Final answer:
To calculate the ∆H°rxn, use the provided tables to determine bond energies for reactants and products, perform the calculation (Σ∆H° products - Σ∆H° reactants), and consider unit conversion if necessary.
Step-by-step explanation:
To calculate the ∆H°rxn (standard enthalpy change of the reaction), you'll typically need to piece together enthalpy changes from given reactions or data points through Hess's law or by using bond dissociation energy values provided in tables. The example given suggests a reaction for which you need to determine the enthalpy change by considering both the bonds broken in the reactants and those formed in the products.
Oftentimes, the ∆H°rxn is given by ∆H°rxn = Σ∆H° products - Σ∆H° reactants, where you must consider the bond energies or formation energies from the provided tables. Without specific values and tables, it's not possible to perform the actual calculation, but this is the general approach used for such problems in chemistry.
Always remember to convert units appropriately, as demonstrated in the second example where J are converted to kJ using (1 kJ/1000 J). This careful attention to units ensures that the final calculated enthalpy change is correct.