From sci.chem Thu Nov 14 17:24:50 1996 From: Jeff Elliott Newsgroups: sci.chem Subject: Re: Lab Accidents....... Date: Tue, 12 Nov 1996 02:14:26 -0500 Organization: HookUp Communication Corporation, Oakville, Ontario, CANADA I had three interesting experiences in my Chem undergrad: Experience #1: In my very first lab of my very first intrductory lab course, the (extremely strict and pushy) lab instructor had finished drilling us on how we were to perform the "experiment". (We were to determine the concentration of an acid solution by titrating NaOH into it, using phenolpthalein indicator. Oh, my.) Most of the other students were still setting up when I made the (drastic) error of *manipulating the stop valve of the burette from the front* instead of the *correct* method of reaching around from behind. (gasp) Determined to make an example of me, the instructor stopped me, gathered the whole class around to observe, and began to do the lab for me, *correctly*, of course. She made a big show of reading the meniscus, asked for my sample beaker, insured that I had added the indicator, and began to titrate. Demostrating proper procedure, she added enough titrant to come close to the expected amount, and (manipulating the stop valve from behind), began to titrate a drop at a time. No colour change. After passing the expected volume, and then some, she stopped and accused me of incorrectly preparing the sample. At that point, I remarked that she was titrating a soap solution, and that I had been cleaning my burette when she stopped me. The remainder of the semester was not easy.... Experience #2: We were writing a midterm in the analytical lab, for lack of another room. One fellow walks in 5 minutes late and looks around for a seat, of which there are none. He pulls a stool over to the end of the bench, and goes to move a large cardboard box full of used glass sample vials to one side. Of *course*, the bottom of the box gave way, and the hushed lab was treated to the waterfall sound of about 200 glass vials plummetting to the ground at his feet. I think his face went from pink to white to red several times before anyone else stopped laughing long enough to help him out of his mountain of broken glass. Experience #3: In Inorganic, we're making a silicon polymer. In step 1, we've made the monomer in (if memory serves) an ether solution. After vacuum-evaporating off the solvent, we're supposed to cook it at 200+ C for a while (above a boiling oil bath). One of the other students plops her product in its vial into the same oil bath as mine. Needless to say, she hadn't removed the ether, and the resulting explosion threw flaming oil and silicon polymer over a few of us nearby. After we had beaten out the flames, I retrieved my sample. I think I had a 3% yield for the experiment, and wound up describing my product as "real crunchy". From sci.chem Thu Nov 14 17:25:25 1996 Path: hakea.adelaide.edu.au!ns.saard.net!harbinger.cc.monash.edu.au!munnari.OZ.AU!news.mel.connect.com.au!news.uwa.edu.au!disco.iinet.net.au!opera.iinet.net.au!news From: clarke@web.net.au (Martin Lindsay) Newsgroups: sci.chem Subject: Re: Lab Accidents....... Date: Wed, 13 Nov 1996 12:19:23 GMT Organization: webnet services Lines: 20 Message-ID: <56ceel$mc8@opera.iinet.net.au> References: <55u90r$2k6@usenet78.supernews.com> Reply-To: clarke@web.net.au NNTP-Posting-Host: grunge164.nv.iinet.net.au X-Newsreader: Forte Free Agent 1.0.82 True story from downunder... A commercial laboratory in QLD set up to assay exploration and mine samples for the gold mining industry. One of their methods involved wet ashing of carbon samples using... Perchloric acid. Twenty samples, five grams of carbon, 20 mL of HClO4 in each went on the hotplate while the chemist left the lab for lunch. The resultant explosion destroyed half the lab including their AA instrument room. they went out of business shortly afterwards, but the report on the accident contained the phrase " The cause of the accident is uncertain but I strongly recommend that this method be discontinued" True...