Chemistry (including Biochemistry)/Gas forming reactions

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QUESTION: Seeking advice on reactions capable of filling a latex balloon to 10 inches in diameter or approximately 500 cubic inches of volume under 1.5 psi.  Non-energetic solutions are preferred, however the desired reaction time is 3 seconds.  Heat generated has to be low enough not to rupture the balloon.  I have researched quite a bit, however am not a chemist.  Any advice you could provide on potential reactions to research would be greatly appreciated.
Thanks so much.

ANSWER: First idea would be to just use a small piece of dry wrapped in a little paper.  Sublimation would then fill the balloon with CO2. The fast part would happen when you add some warm water.

How do you intend to put in your reagents.  The aforementioned strategy involves putting the sliver in through the hole and then tying it off. You would then add the warm water by syringe through a part of the balloon you put scotch tape on.  A 3 second reaction is not going to give you any time to tie off the balloon, so I wanted to get a handle on the set up before sending a bunch of suggestions.

Please follow up.



---------- FOLLOW-UP ----------

QUESTION: Thanks so much Dr. Raymond!  I was hoping for reagents with a shelf life, and the balloon would be mechanically bound prior to mixing the reagents.  Some mechanical design would be needed to create a device to hold the reagents and the balloon, perhaps similar to breaking a glow stick.  
Thanks so much for your time.
Bill.

Answer
Any acid-base neutralization reaction will probably do.  The key will be the addition.  Obviously you could go with the good old baking powder and vinegar run.  This makes a lot of water vapor quick.  

Alternately, I am a huge fan of foaming polymers.  If you are willing to play with a two part system to get the ratio that gives you the fastest expansion, hear is very reasonable kit:
http://www.amazon.com/Innovating-Science-Polyurethane-Foam-Chemistry/dp/B00BUV7U

It's not super fast to begin with, but you can use several things to accelerate it (regular speed https://www.youtube.com/watch?v=wVNeoy2WLm4).

Other walk through: http://www.csun.edu/scied/2-chem/sckit/sckit.htm

This can easily be done in a balloon, you can then tie it up (won't really start going until you mix it).  Shake/squeeze and then set it down.  The nice thing is that it leave a physical foam that the audience can touch.  Warmer is better (ie you can sit the balloon in a hot water bath and it should go quicker.  Follow up if you want to discuss further.  I do a lot of demos with college freshmen courses, and if I know exactly what your goals are educationally, I should have plenty more ideas.

Chemistry (including Biochemistry)

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Dr. Jeffery Raymond

Expertise

Materials chemistry. Materials science. Spectroscopy. Polymer science. Physical Chemistry. General Physics. Technical writing. General Applied Mathematics. Nanomaterials. Optoelectronic Behavior. Science Policy.

Experience

Teaching: General Inorganic Chemistry I & II, Organic Chemistry I & II, Physical Chemistry I, Polymeric Materials, General Physics I, Calculus I & II
My prior experience includes the United States Army and three years as a development chemist in industry. Currently I am the Assistant Director of the Laboratory for Synthetic Biological Interactions. All told, 13 years of experience in research, development and science education.

Organizations
Texas A&M University, American Chemical Society, POLY-ACS, SPIE

Publications
Journal of the American Chemical Society, Nanoletters, Journal of Physical Chemistry C, Journal of Physical Chemistry Letters, Ultramicroscopy Proceedings of SPIE, Proceedings of MRS, Polymer News, Chemical and Engineering News, Nano Letters, Small, Chemistry.org, Angewandte

Education/Credentials
PhD Macromolecular Science and Engineering (Photophysics/Nanomaterials Concentration), MS Materials Science, BS Chemistry and Physics, Graduate Certificate in Science Policy, AAS Chemical Technology, AAS Engineering Technology

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