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nezza
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One synthesis I am not going to repeat is Hydrogen selenide. I took a very cautious sniff of some once and it anaesthetised my nose for about a day. I
could not smell anything. It was quite unpleasant.
If you're not part of the solution, you're part of the precipitate.
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ave369
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Quote: Originally posted by Amos  | | As for iron contamination in general, check Lowe's. The new brand of HCl they stock, at least in all of my city's locations, is water-clear.
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Why buy HCl if you can make one? Table salt and battery acid in a flask, latch it on a distilling setup and distill colorless HCl with a known
concentration (20+some%)
Smells like ammonia....
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careysub
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| Quote: Originally posted by woelen | | Quote: Originally posted by alexleyenda | [...]
The only thing related to physics I see which could a bit explain Joker's statement (which remains false anyways) is that when energy is dispersed in
a spheric 3D way, the power decreases in a cubic way because the area covered by the power increases in a cubic way, so the power becomes a lot less
concentrated very fast in comparison with the radius (linear distance from the explosion). The power of small amount of explosive can get "diluted" so
fast that it appears that using a bigger charge is a lot more powerful as it takes more distance ( a bit more than a linear relation) for the power to
be cubic rooted down to the same level.
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There are some errors in your last paragraph:
The power is not inversely proportional to the cube of the distance, but to the square of the distance. Assume that power is transmitted as a
spherical shockwave and no power is lost between center of explosion and the distance where the explosion is observed. The power is distributed over a
sphere, whose surface area is proportional to the distance of center of explosion. So, this makes the perceived impact of the explosion inversely
proportional to the square of the distance from the center of explosion. In reality, the exponent will be slightly larger than 2, but much less than
3, due to losses of power (e.g. frictional losses between air molecules while the shock wave travels through the air).
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This is a bit late in the thread to comment upon, since this exchange occurred a year and a half ago, but I wanted to insert a correction in this
thread about the nature of explosions, shock waves, and distance scaling.
We need to distinguish between strong shocks (a large pressure increase relative to ambient) and weak shocks (a small pressure increase).
Strong shocks do a lot of work on the medium through which they travel, accelerating, compressing, and heating (in something like that order of
importance). This dissipation of energy is why strong shocks tend to cause things to fly apart. Strong shocks absolutely follow inverse cube root
scaling since energy is being expended in three dimensions.
The limiting case of weak shocks is the "bang" sound you hear a good distance away. It is essentially just a noise (though with a rapid rise) so
inverse square root scaling applies.
There is obviously a transition between strong and weak shocks were the exponent declines from 3 to 2. Modeling this in closed form is a bit
complicated, and usually nomographs and the like are employed, more exactly numerical simulations are used that model the microscopic processes and
give appropriate answers at all scales.
| Quote: |
In reality, the relations will be more complicated, due to losses of energy, due to widening of the shock wave while it travels outwards and due to
different characteristics of explosion for different masses. At a larger distance, the explosive power is not only distributed over a larger surface
area, but it also is distributed over a larger amount of time (widening of shock wave).
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A shock wave is by definition an instantaneous energy transfer. They cannot "widen" because they always have near zero thickness (a few mean free
paths in the medium). Discussions of the "thickness" of a shock are really talking about the time for equilibrium to be reached as the instantaneously
transferred energy redistributes between translation, rotation and vibration of the molecules and is important with polyatomic molecules. This
equilibrium is actually achieved faster on average with weaker shocks than stronger ones since it starts out closer to equilibrium anyway.
As the shock decays into a sound wave it stops being a sudden jump and becomes the very steep leading edge of a sound pulse, but by this point it is
no longer a shock wave. As this sound pulse broadens, the sound stops being a bang and becomes imperceptible to human hearing (Krakatoa pressure wave
you hear of circling the Earth was just such an inaudible pressure pulse).
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woelen
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No problem that this is a response to an old thread. If all responses to old threads were like this then it would be good to have many of such
responses 
Interesting read and good to see that there are people who are knowledgeable about this subject. Thanks for the corrections and making things more
precise. There is one question left for me. Strong shocks have cubic fall off of intensity with increasing distance, but this would mean that a lot of
energy is "lost" (converted to heat), especially near the center of explosion. Is it true that near the center of explosion there is a very strong
heat-up of the air, even if the chemical reaction does not produce that heat? Otherwise I see no possibility of cubic fall off (only sub-cubic, like
exponent 2.5 or even less).
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careysub
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| Quote: Originally posted by woelen |
Interesting read and good to see that there are people who are knowledgeable about this subject. Thanks for the corrections and making things more
precise. There is one question left for me. Strong shocks have cubic fall off of intensity with increasing distance, but this would mean that a lot of
energy is "lost" (converted to heat), especially near the center of explosion. Is it true that near the center of explosion there is a very strong
heat-up of the air, even if the chemical reaction does not produce that heat? Otherwise I see no possibility of cubic fall off (only sub-cubic, like
exponent 2.5 or even less). |
Yes, prompt heat dissipation (that is, a sudden temperature jump along with the pressure jump behind the shock front) is prominent in very strong
shocks, declining in relative importance as the shock weakens (the limiting case is half of the total energy appearing as heat).
It is a reasonable approximation to assume cube root scaling if the shock is intense enough to damage physical objects; square root at a distance when
you are considering only the sound. I recall that for some damage modeling rules-of-thumb an exponent of 2.7 is used (much closer to 3 than to 2).
With very large explosions, at extreme distances, the dissipation of sound can actually fall below inverse square as the sound becomes
channeled by inversion layers within the atmosphere. This creates loud and silent ("shadow") zones on the ground with the audible zones extending
great distances from the sound source. This accounts for people hearing Krakatoa thousands of miles away (a spotty phenomenon, only intermittent areas
heard it).
These refraction sound zones are separate from the inaudible pressure pulse I mentioned in my previous post, the explosion energy in air having split
into separate methods of transmission.
[Edited on 22-12-2015 by careysub]
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crystal grower
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Quite scary was for me reaction of hcl and h2so4 I wasnt expecting anything and it suddenly started making a lot of hcl gas  
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zed
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Ethanol. It has killed billions.
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Atrum
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Sadly, it would be hydrazine sulfate.
.......stop laughing, I can feel you all laughing. ....
"Experience is my one true mistress and I will cite her in all cases. Only through experimentation can we all truly know anything." ~Leonardo da Vinci
My inventory
Recently acquired elements: Iodine , Cobalt, Tungsten, Silicon |
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j_sum1
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Hey. I haven't made hydrazine sulfate yet. It is on my list. So, no laughing here.
My best is either Cl2 or Br2 depending on which you consider more dangerous.
And also some accidental NCl3 in very small quantities. Quite the pop in the beaker.
Of course quantities come into play in a discussion like this one.
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crystal grower
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The most dangerous chemical is .......................
............................my DNA .
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Sulaiman
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Coming up to two years as a hobby the most dangerous substances made or isolated
Mn2O7, Aqua Regia, Pirrhana solution, Br2, NO2.
I have noticed that I,m a lot more careful (respect bordering on fear) doing chemistry than when I was a teenager.
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Eddygp
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Hahaha, best answer to crystal grower (however, let me add that my DNA surely is more dangerous!)
there may be bugs in gfind
[ˌɛdidʒiˈpiː] IPA pronunciation for my Username |
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szuko03
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| Quote: Originally posted by Sulaiman | | I have noticed that I,m a lot more careful (respect bordering on fear) doing chemistry than when I was a teenager. |
Isnt it funny how that works. Up until recently its not that I wasnt concerned I just somehow got more aware of the danger. I watched some documentary
on environmental pollution building up in human bodies, after that I became aware of something i always knew "if you can smell it then its getting
into your blood" and now I cant help but think anytime I smell something "oh man the ventilation isnt good enough, that stuff is getting in my blood"
and that thought like haunts and bothers me. Its good now im at less of a risk for cancer through exposure to fumes from things i suppose, not that i
was purposely inhaling vapors before.
But yeah i dont really deal in danger so just acetone peroxide when i was younger I wont do things like that now.
[Edited on 3-2-2016 by szuko03]
Chemistry is a natural drive, not an interest.
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woelen
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Wisdom comes with the years. This also is true in chemistry 
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crystal grower
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Thanks for compliment, but I don't think anything is more dangerous than DNA of 16 years old curious chemist .
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The Volatile Chemist
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May I second that, I too know what you mean (I'm 16 too)
The most dangerous compound that happens to be forming in my lab is ethanol (a joke, aga, arkoma), but I'm not making it, and it's tainted with an
unknown, wild yeast I'm trying to grow, so it's both useless to me, and not the purpose of the experiment.
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jokull
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Potassium cyanide, however the method is not dangerous.
Kind regards.
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chemplayer..
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Cyanogen iodide and then attempting to isolate it by vacuum fractionally distilling a solution of it in DCM (guess what, it just comes over alongside
the DCM and then vapourises right into the vacuum pump even if the receiver is cooled in ice!).
The brown-polymeric stains of decomposing CNI (slowly emitting even more badly staining iodine) literally took weeks to get off the glassware and out
of the filter pump.
But the crystals forming as the solid evaporated were simply stunning. As thin as a spiders gossamer thread and 7-8 cm long extending through air!
There's an old video of ours which has some of the crystal footage in it.
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Xanax
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I was extracting ricin from castor beans, and abrin from the rosary peas. The FOA (the military forensic station) in sweden was analysing it, and they
said that abrin is about 50 times more poison than ricin. The police said, it was so dangerous that no delivery service wanted to transport it to the
NFC (Nationell Forensic Central), so the police drove self with the bottles. Then it was to poisonous for NFC, so it was sent to FOA...
The newspaper wrote on the first side:
"Hundreds could have died"
WAR AGENTS WAS MADE IN
KITCHEN IN ÄNGELHOLM
Then I was prosecuted on 5 points;
1. Crime against the radition safty law (I had a lot of radioactive material at home)
2. Crime against the radition safty law (yes it was the same on 2 points)
3. Crime against the law about chemical war agents (ricin)
4. Crime against the law about war material (abrin)
5. Illegal enviroments activities (ricin, abrin and nitric acid)
If here is someone who can swedish, you can read the judgment here:
https://docs.google.com/file/d/0B3-9YUgtqBa0RVJWWWpQRmIyczg/...
I was guilty at point 1 and 5, and freed on point 2,3 and 4. I didn't know it was illegal to extract the poison from the beans, because the beans are
sold everywhere. My penalty was fine on 13 600 swedish kronor, it is about little less than 2000 $.
Now I don't lab at home anymore. But had a search warrent for a half year ago. It was my psychopath to ex-girlfriend who wanted to fuck up my life and
tipped the police. They seducted the whole block, and men went in to my apartmen in protection-suits with breathing-units... The bombsquad was also
with them, and they had with them firetrucks and ambulances was ready...
Some pictures (and swedish text) in the newspaper:
http://www.hd.se/2016-04-01/han-forsokte-bygga-karnreaktor-i...
I'm still intressted in specially toxicology. I know how simple it is to make for example botulinum toxin, but I will never do that!
EDIT 1: They took all my toxic and radioactive stuff (even welding-electrodes which was 98% Tungsten and 2% Thorium). But the let my collection of
elements still (except Uranium, Thorium, Radium, Americium and Trithium). There I have some dangerous elements, Thallium, Selene, Arsenic and pure
Cesium. The Cesium is not poisonous, but it will explodes in contact with water. They all are in glass-ampoules.
EDIT 2: Some english news about it:
https://www.theguardian.com/world/2011/aug/03/atom-splitting...
http://www.bbc.com/news/world-europe-14406766
http://www.telegraph.co.uk/news/newstopics/howaboutthat/8679...
EDIT 3: When I was working and extracting ricin and abrin, I got sick, I womited blood, and there was blod in the feaces. I had a little fever, but it
went back...
[Edited on 5-10-2016 by Xanax]
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Tsjerk
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A colleague of mine accidentally made some hydroden-telluride the other day... While making Baird-Parker plates she dropped the last couple of
milligrams in the wast bin. The next colleague dropped some acid in the same bin. The result was hydrogen-telluride. The smell was comparable with
rotten eggs and dead bodies, but it was really hard to tell where the smell was coming from... it was persistent although the room is cleaned of air
every 5 minutes, heavy stuff...
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Sulaiman
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Xanax
1 did you have an actual nuclear meltdown ?
2 did the authorities send you for any medical tests ?
CAUTION : Hobby Chemist, not Professional or even Amateur
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Xanax
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1. It was absolutly not a meltdown, I just made fun of the situation. I was boiling Beryllium, Americium and Radium in 96% sulfuric acid to blend all
the substanses. And suddenly it boiled almost explosivly and splashed down the stove.
2. Yes, I was sent to do a forensic psychiatric investigation.
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Sulaiman
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ok, first answer as expected, just checking.
your second answer surprised me, I was thinking of radioactivity etc.
but then you were rather crazy 
P.S. I hope that you did not get dosed like David Hahn
http://www.dangerouslaboratories.org/radscout.jpg
[Edited on 5-10-2016 by Sulaiman]
CAUTION : Hobby Chemist, not Professional or even Amateur
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Xanax
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The Swedish Radiatonsafty Authorothy said that I probably not was exposed for harmful doses of radiation.
But David Hahn was a big inspiration source for my project.
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TheNerdyFarmer
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Just started so probably nitric acid.
(Considering I forgot to delude the HCL and had a runaway reaction.  OOPS! )
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