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| Author |
Message |
| 25 new of 823 responses total. |
eskarina
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response 500 of 823:
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May 13 21:11 UTC 2002 |
Didn't it explode if it was pure, or something?
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jazz
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response 501 of 823:
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May 13 23:42 UTC 2002 |
Sodium flares up rather spectacularly, if it hasn't oxidized.
Heck with chem lab videos. We actually blew stuff up. You should've
seen the hydrolisation experiment. There's still a big charred "O" in the
ceiling from that.
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lynne
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response 502 of 823:
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May 14 00:15 UTC 2002 |
Yes and yes. It has a nasty habit of catching things on fire; add in the
fact that it's sitting in a bunch of organic (read: flammable) solvent, and
you have an excellent recipe for a nervous-making job. My favorite story:
in undergrad one of my classmates threw not-quite quenched sodium into a
sink full of acetone. Result: wall of fire.
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rcurl
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response 503 of 823:
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May 14 00:29 UTC 2002 |
Sodium is usually stored under kerosene. Doesn't one dispose of it
in absolute ethanol, where the reaction is relatively slow?
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keesan
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response 504 of 823:
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May 14 01:07 UTC 2002 |
Jim just fixed two problems with a grexer's worn-out VCR so now it will load
a tape and play it. Until you put the cover back on. My first computer was
like this, only worked at the store.
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mdw
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response 505 of 823:
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May 14 01:45 UTC 2002 |
I knew sodium was bad, but is calcium hydride really that bad? I seem
to recall seeing bits of "pure" calcium coated with not too much calcium
oxide (or whatever, from reacting with air). I think sodium + ethanol
results in an organic something that's still relatively nasty, though
probably not as explosive.
Moving the sodium should be fun. Can you get the fire department to
send out their Hazmat team?
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jiffer
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response 506 of 823:
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May 14 01:59 UTC 2002 |
Yeah, if you want some fun, flush it down a toilet and RUN.
Honest, I didn't do that... honest...
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i
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response 507 of 823:
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May 14 03:27 UTC 2002 |
Calcium hydride is CaH2. *Very* different from Ca, CaO, Ca(OH)2, etc.
I seem to recall some trick with sodium where you toss it into a narrow
dry well loaded with dry ice, then sprinkle in water. With some care
for the H2 coming off, you wind up with a well full of Na2CO3 & NaHCO3.
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rcurl
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response 508 of 823:
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May 14 04:50 UTC 2002 |
Sodium + ethanol = sodium ethoxide, which is just a rather alkaline
salt, not explosive at all. But hydrogen is given off during the
reaction, except more slowly than reacting sodium with water. But
you *must* use absolute ethanol - no water present.
Calcium hydride also reacts violently with water to produce hydrogen.
However it had been used to produce hydogen, by reaction with water
in the absence of air, to inflate balloons in the field, for meteorological
purposes.
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michaela
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response 509 of 823:
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May 14 08:13 UTC 2002 |
Keesan - if you don't like cars or the smell of a city, why do you live in
a city and not in the country? I've always wondered that.
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jaklumen
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response 510 of 823:
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May 14 08:53 UTC 2002 |
resp:495 resp:496 I don't sleep well, already-- I may have sleep apnea.
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other
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response 511 of 823:
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May 14 13:38 UTC 2002 |
In our chem lab we dropped a sodium chunk roughly 1.5 cm cubed into a 1
liter beaker of water. The sodium skittered about on the surface of the
water, spinning so fact it looked like a sphere, spitting out tiny
sparks. Eventually, the hydrogen in the vicinity accumulated to
sufficient density that one of the sparks ignited it, and there was a
white mushroom cloud which shot up about 6 feet from the top of the
beaker. The funniest part was the entirely startled reaction of Kurt
Magnus, who was sitting closest to the apparatus and was not paying very
much attention to what I was finding so entirely interesting that I
distinctly remember all these details now even though this event happened
in 1986 or 1987. He jumped straight up, nearly knocking over his stool.
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lynne
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response 512 of 823:
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May 14 15:59 UTC 2002 |
Yes, sodium is normally stored in oil or paraffin or kerosene. In this case
it was in pots full of solvent. The accepted quenching method is letting it
stand in isopropanol or t-butanol. Isopropanol didn't do much, so I
gradually added ethanol, methanol, then a small amount of water. The sodium
pots were sort of disappointing--they started bubbling gently after adding
water, continued for a few hours, then stopped. The calcium hydride pots
were much more exciting--they flat out boiled for 20 and 45 minutes,
requiring addition of more isopropanol when it all boiled off. Adding water
seemed to catalyze the reaction--probably the exotherm from reacting with
water kick-started the reaction with alcohols. Anyway, no sparks in the
area so no explosions. Thankfully.
IBB Northworst kicked up their prices another $150 from when I last looked
so I probably won't come home when I wanted to after all. :(
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eskarina
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response 513 of 823:
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May 14 16:37 UTC 2002 |
I did badly in chemisty. I hated the class and my mature 16 year old way of
dealing with this was to play tetris during class and not to my homework too
often. My lab partner and I held the 2 lowest grades in the class. Second
semester she had a D-, I had a D.
We both got fives on the AP Chemistry test. We were quite shocked, especially
since other people who were doing decently in the class did worse than us on
teh AP test.
The only fun thing we ever did in lab: one day, instead of doing our assigned
lab during lab, we got inspired to hold pennies in the flame from the
bunsen burner, and then throw them hot into a beaker of water. If you didn't
know, silver stuff (we think it was nickel) shot out. After a couple cooled
down, we kept them. I think I still have one in a desk drawer at home.
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keesan
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response 514 of 823:
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May 14 22:17 UTC 2002 |
Re 509 - I would be happy to live in the country if there were an electric
trolley line running every 15 minutes until 11 pm so that I could get into
town to go to the library, parks, bank, university, farmer's market, and visit
friends. That would let me put my bike on the trolley and get into town in
20 minutes or so. Do you know of any areas of the US that are like this?
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bru
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response 515 of 823:
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May 15 02:45 UTC 2002 |
Ah chemistry.
Making hydrogen go boom.
Using Liquid nitrogen to freeze things and to play hockey
using red phosphorus to make bombs (this was NOT sanctioned by the school)
and its counterpart
Physics!
Shocking students witht he vandegraph machine.
tearing TVs apart to make electronic instruments
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eskarina
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response 516 of 823:
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May 15 02:46 UTC 2002 |
Whats wrong with biking into town and biking out again?
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lynne
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response 517 of 823:
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May 15 03:04 UTC 2002 |
They don't let you work with anything truly nasty in high school.
Hmph. The sodium wasn't done being quenched, not by a long shot. And now
I've progressed to moving the stills themselves, including dealing with
truly nasty mercury bubblers (they've been abused enough that mercury has
been sucked back into the tubing. They're also going in the trash as soon
as I figure out which waste classification to put them in.)
Between Schlenk lines, copper tubing, and gas fittings I feel more like a
plumber than a chemist.
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mdw
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response 518 of 823:
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May 15 05:04 UTC 2002 |
If the mercury bubblers have significant mercury in them, you might get
good money from a scrap dealer. I think mercury is not far from gold
price-wise, and it's amazing how little gold will make scrap electronics
valuable. It is also worth scrapping worn copper fittings & lead,
although those are obviously not in the same league.
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rcurl
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response 519 of 823:
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May 15 06:33 UTC 2002 |
You may have trouble selling mercury as scrap, especially small quantities.
It is not worth the trouble to purify for reuse, in most cases. It is
also classified now as a (highly) toxic waste, and will probably have
to be "donated" to a hazardous waste processor.
Re #517: you are playing chemical engineer. Within the profession they
sometimes refer to themselves as "educated plumbers" (not to disparage
the plumbing trade, but to express how they feel sometimes).
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michaela
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response 520 of 823:
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May 15 08:19 UTC 2002 |
Breakups suck, and then they keep on sucking...
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jazz
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response 521 of 823:
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May 15 15:07 UTC 2002 |
Neanderthals don't study physics!
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lynne
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response 522 of 823:
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May 15 19:01 UTC 2002 |
Some bright child decided to mix oil with the mercury (bubblers are usually
oilr or mercury, but not both). . Any way you cut it there's a lot of
contaminated tubing as well. It's not worth it to me personally to
try to sell it as scrap (and God forbid anyone mention the possibility to
my penny-pinching boss!) since it's not mine.
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bru
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response 523 of 823:
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May 15 22:51 UTC 2002 |
neanderthals PLAY with physics!
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mdw
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response 524 of 823:
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May 16 06:17 UTC 2002 |
In theory, if you mix water with this, then centrifuge, you ought to be
able to separate the oil & mercury quite easily. You should end up with
a layer of mercury, then lots of broken glass floating on that, then
water, then oil.
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