Thread: Why isn't water flamable?

OK, so if you take the component elements of water, hydrogen- it is highly combustoble, and oxygen-a fire accelerant and combine them into water it is no longer flamable.


How's that work?

Because God made it that way

Originally Posted by Seraphim

OK, so if you take the component elements of water, hydrogen- it is highly combustoble, and oxygen-a fire accelerant and combine them into water it is no longer flamable.


How's that work?

Along the same lines, Table salt, WTF?

Toxic Chlorine, and explosive Sodium.

Yet oh so tasty.

Water is burnt hydrogen. It won't burn again.

Next question: Why does inflammable mean the same as flammable?

burning = oxidation.

combining things that are burning with free oxygen speeds the reaction up because there is more oxygen to oxidize with.

water already contains oxygen, and is stable. no more oxygen will readily combine with it, thus it doesn't burn.

http://en.wikipedia.org/wiki/Burning

I got into this discussion here at work as we are trying to fill out some customs declaration forms that require export control #'s blah, blah, blah...

We are sending replacement parts for a system. The system as a whole was given a "safe" export control mumber for want of a better description. Since we are sending subcomponents of that system, one engineer here said that sine the entire system was classifies as "safe", then the components themselves should also be classified the same way.

So I brought up the argument that water is "safe", and non-flamable, but it's components are not, and thus his argument was flawed.




As far as water being already "burned". Thanks for the explanation, I actually found a similar explanation with a quick Google....however, it would be a simple matter to again break that water down into it's components using electrolysis, etc. At that point the hydrogen would be readily available to burn yet again.

However, if you burn a piece of wood, you cannot reconstitute it to burn again. So, I'm suspicious of the answer of the hydrogen already being "burned" as a bit of sophistry and hand-waving from scientists who really don't want to answer my question or deal with the fact that when you pour water on a flame you are adding fuel to the fire.

There's obviously some sort of high-level cover-up going on here....

Try spraying water on a burning chunk of Magnesium.


It burns pretty good.

Originally Posted by Fnord5

Try spraying water on a burning chunk of Magnesium.


It burns pretty good.

The water isn't burning in that case, it is modifying the way the magnesium itself is burning.

Sort of like if you have a grease fire in a pot on a stove, if you put water on top of it, it causes an explosion. That is not due to the water bursting into flames, what happens is that the water contains the grease, which is still burning, which susequently super-heats due to the blanket of water on top, and then the grease rapidly expands into a big fireball.

Originally Posted by Seraphim

however, it would be a simple matter to again break that water down into it's components using electrolysis, etc. At that point the hydrogen would be readily available to burn yet again.

2 H2 + O2-> 2 H20 that's how hydrogen burns. pure hydrogen burns in pure oxygen to make pure water. in doing so, light and heat (energy) is released, so more properly:
2 H2 + O2-> 2 H20 + energy

in order to perform electrolysis:
2 H2O + energy -> 2 H2 + O2

in other words, you are putting it back in, so to speak.

pure hydrocarbons burned in the presence of pure oxygen should only yield CO2 and water, depending on proportions. and energy. there ARE ways to reverse this, however, they would not yield wood because wood is a complicated living structure. you might get some of the base ingredients, though.

for instance, a very basic hydrocarbon oxidization reaction:
CH4 (methane) + 2 O2 -> CO2 + 2 H2O + energy which IS reversible

of course you can't reconstitute wood, it's a cellular structure and none too pure. also, most things are not burned in a laboratory, they are burned in the atmosphere which is mostly nitrogen, some things have byproducts which are in turn reagents with nitrogen, and form all sorts of nitrates when burned.

Originally Posted by Seraphim

.however, it would be a simple matter to again break that water down into it's components using electrolysis, etc. At that point the hydrogen would be readily available to burn yet again.

However, if you burn a piece of wood, you cannot reconstitute it to burn again.

Ah, but you're adding energy when you use electrolysis. Think of it as the hydrogen and oxygen atoms being separated by a stretched rubber band. When they burn they snap together and join. The energy from the stretched rubber band is released as heat. If you pull the atoms apart again by adding energy, they once more have the potential to go through the process again.

You could in theory do a similar thing with burned wood (as long as you retained the carbon dioxide that was produced.) If you mix the ashes and CO2 with another element that has a more agressive attraction to oxygen (I don't know, maybe phosphorous?), that other element would burn, taking the oxygen from the CO2, leaving just carbon. Which would then be able to burn again.

So it's all about invisible rubber bands you see.