Given:
$\Delta\text{H}^\ominus_{\text{sub}[\text{C(graphite)}]} = 710\text{ kJ mol}^{-1}$
$\Delta_{\text{C}-\text{H}}\text{H}^\ominus = 414\text{ kJ mol}^{-1}$
$\Delta_{\text{H}-\text{H}}\text{H}^\ominus = 436\text{ kJ mol}^{-1}$
$\Delta_{\text{C}=\text{C}}\text{H}^\ominus = 611\text{ kJ mol}^{-1}$The$\Delta\text{H}_{\text{f}}^\ominus$ for $\text{CH}_2 = \text{CH}_2$ is ________ $\text{kJ mol}^{-1}$. (Nearest integer value)
