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The Volatile Chemist
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[*] posted on 23-2-2015 at 12:56


Quote: Originally posted by quantumcorespacealchemyst  
What is the white frost on glass from being near HCl(aq)? It is wipable, smells odd and forms even near sealed acid containers. It seems to certainly be from HCl gas. What it is, I don't know.

[Edited on 22-2-2015 by quantumcorespacealchemyst]

I get it all the time on things in my lab when evaporating HCl solutions. I think it's condensed HCl, or a salt of Cl-, that is, if you have ammonia vapors nearby or something.




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[*] posted on 23-2-2015 at 14:20
Dilute hydrogen peroxide and potassium bitartrate.


I was discussing some homemade stain removers on another sight and this came up as a stain remover. Is it just the fact that cream of tartar is a common OTC acid salt, and the drop in ph is what matters, or if there is some other effect that can't be achieved with a similar salt, or the lowering of ph with an acid solution? In regards to the reported stain removing effects, of course.

Thanks on advance.

[Edited on 23-2-2015 by Bot0nist]




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[*] posted on 23-2-2015 at 15:50


Quote: Originally posted by j_sum1  
Question: Slightly confused about carbon zinc battery.

I have disassembled a few lantern batteries -- for electrodes and other useful things.
First step in purifying the MnO2 paste is to mix with water to form a slurry and then filter. The intention is to dissolve the ZnCl2 or NH4Cl that acts as an electrolyte.
The other day I ran a current through it and discovered to my surprise that a nice grey metal plated out on the cathode. I thought I had a solution of ZnCl2 but of course Zn cannot be electrolytically reduced in aqueous solution. So, what is it that plated out? Do some batteries contain tin compounds or bismuth or something else strange? What is it that I have got?

Bump – cos it disappeared off the bottom of the page.
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[*] posted on 23-2-2015 at 16:07


Umm who told you zinc cannot be plated in aqueous solution? They lied. Have you not heard of galvanization?
Just because the activity series says zinc displaces hydrogen doesn't mean it can't be electroplated, because it can and is, by the ton.




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[*] posted on 23-2-2015 at 16:33


Bloggy mentioned it a while ago. I may have my wired crossed. I'll come back to this one.
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[*] posted on 23-2-2015 at 18:28


Hi! I would need some help...

Would it be possible to make aluminium citrate by reacting aluminium, hydrogen peroxide and citric acid? I think that first, there should be reaction between Al and H2O2, to make Al2O3, which would (or wouldn't?) then react with citric acid, to make C6H5AlO7. I don't need aluminium citrate for any particular purpose, I would make it just for my compound collection... And if anyone could give me some data on C6H5AlO7, that would be really helpful (looks like wikipedia doesn't yet have the page about aluminium citrate). Thanks in advance! :)




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[*] posted on 23-2-2015 at 18:38


Quote: Originally posted by Bot0nist  
I was discussing some homemade stain removers on another site and this came up as a stain remover. Is it just the fact that cream of tartar is a common OTC acid salt, and the drop in pH is what matters, or if there is some other effect that can't be achieved with a similar salt, or the lowering of pH with an acid solution? In regards to the reported stain removing effects, of course.
Thanks in advance.


Tartrate is a pretty good chelating agent, so you'd want to use cream of tartar on rust stains and the like. The peroxide will of course bleach anything the cream of tartar can't deal with.

sparky (~_~)




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[*] posted on 23-2-2015 at 19:57


Thank you! I was too focused on how it may react with affect the peroxide.



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[*] posted on 24-2-2015 at 01:31


Quote: Originally posted by j_sum1  
Bloggy mentioned it a while ago. I may have my wired crossed. I'll come back to this one.
Let's just put this one down to a brain-fart.

I ran a current through the solution a few weeks ago and found what I thought was zinc.
Maybe a week ago I read something here, I think from Blogfast that made me question it. Or maybe I misremembered something. Anyway, I cannot relocate the comment so never mind.
A couple of days ago I was looking up my redox potentials and was comparing Zn with the wrong line and convinced myself that it wasn't possible.

Classic brain fart material. Nothing to see here. Carry on.
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[*] posted on 25-2-2015 at 20:13


Quote: Originally posted by xfusion44  
Hi! I would need some help...

Would it be possible to make aluminium citrate by reacting aluminium, hydrogen peroxide and citric acid? I think that first, there should be reaction between Al and H2O2, to make Al2O3, which would (or wouldn't?) then react with citric acid, to make C6H5AlO7. I don't need aluminium citrate for any particular purpose, I would make it just for my compound collection... And if anyone could give me some data on C6H5AlO7, that would be really helpful (looks like wikipedia doesn't yet have the page about aluminium citrate). Thanks in advance! :)


I tried that and it didn't work, so thanks anyway :)




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[*] posted on 26-2-2015 at 04:35


What type of glass are (large) petridishes usually made of? Soda glass or borosilicate?
I was rather surprised that it shattered so easily earlier today from a relatively weak heat source(very small Bunsen flame, no larger than a lit candle). I couldn't find a Pyrex or some other brand 'stamp' anywhere...

It didn't just crack and break btw... it shattered 'explosively'. Glass everywhere. Luckily I was at the other side of the lab doing other stuff... O_O




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[*] posted on 26-2-2015 at 14:33


Flint glass is most common in the China made Petri's.

I broke quite a few cheap dishes I bought on Ebay in the pressure cooker. I've since been buying only Pyrex / Corning.

Depending on what you are doing I have found the plastic Gosslin dishes from corning do take the heat of a 15psi pressure cooker.

Bottom line is if it is not a marked name brand, it is most likely Flint Glass.

Came back to add on this answer...

"Product Description
The American Educational Flint Glass Culture Petri Dish is a 98mm outside diameter (OD), 90mm inside diameter (ID), 18mm high petri dish bottom for culturing cells and other scientific applications, and is clear for viewing contents. Flint glass may contain an occasional small bubble or surface blemish and is for unheated use. Petri dishes are commonly used in laboratories and other scientific applications."

http://www.amazon.com/American-Educational-Culture-Height-Bu...

Just one example. :cool:

[Edited on 2-27-2015 by Zombie]




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[*] posted on 26-2-2015 at 20:18


Hi, I saw an experiment on youtube when H2O2 reacts with KMnO4... I decided to try it myself too and it's pretty vigorous. But both of the reactants are oxidizers, so even oxidizers can be oxidized if there is another, stronger oxidizer, like KMnO4? :D

[Edited on 27-2-2015 by xfusion44]




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[*] posted on 26-2-2015 at 21:06


We have had this discussion recently. http://www.sciencemadness.org/talk/viewthread.php?tid=61637
As it turns out H2O2 is a stronger oxidiser than KMnO4 so you have that bit the wrong way around.

To add to the confusion, H2O2 is a strange beast. There are situations where it acts as a reducer. Its behaviour is pH dependent. There are four separate equilibria at play here.

What you might be observing is a catalytic effect and the situation is simple decomposition of H2O2 to H2O and O2. I don't recall if the Mn in KMnO4 catalyses this reaction but it sure wouldn't surprise me. (KI does in the classic elephant toothpase reaction.) If it is a decomposition then we are not really talking about redox at all.
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[*] posted on 27-2-2015 at 12:21


Quote: Originally posted by j_sum1  
We have had this discussion recently. http://www.sciencemadness.org/talk/viewthread.php?tid=61637
As it turns out H2O2 is a stronger oxidiser than KMnO4 so you have that bit the wrong way around.

To add to the confusion, H2O2 is a strange beast. There are situations where it acts as a reducer. Its behaviour is pH dependent. There are four separate equilibria at play here.

What you might be observing is a catalytic effect and the situation is simple decomposition of H2O2 to H2O and O2. I don't recall if the Mn in KMnO4 catalyses this reaction but it sure wouldn't surprise me. (KI does in the classic elephant toothpase reaction.) If it is a decomposition then we are not really talking about redox at all.


Hmm, well that's surprising. In the video on yt it says that H2O2 is being oxidised and decomposed.

Thanks for your answer!




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[*] posted on 1-3-2015 at 17:55


If washing arsenic acid and/or arsenous acid crystals in diethyl ether, is there any peroxide formation or other reactions to be aware of?

Arsenic acid, H3AsO4, is an oxidizer. If the contact is brief, only to dislodge them from where they crystallized, will peroxides form?

[Edited on 2-3-2015 by quantumcorespacealchemyst]
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[*] posted on 2-3-2015 at 05:23


I have slowly collected (eBay) a Quickfit 14/23 distillation setup
hopefully for volatiles, acids, hydrocarbons etc.

How do I use the thermometer pocket (SH 4A) correctly?

I had a quick Google search but I'd like to hear any suggestions,
I'm thinking about oil for rapid temperature response
or sand (I have 400 mesh silicon dioxide) to protect the bulb from my clumsiness.

How do you guys use a thermometer pocket?

EDIT:
The thermometer goes into a pocket that looks like this
http://www.scilabware.com/Thermometers/Pocket/p-130-508/
which fits into something similar to this
http://www.scilabware.com/Flasks/Pear-shaped/Claisen-Vigreux...
except instead of a vigreux section there is a vacuum jacket section.

Initially I will use one of my mercury thermometers
later one of my stainless steel clad thermocouples.

[Edited on 2-3-2015 by Sulaiman]
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[*] posted on 2-3-2015 at 20:56
Haloform products + Iodine powder


What is the reaction of I2 with NaOCl haloform products? NaOCl(bleach) + CH3COCHCH3 + (NaOH in bleach)---->CHCl3 + NaOH + NaOOCH3 and then adding equimolar mols of I (as Cl) to the solution?


[Edited on 3-3-2015 by quantumcorespacealchemyst]

if 3NaOCl + CH3COCH3 + NaOH ---> 3NaOH + NaOOCCH3 + CHCl3

does the sodium acetate affect the pH too much effecting the NaOH reacting with the I2?
There is a purple solution after adding half the mols equivalent of Cl, of I (1/2I2). It was heated under boiling and cooled.

[Edited on 3-3-2015 by quantumcorespacealchemyst]
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[*] posted on 3-3-2015 at 03:16
Sulphuric acid from thiosulfate?


Just saw in another forum that H2SO4 was made by sodium thiosulfate and H2O2. He wrote the following equation

Na2S2O3 + H2O2 → H2SO4 + Na2SO4 + H2O

The equation can be balanced but it doesn't mean that the reaction will work that way.

I tried it myself yesterday, added one drop of H2O2 to some crystals of Na2S2O3, a lot of fizzing and a pleasant smell of H2S... I disposed the products and decided to ask before trying again...

I'm thinking that would be an easy way for producing sulphuric acid and someone would have tried it before

Is this possible? Or just another way of making H2S...
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[*] posted on 4-3-2015 at 05:29


Quote: Originally posted by quantumcorespacealchemyst  
What is the reaction of I2 with NaOCl haloform products? NaOCl(bleach) + CH3COCHCH3 + (NaOH in bleach)---->CHCl3 + NaOH + NaOOCH3 and then adding equimolar mols of I (as Cl) to the solution?


[Edited on 3-3-2015 by quantumcorespacealchemyst]

if 3NaOCl + CH3COCH3 + NaOH ---> 3NaOH + NaOOCCH3 + CHCl3

does the sodium acetate affect the pH too much effecting the NaOH reacting with the I2?
There is a purple solution after adding half the mols equivalent of Cl, of I (1/2I2). It was heated under boiling and cooled.

[Edited on 3-3-2015 by quantumcorespacealchemyst]

The purple colour may come from I2 dissolved into CHCl3....
It is not very clear to me what you intend to do?
-NaOH + I2 will produce some NaOI and NaOIO2 (NaIO3) by disproportionation and depending on heat.
-I2 and NaOCl will also lead to NaOI and NaOIO2 (NaIO3) (and maybe NaOIO3(NaIO4)).
-I2 and aceton in basic media usually lead to orange precipitate of CHI3 (iodoform), it is a characteristic test for methyl-ketonic group.

Just as a remark, be carreful with what you write:
NaOCl + CH3COCHCH3 + (NaOH in bleach)---->CHCl3 + NaOH + NaOOCH3
==> CH3-CO-CH-CH3 is uncorrect ... You miss one H atom to get tetravalent carbon -CH- is trivalent... so better write CH3-CO-CH2-CH3 is Methyl-Ethyl-Keton (MEK) or (2-)butanone.
I suspect you wished to write aceton /propanone CH3-CO-CH3
==> NaOOCH3 is uncorrect... would be sodium peroxomethylate! I suspect you wished to write NaO2C-CH3 (sodium acetate)

In your reaction you may get orange CHI3 dissolved into CHCl3 or intermediary CHICl2, CHI2Cl since you may have a certain level of competition between the two halogens...

[Edited on 4-3-2015 by PHILOU Zrealone]




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[*] posted on 4-3-2015 at 06:59


Quote: Originally posted by Argentum  
Just saw in another forum that H2SO4 was made by sodium thiosulfate and H2O2. He wrote the following equation
Na2S2O3 + H2O2 → H2SO4 + Na2SO4 + H2O

It's always best to give a reference to what forum or paper you're citing.
I think you mean this one. I don't see why you didn't bother balancing the equation or even copy/pasting it from your source, where it was already balanced:
Na2S2O3 + 4 H2O2 (aq) → Na2SO4 (aq) + H2SO4 (aq) + 3 H2O (l).
Quote: Originally posted by Argentum  

I tried it myself yesterday, added one drop of H2O2 to some crystals of Na2S2O3, a lot of fizzing and a pleasant smell of H2S... I disposed the products and decided to ask before trying again...

Well asking isn't going to change the nature of this reaction, but disposing of that mess was a good idea. I'm guessing that the equation above predominates over the formation of hydrogen sulfide. I'm nearly certain that the formation of hydrogen sulfide was caused by an excess of sodium thiosulfate. In other words, don't add hydrogen peroxide to sodium thiosulfate, add a solution of the latter to hydrogen peroxide, and add slightly less than the stoichiometric quantity. Hydrogen sulfide is a reducing agent and would not likely form with enough of a strong oxidizer present.
Quote: Originally posted by Argentum  

I'm thinking that would be an easy way for producing sulphuric acid and someone would have tried it before

I'm thinking of all the methods of making the easily available sulfuric acid, this is one of the lousiest, but each to his own. It probably will work, but definitely do this outside or in a fumehood if at all.

[Edited on 4-3-2015 by Molecular Manipulations]




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[*] posted on 5-3-2015 at 04:01


I know this question has come up before, but I don't recall seeing an actual answer.
This product, is it actually pure molybdenum? If not, then what else is in it?
And what do mobile phone repairers use it for anyway? It is all over eBay and other places. I would like to know some details before I get some.
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[*] posted on 5-3-2015 at 06:33


It's used as a knife. Like pulling out a car windshield.

https://www.youtube.com/watch?v=qowrEiDsdTo

They use Molybdenum because of its high tensile strength.

No idea on the purity tho. I guess you would have to find the manufacturer, and verify that yourself.

I wouldn't trust asking a seller. unless the label or packaging clearly states this.





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[*] posted on 5-3-2015 at 19:59


Since I am buying some sodium metal for the 'transparent sodium' experiment
I would like to know of other uses for sodium metal
I may make some sodium methoxide to try small scale transesterification

other than these two are there any other interesting uses for sodium metal?
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[*] posted on 5-3-2015 at 20:12


https://www.youtube.com/watch?v=RAFcZo8dTcU

:D:D:D:D:D:D:D:D:D:D:D:D:D:D:D:D:D:D:D:D:D:D:D




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