Question

Hydrogen bromide breaks down into diatomic hydrogen and bromine in the reaction shown.

2HBr → H2 + 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)
Responses

−
−
102 kJ/mol, exothermic
negative102 kJ/mol, exothermic

−
−
102 kJ/mol, endothermic
negative102 kJ/mol, endothermic

102 kJ/mol, endothermic
102 kJ/mol, endothermic

102 kJ/mol, exothermic

Answer 1

ΔE = E_products − E_reactants = 630 − 732 = −102 kJ/mol.
Negative → 102 kJ/mol released, so the reaction is exothermic.