## Bond Enthalpies

$\Delta U=q+w$

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Victoria Luu - 1C
Posts: 60
Joined: Fri Sep 28, 2018 12:15 am

### Bond Enthalpies

Why is it that the bonds formed will always have a negative sign? Is it because they are releasing heat after the bond is formed?

Danielle_Gallandt3I
Posts: 70
Joined: Fri Sep 28, 2018 12:24 am

### Re: Bond Enthalpies

Yes, that is correct. The bonds that form spontaneously release energy because the molecule formed is more stable (and therefore at a lower energy) than each of the elements separately. The molecule therefore releases energy by forming a bond, so q (or delta H) is negative

beckyolmedo1G
Posts: 34
Joined: Fri Sep 28, 2018 12:21 am

### Re: Bond Enthalpies

yes, I believe so. When bonds break, energy is required to break the bond so it is positive. However, when bonds are formed, energy is released that is why it is negative. So breaking a bond is endothermic while forming a bond is exothermic.

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