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

Question

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)

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

–102 kJ/mol, exothermic
–102 kJ/mol, exothermic

102 kJ/mol, exothermic
102 kJ/mol, exothermic

–102 kJ/mol, endothermic

Answer 1

To find the total energy of the reaction, we need to subtract the energy of the products from the energy of the reactant.

Total energy of the reaction = Energy of the reactant - Energy of the products
= 732 kJ/mol - 630 kJ/mol
= 102 kJ/mol

The total energy of the reaction is 102 kJ/mol.

Since the reaction releases energy (energy of the reactant is higher than the energy of the products), the reaction is exothermic. Therefore, the correct answer is:

-102 kJ/mol, exothermic.