Given the following reaction:

Question

2NH₃ → N₂ + 3 H₂
If the total bond energy absorbed by the reactant , NH₃, is 2316 KJ/mol and the total bond energy
released when the products are formed is 1967 KJ/mol, is the reaction endothermic or exothermic?
(1 point)
Exothermic because the result is negative
Endothermic because the result is negative.
Endothermic because the result is positive.
Exothermic because the result is positive.

Answer 1

To determine whether the reaction is endothermic or exothermic, we need to compare the total bond energy absorbed by the reactants to the total bond energy released by the products.

1. Bond energy absorbed by the reactants (NH₃): 2316 kJ/mol
2. Bond energy released by the products (N₂ + 3 H₂): 1967 kJ/mol

Next, we can find the net energy change for the reaction by calculating the difference:

\[ \text{Net energy change} = \text{Energy absorbed by reactants} - \text{Energy released by products} \] \[ \text{Net energy change} = 2316 , \text{kJ/mol} - 1967 , \text{kJ/mol} = 349 , \text{kJ/mol} \]

Since the net energy change is positive (349 kJ/mol), this indicates that more energy is absorbed than is released, meaning the reaction requires energy from the surroundings.

Therefore, the reaction is endothermic.

The correct answer is: Endothermic because the result is positive.