Given the reaction:

2NH3(g) + 3O2(g) → 2NO(g) + 3H2O(g)

The standard enthalpy change of formation (Hf°) for NH3(g), NO(g), and H2O(g) are -46.19 kJ/mol, 90.4 kJ/mol, and -241.82 kJ/mol, respectively. Calculate the standard enthalpy change (H°) for the reaction at 298 K.

Note: This question requires knowledge of Hess's Law and the concept of standard enthalpy change of formation.