Question

The bond energies are: C-H 416 kJ/mol; C-C 356 kJ/mol; O=O 498 kJ/mol; C=O 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

The total amount of energy gained from the bond formation in the products of a reaction that forms carbon dioxide and water is 2540 kJ/mol, which includes the energy from two C=O double bonds and two H-O single bonds.

Step-by-step explanation:

The question concerns the bonding energies involved in the formation of carbon dioxide (CO₂) and water (H₂O) from the combustion of hydrocarbons or similar chemical reactions. The bonds in CO₂ and H₂O have different bond energies, and we can calculate the total amount of energy released when these bonds are formed by adding up the respective bond energies.

For CO₂, there are two double bonds between carbon and oxygen, each with a bond energy of 803 kJ/mol. Therefore, the energy released from forming CO₂ is 2 × 803 kJ/mol = 1606 kJ/mol. For water, there are two single bonds between hydrogen and oxygen with a bond energy of 467 kJ/mol each, amounting to 2 × 467 kJ/mol = 934 kJ/mol for H₂O.

By adding the energies for CO₂ and H₂O, we get the total energy gained from bond formation in the products side of the reaction, which is 1606 kJ/mol + 934 kJ/mol = 2540 kJ/mol.