Hi, I am an engineering student who needs help finding a chemical reaction for a class project.  We were assigned to design and build a miniture car that is propelled by a chemical reaction.  My initial reaction is to find a combustion reaction or an acid base reaction, but I want something orignal that no one else is likely to use. I figure any reaction that releases a significant volume of gas will do the job, but my limited experience in chemistry does not provide me with a reaction that is adiquite and safe.
Any sujestions?

Thanks
Deciple

If the chlorine reaction was on a big enough scale, might it not lead to heating of the NaOH?
hypochlorite is produced from Cl+NaOH only when quite cold, at higher temperatures, the reaction produces entirely the chlorate salt instead.

Jdurg, for making Cl, I reccomend dripping conc. HCl on to KMnO4, that is the method I use to generate all of the Cl that I use, Cl evolution is fast and in large quantities.

I imagine that would also corrode the spoke/engine like nobodies buissiness (and smell bad )

Chlorine is smelly and is not a very safe gas. Using baking soda and vinegar to produce carbon dioxide would be safer.

On the other hand if you are allowed to be slightly unsafe and want a hoot – build a small wood car from a kit (there are several used by kids for contest) and put a small rocket motor on it (those are found in hobby shops). It will scoot right along. Might need a foam barrier to catch it at the other end or pop a parachute.

http://www.usahobby.com/pinecar/blocks.html
http://www.redarrowhobbies.com/estes_engines.htm

Depending on how complex you want to get based on how well stocked the lab is you can do hydrogen from HCl and a metal. Then you could use it for a small jet engine.


Back to safe – I think you might be able to get sufficient electricity out of a lemon juice reacting with a metal.

http://www.hilaroad.com/camp/projects/lemon/lemon_battery.html

Of course a batter of any kind is a chemical reaction. So a hunk of wood with toy wheels, an electric motor, and battery, will meet the criteria. Or one of those radio shack remote control cars.

Regards,
Bill

HCl of 16% to 30% conc. is available cheaply as a rust remover/pathcleaner, I buy mine in   1 gallon plastic bottles for a few pounds in the UK.

Distillation at a low temperature would serve to concentrate the HCl to a far greatert degree, I need not add, take care not to come into contact with the HCl, or breathe the fumes in.
Although the 16% conc. wont cause immadiate pain or anything short of mild redness, make sure you wash it off.

I don't think chlorine gas is suitable for the job because of its corrosive nature, plus it's a hazard in itself. You probably will need additional protective measures to prevent your miniature car from breaking down under the action of chlorine on it, plus protective gears for yourselves.

I was thinking along the line of solid sodium nitride. Action of heat will produce nitrogen gas fast. Nitrogen gas is inert and the rate that it is being produced should provide more than sufficient power to drive the car. Nitrogen is also an environmental friendly gas, so you need not worry about toxic emmissions too.

I had meant sodium azide, not sodium nitride. It is employed in the emergency inflation of airbags in your vehicles.

It breaks down under heat according the following equation:
3NaN₃ -> Na₃N + 4N₂

I think you've to source the Material Safety Data Sheet (MSDS) for NaN₃ and Na₃N yourself. You would need these information to confirm if sodium azide is the best fuel for your car.

Ok, I did a little reading on sodium azide.  It sounds very dangerous, but it seems that it could provide the type of reaction I am looking for.  Can someone discribe to me how to handle it and achive the desired reaction, and how do I ensure that it only releases N2 and not other leathal gasses.  I am preforming this reaction for a groupe of college students and I would prefer not to kill anyone.  Remember I am an engeneering student not a chemist.

Thanks
deciple

Hey guys
I had some old sodium azide solution sitting in a refrigerator. I figured mixing it with hydrogen peroxide could yield safe nitrogen and oxygen gas.
So I mixed it with cold 30% H2O2. The reaction started slow, then got hot with lots of gas evolution.
Adding azide solution to solid sodium peroxide works too.