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actually_a_dog

Most definitely.

Interestingly enough, Google told me there are only 14 gasses that are lighter than air. They are:

* acetylene

* ammonia

* carbon monoxide

* diborane

* ethylene

* helium

* hydrogen

* hydrogen cyanide

* hydrogen fluoride

* methane

* methyl lithium

* neon

* nitrogen

* water vapor

Wiki lists most of them at https://en.wikipedia.org/wiki/Lifting_gas , although it leaves out ethylene, methyl lithium, and diborane for some reason. It also doesn't explicitly list carbon monoxide, but talks about it under "coal gas."

Of those, only hydrogen and helium are even vaguely suitable for party balloons, due primarily to their nasty chemical properties and/or expense.

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I used hydrogen cyanide for the balloons at my birthday party, and I didn't hear anyone complaining afterwards.

Bear in mind that it boils/condenses at about 26C, so it's only suitable for parties with lots of dancing or warm summer nights.

> I used hydrogen cyanide for the balloons at my birthday party, and I didn't hear anyone complaining afterwards

Wow, that got dark quickly.

I like a similar joke that goes:

Give a man a fire, he'll be warm for a day.

Set a man on fire, and he'll be warm for the rest of his life.

Less similar, but another classic of dark humor, is the poster of Stalin captioned:

Dark humor is like food.

Not everyone gets it.

Way darker than my acetylene joke, that’s for sure

The third sentence of the article: "Only certain lighter than air gases are suitable as lifting gases."

Diborane, among other things, autoignites in an oxygen atmosphere at 38C, and also burns on contact with water. It manages a rare NFPA fire diamond of 4 4 3.

It is tough to be a less practical lifting gas than hydrogen cyanide or hydrogen fluoride, but I think diborane manages it.

>Because of the exothermicity of its reaction with oxygen, diborane has been tested as a rocket propellant.[32] ... Diborane is pyrophoric gas. Commercially available adducts are typically used instead ... The toxic effects of diborane are mitigated because the compound is so unstable in air. The toxicity toward laboratory rats has been investigated.[38]

This seems like a great candidate for Derek Lowe’s “Things I Will Not Work Worh” column.

Note that hydrogen fluoride was the first thing featured on that column, even before the name of the series settled down: https://archive.md/gX3xF

> HF has actually been used right out of the cylinder for a long time in Merrifield peptide synthesizers. It’s the traditional way to cleave the peptide off the resin at the final step, so there are actually a lot of people who’ve used the stuff. But it’s in a dedicated apparatus that is (that had better be) well sealed, and people treat it with due respect. At a former employer of mine, there was an accident with one of these machines right before I joined the company. The shout “HF LEAK!” went out into the halls, and I’m told that the whole area set a never-to-be-equaled evacuation record.

By the fire diamond metric, HF is relatively tame, at 4 0 1, except that anything with a health rating of 4 ("very short exposure could cause death or major residual injury") is unsuitable for most purposes. So you can't set it on fire. Doesn't matter.

Thanks for that link, I really do enjoy his writing. "Relatively tame" isn't something I expect to see with a health rating of 4, but I suppose it's an accurate statement when you're talking 4x3 ratings.

> Of those, only hydrogen and helium are even vaguely suitable for party balloons, due primarily to their nasty chemical properties and/or expense.

Filling your party balloons with hydrogen is one way to make sure your party goes off with a bang!

Well, balloons filled with pure hydrogen tend to go poof, but fill them with a stoichiometric mixture of hydrogen and oxygen (like the output of a water electrolysis cell) and the have a pretty powerful explosion.

I wonder if it's really that risky to use hydrogen for party balloons that will be outdoors. Weather balloons and other un-manned lifting platforms already use it.

https://www.fp2fire.com/hydrogen-balloon-inflation/

Manned hydrogen ballooning is definitely still a thing.

Methane, nitrogen, and neon wouldn't be too bad from a toxicity perspective, though neon would be expensive, and nitrogen isn't all that great in terms of density.

While methane is a greenhouse gas, as the article mentions, the amount used for balloons under any realistic scenario is going to be dwarfed by the megatons of methane that enter the atmosphere from natural processes (and, of course, natural gas is mostly methane). It's also dirt-cheap.

Methane balloons would probably be a pretty significant fire / explosion risk, no?

Yep, it's definitely flammable.

I think it's probably easier to avoid dangerous leaks than with hydrogen, though. Hydrogen molecules are small and sneaky.

Why not nitrogen?

I would assume it’s not significantly less dense than air.

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