Fire

This may be incorrect as such but isnt it basicly oxygen that is so hot you can see it( thats what ive heard said)

Delightful speculation,my best shot would be to say that all things are process,certainly fire must be one of the purest examples of process.As to your question,it can't change mass,so what happens when it goes out? The process has stopped,what mass really did it have? It is a process which brings together things which together constitute fuel,its sum properties constitute flame----and considered it in isolation, it is not!----------or something like that,or perhaps it is the ever elusive, SOUL!

You've been Wikipedia'd on.

Flame
Main article: Flame
A flame is an exothermic, self-sustaining, oxidizing chemical reaction producing energy and glowing hot matter, of which a very small portion is plasma. It consists of reacting gases and solids emitting visible and infrared light, the frequency spectrum of which depends on the chemical composition of the burning elements and intermediate reaction products.
In many cases, such as the burning of organic matter, for example wood, or the incomplete combustion of gas, incandescent solid particles called soot produce the familiar red-orange glow of 'fire'. This light has a continuous spectrum. Complete combustion of gas has a dim blue color due to the emission of single-wavelength radiation from various electron transitions in the excited molecules formed in the flame. For reasons currently unknown by scientists, the flame produced by exposure of zinc to air is a bright green, and produces plumes of zinc oxide. Usually oxygen is involved, but hydrogen burning in chlorine also produces a flame, producing hydrogen chloride (HCl). Other possible combinations producing flames, amongst many more, are fluorine and hydrogen, and hydrazine and nitrogen tetroxide.
The glow of a flame is complex. Black-body radiation is emitted from soot, gas, and fuel particles, though the soot particles are too small to behave like perfect blackbodies. There is also photon emission by de-excited atoms and molecules in the gases. Much of the radiation is emitted in the visible and infrared bands. The color depends on temperature for the black-body radiation, and on chemical makeup for the emission spectra. The dominant color in a flame changes with temperature. The photo of the forest fire is an excellent example of this variation. Near the ground, where most burning is occurring, the fire is white, the hottest color possible for organic material in general, or yellow. Above the yellow region, the color changes to orange, which is cooler, then red, which is cooler still. Above the red region, combustion no longer occurs, and the uncombusted carbon particles are visible as black smoke.
The National Aeronautics and Space Administration (NASA) of the United States has recently found that gravity plays a role. Modifying the gravity causes different flame types.[1] The common distribution of a flame under normal gravity conditions depends on convection, as soot tends to rise to the top of a general flame, as in a candle in normal gravity conditions, making it yellow. In microgravity or zero gravity, such as an environment in outer space, convection no longer occurs, and the flame becomes spherical, with a tendency to become more blue and more efficient (although it will go out if not moved steadily, as the CO2 from combustion does not disperse in microgravity, and tends to smother the flame). There are several possible explanations for this difference, of which the most likely is that the temperature is evenly distributed enough that soot is not formed and complete combustion occurs.[2] Experiments by NASA reveal that diffusion flames in microgravity allow more soot to be completely oxidized after they are produced than diffusion flames on Earth, because of a series of mechanisms that behave differently in microgravity when compared to normal gravity conditions.[3] These discoveries have potential applications in applied science and industry, especially concerning fuel efficiency.
In combustion engines, various steps are taken to eliminate a flame. The method depends mainly on whether the fuel is oil, wood, or a high-energy fuel such as jet fuel.

So, basically, when organic matter is using enough energy, it creates the illusion we call 'fire'?

Can illusions put you in a burn center?

I apologise, I used the wrong word. I forgot the word I was going to use, so we'll just stick with 'substance'.

Its plasmic, excited gases, with mingled particles of matter from the fuel.

That's interesting; I've never looked at fire that way before...

Everything pretty or grotesque can be broke down into basic constituents. Its really anti-sexy.

Wow... that explains a lot... >.>

Fire is process,once it has spent its mass,it is no more.

Fire is created from a combustible reaction and is a release of energy.