Use standard enthalpies of formation to calculate ΔH°rxn for the following reaction: N2O4(g) + 4H2(g) → N2(g) + 4H2O(g). Which of the following is the correct ΔH°rxn value?

Identify the standard enthalpies of formation (ΔH°f) for each compound involved in the reaction. These values are typically found in tables in chemistry textbooks or reliable online resources. For this reaction, you need the ΔH°f for N2O4(g), H2(g), N2(g), and H2O(g). Note that the ΔH°f for elements in their standard state, such as N2(g) and H2(g), is zero.