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Author: Subject: Bad Chemistry on TV
NeutralIon
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[*] posted on 12-5-2009 at 13:09
Bad Chemistry on TV


Its really amazing what they can do with chemicals on TV!

The episode of CSI:Miami last night had the deceased victim floating in a swimming pool full of NaOH. The concentration was strong enough to eat through glass.

When the CSI guys realized it was an alkali they knew they needed to neutralize it in order to retrieve the body. So they send one of the team to the local grocery store for vinegar. They proceed to pour the vinegar from gallon jugs into the pool dropping the pH from almost 13 [just after they started adding the vinegar] to exactly 7.0 -- all within a few seconds, and without any stirring.

Now, I'm no expert on chemistry but I do know that vinegar is, at best, 5% acetic acid and acetic acid is a weak acid so even with equal molar amounts of NaOH and CH3COOH you would not get down to 7.0. To get that low you would need a large excess of vinegar -- somewhere around 20 times the volume of water in the pool!!! Yet they poured this all in from gallon jugs in under a minute and the pool did not overflow.

Somebody in the Miami area please check your local grocery stores and find out what brand of vinegar they are selling.
:D




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Saerynide
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[*] posted on 12-5-2009 at 16:32


I was thinking more like the body should have turned into soap by the time the cops got there :D



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BromicAcid
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[*] posted on 12-5-2009 at 17:39


Remember that pH is a logarithmic scale. A 0.5% solution can have a pH of 13-14. That's only 5 g NaOH/ Kg of water (w/w). Point being that it doesn’t take much sodium hydroxide to change the pH quite a bit.

Assuming average pool size of 20 x 40 ft and 5.5 ft deep, volume is 33000 gallons, is equivalent to 124918 L so assuming 1.0 Kg/L density that gives 124918 Kg of solution which contains 624 Kg NaOH. Converting to mols, 1561 mols NaOH. Molarity of store bought vinegar ca. 0.8 M so doing the math and just trying to neutralize the sodium hydroxide and ignoring the buffer effect of the acetate anion...

1951 L of vinegar will do it. Or, 515 of those 1 gallon containers. In the scheme of things, that's only 1.5% the existing volume in the pool. So, I wouldn't say overflowing but it would take some time to add for sure. And I think they would have to visit quite a few stores to get that much vinegar. Considering the dilution of it though I wouldn't worry too much about mixing, by the time it was all added from 1 gallon containers with the circulation pumps in a pool it should all be pretty good. By the way, the bleach we use in the kitchen has a similar pH and I've know lots of people who will clean whole kitchens using straight bleach with a sponge and no gloves. How badly was the glass eaten?

I've seen plenty of bad chemistry on TV, I would consider this an exaggeration, like in cooking shows when they cut to the finished product but not anything egregious.


[Edited on 5/13/2009 by BromicAcid]




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NeutralIon
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[*] posted on 14-5-2009 at 10:34


Bromic --

I think you are right -- I somewhat overestimated the amount of vinegar needed.

But your analysis may be a bit low. Adding 1561 moles of acetic acid in the form of 1951 L of vinegar only drops the pH down to the equivalence point which for the chemicals involved is about 9.2. On the show they did show the pH going to 7.0 so some additional acid would be needed to get there.

Either way -- a lot more vinegar than they showed.






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kclo4
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[*] posted on 14-5-2009 at 14:59


Another example is the anti-smoking commercials. They have the symbol for lead as PB, not Pb. They also suggest that it is found in high enough concentrations in cigarettes to worry about, which seems stupid since I would bet tomatoes would have similiar concentrations.





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[*] posted on 14-5-2009 at 20:51


Similarly, the anti-cigarette ads talking about Sodium Hydroxide in cigarettes. Hmm, those of us who bother to read labels know it's in eye drops too. :P



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[*] posted on 23-5-2009 at 17:32


Hah that reminds me of the anti-meth posters that are trying to tell you that the various reagents and solvents used to manufacture it are actually in the final product. '"Oh my god there's lye and paint stripper in my meth!" It's hilarious.

Its amazing how people have such a hard time understanding that all the various "ingredients" are simply used to manipulate a specific molecule, rather than being tossed together and magically making a mixture that happens to get you high..


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[*] posted on 28-5-2009 at 20:48


On the other hand, for basement-made meth (basically all of it), I would expect you get a slight to not-so-slight amount of impurities. Maybe not volatile-as-hell paint stripper, but certainly unpleasantness. Not that the unpleasantness could easily be worse than the meth itself, but ya know.



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[*] posted on 29-5-2009 at 09:51


that exceeding the buffering effect :)
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everythingischemistry
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[*] posted on 18-7-2009 at 00:56


The water supplies in the UK still extensively have lead pipes from the community mains to each home. We don't all fall over with lead poisoning. Most people don't even know their water comes through lead pipes. I've handled lead without gloves, etc many times (in the form of fishing weights) and not bothered to wash my hands afterwards before eating/drinking. Nothing bad happened. Of course I wouldn't want to EAT the lead or inhale it (in any sort of visible quantity, some idiots actually smoked cannabis with visible bits of lead in it according to news reports) but it's not AS dangerous as most people think.

Bleach isn't that dangerous on it's own either. You could have a swig from the bottle (assuming it's just sodium hypochlorite, which most "bleach" in the UK isn't) and while you will sure as hell wish you didn't (don't try this at home kids) it's unlikely to kill without having a fair bit. Personally I would wear gloves with this one but I don't bother to wash my hands after holding the bleach bottle or anything if I was just using it to sanitize something, despite the overblown warnings on the label.

People get so scared of the "chemicals" these days. It's a pity the powers that be are so paranoid of having an enlightened society they fuel this nonsense. They are doubly stupid as 1) There is a thing called the army which will always have bigger and badder stuff than everyone else so the government as a "team" has nothing to concern itself over and 2) If someone really, really, really wants to kill the president/prime minister/anyone else and isn't a complete idiot then they are going to. The IRA have almost killed our PM on a few occasions and the technology they used while not available in a store near you isn't very advanced either and not something you can stop people doing if they are really dead set on doing it.

Doesn't CSI get a lot of flack for doing things badly? I've read in other pieces of fiction before bemoaning the "CSI effect" where juries and others have unrealistic expectations of forensics because of CSI but I don't watch it myself and don't know how valid these criticisms are, anyone? Are CSI proponents of bad science often?
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[*] posted on 18-7-2009 at 03:10


CSI just sucks and creates false ideas about the whole subject.
I have seen people on TV say that cigarettes contain carbon monoxide.
I mean what the fuck, it seems to be allowed to speak about things that one doesnt know shit about.
False ideas and throwing it on scare politics.




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DJF90
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[*] posted on 18-7-2009 at 07:38


Cigarettes DO contain carbon monoxide! I'm pretty sure if you look at a cigarette packet you'll see some numbers for nicotine and carbon monoxide, per cigarrette. IIRC carbon monoxide is generally about 10mg, and nicotine about 2mg? But its been a long time since I've seen a cigarette packet as I dont smoke. I'm pretty sure this information is on most products, I know for sure that Lambert&Butler and also SilkCut divulge this information.
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[*] posted on 18-7-2009 at 08:12


Are you sure that cigarettes actually CONTAIN carbon monoxide, or that it is just produced durning combustion. I can't really see even 10mg of CO trapped in the cigarrete itself.



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[*] posted on 18-7-2009 at 11:34


The almost routine filmsci presentation is glassware with colored liquid in weird places like the condenser coils or an anti-foaming device such as in Air America and there are much worse examples I just can't recall right now..anyway, it embarasses



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[*] posted on 18-7-2009 at 12:02


Quote: Originally posted by everythingischemistry  
Nothing bad happened. Of course I wouldn't want to EAT the lead or inhale it (in any sort of visible quantity, some idiots actually smoked cannabis with visible bits of lead in it according to news reports) but it's not AS dangerous as most people think.

If water in lead pipes falls below a certain pH some lead will dissolve and such water will have high toxicity---any underestimation of lead's toxicity is foolish as lead is an insidious cumulative poison. . .
The NaOH in commercial bleach is much more toxic than NaClO, but solutions of NaClO disproportionate so that these solutions normally contain NaCl + NaClO + NaClO3.
Chlorates were once used as an anti-bacterial in throat lozenges. . .
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[*] posted on 18-7-2009 at 12:14


Quote: Originally posted by BromicAcid  

Assuming average pool size of 20 x 40 ft and 5.5 ft deep, volume is 33000 gallons, is equivalent to 124918 L so assuming 1.0 Kg/L density that gives 124918 Kg of solution which contains 624 Kg NaOH. Converting to mols, 1561 mols NaOH.
[Edited on 5/13/2009 by BromicAcid]


I just noticed this, and maybe I'm totally off here, but the molar mass of NaOH is ~40g, so 624kg would make about 15,610 mols NaOH.

Am I missing something?




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[*] posted on 18-7-2009 at 14:00


Lead is more soluble in soft water than hard water. IRC England has some impressive limestone deposits so I would think the water pretty "hard" with calcium and magnesium bicarbonates. Correct me if I am wrong about England's mineralogy

We need to get the message out to the powers that be that this oppresive and restrictive society is actually more insecure and unsafe then when we had relative freedom in years past.




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[*] posted on 23-7-2009 at 15:17


I watched an episode of some CSI show and noticed that they claimed--wait, no, it was House (a doctor TV show)--that some guy had been killed by mixing ammonia and bleach and breathing in too much chlorine gas.

This seems to be a common mistake. Is there any chlorine gas released by such a mixture? I know it can't be much because I have tried it on a small scale (and noticed no color and little Cl2 smell; not that I was going out of my way to smell it).

Also less common (but worse) is that ammonia and bleach will produce "mustard gas".

Even worse is that gasoline and "moth balls" produces nitroglycerin.




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[*] posted on 23-7-2009 at 15:35


No Cl2 if there is an excess of ammonia which would react with it. I know interactions of aq. -ClO and NH4 salts is somewhat complex, those I know can release some Cl2.

In one of my old favorite shows called the Pretender, there was an episode where a stalker would take pictures of his stalking victims. Then he took the pictures and dripped an acid to dissolve some portion of the picture, it just ate right through the picture.
I don't think such a compound exists :P. Maybe HSbF6.
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[*] posted on 23-7-2009 at 17:22


Quote: Originally posted by Formatik  
No Cl2 if there is an excess of ammonia which would react with it. I know interactions of aq. -ClO and NH4 salts is somewhat complex, those I know can release some Cl2.

In one of my old favorite shows called the Pretender, there was an episode where a stalker would take pictures of his stalking victims. Then he took the pictures and dripped an acid to dissolve some portion of the picture, it just ate right through the picture.
I don't think such a compound exists :P. Maybe HSbF6.


I used to take a Q-tip soaked in concentrated HCl and touch photos and poloroids I did not like. It only removed the image and noting more.

I also see too many programs using dry ice in brightly colored liquids to cause room temperature boiling and plumes of mysterious fog.




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[*] posted on 24-7-2009 at 21:10


I liked the one on "Breaking Bad" where, having recieved orders to dispose of a corpse, some idiot places the decedent in the upstairs bathtub and adds a large quantity of conc. HF. THe bathtub dissolves and the carcass soon falls through the floor into the downstairs hallway. It was unclear as to what effect the HF fumes had on the dimwitted perpetrater while splashing the acid all around in the enclosed bathroom space!

[Edited on 25-7-2009 by Elawr]




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[*] posted on 25-7-2009 at 00:20


Also on breaking bad, I believe he had a large crystal of mercury fulminate.. sounds a bit impossible, they only recently discovered its crystal structure IIRC.



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[*] posted on 25-7-2009 at 01:42


Yeah that mercury fulminate feature was entertaining.. Convenient how it happened to look identical to the crystal meth...

I was just waiting for him to try crushing a crystal up with the butt of his knife like he did before... That wouldn't have been pretty.. :P
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[*] posted on 25-7-2009 at 01:44


Quote: Originally posted by MagicJigPipe  
I watched an episode of some CSI show and noticed that they claimed--wait, no, it was House (a doctor TV show)--that some guy had been killed by mixing ammonia and bleach and breathing in too much chlorine gas. This seems to be a common mistake. Is there any chlorine gas released by such a mixture? I know it can't be much because I have tried it on a small scale (and noticed no color and little Cl2 smell; not that I was going out of my way to smell it). (cut)
Even worse is that gasoline and "moth balls" produces nitroglycerin.

Mixing ammonia and hypochlorite bleach would probably result in chloramines, NH2Cl and NHCl2; and, if an excess of bleach is used, nitrogen trichloride, NCl3, which is a dangerously unstable explosive (too dangerous to use commercially) as the French discoverer, Dulong, found out.
Gasoline is a mixture of low to medium weight hydrocarbons (unless alcohol has been added) with about 5 to 12 C atoms, with the branched-chain saturated aliphatic species obtained by catalytic cracking with addition of H2 to unsaturated species being most valued; while mothballs are either naphthalene, C10H8, or dichlorobenzenes (especially the para isomer), which smell similar. The mothballs would simply dissolve in the gasoline.
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[*] posted on 25-7-2009 at 13:21


I saw that House episode and laughed. Normally I like House, but I have found a few errors lately. One of them was the chloramine one. Another I noticed that in one episode they did the standard tested for amyloidosis but skipped the addition of KMnO4, yet were still able to see that it was amaloid AA.



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