#7: Pepto-Bismuth

I was in the pharmacy the other day when I saw something neat that I didn't think still existed: Pepto-Bismol. For those who don't know, Pepto-Bismol is a digestive medicine that has been around for quite a long time. The reason I was interested in it was not because I had a terrible stomach ache, but because of the drug's chemical makeup. I had heard a while back that the medicine contained bismuth as part of its active ingredient bismuth subsalicylate (C7H5BiO4). Bismuth is a non-toxic heavy metal that resembles lead in a lot of ways. If you saw my first post about diamagnetic levitation, you'll also know that it weakly repels strong magnets. Anyway, I decided to buy a small pack of Pepto-Bismol tablets with the hope of somehow extracting bismuth from them. After going online and finding the correct procedure, I learned that my hope could easily become a reality.

I started by crushing up the majority of the bright pink tablets in my mortar and pestle. I then placed the neon powder in a beaker and added some diluted hydrochloric acid (HCl). It took a while, but I eventually dissolved the Pepto-Bismol into the hydrochloric acid with a good amount of stirring. After filtering out any leftover solids, I placed a strip of aluminum into the pale pink solution and let it sit for a while. What happened was that the chlorine ions from the HCl let go of the bismuth ions and bonded with the aluminum ones instead. This left the bismuth to simply clump together and form a gray precipitate. I was then able to collect these bismuth particles using a coffee filter. After allowing the powder to dry and putting it into a steel ladle, I attempted to melt it over our stovetop.

Sadly, I never got the shiny silver liquid that I was looking for. Instead the dark dust simply fused together and turned mustard yellow. After thinking about it, I would say that there were most likely too many impurities. As far as the yellow color goes, I suspect that this was due to the oxidation of either the bismuth or the leftover aluminum. I may never know.

Bright pink Pepto-Bismol digestive medicine containing minor amounts of the element bismuth.

Precipitation of solid bismuth
out of HCl using aluminum. 

Pure bismuth metal from my "Diamagnetic Levitation" project.

Impure bismuth sludge.

To perform this experiment yourself...

http://www.popsci.com/diy/article/2012-07/gray-matter-extracting-bismuth-pepto-bismol-tablets

#6: Burning Sulfur

In my last post I mentioned how I sometimes break off chunks of my sulfur specimen to use in experiments. So this time I am going to do just that. While I have done this experiment before, I thought it would be neat to try it again and record it this time. To start, I simply chiseled off a few pieces of elemental sulfur and ground them into a fine powder. After placing this powder on a piece of wood, all I had to do was ignite it. Due to its low melting point, the sulfur actually melts upon contact with a lit match and burns quite steadily. While it may seem in the video below that there is no flame, it is merely too dim to see during the day. Luckily, you don't get to smell the horrible stench of rotten eggs that is produced.

What happened was that the heated sulfur bonded with the surrounding oxygen to produce sulfur dioxide (SO2) and sulfur trioxide (SO3). Both of these products are poisonous and here is the interesting reason why. These gases bond with water molecules in the air, or on the surface of your body, to form both sulfurous acid (H2SO3) and sulfuric acid (H2SO4) on the spot! While this reaction isn't extremely dangerous, it should obviously be performed outdoors or in a fume hood. In my opinion, sulfur is a fascinating element with many unique aspects.

As you can see, sulfur burns somewhat strangely.

If you would like to learn a bit more about sulfur...

http://en.wikipedia.org/wiki/Sulfur