[Cat(ionic)woman]

Hi there, I was wondering if there is any unambiguous definition of what constitutes a combustion reaction? Any reaction where one of the reactants is molecular oxygen? Any reaction where one of the reactants is molecular oxygen and the enthalpy change is negative ...has a negative Gibbs energy at room temperature?

Consider the following reaction: 4 Na(s) + 2 O2(g) -> 2 Na2O(s)    , T=298 K

If you disregard the fact that it involves metallic sodium, would you spontaneously say that this is clearly a combustion reaction? Why? (other than, you know... it's sodium)

[Arkcon]

From an earlier thread, the definition of combustion reaction is hard to come by.  Briefly, combustion is meant when a complex molecule reacts with oxygen into smaller molecules.  As such, it doesn't apply to active metals reacting with oxygen.  I can't even find the definition in Wikipedia, I think its just not used anymore: http://www.chemicalforums.com/index.php?topic=21742.msg83069#msg83069

[Cat(ionic)woman]

Thanks for the reply! That was helpful.