Approach to Bond Enthalpies

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Rachel Lipman
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Joined: Fri Sep 25, 2015 3:00 am

Approach to Bond Enthalpies

Postby Rachel Lipman » Sun Jan 24, 2016 6:29 pm

Is the only way to approach a question asking one to solve for the bond enthalpies by first drawing out the lewis structures and determining where bonds are broken and formed? Is there a simpler way to go about solving these problems? What is the best method overall?

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Re: Approach to Bond Enthalpies

Postby Chem_Mod » Sun Jan 24, 2016 6:41 pm

The way you have mentioned is the best/safest way to go about solving for the heat of formation from bonds. Another way is to only determine which bonds are broken and which bonds remain the same (such as the enthalpy of formation from bromine being added to an alkene). Thus the only change in enthalpy will result in the difference between product and reactant bonds formed and broken, and you won't need to sum every bond in the products/reactant.

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