This video arrived in the ChemBark mailbag today courtesy of Robert. It is best watched with laser goggles of OD 50 or higher.
And this video from the same channel addresses a practice that has escaped proper ridicule for far too long:
Today’s WWWTP? submission comes from my good friend Charlie, who snapped this picture of a dry cleaners in his Boston neighborhood:
I love the capital “O”. And to be honest, there actually might be nothing wrong with this picture. If the store is using the standard dry-cleaning agent, tetrachloroethylene (“perc”), then they’re certainly using an organic solvent in my book. This might not mesh with what some other people classify as ”organic”, but if ambiguous advertising is what it takes nowadays for dry cleaners to stay in business, then I’m all for it.
It’s time for another edition of everybody’s favorite game: What’s Wrong with this Picture? Today’s image is pulled from the ChemBark mailbag, sent by regular commenter “Handles”.
That’s the cover of the April 2011 edition of R&D Directions. It is published by PharmaLive, the self-proclaimed “Pulse of the Pharmaceutical Industry”.
Larry the Crystal Guy e-mailed me the following discussion from a science forum. It’s ancient, but interesting. The exchange begins with an inquiry from a citizen with a rust problem. I’ve reproduced the authors’ typos and larger morsels of stupidity unedited…
I have recently acquired a large trunk for sotring things in, however the metal on the edges and corners has gone very rusty, through being sat in a cupboard for a long time. Anyone have any ideas, or know any good ways for how I can get rid of it? Cheers!
The best chemical I know to dissolve rust is hydrofluoric acid HF. Here in italy is sold in dilute acqueous solution (~10%) to use with textiles. On the other hand, it’s better not to use more concentrated solutions or there is the risk to attack the metal too. If you want to use it with a piece of metal, you should find a way to make the solution in a gel or sirup form, otherwise the solution slips away and/or dries too quickly. Once, I dissolved a large amount of sugar to that solution for this purpose (but there will surely be better ways than this one); of course the reactivity is lower.
Don’t go anywhere near HF, working in a materials lab for 5 years, this was the only chemical people were actually scared of – a suggested damage limitation measure invovles an axe! If you get it on your skin it will get rapidly into your flesh and then proceed to break down your bones…
I wrote: “dilute acqueous solution (~10%)”. It’s sold in most supermarkets! I have tried oxalic acid, phosphoric acid and acetic acid (the active chemical in vinegar) and only HF works, unless the rust is thin or in a “good” composition/physical structure. Infact, rust is not a specific compound, it can vary from Fe(OH)3 to FeOOH to Fe2O3..ecc. The first form, Fe(OH)3, is the easiest to remove chemically. But try to dissolve Fe2O3 with vinegar or oxalic acid. (I have tried).
An astute reader passed along the following nomination for the official Chemistry Hall of Shame (accept no imitations). It’s another chemistry advertisement, published on page 66 in the June 18th edition of C&EN:
All this succinimide/glutarimide business reminds me of my favorite chemistry mnemonic—the one for remembering the straight-chain diacids (from two carbons to seven):
Oh My, Such Good Apple Pie
(Oxalic Malonic Succinic Glutaric Adipic Pimelic)
Now, I’m not going to do something as hackneyed as ask, “What is your favorite chemistry mnemonic?” Nope. Not going to do it.
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