Subject: Does energy from burning fuel arise due to mass/energy conversion?

Nuclear energy arises from the rearrangement of nucleons. This 
rearrangement brings about a 'decrease in mass'and according to E=mc2 the 
loss in mass results in the formation/release of energy.  Burning is a 
rearrangement of electrons and should bring about a 'decrease in mass' just 
like the nuclear reaction.  I know that the normal explanation is that the 
rearrangement of electrons lowers the potential energy of the electrons/
atoms and this lowering results in the release of this energy in a new form 
such as heat.  Can the explanation be taken to a deeper level as I am 
proposing or am I way off base?  Is the change in potential energy really a 
change in mass?

Re: Does energy from burning fuel arise due to mass/energy conversion?