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### Double bonds

Posted: Mon Feb 03, 2020 12:00 am
I am a little bit confused about what to do when only one bond within a double bond is broken. I'm using the value listed in the table, but I am not getting the right answer. I am using the same method as with the other problems, and the only difference I can tell is that there is a double bond involved. How do I do this sort of problem correctly?

### Re: Double bonds

Posted: Mon Feb 03, 2020 12:53 am
I'm not sure if this is the answer you're looking for, but you can't break one bond of a double bond. You have to break the whole thing and reform it as a single bond. You'll have different bond enthalpies for the same atoms bonded with a single bond versus a double bond.

### Re: Double bonds

Posted: Mon Feb 03, 2020 12:59 am
The conversion from a double bond to a single bond is a new bond being formed. for organic compounds for example it could be a C-H bond forming. the bond enthalpies of C=O and C-O + C-H are different.

### Re: Double bonds

Posted: Mon Feb 03, 2020 12:55 pm
(at least in this class, as far as I know) A double bond isn't 2 separate bonds but rather 1 stronger bond. So when you break a single double bond, you're breaking that entire bond. There aren't 2 bonds within a double bond.

### Re: Double bonds

Posted: Mon Feb 03, 2020 1:05 pm
Meredithe DeGuzman4G wrote:I'm not sure if this is the answer you're looking for, but you can't break one bond of a double bond. You have to break the whole thing and reform it as a single bond. You'll have different bond enthalpies for the same atoms bonded with a single bond versus a double bond.

^^ This is true, so you have to break the whole double bond, so you need to use that bond enthalpy in the bonds broken value and then for bond formed you need to include the new formation of that single bond. You can not just break a half of a double bond. You have to treat the bonds of the reactants and products separately.