Sciencemadness Discussion Board

The Short Questions Thread (4)

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artemov - 24-12-2020 at 20:55

Quote: Originally posted by Antigua  
Why not? Alcohols don't form peroxides like ethers.



Erm I thought secondary alcohols do?

https://chemistry.stackexchange.com/questions/4597/isopropyl...

itsallgoodjames - 25-12-2020 at 08:01

If I recall correctly, only anhydrous isopropanol forms peroxides, though I don't have a source for that. If you're really concerned, test it for peroxides. It isn't that hard. Obviously don't distill to dryness, and follow all the common distillation precautions, but I wouldn't be to concerned about peroxides.

SHADYCHASE54 - 22-1-2021 at 08:35

Hello all,
I am wondering if someone could give me guidance as to where in western Canada I could have a couple samples spectographically analysed? I am looking for either Rahman or FTIR analysis, furthermore what range of cost would I be looking at?

Thanks for any help.
S.C54

artemov - 29-1-2021 at 01:06

Hi all, I am crystallising out some potassium chromate, what liquid can I use to wash the crystals with minimal loss?
It's very soluble even in cold water, and it will react with alcohols. Would acetone or MEK work? Cheers.

fusso - 2-2-2021 at 15:10

In the wiki page for isocyanic acid it said 'isocyanic acid hydrolyses to carbon dioxide and ammonia' but didnt state the rxn conditions, does anyone know what conds are needed, other than adding water?

[Edited on 210203 by fusso]

CharlieA - 2-2-2021 at 16:35

water?:D

fusso - 2-2-2021 at 16:44

@Charlie assuming you're replying to me, what else, if you know?

B(a)P - 2-2-2021 at 17:52

Quote: Originally posted by fusso  
@Charlie assuming you're replying to me, what else, if you know?


I think you will find some useful information in here
https://acp.copernicus.org/preprints/15/24217/2015/acpd-15-24217-2015.pdf

Lion850 - 3-2-2021 at 19:04

How can I extract Gallium iii iodide GaI3 from concentrated hydrochloric acid? Solvents I have access to are DCM, Toluene, Xylene, Methanol, carbon tetrachloride, and carbon disulphide. Thanks in advance.

yobbo II - 13-2-2021 at 15:43

Could someone direct me to a (sodium) nitrate titration procedure using ferrous sulphate

Thanks

Sulaiman - 13-2-2021 at 17:12

A few choices :
https://www.google.com/search?q=Nitrate+ferrous+sulphate+tit...

artemov - 16-2-2021 at 21:40

Are my nickel sulfate crystals overdried? What are those whitish-green stuff?

20210217_115446.jpg - 101kB

woelen - 17-2-2021 at 14:03

Looks like anhydrous nickel sulfate. Pure anhydrous nickel sulfate looks as follows:

https://woelen.homescience.net/science/chem/compounds/nickel...

artemov - 17-2-2021 at 22:17

Quote: Originally posted by woelen  
Looks like anhydrous nickel sulfate. Pure anhydrous nickel sulfate looks as follows:

https://woelen.homescience.net/science/chem/compounds/nickel...


Thanks woelen!

Panache - 22-2-2021 at 23:58

Quote: Originally posted by artemov  
Quote: Originally posted by woelen  
Looks like anhydrous nickel sulfate. Pure anhydrous nickel sulfate looks as follows:

https://woelen.homescience.net/science/chem/compounds/nickel...


Thanks woelen!


A clickbait answer....as are all of woelens pages..well i find anyway. Your site for home chemists is kinda like facebook, you open it for a reason then three hours later not only have you not attented to the reason you looked there in the first place, you longer care about it as your interest in other stuff has been piqued!!.

If someone hasn't complimented you lately woelen on your digital presence. Its pretty fucking excellent and has been for a very longtime.
Good one.

wg48temp9 - 23-2-2021 at 01:02

Just in case someone gets the wrong idea, there is none of the usual click bate or storm of ads or popups on woelen site or this site. Which is a refreshing difference.

So yes thanks woelen and SM

arkoma - 23-2-2021 at 09:31

"clickbait" is a pretty damn disparaging word, sir.

Panache - 2-3-2021 at 16:47

Regarding offence taken by my use of the clickbait word. I understand however...i ...was...using..it
in a metaphorical manner.....isn't english a great language.

Terribly sorry if my metaphor was shit and confusing (which it was). I was merely attempting to describe the captivating nature of the website.

And there ain't a single ad just lots of stuff about Jesus....(that was joke there's no stuff about jesus)

yobbo II - 5-3-2021 at 18:18


Better to say that 'Woelens site is good'. (including the stuff about Jesus). :-)


Thanks for the link way above Sulaiman.

Can anyone get me a phase diagram for the system KNO3, NaCl and water.
It does not appear to exist for some reason or other.

Yob

itsallgoodjames - 21-3-2021 at 13:34

What's a reasonable wattage for a heating mantle? Is 300w reasonable for 250ml? What about 500ml or 1000ml?

Antigua - 21-3-2021 at 13:36

You need less power for heating mantles than for hotplates in terms of heating (1/2 the power, as a rule of thumb, or even less). I have a 100ml heating mantle that is made from a 100W heating wire and it's very powerful. 200W should be more than enough for 500ml. I'd go for 300 or 350W for 1L.

itsallgoodjames - 21-3-2021 at 14:14

Quote: Originally posted by Antigua  
You need less power for heating mantles than for hotplates in terms of heating (1/2 the power, as a rule of thumb, or even less). I have a 100ml heating mantle that is made from a 100W heating wire and it's very powerful. 200W should be more than enough for 500ml. I'd go for 300 or 350W for 1L.


Ok, thanks :)

Panache - 25-4-2021 at 17:40

Quote: Originally posted by yobbo II  

Better to say that 'Woelens site is good'. (including the stuff about Jesus). :-)


Yob


Yes couldn't agree more

paulll - 25-4-2021 at 23:59

Do bromide salts usually have a vinegar-esque whiff about them or should I be suspicious about this vaguely-acetic-smelling KBr?

njl - 26-4-2021 at 04:24

Nope, all my samples are odorless.

paulll - 27-4-2021 at 11:22

Quote: Originally posted by njl  
Nope, all my samples are odorless.


Good to know, ty.

S.C. Wack - 27-4-2021 at 17:48

My NaBr is slightly halogeny...perhaps from the original crystallization or reaction with the container at some point. Our noses are very sensitive analytical instruments sometimes...e.g. a super low concentration of IPA smells pleasant and is unrecognizable as such.

Hypotherical hydrogen cyanide synthesis

j_sum1 - 4-5-2021 at 15:56

I just composed a problem for my students – calculation of enthalpy of reaction from tables of average bond energies.

Seemed like an ok example of the concept. But is there a feasible reaction schema that produces HCN from ammonia and carbon monoxide?

Just curious.

Bond Energy question.jpg - 2.1MB

DraconicAcid - 4-5-2021 at 16:14

I don't think so, but that's a good example.

njl - 4-5-2021 at 16:30

Carbon monoxide is a better reducing agent than it is an oxidizing agent, and ammonia needs to be oxidized to give cyanide.

j_sum1 - 4-5-2021 at 17:03

Quote: Originally posted by njl  
Carbon monoxide is a better reducing agent than it is an oxidizing agent, and ammonia needs to be oxidized to give cyanide.

Should have thought of that.
(Shhh. I won't tell the students. It will ruin the illustration.)

paulll - 4-5-2021 at 17:13

Quote: Originally posted by j_sum1  

(Shhh. I won't tell the students. It will ruin the illustration.)


Too late to offer bonus marks for balancing the equation?

j_sum1 - 4-5-2021 at 17:34

Quote: Originally posted by paulll  
)[/rquote]

Too late to offer bonus marks for balancing the equation?

It is an exercise to introduce a concept and not an assessment. So, no marks. What is required is clarity, and a situation that is non-trivial to give purpose to the exercise and so that the required concepts are repeated a few times. This meets those criteria.

Question

scienceboi - 26-5-2021 at 15:04

Can metals become plasmas? And how easy or useful is it to make them plasma?

I was just looking up sputter deposition for silicon wafers and it got me thinking.

Hoffit - 27-5-2021 at 00:09

Applied science has some nice videos about sputtering like this one https://www.youtube.com/watch?v=9OEz_e9C4KM

pneumatician - 29-5-2021 at 22:43

What is the ideal acid nitric concentration for dissolving Iron? 30%? 20%? 10%?...

Pure of around 99,9x% and "normal" Iron filing?

[Edited on 30-5-2021 by pneumatician]

Fulmen - 30-5-2021 at 00:34

I would say it depends on what you're after. If it's reaction speed it would probably be strong acid, but that tends to produce lots of NO and NO2. For a clean reaction with little loss I would keep the concentration below 20%.

B(a)P - 30-5-2021 at 00:39

Concentrated nitric acid will passivate iron.

clearly_not_atara - 30-5-2021 at 05:54

Quote: Originally posted by j_sum1  
I just composed a problem for my students – calculation of enthalpy of reaction from tables of average bond energies.

Seemed like an ok example of the concept. But is there a feasible reaction schema that produces HCN from ammonia and carbon monoxide?

If you factor entropy into your calculations I'm betting you'll find that delta-G is always positive for the forward reaction (forbidden). But IIRC you can do it in two steps, by making formamide first and using a selective catalyst second.

pneumatician - 31-5-2021 at 20:50

what is the Pepy's apparatus???

Belowzero - 6-6-2021 at 12:21

Will acrylate or plexiglass resist ~30% nitric acid for long periods of time at room temperature?
Or PVC?

CharlieA - 6-6-2021 at 14:51

Quote: Originally posted by pneumatician  
what is the Pepy's apparatus???


https://en.wikipedia.org/wiki/William_Haseldine_Pepys

May be this will help? You didn't mention in what activity the apparatus might be used in.

njl - 6-6-2021 at 16:12

Carboxylic acids can be activated by formation of mixed anhydrides. Could the acid instead be reacted with isocyanate to yield a carbamate (mixed carbamate anhydride)?

pneumatician - 9-6-2021 at 00:17

someine use one of this? ocerall qlty?? leaks in joint???

https://www.ebay.de/itm/152510588408?ssPageName=STRK%3AMEBID...

pneumatician - 9-6-2021 at 00:25

Quote: Originally posted by CharlieA  
Quote: Originally posted by pneumatician  
what is the Pepy's apparatus???


https://en.wikipedia.org/wiki/William_Haseldine_Pepys

May be this will help? You didn't mention in what activity the apparatus might be used in.


near 0 info in archive and gbooks! :-?

SHADYCHASE54 - 10-6-2021 at 06:01

Hello fellow S.M'ers,
I am wondering if I were to make hypophosphorus acid with it's Na salt and 32% HCl; then flash distill the resulting solution under strong vacuum to remove H2O, precipitate most of the NaCl while keeping the acid's boiling point below its d-comp. What would be, after diluting the acid to 10-15 percent of course, the most suitable exchange resin(s') to remove the Na and Cl impurities? Would reacting the diluted solution first with H+ strong acid cation exchange resin convert the remaining NaCl to HCl? Furthermore I am wondering if I were then to react the resulting solution with a strong anion exchange resin in the Cl- form would this remove the Cl from the HCl impurity thus liberating the hydrogen (g)?

I have no idea if this would work past making the acid solution. Anyone with experience or knowledge with or about exchange resins, who is willing to point me in the right direction, I would really appreciate it.

2 side notes: 1 yes I am aware of the danger of this acid's decomp. products. 2 the hypo is not for any illicit use, truthfully I haven't even decided what I intend to reduce yet? As the real experiment is in reaction conditions and comparing those to similar reducing agents. I am also interested in comparing it's reducing capacity under various reaction conditions. Such as simple reflux, microwave irradiation and under pressure. (In an actual pressure bomb). There I'm done.

Any help would be appreciated.

TCCA + EtOH = Chloroform?

Sulaiman - 22-6-2021 at 20:38

I have performed the classic acetone + hypochlorite haloform reaction a couple of times,
I would like to try TCCA instead of hypochlorite,
will it make much difference if I use EtOH (85% or more) instead of acetone.
(I have lots of (pool grade, 90%)TCCA and diy EtOH)

is it possible to isolate any chlorinated compound by burning propane in chlorine?

BauArf56 - 29-6-2021 at 11:33

Once i wanted to see how does propane (or butane) burn in chlorine gas, so i lighted up the blowtorch inside a bottle filled with chlorine. It burned with a bigger flame and it was quite luminous too. After a few seconds of burning inside the bottle there was no smell of chlorine at all, just the typical sweet smell of chlorinated compounds. Can anyone explain which compounds form and if is it possible to isolate them as liquids? Thanks

macckone - 29-6-2021 at 11:46

Quote: Originally posted by pneumatician  
someine use one of this? ocerall qlty?? leaks in joint???

https://www.ebay.de/itm/152510588408?ssPageName=STRK%3AMEBID...


I have not bought that particular one, but they are commonly used in labs. For large quantities they have significant advantages in filling and cleaning. The top portion generally uses a standard 100mm opening, you can buy various sealing rings but the ground glass joints should meet as well as a standard vacuum desiccator.

You can buy various tops for the flask:
https://www.ebay.com/sch/i.html?_from=R40&_trksid=p23220...

macckone - 29-6-2021 at 12:04

Quote: Originally posted by Sulaiman  
I have performed the classic acetone + hypochlorite haloform reaction a couple of times,
I would like to try TCCA instead of hypochlorite,
will it make much difference if I use EtOH (85% or more) instead of acetone.
(I have lots of (pool grade, 90%)TCCA and diy EtOH)


TCCA will not work by itself. You will have to add a soluble hydroxide base. And you will need extra as the cyanuric acid will need to be neutralized to form the final product.
There is actually a thread on TCCA.
http://www.sciencemadness.org/talk/viewthread.php?tid=5686

Ethanol will work, It has an alpha carbon.
Ethanol was used in the first haloform reaction.
Since you normally add water in the form of bleach or to dissolve the calcium hypochlorite, the water content won't matter much.

However, ethanol and chloroform give an azetrope so you need to be sure your ethanol totally reacts. Acetone has a similar issue with separation.

macckone - 29-6-2021 at 12:15

Quote: Originally posted by BauArf56  
Once i wanted to see how does propane (or butane) burn in chlorine gas, so i lighted up the blowtorch inside a bottle filled with chlorine. It burned with a bigger flame and it was quite luminous too. After a few seconds of burning inside the bottle there was no smell of chlorine at all, just the typical sweet smell of chlorinated compounds. Can anyone explain which compounds form and if is it possible to isolate them as liquids? Thanks


A wide variety of chlorinated compounds will form. Industrially, chlorinations are done in such a way as to avoid long chain hydrocarbons at high temperatures and high chlorine concentrations. Generally the amount of chlorine is regulated to give a mono, di or tri substituted base. Separating the compounds requires a lot of work unless it is something simple like methyl chloride, methylene chloride, chloroform and carbon tetrachloride.

KOH or CaCl2 to dry KI?

Sulaiman - 3-7-2021 at 06:29

I want to dry 20g of KI to weigh it for redox titrations, I intend to use a jam jar as a dessicator

IMG_20210703_220859.jpg - 1.6MB
(disposable lighter for scale reference only)

which would be 'best', CaCl2 or KOH?

I guess that the long narrow neck of the bottle will slow down the dehydration,
but I'm not in a hurry.

Sulaiman - 4-7-2021 at 18:32

Answered my own question...I have 3A molecular sieves.
IMG_20210705_102821.jpg - 1.6MB

Fulmen - 8-7-2021 at 11:00

Is there any interesting to do with ammonium dihydrogen phosphate from fire extinguishers? I have at least 5kg of the stuff, but it's pretty messy to work with. I don't know if it's treated with anything hydrophobic but it doesn't really mix with water.

BauArf56 - 9-8-2021 at 02:42

3 stupid questions:
1. How to make calcium nitrate from potassium nitrate? I tried mixing KNO3 and CaCl2 but i don't really know if it worked and if i can separate it from potassium chloride.
2. How to make ammonium nitrate from KNO3?
3. i distilled a mix of sodium bisulfate and potassium nitrate (40g of NaHSO4 and 20g of KNO3, as NurdRage says) and got a few drops of yellow nitric acid, plus lots of nitrogen dioxide. Strange thing is that it fumed when i blown over it, so could it be the super concentrated stuff? And why a such low yield?

Keras - 9-8-2021 at 03:56

I would turn KNO₃ into pure nitric acid (you can do that with NaHSO₄, as demonstrated by Nurd Rage's video), and then you neutralise your acid with either calcium carbonate (lime stone) or ammonia, case 1. and 2. I'm pretty sure you can't get Ca(NO₃)₂ from KOH – though that might work to some extent [this is linked to the relative alkalinity of KOH and Ca(OH)₂]. However, NH₃ being a weak base, there's no way to turn KNO₃ into NH₄NO₃.

3. Pay attention to stoichiometry. Nurdrage uses 43 g of KNO₃ and 150 g of NaHSO₄. If you use 20 g of potassium nitrate, you would have to use 80 g of sodium bisulphate to place yourself in the same conditions and get the same yield.

karolus28 - 31-8-2021 at 08:09

A question related to the legendary lead chamber processe:
Let me start by saying that I did the lead chamber process but it was kinda shit, 20-25 burning cycles, about 300 ml of water at the bottom, small burning pot on a 250 beaker, the bottom of the beaker would get some nitrosylsulfuric acid after a few burns. I didn't actually do much stoichiometry because I didn't have a good scale and that might explain why it was dilute as shit even after boiling to 20 ml, although it worked since I previouslu used a copper stand and the solution got a bit of blue. Now bact to the problem -the sulfur and KNO3 wouldn't react- both were bought as reagents, mixed together, no matter how much heat would I put into it, the sulfur just burned for a while and then went off leaving clumped/molten KNO3 on the top. I realized that I can use a tiny tiny amount of sugar to make the magic happen, so the plan was to put some KNO3 in the pot(45 degree angle), and then on top put a mixture of sulfur, little bit of sugar, little bit of KNO3 and on top of that put pure sulfur that gives me time to close the bucket before the violent reaction starts that lasts like 10-15 seconds.

The actual question is, how do I make the mix burn like it is in theory mean to burn?
In this video the NO2 fumes are clearly visible: https://youtu.be/7XVt_ca97WE?t=305

This is how I usually ignited all that https://www.youtube.com/watch?v=KwYA7ojSodc


Good God why do I talk so much?

TheMrbunGee - 31-8-2021 at 11:50

Quote: Originally posted by karolus28  
A question related to the legendary lead chamber processe:
Let me start by saying that I did the lead chamber process but it was kinda shit, 20-25 burning cycles, about 300 ml of water at the bottom, small burning pot on a 250 beaker, the bottom of the beaker would get some nitrosylsulfuric acid after a few burns. I didn't actually do much stoichiometry because I didn't have a good scale and that might explain why it was dilute as shit even after boiling to 20 ml, although it worked since I previouslu used a copper stand and the solution got a bit of blue. Now bact to the problem -the sulfur and KNO3 wouldn't react- both were bought as reagents, mixed together, no matter how much heat would I put into it, the sulfur just burned for a while and then went off leaving clumped/molten KNO3 on the top. I realized that I can use a tiny tiny amount of sugar to make the magic happen, so the plan was to put some KNO3 in the pot(45 degree angle), and then on top put a mixture of sulfur, little bit of sugar, little bit of KNO3 and on top of that put pure sulfur that gives me time to close the bucket before the violent reaction starts that lasts like 10-15 seconds.

The actual question is, how do I make the mix burn like it is in theory mean to burn?
In this video the NO2 fumes are clearly visible: https://youtu.be/7XVt_ca97WE?t=305

This is how I usually ignited all that https://www.youtube.com/watch?v=KwYA7ojSodc


Good God why do I talk so much?


I am unfamiliar with this process, but I have played with KNO3/S pyrotechnic mix, and know they do react. As I understand there is not a lot of KNO3 in that mixture, that is why reaction is not energetic at all.

I would recommend grinding KNO3 (and sulfur) as fine as You can or even use water to mix it with S, making a paste and actively drying it making homogenous mix of molecules, that might help it burning completely. I guess sulfur boiling point is lower than decomposition of KNO3, so it never does. (too lazy to check)

karolus28 - 31-8-2021 at 12:25

Well, I tried mixing the sublimed sulfur with somewhat powdery KNO3 1:1, blasted it with a mini blowtorch and nothing really happened. If you put a pinch of sugar it burns like rcandy with very bright light. I might try doing this again

TheMrbunGee - 31-8-2021 at 12:46

Quote: Originally posted by karolus28  
Well, I tried mixing the sublimed sulfur with somewhat powdery KNO3 1:1, blasted it with a mini blowtorch and nothing really happened. If you put a pinch of sugar it burns like rcandy with very bright light. I might try doing this again



I think You need about 1 part of S for 4 parts of KNO3, try that mixture. Otherwise molten sulfur just extinguishes reaction like water would.

Edit: The sulfur melts first, so fineness of it does not matter as much as fineness of KNO3. Only bet to get this working with Your proportions is to get KNO3 as fine as possible, If its doable at all.

[Edited on 31-8-2021 by TheMrbunGee]

karolus28 - 1-9-2021 at 12:30

Tried 1:4 today, worked. The only difference was that I had the mixture on Al foil with a lighter underneath. It's just that lighting it from the top doesn't work.

thanks

karlos³ - 1-9-2021 at 16:44

Ok so I want to follow this theobromine extraction procedure: https://biochemicalponderings.wordpress.com/2017/03/18/theob...

Even made magnesium hydroxide just for this process, but that crappy substance is so hard to filter out :(

My short question would be, can I replace the magnesium hydroxide simply with sodium hydroxide, it is used to form insoluble tannate salts, would NaOH be a suitable substitute for this?

DraconicAcid - 1-9-2021 at 17:21

Sodium hydroxide should be okay, but calcium carbonate should also work (that's the base of choice in the caffeine extraction I have notes for), and is less harsh.

karlos³ - 1-9-2021 at 17:38

Thank you! :)

I just can't get the Mg(OH)2 I made out of the aqueous suspension it is in, so I guess I'll stick with NaOH.
If it turns out this was not an as well working alternative, then I guess I can still fix any issues resulting from that later, shouldn't be that bad.

UC235 - 1-9-2021 at 18:25

How about buying some food grade lime? Calcium hydroxide. That will be a lot closer than NaOH.

DraconicAcid - 1-9-2021 at 18:28

You can't get magnesium hydroxide as an antacid where you live? Unflavoured antacid tablets should work just fine for this prep.

karlos³ - 1-9-2021 at 21:11

Well I have around 800ml of selfmade "milk of magnesia" now, it just clogs up everything.
I actually took the required amount of MgSO4 7H20, dissolved this in water and added the respective amount of NaOH to precipitate the Mg(OH)2, its just that this annoying fine precipitate is a bit like cement when fresh prepared, or such...

Guess I could try it through a piece of cloth instead, that might work better.
I mean, its the exact quantity and substance I need, even if I can't filter it through the frit, I should still try to filter it out somehow.

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