To calculate ΔHrxn using bond energies, we will use the following equation:
Write the combustion reaction of octane:
• Hexane is a a hydrocarbon composed only of carbon and hydrogen.
• The prefix oct- means 8 carbons.
• General Formula: CnH2n+2 where n = number of carbons
• Hexane: C8H18
Balanced Combustion reaction:
The table below shows the average bond energies for some common bonds among carbon, hydrogen, and oxygen.
|C - C||347|
|C - H||414|
|C - O||360|
|C = O||799|
|H - H||436|
|H - O||464|
|O - O||142|
|O = O||498|
Calculate ΔHrxn for the combustion of octane by using enthalpies of formation from the transition above.
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