Use the reaction equation and bond energies to answer the question.

Question

Use the reaction equation and bond energies to answer the question.

2H2O → 2H2 + O2

H-O: 467 kJ/mol

H-H: 432 kJ/mol

O=O: 498 kJ/mol

What is the total energy of the reaction? Is this an endothermic or exothermic reaction?

(1 point)
Responses

506 kJ/mol, exothermic
506 kJ/mol, exothermic

–506 kJ/mol, exothermic
–506 kJ/mol, exothermic

–506 kJ/mol, endothermic
–506 kJ/mol, endothermic

506 kJ/mol, endothermic

Answer 1

–506 kJ/mol, exothermic (Note: The bond energies of the reactants are greater than the bond energies of the products, indicating that energy is released during the reaction, making it exothermic. The total energy can be calculated as follows: 2(4 H-H bonds x -432 kJ/mol) + 2(2 O-H bonds x -467 kJ/mol) - 1 O=O bond x -498 kJ/mol = -506 kJ/mol.)