Date: Mon, 25 Jan 2010 11:22:01 EST
Reply-To: DCHAS-L Discussion List <DCHAS-L**At_Symbol_Here**LIST.UVM.EDU>
Sender: DCHAS-L Discussion List <DCHAS-L**At_Symbol_Here**LIST.UVM.EDU>
From: ACTSNYC**At_Symbol_Here**CS.COM
Subject: Re: Possible cause for this HS chem accident

Welllllll, I wouldn't be that specific in my warning about tartaric acid.  You'll note under incompatibilities is says "organic matter?"   Take it from this old pyrotechnic wonk, adding powder sugar will make a hell of a bomb out of potassium chlorate. So will adding powdered charcoal, finely divided vinyl chloride polymer, and a FLOCK of other substances pyros use.  You don't want ANYTHING other than potassium chlorate in potassium chlorate. 

Because it makes such easy bombs, I think it ought to be out of the HS curriculum altogether before the students figure this one out.'

And if they are really interested, on the internet, there are occassional sales of fireworks ingredients where you can get 10 pounds of potassium chlorate free if you buy $100 worth of other products.  You have to pick it up physically yourself because they can't legally ship it, but it's easy to get--in just about any quanitity.   Where is Homeland Security when you need them?


In a message dated 1/25/2010 10:38:43 AM Eastern Standard Time, kauletta**At_Symbol_Here**NOTES.CC.SUNYSB.EDU writes:

I think I have a possible cause for this HS chemistry class accident. I asked one of our researchers here who was a former food science chemist. She said that it if the teacher used the SOUR flavor, they set up an incompatible reaction.

Tartaric acid is used in the food industry to make the "sour" taste for gums and candy. The JT Baker MSDS for potassium chlorate ( specifically lists tartaric acid as an incompatible material:

Iodides, tartaric acid, aluminum, sulfuric acid, hypophosphite, powdered metals, organic matter and many other oxidizable substances.

It is also possible that all of the candy/gum wrapper was not removed and the caused a more vigorous reaction than anticipated.

This experiment, which appears to be common in HS chemistry classes, should have the following safety instructions included for all who demonstrate this reaction:

1. Read the MSDS for all chemicals before you use them. Make sure to read more than 1 manufacturer's MSDS - not all listed the specific chemical incompatabilities.
2. Do not use the SOUR flavor for the candy.
3. Check all glassware for any nicks, scratches, etc. Do not use if present.
4. Use a plexiglass or lexan shield between the students and the demonstration.

These shields can be purchased from Fisher (cat.# 1429340), VWR, Flinn (cat. #SE225) or other companies. They are expensive, but can be made relatively cheaply - buy a large sheet of lexan or plexiglass 5 to 20 mm thick and ask the Tech Teacher to cut it and mount it on a metal base.

Remember that the OSHA Lab Standard requires that there are written protocols for all experiments. These protocols must include the safety requirements!

Kim Auletta
Lab Safety Specialist
Stony Brook University
EH&S Web site:

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