Question

Consider the following equation that describes the complete combustion of propane, C₃H₈.

C₃H₈ + 5O₂ -> 3CO₂ + 4H₂O
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 total amount of energy required to break all of the bonds in propane?

a) 1,862 kJ/mol
b) 2,222 kJ/mol
c) 2,588 kJ/mol
d) 4,450 kJ/mol

Answer 1

The total amount of energy required to break all of the bonds in propane is 4,450 kJ/mol.

Step-by-step explanation:

The total amount of energy required to break all of the bonds in propane can be calculated by summing the bond energies on the reactant side of the equation. In this case, there are 8 C-H bonds and 1 C-C bond in propane. The average C-H bond energy is given as 415 kJ/mol, so the total energy required to break all of the C-H bonds in propane is 8 x 415 kJ/mol = 3320 kJ/mol. The C-C bond energy is given as 356 kJ/mol, so the total energy required to break the C-C bond is 356 kJ/mol. Adding these two values together gives a total energy of 3320 kJ/mol + 356 kJ/mol = 3676 kJ/mol. Therefore, the correct answer is (d) 4,450 kJ/mol.