What if H2O became just H and O?

[Grinder]

I posed this question to Any Questions Answered when they first started offering the service. The answer was rubbish (basically "it wouldn't happen") and I got my £1 back.

So my learned colleagues here is my pseudo-science question for you.

If all the water in the world somehow* got converted to Hydrogen and Oxygen, what would be the resultant proportion of gases in our atmosphere and would it be breathable?

* I'm thinking of some non-existing catalytic process, perhaps caused by research into alternative fuels. I know it wouldn't actually happen.

Please note I am writing a movie script based around this scenario, so please no one can use if for that.

[TykeMerc]

Put simply there would be a damn big bang as soon as any source of ignition was provided. Probably big enough to destroy and atomise much of the surface of the planet.

I can't be bothered to work out the atmospheric percentages, but prior to the gigantic explosion I would expect the mixture to be breathable as you've not excluded the existing atmospheric gasses.

[Moscow Mule]

Hydrogen won't do you any harm if you breath it, but it's not used in a breathing gas normally as it's pretty unfriendly next to any ignition source.

Google hydrogen trimix

http://books.google.com/books?id=CUp...esult&resnum=5

[TimberWolf]

The atmosphere would be a lot denser (perhaps 300 times current atmospheric pressure) so moving around might be more fish like. We would certainly be more buoyant and could probably fly.

[thunderlizard]

The hydrogen would just float up to the top wouldn't it?

[BrilloPad]

"it wouldn't happen"

would you like a refund?

[TimberWolf]

The hydrogen would just float up to the top wouldn't it?

Most of it would probably escape into space eventually but the hydrogen probably won't float to the top in a hydrogen layer because the gases will be wizzing around at 100's of metres per second and mix quite thoroughly. The atmosphere would be about 2/3 hydrogen and 1/3 oxygen, which I guess would be breathable until the first spark.

[Grinder]

So do all our 'experts' think the quantity of gas 'created' from the Oceans would be greater than that existing in the present atmosphere? Would the 88% nitrogen not dull the explosive properties of the new hydrogen?

[original PM]

well I think 1 cm cubed of water creates 1000cm cubed of steam

would this also apply to sperating out water into it s constituaent gases?

if so then you should be able to work out the volume of gas created as we know the volume of water in the earhs oceans (i think!)

[TykeMerc]

So do all our 'experts' think the quantity of gas 'created' from the Oceans would be greater than that existing in the present atmosphere? Would the 88% nitrogen not dull the explosive properties of the new hydrogen?

Without working it out I'm not sure of the volumes, but the Nitrogen wouldn't have any noticable effect on the explosive potential of that quantity of H and O you suggest. Since you didn't specify that it would be in the form of H2 and O2 they wouldn't need any excuse to react explosively given even the tiniest bit of encouragement.

The reason I can't be bothered to work out the volumes is that it would need dissolved gasses currently lurking in the liquid and frozen water to be estimated as they would also be liberated and I'm not certain of the volume of frozen water on the planet either. It would also be necessary to estimate the volume of vapourised water in the current atmosphere too and factor that in.

Whichever way you cut it there would be an almighty worldwide bang as soon as any source of ignition occurred and might even be keyed off by solar energy acting on free Oxygen and Hydrogen atoms.