Chapter 9, Problem 93AE

The standard enthalpy of formation of ${\text{H}}_{\text{2}}\text{O(l)}$ at $\text{298 K}$ is $-\text{285}\text{.8 kJ/mol}$ . Calculate the change in internal energy for the following process at $\text{298 K}$ and $\text{1 atm}$ :

${\text{H}}_{\text{2}}\text{O(l)}\to {\text{H}}_{\text{2}}\left(\text{g}\right)+\frac{1}{2}{\text{O}}_{\text{2}}\text{(g)}\text{ΔE°}\text{=}\text{?}$