Answer:
3153 KJ/mol.
Step-by-step explanation:
To calculate the total energy needed to break the bonds in the reactants, we need to determine the number of moles of each reactant, then multiply that number by the bond energy for the type of bond being broken.
In the reactant methane (CH4), there is 1 mole of C-H bonds and 4 moles of H-H bonds. The bond energy for a C-H bond is 413 KJ/mol, and the bond energy for an H-H bond is 436 KJ/mol. Therefore, the total energy needed to break the bonds in 1 mole of methane is:
(1 mole C-H bonds * 413 KJ/mol C-H) + (4 moles H-H bonds * 436 KJ/mol H-H) = 413 KJ/mol + 1744 KJ/mol = 2157 KJ/mol
In the reactant oxygen (O2), there are 2 moles of O=O bonds. The bond energy for an O=O bond is 498 KJ/mol. Therefore, the total energy needed to break the bonds in 1 mole of oxygen is:
2 moles O=O bonds * 498 KJ/mol O=O = 996 KJ/mol
To find the total energy needed to break the bonds in both reactants, we can add the energy needed to break the bonds in methane and oxygen:
2157 KJ/mol + 996 KJ/mol = 3153 KJ/mol
Therefore, the total energy needed to break the bonds in the reactants (methane and oxygen) is 3153 KJ/mol.