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On 16 Jul 2005 23:22:16 -0700, ngdbud@xxxxxxxxxxx wrote:
>This is a really stuid question. I'm just about certain that that mix
>of gasses produced during the electrolysis of water expand when burned
>together but it makes sense that they'd contract considering that three
>seperate atoms combine to make one molocule it seems like after the
>atoms combine they would take up less space. make an implosion, not an
>explosion, makeing this fuel unsuitable for jet, rocket, or internal
>combustion engines, but if this were true then it wouldn't be s
>valuable to our future. So, i just seet myself up for a series of
>"duh's" and "get a brain's" but I'm so confused it's worth it. Thanks
>in advance.
>
When H2 and O2 react, the product is water and a whole lot
of heat. The result is very hot steam. The shuttle main
engines burn large quantities of LH2 and LO2. If you watch
them ignite, you will note that after the initial flames
disappear, the exhaust goes almost transparent, and the
escaping hot steam provides enough thrust to lift the
shuttle into orbit (with the help of the SRB's of course).
If, on the other hand, you react a small amount of the mixed
gases in, say, a test tube at atmospheric pressure, there is
so little mass present that the resulting steam can quickly
condense back to water, which, as you point out, occupies
less volume than the reactants, causing a drop in pressure.
The result always depends on whether the final temperature
of the product is above the boiling point. Rocket engine
exhaust always is, lab demos with test tubes aren't.
I believe your question is perfectly reasonable and a good
use of the newsgroup. You did not ask a dumb question.
Regards,
Bill Ward
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