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elementcollector1
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[*] posted on 12-9-2013 at 11:20


Quote: Originally posted by confused  
Hi,
what causes the errosion of carbon electrodes during electrolysis of a copper sulfate solution?

Mainly the production of sulfuric acid. Carbon seems to be soluble in it to some extent, and carbon electrodes may form some sort of intercalated 'graphite oxide' from the oxygen of the water which degrades the structure.
This is all speculation, though.




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[*] posted on 13-9-2013 at 00:57


In esterifications using acid anhydrides, is the anhydride a uniquely (more) reactive species that reacts more readily with an alcohol than does the carboxylic acid alone, or does the anhydride facilitate the reaction only by removing formed water?
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[*] posted on 13-9-2013 at 10:21


Quote: Originally posted by manimal  
In esterifications using acid anhydrides, is the anhydride a uniquely (more) reactive species that reacts more readily with an alcohol than does the carboxylic acid alone, or does the anhydride facilitate the reaction only by removing formed water?


It's more reactive. The fact that it doesn't produce water to reverse the reaction is a bonus.




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[*] posted on 16-9-2013 at 07:48


Is it possible to buy an electrical heater that is shaped like this, so that I may insert it into a tube? I don't know what they may be called. Ideally only the top would get hot, but it is not too important.


[Edited on 16-9-2013 by sonogashira]
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[*] posted on 16-9-2013 at 09:31


http://www.made-in-china.com/showroom/sonnong168/product-det...

http://zh4u.en.alibaba.com/product/1150672030-200418709/MCH_...

would this be close to what you are looking for?

i searched for "ceramic heating element" in google
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sonogashira
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[*] posted on 16-9-2013 at 12:11


Thanks. That might do. :)
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[*] posted on 16-9-2013 at 16:47


I know that highly concentrated solutions of sodium hydroxides can dissolve glass.
Is this also true if the sodium hydroxide had been dissolved in say 90% ethanol?

Seems to me like it should but I am not sure. I have been looking at some XPS data and there seems to be a silicon peak in the scan (of these particular samples), and the only source I can think for this would be from the glass beaker that was used to prepare the reaction mixture.
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[*] posted on 17-9-2013 at 04:26


What is the best source to get chemicals from? Sigma-Aldrich?



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elementcollector1
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[*] posted on 17-9-2013 at 05:08


Quote: Originally posted by Gooferking Science  
What is the best source to get chemicals from? Sigma-Aldrich?

Definitely not. Try elemental-scientific, United Nuclear, HMS-Beagle, and/or Metallium.




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[*] posted on 17-9-2013 at 06:17


Quote: Originally posted by Squall181  
I know that highly concentrated solutions of sodium hydroxides can dissolve glass.
Is this also true if the sodium hydroxide had been dissolved in say 90% ethanol?

Seems to me like it should but I am not sure. I have been looking at some XPS data and there seems to be a silicon peak in the scan (of these particular samples), and the only source I can think for this would be from the glass beaker that was used to prepare the reaction mixture.

Yes, as long as there is water in the mix, it is capable of attacking glass. The etching process will lead to formation of soluble silicates, which probably also are somewhat soluble in 90% ethanol.




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[*] posted on 17-9-2013 at 11:03


It all depends on the chemical. Sigma sells a great variety and has consistent purity, but their prices are insane. For amateur purposes, try your local hardware store or Ebay first. You may want to synthesize the chemical you want yourself if the precursors are cheap but the product is hard to get due to shipping restrictions (like bromine or nitric acid).



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[*] posted on 19-9-2013 at 12:57


Quote: Originally posted by Squall181  
I know that highly concentrated solutions of sodium hydroxides can dissolve glass. Is this also true if the sodium hydroxide had been dissolved in say 90% ethanol?


Yes, this is also known as a "base bath", where a mixture of alcohol and strong base is used to clean glass, and will etch it is left long enough, or just dissolve glass frits.

Bob
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[*] posted on 20-9-2013 at 18:30


Where can I buy 10 - 20 ml ampoules at a decent price? I can't find them anywhere.....



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[*] posted on 21-9-2013 at 08:25


I was planning on purchasing some manganese sulphate however I cannot seem to find a Canadian supplier and all american suppliers will not ship to Canada, specifically I was looking at Alpha Chemical's product.

Is there a reason it is so hard to find in Canada, I cannot think of any reason for it to be banned, and I looked around and couldn't see any law against it? So do you think if I ship from the US it will get stopped at Customs?
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[*] posted on 21-9-2013 at 15:15


I have a quick question regarding cation exchange resin H+

My question is will H+ resin exchange only Na cation in a inorganic salt or can it swap other inorganic salts such as K, Li or Cs. I realize that the H+ cation exchanger would have the greatest affinity for Na cations' however in the absence of Na cations will the resin also exchange other alkaline metal cations?
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[*] posted on 21-9-2013 at 15:47


Quote: Originally posted by SHADYCHASE54  
My question is will H+ resin exchange only Na cation in a inorganic salt or can it swap other inorganic salts such as K, Li or Cs.

The proper question would be, that does sulfuric acid react with all alkali salts on the same way? The answer is yes. However a little difference will be, depending on the alkali, but at all, it is really similar.

What are strongly acidic ion exchange resins?

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[*] posted on 21-9-2013 at 15:53


Quote: Originally posted by sonogashira  
Is it possible to buy an electrical heater that is shaped like this, so that I may insert it into a tube? I don't know what they may be called. Ideally only the top would get hot, but it is not too important.
Cylindrical? They're called cartridge heaters or cartridge heating elements.
Quote: Originally posted by Gooferking Science  
What is the best source to get chemicals from? Sigma-Aldrich?
Keep working on a positive posting record, then request access to References. I have compiled a fairly comprehensive list of suppliers and manufacturers, including many which are known to be amateur friendly. (It was moved there to keep it secret... not my idea.) Which reminds me, it's been a while since I last updated it...

[Edited on 21.9.13 by bfesser]




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[*] posted on 21-9-2013 at 16:10


Quote: Originally posted by Gooferking Science  
Where can I buy 10 - 20 ml ampoules at a decent price? I can't find them anywhere.....


you can make ampoules out of glass tubing

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[*] posted on 11-10-2013 at 14:22
Question:


Does anybody have an empty 1250ml amber glass pharmapac bottle they could weigh for me?
like this one in the foreground:
2013-05-08 14.03.06.jpg - 94kB

In this bottle is that dry unstabilized RP, I need to know approximately how much it contains but don't want to risk emptying it just to weigh it. (total mass=+-1000g)

Answer:
you can buy ampules at http://www.sciplus.com/ in the US and at:
http://www.ebay.nl/itm/275-st-5-ml-leer-Ampullen-aus-Glas-/3...
check his other listings, he has ampules in sizes 1ml-5ml-10ml is clear and brown glass

[Edited on 11-10-2013 by Pyro]

[Edited on 11-10-2013 by Pyro]




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[*] posted on 11-10-2013 at 15:39


Can't help, per se. But as far as weight goes you would be better off dumping the contents into something clean, weighing/taring the bottle, filling etc. I have found that identical vials, bottles, jars etc always have differences in the 1-1.5g range. Is this an issue or are you looking for an average mass?
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[*] posted on 12-10-2013 at 03:01


I mentioned why I didn't want to empty it as its over half full of finely powdered, dry and unstabilized RP. don't want to take the risk of transferring all that for the sake of weighing.
I just need an estimate on how much RP I have left, or might face a nasty surprise when I run out in the middle of a synth.




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[*] posted on 13-10-2013 at 13:27


Could chloroform be made by bubbling chlorine gas through acetone with a bit of sodium hydroxide dissolved in it? The definition of the haloform reaction is "the excessive halogenation of a methyl ketone in the presence of a base." so I figure it should work...



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[*] posted on 13-10-2013 at 13:40


Quote: Originally posted by Gooferking Science  
Could chloroform be made by bubbling chlorine gas through acetone with a bit of sodium hydroxide dissolved in it? The definition of the haloform reaction is "the excessive halogenation of a methyl ketone in the presence of a base." so I figure it should work...


You'd be better off bubbling Cl2 into sodium hydroxide solution and then adding acetone. or just buying unscented bleach by the gallon and skip the chlorine gas all together.




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[*] posted on 13-10-2013 at 13:46


I believe that this makes chloroacetone with some NaOCl. Some chloroform would be formed hovever not much due to the reaction of chlorine and acetone also you would need quite a bit of sodium hydroxide not just a bit.
http://en.wikipedia.org/wiki/Chloroacetone
I would make chloroform from NaOCl bleach and acetone.
P.S. I found a unique way to make chloroacetone for anyone who needs it.
http://www.erowid.org/archive/rhodium/chemistry/haloacetone....




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[*] posted on 15-10-2013 at 14:05
Question


What's a typical amount of 4A molecular sieves to add to say 500 mL of ether to maintain dryness in storage? Enough to cover the bottom of the bottle? Less?
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