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Burning Hydrogen


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would this work?

 

(1) electrolysis water, collect hydrogen in flask [above cathode - negative]

(2) hydrogen is lighter than air so the hydrogen should stay in the flask [if the flask is upside down]:

(3) light match and immeditaely turn flask with hyrdogen the right way up so that the hydrogen comes up and catches fire [from the match]

 

will you have a slow but sure mini flamethrower?

or will it all go up in flames at once?

or will it not work?

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I think it will work (especially with a pure hydrogen + pure oxygen mix, that burns like hell :) ). Just hydrogen ignited produces a not-so-observable flame in small quantities though.

 

Edit: And about that flame thrower thing, hydrogen burns pretty much all at once. And if there's not enough space for it to burn (narrow mouthed flask) it goes *boom*. :)

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so if i have a flash with O2 and a flask with H, how would i combine the two?

 

remember that the H flash will still have some water in the bottom, take it out of the water [what i performer electrolysis on] then air wil get in.

is oxygen heavier or lighter than air? which way should i keep the oxygen?

remember that they will both have water, once taken out of the water, air gets in.

 

also i have seen pure H + O2 explode, about 1.5litres of the stuff... it was wicked!

 

what happens if some air gets into the sollution?

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would this work?

 

(1) electrolysis water' date=' collect hydrogen in flask [above cathode - negative']

(2) hydrogen is lighter than air so the hydrogen should stay in the flask [if the flask is upside down]:

(3) light match and immeditaely turn flask with hyrdogen the right way up so that the hydrogen comes up and catches fire [from the match]

 

will you have a slow but sure mini flamethrower?

or will it all go up in flames at once?

or will it not work?

I have done this before. It goes "pop" and the match goes out.
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It is rather dangerous to burn hydrogen because it always mixes in some extent with air and usually it will make that same thing you described with mixture of H2 and O2. I have seen glassware going into pieces all over the room because hydrogen was not pure enough.

 

You may better try such experiment. Take some soup plate pour your electrolyte there and add a drop of schampoon or soap. Sink electrodes and switch power on. Let bubbles get big enough, light a match and move it near to cathode to see what happens. Use only diluted acid as electrolyte becuse it may spray you all over.

 

If you still want to burn bigger amounts of hydrogen its god idea not to use glass vessels for experimenting.

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I have done this before. It goes "pop" and the match goes out.
not with large amounts of hydrogen and oxygen [in the same container, not chemically bonded - not water]. this guy filled up one of those 2 litre bottles with i think about 1/2 hyrdogen and 1/2 oxygen.... the whole thing burst into a ball of flames [mini-bomb-like-explosion]. quite quick, but bit more than a "pop", probably because of the quantities and the pure oxygen.
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in a vessel unpresurised it will most certainly explode! however if a hydrogen jet is set fire to (as in Oxy-Hydrogen cutting torches) it`s perfectly safe. you dont have the apparatus to do that, so never ignite more than a small test tube full in one go, putting the Hydrogen and Oxygen mix into a ballon and setting fire to it will give you a good idea of what it would do to a glass vessel!

and NEVER do it indoors, it can blow windows out (I know, I`ve done it).

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hydrogen explodes like flour dust...it doesnt seem like its gonna be big, but it makes one hell of a pop. last semester my professor filled a balloon with it, then attached it to a ruler and placed it over a bunson burner. BAM....i definately wouldnt mess with it. it could do some harm in high quantities.

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hydrogen doesn't burn; it "blows up" with a popping noise.

 

I think you have that backwards. Hydrogen doesn't explode - it burns very fast.

 

Burning hydrogen uses 3 moles of reactants to produce 1 mole of products, so the result is a 3:1 reduction in volume of gas. All expansion comes from the energy release, as opposed to products that go solid or liquid -> gas, that expand as a result.

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I think you have that backwards. Hydrogen doesn't explode - it burns very fast.

 

Burning hydrogen uses 3 moles of reactants to produce 1 mole of products' date=' so the result is a 3:1 reduction in volume of gas. All expansion comes from the energy release, as opposed to products that go solid or liquid -> gas, that expand as a result.[/quote']

 

Actually, it's 3 moles of reactants producing 2 moles of products. So while it is a reduction in moles, it's not a 3:1 reduction. It's only a 3:2 reduction. But when you have the perfect mixture of hydrogen and oxygen, that reduction is a very loud reduction. hehe. :D

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so once i have hydrogen and oxygen in two seperate test tubes [from electrolysis of water] how do i combine the two into one?

and then presummably you can just stick a match in [the match being already alight] and bang!

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or just collect it in one bigger tube!!!

oops, yeah, that was a bit of a stupid question, i was thinking that some of the gases would escape, then i though, just put both electrocdes beneath the same thing, maybe a plastic cup, then that will melt with the explosion... not glass, coz i dont wanna be showered by bits of it!

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erm' date=' the O2 will dissipate! you may get lucky with the H (if it`s not draughty) but the O2 will vanish :)

 

you need a sealed containment vessel, idealy a water trap.[/quote']no no, you miss the idea.

 

the cup brim will be under the water line, so no air can escape unless it goes under the collecting beaker through the water and out the water.

 

i tried doing an image wrapped in [ code ] [/ code ] tags, but it didnt work :(

 

but i think you should get the idea! the water acts as the sealant, the water beaker is full to the brim, the collecting beaker's brim is under that water level.

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got ya, in that case, use the plastic cup (the cheap give-away coffee cups from a machine are ideal, it`ll still explode (I hope you take it out the water and apparatus 1st!

but it`ll not cause you any harm, I still would reccomend gauntlets, and CERTAINLY! eye protection, as for ears... a 200ml cup won`t hurt you :)

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lol, dude, you're gonna lose a hand doing this...i find it a lot more amusing to stick a lighter in front of a can of WD-40 and see how long i can make the flame last...

assuming you`re talking about my post (the one above this) a 200ml plastic cup will cause no such hand injury!

 

the WD-40 flame-thrower trick is old hat and quite dangerous, even if the can is still new and under full pressure, dribbles of the solvent leecjhing out of the seals (and it does!) are still quite flamable and more than `willing` to catch unaware!

 

it`s a foolish trick to do, and only worthwhile in an emergency where greater risk is a predominant factor, otherwise it`s just plain dumb!

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