Reactions that produce harmless gas

[ufo101]

What reactions with easily obtainable reactants produce large amounts of harmless gas?

We want to make latex or rubber balloons that inflate by themselves. We would also like to reduce the amount of liquid or solid products left in the balloon, if possible.

Thanks!

 

[DaleSwanson]

Vinegar and baking soda make carbon dioxide, which is harmless at small quantities. There is probably something better, but that's the first one that popped into my head.

 

[Borek]

Perhaps something with a very low boiling point, that will evaporate once the balloon gets heated to the room temperature?

 

[ufo101]

I don't think Vinegar and baking soda in small quantities are enough to blow up a balloon. I was thinking more along the lines of dry ice + water, but don't know if that will work. and dry ice itself is too cold anyway. the ideal solution would be a fairly slow chemical reaction that start with a bit of reactants and end up producing lots of gas.

 

[Borek]

I doubt you will find something like that (working in terms of chemical reaction). My first idea was dry ice as well.

 

[DaleSwanson]

I don't think Vinegar and baking soda in small quantities are enough to blow up a balloon. I was thinking more along the lines of dry ice + water, but don't know if that will work. and dry ice itself is too cold anyway. the ideal solution would be a fairly slow chemical reaction that start with a bit of reactants and end up producing lots of gas.

Well, baking soda is sodium bicarbonate (NaHCO₃) with a molar mass of 84.007 g/mol. Vinegar is acetic acid (CH₃COOH) with a molar mass of 60.05 g/mol. Each molecule of sodium bicarbonate give one molecule of CO₂ with a molar mass of 44.0095 g/mol and density of 1.98 g/L as a gas.

So you need 1.98 grams of CO₂ for a liter of gas. This is 0.045 mols, which would mean 2.7g of acetic acid, and 3.78g of sodium bicarbonate. There would also be 3.7g of sodium acetate, and 0.81g of water left over. I'd guess a party balloon is about 4 liters, so you'd need about 10g acetic acid, and 15g sodium bicarbonate. I'm not sure how pure sodium bicarbonate baking soda is, or the same for vinegar. If you were looking to do this commercially though you could get them both in bulk.

 

[alxm]

I'd go with just dry ice, really. You need so little that you probably won't need to worry about either the cold, or use water to get it to sublimate faster.

 

[Borek]

The only thing I am not sure about dry ice is whether it will not do damage to the balloon, especially if allowed to contact it directly. It will cool down the surface making it loose its elasticity and being more prone to rupture. Could be that's not an issue.

 

[chemisttree]

I'd go with just dry ice, really. You need so little that you probably won't need to worry about either the cold, or use water to get it to sublimate faster.

I wonder what the shelf life would be for this propellant?

There has to be a relatively safe azide that you can try. I don't know of any but a sufficiently bulky one should be fairly stable and generate enough N2 to inflate the balloon.

It seems like a lot of work and danger to do such a simple thing, though.

 

[iceburn250]

clorox bleach and tin foil.

 

[chemisttree]

Hydrogen is NOT a harmless gas.

 

[FedExDriveBy]

i used NaHCO3 and HCL and it inflated a 1 quart ziploc bag pretty well