Fire is the common term for an exothermic chemical reaction between a fuel and an oxidant. The oxidant may or may not be (or even contain) oxygen.
For instance UO2 (uranium dioxide) will burn in F2 gas, and sodium will burn in carbon dioxide gas.
While some fires have chemical reactions which occur in the gas phase and involve plasmas, some fires only occur on the surface of a solid. Such as the burning of aluminium or titanium metal in air are likely to be reactions on the surfaces of solids.
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Health is a state of physical, mental and social wellbeing and not merely the absence of disease or infirmity
I am not a jigsaw, I am a free man !
Diagnosed under the DSM5 rules with autism spectrum disorder, under DSM4 psychologist said would have been AS (299.80) but I suspect that I am somewhere between 299.80 and 299.00 (Autism) under DSM4.