Science behind bond breaking at a molecular level

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Offline bassplayer

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I'm doing an independent research project for my AP Chem class on endothermic reactions for the purpose of making a coldpack.  It is apparent from everything that is written about endothermic reactions that the reason they "go cold" is that when the bonds are broken (ie ionic bonds in the zinc nitrate im using for my coldpack when it is desolved in water)energy is absorbed from the environment.  Try as i might i havent been able to figure out exactly where that energy is going nor what its is doing when it is absorbed.  So far all of the sources ive found simply say that energy is absorbed.

Any Ideas?



Offline daveshorts

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Re: Science behind bond breaking at a molecular level
« Reply #1 on: 20/02/2006 20:37:06 »
Basically into electrostatic potential energy - as an analogy imagine taking two magnets and pulling them apart, you have to put energy in to break the bond, we say this has converted into potential energy, as if you let them come together again this energy will be released.  

With the dissolving zinc chloride heat is converted into this electrostatic potential energy so it gets colder.