Question

Consider the following equation that describes the complete combustion of propane, C3H8. The bond energies are: C H 416 kJ/mol; C C 356 kJ/mol; OO 498 kJ/mol; CO 803 kJ/mol; H O 467 kJ/mol. Which is the amount of energy gained on making all the bonds in carbon dioxide and water according to the equation?

Answer 1

8,554 kJ/mol

Step-by-step explanation:

The equation of the complete combustion of propane is:

C₃H₈ + 5O₂ → 3CO₂ + 4H₂O

The molecule of carbon dioxide is OCO, so there are 2 CO bonds, and the molecule of water is HOH, so there are two H O bonds in the molecule.

The total bond energy is the sum of the energy of each bond. Because there are 3 moles of CO₂ and 4 moles of H₂O, the energy gained is:

3*2*803 + 4*2*467 = 8,554 kJ/mol