Enthalpy of Formation Practice Test

Given the following $\Delta H_f^\circ$ values at 298 K: $\Delta H_f^\circ\mathrm{H_2O(l)}=-286\ \mathrm{kJ,mol^{-1}}$, $\Delta H_f^\circ\mathrm{H_2O(g)}=-242\ \mathrm{kJ,mol^{-1}}$. What is $\Delta H_{\mathrm{rxn}}^\circ$ for $\mathrm{H_2O(l)\rightarrow H_2O(g)}$?

Use the standard enthalpies of formation, $\Delta H_f^\circ$, to calculate $\Delta H_{\text{rxn}}^\circ$ for the reaction at 298 K:

$2\text{NO}(g) + \text{O}_2(g) \rightarrow 2\text{NO}_2(g)$

Formation data (kJ/mol): $\Delta H_f^\circ\text{NO}(g) = +90$, $\Delta H_f^\circ\text{NO}_2(g) = +33$, $\Delta H_f^\circ\text{O}_2(g) = 0$.