bond enthalpies

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haleyf 2I
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Joined: Fri Sep 25, 2015 3:00 am

bond enthalpies

Postby haleyf 2I » Wed Feb 17, 2016 3:52 pm

If during a reaction a carbon-carbon single bond turns into a carbon-carbon double bond, do you need to break the single bond and then form the double bond in order to calculate the change in enthalpy using bond enthalpies? Or just use the enthalpy of forming a double bond and ignore that there was originally a single bond?

Matthew Oh 3I
Posts: 20
Joined: Fri Sep 25, 2015 3:00 am

Re: bond enthalpies

Postby Matthew Oh 3I » Wed Feb 17, 2016 4:10 pm

I believe that you must break the bond first, then a double bond forms.

vanessachin2h
Posts: 10
Joined: Fri Sep 25, 2015 3:00 am

Re: bond enthalpies

Postby vanessachin2h » Wed Feb 17, 2016 5:02 pm

Another way to think about it is that the average bond enthalpy for breaking a single c-c bond is 348 kj/mol, whereas the average bond enthalpy for breaking a double c=c bond is 614 kj/mol. The c-c bond enthalpy is not exactly half of the c=c bon enthalpy.


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