Energy in Bonds

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Energy in Bonds

Name: Pavel
Status: student
Grade: 9-12
Location: N/A
Country: N/A
Date: 11/29/2005

Question:

Is energy really stored in chemical bonds? It is said almost everywhere that it is, but I found some serious text that it is not true. See

http://science.uniserve.edu.au/disc/phys/aippeg/ozcupe5/sefton.html.

Please, can you make it clear?

Replies:

Energy is a conserved quantity that flows when there is a change.

In a chemical bond, the energy is at a local minimum. For a chemical reaction to occur, an activation energy must be added. In some cases, the electric field of another molecule in close proximity is enough to set the reaction off spontaneously. The daughter products (at a new local minimum of energy) are collectively at a lower energy than the parent materials. This difference in energy between parent bonds and daughter bonds is what is released. In the vernacular, it is referred to as energy stored in the bonds. To be more precise, it is the energy in the electric field between reactants that is released. The common usage of the energy "stored in bonds" leads to many misconceptions, and should probably not be used.

---Nathan A. Unterman

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