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

Answer 1

To find the total energy change of the reaction, we can subtract the total energy of the products from the total energy of the reactants:

\[ \text{Energy change} = \text{Energy of reactants} - \text{Energy of products} \]

Given:

• Energy of reactants (HBr) = 732 kJ/mol
• Energy of products (H2 + Br2) = 630 kJ/mol

Now, calculate the energy change:

\[ \text{Energy change} = 732 \text{ kJ/mol} - 630 \text{ kJ/mol} = 102 \text{ kJ/mol} \]

Since the energy of the reactants is higher than the energy of the products, this indicates that energy is released in the reaction.

An exothermic reaction releases energy to the surroundings, while an endothermic reaction absorbs energy. Therefore:

• The reaction is exothermic.

The correct response is: 102 kJ/mol, exothermic.