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Posted

Sorry, its just too fun to make for me to buy it. I'm not a professor giving lectures or anything, I'm just a high school student showing cool chemistry stuff to friends. Don't worry about me getting hurt or anything, I value my health, and I'm not going to breathe anything that I'm not absolutely sure is safe to breathe.


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Tomorrow I'm going to build a filtering apparatus for the method by which I react aluminum with water using sodium hydroxide. There were no suggestions that I knew for sure were safe, and were faster than the reactions I already knew of, so yea, I'll just use NaOH and purify the H2. Thanks for all the suggestions guys! Oh, and I was also tempted to try reacting magnesium with water at high temperatures, so I've bought myself some pencil sharpeners, and once I get some welding goggles, I'll have some fun with that too. (Not to mention making vacuums, as Magnesium is good at reacting with every gas it comes in contact with for a period before it cools down.) Maybe I'll make my first cathode ray tube. I just got into chemistry and electronics last year, so there's tons of stuff for me to try.

Posted

justonium, thats why i said to bubble the gas through water to remove sulphuric acid vapours. it would be absolutely fine unless you breathed it constantly one ore two lungfuls will be perfectly harmless.

Posted

Breathing a single breath of any pure gas will knock you out and halt your brain activity nearly immediately! Never breath in lab grade gasses!

Posted
justonium, thats why i said to bubble the gas through water to remove sulphuric acid vapours. it would be absolutely fine unless you breathed it constantly one ore two lungfuls will be perfectly harmless.

 

Yea, that's what I'm doing, partly because of your suggestion, but I'm just using sodium hydroxide instead because I know more about it, and how it doesn't form vapors. Any liquid has some amount of vapors, and I'm just not going to risk breathing anything that came off it. Will it be safe? Probably. But I just don't want to find out by breathing it.

Posted
Breathing a single breath of any pure gas will knock you out and halt your brain activity nearly immediately! Never breath in lab grade gasses!

 

Oh no it won't.

It didn't when I did it and it didn't when countless entertainers did it.

The body has some reserves of oxygen. A single breath of an inert gas won't do you any harm directly.

However it may leave you feeling a bit faint which can be a problem if, for example, you fall and crack your head.

It may be a bloody stupid thing to do but overstating the risk like that doesn't help anyone.

Posted
Oh no it won't.

It didn't when I did it and it didn't when countless entertainers did it.

The body has some reserves of oxygen. A single breath of an inert gas won't do you any harm directly.

However it may leave you feeling a bit faint which can be a problem if, for example, you fall and crack your head.

It may be a bloody stupid thing to do but overstating the risk like that doesn't help anyone.

 

100% pure will, as it sucks the oxygen reserve out of the blood effectively...

Posted

The question of how long it will take to suffocate someone, is to me a moot point. Inhaling anything which is even questionable is a very, VERY stupid thing to do and I don't think we should in anyway encourage this on this forum.

Posted
100% pure will, as it sucks the oxygen reserve out of the blood effectively...

 

One breathful won't replace all the air in your lungs, it won't react with the oxygen at ordinary temperatures without catalysis, and it doesn't have an affinity for hemoglobin greater than oxygen like carbon monoxide does. I'd say that it isn't a great idea, but probably not going to kill you.

Posted

you just need to lower the % of oxygen in the lungs enough to cause diffusion from the blood into the lungs instead of from the lungs into the blood...

Posted
you just need to lower the % of oxygen in the lungs enough to cause diffusion from the blood into the lungs instead of from the lungs into the blood...

 

but that won't happen with a single breath. your lungs, even when you exhale as much as you are able to, still have a good few litres of air in them. this will prevent oxygen from being sucked out of your blood unless you inhale an agent which actively removes free oxygen in which case you have a whole lot more to worry about.

 

a one off lungful of hydrogen or helium isn't going to do any harm other than make you bit dizzy. as long as you are not breathing it in repeatedly with only short intervals there is very little risk unless you have an existing respiratory condition.

Posted
100% pure will, as it sucks the oxygen reserve out of the blood effectively...

 

The helium supply in our lab has a declared purity of 99.99% What difference will the extra 0.01% make?

 

For a person at rest the blood circulation time is about a minute. There's no way that anything in the lungs could remove the oxygen in the blood faster than that because that's how long it would take for the blood to get back to the lungs.

So, if you filled your lungs (which is very difficult) with pure helium (which you can't get) and waited for at least a minute the oxygen in the blood would come to eqm with the gas mixture in the lungs.

The usual ballpark figure given for the brain (the most sensitive organ) to fail due to lack of oxygen is about 3 minutes so it's not unreasonable to supose that the body has reserves that are equivalent to about 3 minutes use (feel free to come up with a better estimate).

 

Normal breathing rates are of the order of 5 to 10 litres/ minute so, you have the equivalent of something like 15 to 30 litres of air stored in your body. The total volume of the lungs is 1 or 2 litres so, when this gas all gets mixed most of it is air and only about 1/7 of it is helium.

 

The maths, as well as plenty of experimental evidence, show that you really can breathe a lungfull of He and survive.

Posted

My lungs hold 4 liters (not including what is already inside them when I have fully exhaled), and when I breathe hydrogen, I only inhale about a liter. A lot of the hydrogen I breathe doesn't even make it to my lungs, so the air in my lungs is still mostly just air. The goal is only to make hydrogen present in my vocal cords so I can say "So this is what happens to my voice when I breathe hydrogen," or whatever. I have never even felt lightheaded after doing this, because my lungs maintained contact with oxygen rich air the entire time. The hydrogen hardly has time to mix with the rest of the air in my lungs in the small period that it is inside of me.

Posted

I still think this is a bad idea. Anyone who does chemistry has a responsibility to the general population (particularly the less well mentally endowed) to show them that putting things from your lab into your mouth is not wise. never inhale, eat or drink any substance in or from a laboratory, even if it is pretty safe. And inhaling an incredibly flammable substance like hydrogen isn't entirely safe anyway.

Posted

Oh, come on, think of it as a stunt. It's hilarious, and I'm not exactly encouraging them to go home and make their own gasses to breathe.

 

Oh, that apparatus I made to make nearly pure, NaOH mist free hydrogen turned out badly, I must have mixed the epoxy wrong, because it didn't fully set, and remained rubbery and fuming. I'll get it right though.

Posted

a responsible chemist doesn't do "stunts". It's not that funny, it can be done ten bazillion times more safely using helium, and it has the potential to kill you in three different ways.

Posted

it is actually since hydrogen is some orders of magnitude more reactive. helium does nothing in the body, hysdrogen will be absorbed, react and other stuff.

Posted (edited)

How fine is the Al that you are currently using, because if you just increase the surface area (finer powder) of your Al the reaction will be a lot faster !

 

If you are using Al shavings then i suggest trying Al foil (yes the normal stuff you bake with). Just put some foil in a blender and you end up with reasonably fine Al.

 

Cheers

 

Also just on the safety side...

 

What do you suppose would happen to your lungs/upper body if somehow the H2/air mix light from something (static in your hair for instance)... I don't know how imaginative you are but i see a person with a nice big tear where his ribcage used to be :)

 

Helium definitely better than tear in torso ! ; )

Edited by person
Posted
it is actually since hydrogen is some orders of magnitude more reactive. helium does nothing in the body, hysdrogen will be absorbed, react and other stuff.

 

OK, I'll bite.

What compounds generally present in the body will react with hydrogen at any meaningful rate under physiologically relevant conditions? (and I mean real chemical reaction, rather than hanging out with a really unselective receptor; xenon can do that)

 

BTW, you had better tell these people about it.

http://en.wikipedia.org/wiki/Hydrox_(breathing_gas)

 

Breathing hydrogen (or He for that matter) is a fairly dumb thing to do.

On the other hand saying things like "it will kill you instantly" is irresponsible too; did you ever hear of the boy who cried wolf?

Posted

certainly it won't kill instantly but in certain circumstances it could, whereas it's much less likely with helium, which will give identical results.

Posted (edited)

The results are not identical, hydrogen is half as dense as helium.

 

Oh, I was using aluminum foil, yes, and the reaction is very slow without sodium carbonate and calcium hydroxide. Please stop telling me how dangerous it is to breathe hydrogen, I know the dangers, you don't need to warn me.

Edited by Justonium
Posted
Please stop telling me how dangerous it is to breathe hydrogen, I know the dangers, you don't need to warn me.

 

I take it then that you won't be huffing H2? Excellent!

Posted

Justonium. I won't tell you not to breath hydrogen (although i would strongly advise that you dont) but I will request that you don't try to tell the entire science communinty it's perfectly safe on this forum. We don't want our members blowing holes in their chests or asphyxiating themselves just because you assumed they knew something about safety.

 

This isn't a matter for debate, it is part of our hazmat policy and also simply a matter of common sense.

Posted (edited)

Read the beginning of my first post, nuff said.

 

And I've already got my filtration apparatus working with NaOH, so this thread is now OLD.

Edited by Justonium
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