}}_3\text{OH}$):Carbon's standard state is C (graphite).Hydrogen's standard state is ${\text{H}}_{2(g)}$.Oxygen's standard state is ${\text{O}}_{2(g)}$.The equation is: $\text{C(graphite)}+\frac{1}{2}{\text{O}}_{2(g)}+2{\text{H}}_{2(g)}\to {\text{CH}}_3{\text{OH}}_{(l)}$.