Anyone care to explain?
2007-02-06 11:39:52 · 9 answers · asked by Anonymous in Science & Mathematics ➔ Chemistry
Oxygen is the reactant for combustion/burning.
Air is but a mixture of gases, containing only about 21% oxygen. So combustion will take place more violently in pure oxygen as there are higher chances of effective collisions with oxygen molecules to allow combustion rather than in normal air.
The rest of the gases in normal air do not support combustion/burning.
2007-02-06 11:45:09 · answer #1 · answered by Anonymous · 3⤊ 0⤋
The speed of the reaction is proportional to the concentration of the substances that enter into that reaction. On the molecular level, you can visualize that as the probability of two "right" molecules to bump into each other and form a bond. Obviously, if "right" molecules (such as Oxygen, in that case) are few and far in between, the probability (and hence the rate) of such bond formation will be low. Air is only 21% oxygen and the rest is neutral stuff, a ballast.... In pure oxygen, due to 100% concentration, the rate of "useful" collisions between the molecules of the combustinble substance (fuel) and the oxydant (O2) will be much higher, hence the reaction goes much faster and you get what you describe as "violent" combustion.
Since the rate of the reaction is also tempereture dependent, the effect is non-linear and even more "explosive" - higher initial rate will produce more heat per unit time, which will lead to higher local temperatures, which in turn will increase the rate of the reaction etc.
2007-02-06 19:46:43 · answer #2 · answered by stopwar11112 3 · 0⤊ 0⤋
Because air is mostly nitrogen. Pure oxygen is just that - oxygen and pretty much only oxygen. Air, however, is about 78% nitrogen, 21% oxygen, 0.93% argon, 0.04% carbon dioxide, and trace amounts of other gases, plus water vapor (H2O). CO2 does not support flame, nor does nitrogen. Argon is an inert gas. However, oxygen supports a fire. But as air is only 1/5 oxygen, or about 20% "pure" oxygen, the flame is not as "violent" as it would be in a pure oxygen environment.
2007-02-06 19:46:01 · answer #3 · answered by doctoru2 4 · 1⤊ 0⤋
Love to.
Oxygen is required for combustion.
Air is a mix of elements and chemicals. Oxygen makes up about 21% of air.
Pure oxygen is 100% oxygen.
If you use pure oxygen, the combustion reaction has more O to work with and so the reaction rate faster. This gives off more heat (burns mor violently)
Hope this helps :-)
2007-02-06 19:45:46 · answer #4 · answered by natureandromeda 1 · 1⤊ 1⤋
Air is not an element it is made up of many different gasses while O2 is in it. Like in fire it needs oxygen to survive so it burns better and also it would have to do with what it is burning on.
2007-02-06 19:57:44 · answer #5 · answered by Who said my name? 2 · 0⤊ 0⤋
My guess: Because fire needs oxygen to grow, and the air is only part oxygen and part other things (mainly nitrogen) which do not feed a fire. Pure oxygen has more oxygen in it (lol) than air.
2007-02-06 19:48:18 · answer #6 · answered by blahblah 4 · 0⤊ 1⤋
Fire IS the combining of whatever is burning with oxygen. More oxygen, faster burning.
2007-02-06 19:47:26 · answer #7 · answered by Anonymous · 0⤊ 1⤋
Because oxygen is more pure than air. Air has more water in it.
2007-02-06 19:43:26 · answer #8 · answered by smittybo20 6 · 0⤊ 2⤋
Check for the composition of what we call "air". That should help you arrive at an answer
2007-02-06 19:44:04 · answer #9 · answered by OtherResources 2 · 0⤊ 1⤋