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The heat of reaction for a chemical reaction can be calculated by finding the sum of the bond energies of the products and subtracting that from the…

The heat of reaction for a chemical reaction can be calculated by finding the sum of the bond energies of the products and subtracting that from the sum of the bond energies of the reactants:
Heat of reaction
=
=
Sum of the energy for the bonds broken − Sum of the energy for the bonds formed
Sum of reactant bond energies − Sum of product bond energies
When calculating the sum of the bond energies, each bond in the reaction must be accounted for. For example, CH
4
 is a reagent with a coefficient of 1 in the reaction. There are four C−H
 bonds in methane and one methane molecule per reaction, for a total of four C−H
bonds on the reactant side. All four bonds must be accounted for when finding the sum of the bond energies for the reactants.
Calculate the heat of reaction using the average bond dissociation energies given in the introduction and your answer to Part B for the reaction
CH
4
 + 2O
2
 → CO
2
 + 2H
2
O