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Author: Subject: The Short Questions Thread (4)
Amos
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[*] posted on 26-9-2014 at 10:15


Quote: Originally posted by gdflp  
When did he say that? I think by "lower concentrations" he meant 20%, though I could be wrong.


I mean, I don't see any reason why it wouldn't work. Depending on the solubility of methyl ethyl ketazine in water you might lose more of your product in the end. You could always add a base to the ammonium hydroxide solution you have and heat it, driving out the ammonia and channeling it into some freezing cold ammonium hydroxide solution that you already have, in order to increase the concentration.




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[*] posted on 26-9-2014 at 11:00


I've got 2kg of aluminum sulfate laying around, but I have no idea what to do with it, considering that some reactions with it make Al(OH)3, which is awful to deal with... http://www.sciencemadness.org/talk/viewthread.php?tid=31603#...
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[*] posted on 26-9-2014 at 17:12


Quote: Originally posted by No Tears Only Dreams Now  
Quote: Originally posted by gdflp  
When did he say that? I think by "lower concentrations" he meant 20%, though I could be wrong.


I mean, I don't see any reason why it wouldn't work. Depending on the solubility of methyl ethyl ketazine in water you might lose more of your product in the end. You could always add a base to the ammonium hydroxide solution you have and heat it, driving out the ammonia and channeling it into some freezing cold ammonium hydroxide solution that you already have, in order to increase the concentration.


Yeah, I was trying to avoid doing that though. I think methyl ethyl ketazine is somewhat soluble in water, but I can't find any references about this.
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[*] posted on 3-10-2014 at 07:59


Hi Folks,

What do you think this device did in its good days? I scavenged it from a closed analytical lab. The shiny part at the end looks like gold to me:))

Thanks for your help!


IMG_3157.JPG - 374kBIMG_3158.JPG - 415kBIMG_3162.JPG - 418kB
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[*] posted on 3-10-2014 at 11:05


It looks a bit like a pH probe electrode to me, though it seems a bit too complicated to be just a ph probe. Maybe someone else will have a more convincing answer than me :p

[Edited on 3-10-2014 by alexleyenda]




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[*] posted on 3-10-2014 at 12:09


I do not think that it was used in liquid, rather measure the moisture content of some gas somehow, the small orange bulb is probably for temperature measurement, but I can only guess. The metal on some other metallish surface reminds me of the electrical element of rectifier.
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[*] posted on 6-10-2014 at 14:21


Any ideas for a easy aquiring/homemade selective membrane for a potassium chloride electrolytic cell to make potassium hydroxide? I've tried gelatin but it came off from the PVC pipe that connects the two half-cells.

[Edited on 6-10-2014 by AlphaDecay]

[Edited on 6-10-2014 by AlphaDecay]
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[*] posted on 6-10-2014 at 14:25


Quote: Originally posted by AlphaDecay  
Any ideas for a easy aquiring/homemade selective membrane for a potassium chloride electrolytic cell to make potassium hydroxide? I've tried gelatin but it came off from the PVC pipe that connects the two half-cells.

There should be more than a few topics on this subject - some of them started by me, if I recall. Ceramic was mentioned.




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[*] posted on 8-10-2014 at 13:57


Why does ATP not spontaneously react with water?



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[*] posted on 9-10-2014 at 03:15


It does. It's why it's synthesised as needed, rather than stockpiled in the cell, because it doesn't hang around for very long.

[Edited on 9-10-2014 by Pyrovus]




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[*] posted on 13-10-2014 at 10:14


Forgive me if this is a stupid question but, would an aromatic aldehyde be sufficiently acidic to react with a phenol to produce a ketone? Specifically I'm wondering if p-dimethylaminobenzaldehyde will react with p-dimethylaminophenol to yield Michler's Ketone?
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[*] posted on 13-10-2014 at 10:39


Aldehydes aren't acidic, but you don't want an acid, you want an oxidizing agent. Aldehydes aren't very good oxidizing agents, so I'd guess "no".



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[*] posted on 13-10-2014 at 10:52


Would the aldehyde be an oxidizing agent? I was hoping a reaction like the following would happen. Maybe the equilibrium could be driven by the addition of sulfuric acid? (Sorry about the terrible picture)

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[*] posted on 13-10-2014 at 11:08


If you wanted this to happen, you'd have to use an aryl halide instead of a phenol, convert it to a Grignard, then react that with the aldehyde.



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[*] posted on 13-10-2014 at 12:22


So for amphoteric hydroxides like Cr and Cu what would happen if you attempted to react them with NaOH? Would they form Chromate/chromite or cuprate and release ammonia or what would happen?




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[*] posted on 13-10-2014 at 13:07


Quote: Originally posted by bismuthate  
So for amphoteric hydroxides like Cr and Cu what would happen if you attempted to react them with NaOH? Would they form Chromate/chromite or cuprate and release ammonia or what would happen?


Cr(OH)3 will react with hydroxide ion to give the soluble Cr(OH)4- ion (which can be oxidized to chromate). Zinc, lead, and aluminum hydroxides will similarly dissolve in excess hydroxide, but copper hydroxide is barely amphoteric- you may get a bit of blue in the solution, but you won't dissolve a significant amount of it without an outrageous concentration of base.




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[*] posted on 13-10-2014 at 13:08


Yes but what would happen if I tried to dissolve the ammonia complexes of the hydroxides in base?




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[*] posted on 13-10-2014 at 13:23


Quote: Originally posted by bismuthate  
Yes but what would happen if I tried to dissolve the ammonia complexes of the hydroxides in base?


Tetramminecopper(II) ion is stable towards hydroxide ion (I have a book somewhere that discusses the preparation of tetramminecopper(II) hydroxide and its use in dissolving cellulose). The chromium complex may slowly react with hydroxide to replace the ammonia ligands (Cr(III) complexes are notoriously slow to replace their ligands, but strong base will catalyze the reaction through deprotonation of the amine ligands).




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[*] posted on 15-10-2014 at 20:05


Hello all, recently I decided to convert 10gr. of 30% palladium hydroxide on carbon to palladium II chloride dihydrate. I achieved
this by digestion of said catalyst with dilute HCl I am left with, after filtration and flash distillation, a maroon powder with a strong hydrochloric fragrance. my question is does anyone have a suggestion of the best solvent a or duel solvent for recrystalization? Any knowledgable suggestion would be appreciated.
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[*] posted on 20-10-2014 at 08:57


Sorry if I am asking a question before the one above had been answered - I waited until now, but I kind of need to know somewhat urgently: can you suggest a method for passivating nickel? I know nickel is corrosion resistant, so "passivation" in this case is not meant as a way to protect the nickel part, but to actually protect the chemicals in contact with nickel from its catalytic activity. These chemicals will be dissolved in a mixture of polar solvents (including water).

One idea I had was treating nickel with oxalic acid. Nickel oxalate seems mostly insoluble in water and other polar solvents, and it is not, as far as I know, a common catalyst, so few or no reaction would be catalyzed by it. Problem is, this layer is probably thin and not very resistant to wear.

Please suggest some better passivation materials. I'm thankful for any idea.
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[*] posted on 20-10-2014 at 09:00


Is your solution acidic or basic?

Do you have to use nickel? Why not glass?




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[*] posted on 20-10-2014 at 09:12


Quote: Originally posted by Cheddite Cheese  
Is your solution acidic or basic?

Do you have to use nickel? Why not glass?


Ph will be no less than 4 and no greater than 8... I think. I am not sure about the upper threshold, but the solution is likely to be mildly acidic.

Can't be glass because it has to be ferromagnetic. Nickel seemed OK, since it usually doesn't corrode easily, but, as I said, it might catalyze some reactions.

I must note that I can, if push come to shove, deposit a thin layer of silicon oxide over the nickel by chemical vapor deposition, but I'd rather not use that high-tech solution, if I don't have to. Besides, I am not sure how good is CVD SiO2 adhesion to nickel.
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[*] posted on 23-10-2014 at 02:36


I just made some copper "asprinate" and i can't find much info regarding its toxicity(msds)? Its not that dangerous is it? (it is a potential medicine). Just curious.



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[*] posted on 23-10-2014 at 05:16


This page lists an LD50. I don't think it has many other hazards, I'm guessing the toxicity will be very similar to that of another insoluble copper compound such as copper carbonate.
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[*] posted on 23-10-2014 at 12:36


Quote: Originally posted by gdflp  
This page lists an LD50. I don't think it has many other hazards, I'm guessing the toxicity will be very similar to that of another insoluble copper compound such as copper carbonate.

Thanks! I just checked and it seems to be less toxic than aspirin itself in rats. Interesting!




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