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You can't burn water, because it's already burnt (lemmy.ml)
submitted 3 years ago by to c/showerthoughts@lemmy.world
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Fire is the rapid oxidation of a material. Water is 2 hydrogen and 1 oxygen. Every molecule is fully oxidized. It's also a common byproduct of fire. Therefore, you can't burn it, because it's already burnt

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[–] 101 points 3 years ago (4 children)

Oh man... Wait until you hear about fires hot enough that if you put water on then, it breaks the water molecule and the hydrogen molecules cause an explosion.

Look up class D fires.

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  • [–] 46 points 3 years ago (4 children)

    Furthermore, you can burn water with a strong enough oxidizer. Oxygen, despite lending its name to the word "oxidize", is not the best oxidizer out there. That belongs to things with fluorine in it. You can burn water with pure fluorine gas to produce hydrogen fluoride and oxygen.

    Don't try this at home. Both fluorine and the resulting HF is deadky.

    HF is itself a super nasty piece of work -- a deadly acid that seeps through your skin and kills you from the inside.

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  • [–] 14 points 3 years ago* (last edited 3 years ago) (1 child)

    The fun part about that: you can burn hydrogen with fluorine because fluorine is the best oxidizer; it's then deadly (and caustic) because hydrogen is not the best reducer - it's both an oxidizer and a reducer and, as a result, it's basically middle-of-the-road for both properties. Specifically, most metals are better. So the HF will happily drop its hydrogen for many metals to oxidize (fluoridate) them instead. Lead, iron, zinc, aluminum, magnesium, and lithium will each make a way more stable fluoride than does hydrogen.

    In solution (say, if you inhale HF, it'll dissolve into the moisture in your lungs), it breaks apart into H⁺ and F⁻ ions - both of which are just straight-up electrochemically promiscuous. The pair'll run through your lungs breaking up organic bonds like couples at an orgy.

    Even so, HF doesn't hold a candle in terms of danger (and oxidation potential) compared to fluorine peroxide / dioxygen difluoride / FOOF.

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  • [–] 14 points 3 years ago* (2 children)

    Or Chlorine Trifluoride. That's some "no way in hell" stuff right there.

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  • [–] 3 points 3 years ago

    Flourine by itself is nothing compared to chlorine triflouride (CTF) though.

    There were some ideas to use it in rockets, but, as John D. Clark put it:

    It is, of course, extremely toxic, but that's the least of the problem. It is hypergolic with every known fuel, and so rapidly hypergolic that no ignition delay has ever been measured. It is also hypergolic with such things as cloth, wood, and test engineers, not to mention asbestos, sand, and water—with which it reacts explosively. It can be kept in some of the ordinary structural metals—steel, copper, aluminum, etc.—because of the formation of a thin film of insoluble metal fluoride that protects the bulk of the metal, just as the invisible coat of oxide on aluminum keeps it from burning up in the atmosphere. If, however, this coat is melted or scrubbed off, and has no chance to reform, the operator is confronted with the problem of coping with a metal-fluorine fire. For dealing with this situation, I have always recommended a good pair of running shoes.

    There were a few successful test fires with a CTF rocket on the ground, but to avoid explosions they had go through an elaborate multiple hour long cleaning procedure, and it ended up being too expensive and dangerous.

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  • [–] 7 points 3 years ago (1 child)

    Ah so it's hot enough to electrolyze water and then when the hydrogen and oxygen gas move out of that heat zone, they're still in a hot enough area to re-oxidize into water, burning the hydrogen. Neat.

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  • [–] 2 points 3 years ago (1 child)

    Nothing about this makes sense. Is it reoxidizing or burning?

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  • [–] 6 points 3 years ago

    Yes.

    Not only will metal fires break apart the water into oxygen and hydrogen, but they will consume the oxygen, as the metal oxide is a more stable energy state than is water. So you end up with a billow of hydrogen coming off the fire that mixes with the oxygen just above (because lighter gases rise) the oxygen-depleted zone of the fire, and it combusts there.

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  • [–] 5 points 3 years ago (1 child)

    There was some other thread talking about invisible fire produced by burning a particular gas... imagine getting burned and not being able to identify the source

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    • [–] 85 points 3 years ago (3 children)

    Reddit hasn't had a quality shower thought like this on the front page in years. Well done fediverse.

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  • [–] 6 points 3 years ago

    Any time I tried to post a shower thought on Reddit it was deleted because it either was posted previously (at any point in time, even if it was years ago) or was posted somewhere else online, not just Reddit, also at any point in time.

    Nuts.

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  • [–] 3 points 3 years ago

    I've seen a few great ones lately, but I've also been seeing a ton from people who don't understand the concept very well. Things like "it's not nice to be mean to people" or "there are more countries in Asia than China, Japan, and South Korea." I can't really say much as I haven't posted anything myself, but c'mon people!

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    • [–] 31 points 3 years ago (1 child)

    I guess that makes water Hydrogen rust...

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    • [–] 19 points 3 years ago (1 child)

    Next time it snows, remember: you're being gently coated in stellar ash.

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    • [–] 18 points 3 years ago (1 child)

    Water is also hydrogen and oxygen floating around in a sea where they are constantly switching partners. An orgy if you will.

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    • [–] 18 points 3 years ago (6 children)

    So, I'm no chemist, but if H2O is already oxidized, what do you call it when you make hydrogen peroxide - H2O2?

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  • [–] 20 points 3 years ago* (1 child)

    You call that an unstable compound that doesn’t want to exist. Hydrogen peroxide is constantly looking for an excuse to decompose back into water and oxygen. Making it is like rolling a barrel uphill. As soon as you let go, the barrel will roll back down to the bottom of the valley.

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  • [–] 11 points 3 years ago

    The oxygen atom in a water molecule has an oxidation number of -2 (which is as reduced as it can get in common compounds you’re likely to find, and it has no reason to react further). In hydrogen peroxide, the oxygen atoms have an oxidation number of -1, so not quite as reduced as oxygen would rather be (which is why H2O2 is gonna oxidize whatever is around it. Those oxygen atoms are gonna get those sweet, sweet electrons one way or the other by god!)

    The hydrogen atoms are identical between H2O and H2O2; that’s not where the magic happens, so to speak.

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    • [–] 10 points 3 years ago (1 child)

    You just have to wait for it to get hot enough to grill steam the burgers and franks.

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  • [–] 7 points 3 years ago (1 child)

    Mmm, mouth-watering hamburgers

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    • [–] 9 points 3 years ago

    Entropy's a bitch.

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    [–] 8 points 3 years ago (1 child)

    Did you try to burn the water while showering?

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    • [–] 5 points 3 years ago (1 child)

    So what would you call it when you combust water by exposing it to burning metals like magnesium?

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  • [+] 11 points 3 years ago* (last edited 7 months ago) (1 child)
    [deleted]
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  • [–] 6 points 3 years ago

    Both contribute to the combustion, but it's the metal that's fuelling it while water plays the role that air/oxygen usually would. I think codyslab did a video where he had a flame fed by air in an atmosphere of methane which demonstrates the concept that actually you need both fuel and oxidiser for the flame, and one "burns" in an "inert" atmosphere of the other

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    • [–] 5 points 3 years ago (1 child)

    Reminds me of a joke me and my freinds made about a hipster restaurant that sells "deconstructed water" that's just a balloon filled with hydrogen and a match.

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    [+] 1 point 3 years ago* (last edited 2 years ago) (2 children)
    [deleted]
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  • [–] 2 points 3 years ago

    They are, well a specific type of reaction anyway. Combustion is defined as a "high-temperature exothermic redox chemical reaction between a fuel (the reductant) and an oxidant, usually atmospheric oxygen, that produces oxidized, often gaseous products, in a mixture termed as smoke." According to Wikipedia.

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