Final answer:
To find the standard formation enthalpy of N2O(g), we use provided reaction enthalpies and apply Hess's Law. Other known standard enthalpies of formation must be used to calculate the unknown enthalpy for N2O(g), similarly to how the standard molar enthalpy of NO(g) can be determined using given data and reaction enthalpies.
Step-by-step explanation:
To determine the standard formation enthalpy of N2O(g), we need to use Hess's Law to combine chemical reactions to achieve the target reaction, which in this case is the formation of N2O(g) from its elements in their standard states. According to the information provided, the reaction NH4NO3(aq) → N2O(g) + 2H2O(l) has an enthalpy change (ΔH°) of -146.7 kJ/mol. The standard enthalpy changes of formation for the other substances involved in the reaction must be known or provided to determine the formation enthalpy for N2O(g).
To illustrate this process with another example, let's look at NO(g) formation: To calculate the standard molar enthalpy of formation of NO(g), we can use the given reactions and their enthalpy changes. First, we have the formation of nitrogen dioxide (NO2), N2(g) + 2O2(g) → 2NO2 (g) with ΔH° = 66.4 kJ. Next, from the reaction 2NO(g) + O2(g) → 2NO2(g) with ΔH° = -114.1 kJ, we can determine the enthalpy of formation for NO(g) by manipulating these equations.