Potassium Chlorate and Gummy Bear

[jayhawker]

I have a quick question that I hope some of you all may be able to help with – every year I do the gummy bear molten potassium chlorate demo to illustrate Cellular Respiration. However after speaking with another science teacher in the area he told me I probably shouldn’t do this demo due to the high risk of impurities in the potassium chlorate – which could lead to disastrous results. Do any of you have any experience with this, or maybe elaborate more on the risks? Thanks

[Cap'n Refsmmat]

The most disastrous results I've seen involved the test tube shattering. Our chemistry teacher did the demo with potassium chlorate and marshmallows, and the students secretly compacted three or four marshmallows into a small ball for her to use in the reaction. It was violent enough to smash the test tube. Pretty impressive, I'd say.

 

You should be able to check the chemical bottle for information on potential impurities. Most bottles I've seen (from places like Flinn Scientific) give a detailed composition of the contents of the bottle and state what any impurities might be.

[lucky45]

I have a good deal of Knowledge with KCLO3.and KCLO4/ Potassium chlorate is a very strong Oxidizer, so is Potassium perchlorate. The thing with KCLO3 is that if you mix sulfer!! or any kind of organic property with it ,it becomes VERY UNSTABLE. I HIGHLY!! recomend if you want to do any science experancees with KCLO3. you should use KCLO4 instead of KCLO3. because it is alot more stable than KCLO3. Please take me seriously!! I konw what Im talking about.

[John Cuthber]

It's true that perchlorate is more stable. That's why you shouldn't use it.

Because it's more stable it doesn't do anything unless you get it so hot that, once the reaction starts, it's even more violent. Also, of course, it has more oxygen in it. It also has a much higher melting point too so, if things go wrong, it's hotter.

 

Generally anyone who closes their post with "Please take me seriously!! I konw what Im talking about." should raise a flag about their ability, even more so if they can't spell sulphur.

 

There is, with this experiment, a small risk. If the chlorate is contaminated with some reducing material then the reaction may well become violent, even before adding the sweets.

You can check this by heating a small amount of the chlorate behind a blast screen before you start. Of course, if it's the same batch as you used last time and it was OK then, you should be able to use it again (provided, of course, that you can be sure that it hasn't been contaminated in the mean time).

[jayhawker]

Thanks, I will make sure to heat up a gram or so prior.