Concerning the breaking of chemical bonds releasing energy, the following site may provide interesting information. I seem to remember some of this from O Level Chemistry, but to be honest, that was a while ago...
<A HREF="http://www.ultranet.com/~jkimball/BiologyPages/B/BondEnergy.html" TARGET="_blank">http://www.ultranet.com/~jkimball/BiologyPages/B/BondEnergy.html</A>