O/T Chemistry experts

Why does hydrogen hold up the Hindenburg and not a toy balloon? We built a hydrogen generator and have been filling balloons but they don't float. What is wrong? Thanks, Fritz

Called volume as in cubic inches of Hydrogen to the mass of the balloon. Most balloons simply will not hold enough hydrogen to cause lift before they explode. Way back when we did that in school and that close was like a full week of science class and that was all we did that week and found the balloon mass to be to much for the volume of hydrogen we could put in but a weather balloon on the other hand will hold enough volume to float. Does that compute????

If you are generating hydrogen gas using an acid and a metal like Zinc, what is produced is NOT pure hydrogen. There may be some water vapor in there, possibly HCl vapor if you useed hydrocloric acid as your acid. If you used sulfuric acid, some H2SO4 in a vapor stage may also be there, or could be abit of SO2 vapor, all which are alor heavier than hydrogen gas.

If helium lifts a balloon, then hydrogen will lift it better.

You are not making pure hydrogen, probably contains water vapor which is heavy.

I will add, that you need enough molecules of hydrogen to lift it. The same pressure of hydrogen as helium will be needed. You will probably need a compressor to get it into the balloon.

The hydrogen they make today isn't as good as the hydrogen they used to make back in the 30's. I think they're using chinese parts. ;o)

When we fooled around making hydrogen and oxygen from water in Chemistry class, the hydrogen would ignite very readily and there was always a bit of water in the test tube. I don"t know if it was all from the hydrogen combining with oxygen to form water, or if some of it was from water vapor.

Maybe water vapor is the problem, but something will float in water or air by weighing less than the water or air it displaces. My guess is that there is not enough hydrogen in the balloon to weigh less than the air a balloon+hydrogen of that size displaces. It might work to fill the balloon with more hydrogen. And I would guess that there is some way to remove the water vapor from the hydrogen.

Hydrogen is notoriously difficult to contain. They had a terrible time containing the hydrogen in the pressurized gas bags in the Hindenburg and other lighter than air craft of the day. Modern plastics might work better, but hydrogen will always be difficult to work with and very inflammable. I doubt that we ever see large craft lifted by hydrogen again, at least in commercial service.

Have fun with your balloons, but remember, the hydrogen will burn very rapidly and could be dangerous to you or others. Good luck!

I remember making hydrogen in chemistry class too. We were supposed to use test tubes to capture the hydrogen and then ignite it. It would make a nice popping sound. I was short of test tubes at my lab desk, so the farmer in me decided to improvise with a larger container. Lets just say the resulting "pop" got the instructors (Mr Taylor) attention.

Blame it all on global warming and George Bush.

Be carefull, If I remember correctly from AF Tech school hydrogen has an explosive range of from 2 to 76 percent. Its some pretty wicked stuff,its also extremely leaky.
Joe

The generator may be putting the oxygen back into the mix (easily explodes and is not safe at all). The hydrogen should be able to be taken directly from the process separately from the oxygen. Hydrogen is some better than helium for lifting, so if it is not lifting it is not hydrogen. Jim

I agree with the others, you probably don't have a very high concentration of hydrogen. What kind of hydrogen generator are you using?

Hydrogen and helium are very small molecules that are hard to contain. Helium is used for leak testing air conditioning components. Hydrogen would work even better, but it is too dangerous if you have too many leaks inside a factory.

First, get some large "Party Balloons", NOT the cheap "penny balloons". Next you'll need a can of Draino Crystal Drain Cleaner, a heavy wall glass bottle such as the old hour-glass style Coke bottles, some heavy duty Aluminum Foil, and a wad of cotton.

Put three Tablespoons of Draino (crystaline Sodium Hydroxide / Potassium Hydroxide & Aluminum granules) into the bottle. Next take a 6" x 6" piece of heavy duty Aluminum foil and stuff it into the bottle. Then add 2 ounces of water to the bottle (no more or you will drown the mix), and quickly stuff the cotton into the NECK of the bottle (this keeps the water in the bottle but lets the Hydrogen pass through), and quickly stretch the neck of your balloon over the mouth of the bottle.

After the chemical reaction (caustic alkali attacks and dissolves Aluminum giving off copious quantities of Hydrogen gas, the Aluminum ions combine with the Oxygen molecules from the water and some of the Hydrogen molecules to form Aluminum Hydroxide) has finished, tie a piece of string tightly around the neck of the balloon BEFORE removing it from the bottle.

Be careful handling the bottle, the chemical reaction is an EXOTHERMIC reaction which means that it generates HEAT and the bottle will be hot.

When I was in Jr. High School back in the late 50's & early 60's , my friends & I would do this quite often.

Chemistry teacher would make hydrogen and then rigged up a way to make soap bubbles full of hydrogen. Soap bubble would float to the ceiling, where he used a match taped to a meter stick to ignite it. Big bang and a ball of fire.

Balloon weigh too much.

(quoted from post at 14:00:13 12/29/12) Why does hydrogen hold up the Hindenburg and not a toy balloon? We built a hydrogen generator and have been filling balloons but they don't float. What is wrong? Thanks, Fritz

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urity is the problem. If you buy a cylinder of hydrogen & fill a balloon or even a 30 gallon trash bag with it, they will rise.
Experience speaking.

These are ruff numbers. One liter of air has a mass of 1.2 grams. So if hydrogen weighs nothing, which it doesn't, then for every one liter of hydrogen the ballon has to weigh less than 1.2 grams. Do the math. The volume of a sphere is
volume = (4/3) · ð · r3.

This is a math, chemistry and a little physics question. Test tomorrow.

A stack of stainless steel washers in a mason jar powered by a 12V charger. The mix is sodium hydroxide and water.

Myth busters did that one, used a 5 gallon bucket of soap water, bubbled H into it, and lit it. Not so much of a bang, more like a WHOOOOOOOOOOOOOOOOOOF! Google it, it's bound to be on youtube.