Explanation:
Enthalpy change is defined as in a chemical reaction the amount of energy absorbed or evolved in the form of heat at constant pressure.
For the given reaction, [tex]N_{2} + 3H_{2} \rightarrow 2NH_{3}[/tex] calculate the enthalpy change as follows.
[tex]\Delta H[/tex] = Bond energy of reactants - Bond energy of products
= {[(2 × 942) + (3 × 432)] - [6 × 386]} KJ/mol
= {[1884 + 1296] - 2316} KJ/mol
= {3180 -2316} KJ/mol
= 864 KJ/mol
Thus, we can conclude that the enthalpy change for the given reaction is 864 KJ/mol.
