Question

total bond energy quick check
hydrogen bromide breaks down into diatomic hydrogen and bromine in the reaction shown.
$2\ce{hbr} \
ightarrow \ce{h2} + \ce{br2}$
the energy of the reactant is 732 kj/mol, and the energy of the products is 630 kj/mol.
what is the total energy of the reaction? is this reaction endothermic or exothermic?
(1 point)
\\(\circ\\) 102 kj/mol, endothermic
\\(\circ\\) $-102$ kj/mol, exothermic
\\(\circ\\) 102 kj/mol, exothermic
\\(\circ\\) $-102$ kj/mol, endothermic

Explanation:

Step1: Calculate reaction energy

Reaction energy = Energy of products - Energy of reactants.
Given reactant energy = 732 kJ/mol, product energy = 630 kJ/mol.
So, reaction energy = \( 630 - 732 = -102 \) kJ/mol.

Step2: Determine reaction type

If reaction energy (ΔH) is negative, energy is released (exothermic); if positive, energy is absorbed (endothermic).
Here, ΔH = -102 kJ/mol (negative), so it’s exothermic.

Answer:

-102 kJ/mol, exothermic (the option with this text, e.g., the second option: \(-102\) kJ/mol, exothermic)