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Brain&Force
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People who join metal together are welders.
In the case of burning hydrocarbons, the blue part of the flame is an emission band. I've seen this myself with a diffraction grating. It's not
blackbody radiation because you need temperatures of tens of thousands of degrees Kelvin. And there wouldn't be bands.
In the case of wood fires the bluest part of the flame is the hottest because it's more exposed to oxygen and therefore burns clean and hot.
DraconicAcid's suggestion of copper perchlorate works because a large amount of oxidizer (solid perchlorate) is available and the flame burns clean,
thus permitting coloration.
At the end of the day, simulating atoms doesn't beat working with the real things...
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alexleyenda
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You're right about the blue hydrocarbon flame, as soon as I read what you wrote it flashed in my head, i'm so stupid, it takes a temperature of around
6500 K to get a maximum blackbody radiations around blue wavelenghts while a propane flame's maximum is around 2000k... I'm so ashamed, I really
contradicted myself :p Anyways, they say intelligent people are those who made every mistake, i'm on my way for that :p
About the fact that the hottest part is the bluest, then, I guess it is because the energy needed to excite the electrons to the level from which they
emit blue (in the case of hydrocarbons) is high, so the flame needs to be really hot (burn well, be oxidized completely), if not it is only the
blackbody radiation that is seen. Right?
[Edited on 19-5-2014 by alexleyenda]
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arkoma
Redneck Overlord
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Can I dry acetone with NaOH? Happen to not have MgSO4 at the moment.
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Mailinmypocket
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No. It will cause an aldol condensation with acetone (http://www.chem.ucalgary.ca/courses/351/Carey5th/Ch18/ch18-3...) you could always use anhydrous copper sulfate though!
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Haber
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I recently made some 5-bromovanillin.
It was an in situ bromine method, which was something like this:
To a mixture of vanillin, potassium bromide, water and methanol there is added sulphuric acid and hydrogen peroxide, and stirred for 45 minutes,
Temperature were kept at 18-20C under the procedure.
The mixture was added to cold water and filtered and then washed with cold water.
The crude product obtained had a a quite strong yellow color. mp: 162-164C
It was not recrystallized.
Now i few days later the product has changed color to something more green, some parts have even turned black.
My first thought was that it has oxidated to the carboxylic acid since it was not stored air-tight, but I have also read somewhere that these
substituted aromatic aldehydes dont oxidize very easily. Not sure what to think.
I should also note that the sulphuric acid used was a dirty (purple color) drain cleaner.
Anyone have some thoughts on this?
Help would be greatly appreciated, thanks!
[Edited on 22-5-2014 by Haber]
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Bezaleel
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A while ago I put a spatula of microcrystalline nickelhydroxide in some 50ml water and added three spatulas of ammoniumthiocyanate to it. After some
swirling, the solution became green and a faint smell of ammonia was noticed. I let it stand for a week, swirling the flask and heating gently now and
then. Only a small portion of the nickelhydroxide dissolved.
I then decided to filter the undissolved hydroxide off and let the clear green solution evaporate on a petri dish. When it dried, a black substance
with a hint of yellow/brown formed. This seems to be the normal colour for nickelthiocyanate and its dihydrate, according to atomistry.
 
The question I am left with is where the excess ammoniumthiosulfate has gone. Are there any double salts known?
[Edited on 24-5-2014 by Bezaleel]
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solo
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Quote: Originally posted by Cheddite Cheese  |
edition of what?
Also, what would prevent the alkene from being halogenated?
Can you be more specific about conditions, substrate, etc.? |
March's Advanced Organic Chemistry: Reactions, Mechanisms, and Structure [Hardcover] 5th edition
"Also, what would prevent the alkene from being halogenated?" ......thats my question
.....any aldehyde with the coditions stated i.e. an aldehyde with no alpha carbon hydrogen , with a double bond adjacent to the alpha carbon....solo
It's better to die on your feet, than live on your knees....Emiliano Zapata.
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TheAlchemistPirate
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Has anyone here synthesized ruby? I have been looking around on the internet and am interested in making synthetic rubies, and have some questions. I
know that synthetic ruby is made by reacting chromium oxide with aluminum oxide at 2000+ degrees Celsius, but I have seen on this forum where someone
who did the reaction used a platinum-lined crucible to contain the reactants. I don't see why this would be necessary, since as far as I know the
reagents aren't acidic and don't need platinum as a catalyst. If a platinum crucible is required I will probably forget the idea since platinum is so
ridiculously expensive.
I also cant seem to find out how long the reactants need to be heated, I did see an article on the industrial process which apparently takes around 20
minutes...? The process involved using oxygen and hydrogen to heat the mixture and dripping the melted product onto a seed crystal, of course I cant
do this and was thinking of another method which involves dipping a rod with a seed crystal into a crucible filled with the mixture. The crystals
would then form on the rod.
I figured that I could use the latter method by making a furnace with firebrick and a graphite crucible, putting a graphite rod into the melted
mixture and getting the rubies. I would very much hope this would be the case as it would be very awesome to be able to make your own gemstones.
Unfortunately there isn't very much talk about homemade gemstone synthesis on the internet and all I can find is industrial processes, I hope you guys
can help.
"Is this even science anymore?!"
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Zyklon-A
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I've thought about it, but never got around to it. How are you going to make the furnace? What fuel will you use.
I would use electricity as a heat source, rather than any sort of furnace.
Do you want to make them just to make them (basically to show off a homemade ruby), or do you have a practical application for it? For me it would
certainly be the former hehe. Sapphire would be nice to... I'm guessing they contain copper?
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TheAlchemistPirate
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I would make a coal furnace and load it with charcoal, and use a graphite crucible as said above. I would also connect a steel pipe to the walls of
the furnace and insert a vacuum cleaner on reverse, I think that would be enough. I would preferably use an electric furnace(obviously) but I don't
have $700. I would initially make them to show off that I can make a homemade ruby, then I would experiment with making various shapes and sizes. I
also think that it would be cast-able into various shapes and maybe even into lab equipment, imagine blast-resistant and acid-resistant labware for
energetics syntheses?! I believe sapphire can be synthesized with nearly the same method as it also contains mostly corundum.
[Edited on 25-5-2014 by TheAlchemistPirate]
"Is this even science anymore?!"
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Zyklon-A
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2000°C with a charcoal furnace? I highly doubt that's even possible. Even with pure oxygen it would take a huge furnace, not even sure if it would
work at all.
Just make an electric furnace, wont cost even close to $700.
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TheAlchemistPirate
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I will probably look into making an electric furnace. I still haven't found anything involving using a platinum crucible, it might've been something
completely different lol. Another thing I noticed is the essential requirement of very pure reagents, or the crystal will be opaque. I plan on
spinning a graphite rod skimming the mixture and making large indestructible crystal clusters at first, then I will work on making uniform ones to
possibly sell. I will post my results and possibly start a thread on this if I get it to work.
"Is this even science anymore?!"
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Haber
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All of the product have now turned into a black dusty powder. Vanillin smell almost completely gone.
Even if it was 5-bromovanillic acid it shouldn't be black.
I'm very curious what has happened. Nobody who have any guess?
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Zyklon-A
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When gasses that exist at equilibrium are produced, are they made already at equilibrium?
For instance, in this reaction: 2 NO + O2 → 2 NO2, is the resulting nitrogen dioxide already at equilibrium with
dinitrogen tetroxide? Or does it have to reach it's equilibrium after it's formation.
Also, at lower temperatures, would this reaction happen: NO + O2 → N2O4? Or does it make nitrogen dioxide, and
then the slowly form dinitrogen tetroxide as it would at whatever the temperature is: 2 NO2 ↔ N2O4.
[Edited on 27-5-2014 by Zyklonb]
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The Volatile Chemist
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| Quote: Originally posted by TheAlchemistPirate | | I will probably look into making an electric furnace. I still haven't found anything involving using a platinum crucible, it might've been something
completely different lol. Another thing I noticed is the essential requirement of very pure reagents, or the crystal will be opaque. I plan on
spinning a graphite rod skimming the mixture and making large indestructible crystal clusters at first, then I will work on making uniform ones to
possibly sell. I will post my results and possibly start a thread on this if I get it to work. |
The crucible material probably has to do with the corrosiveness of molten oxides. I'm not entirely sure, but the periodic table of videos' video on
aluminum talks on some odd properties of aluminum oxide.
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bismuthate
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So I was just wondering: why is it OK for citizens to dump copper sulfate root killer down their toilets yet we can't dump copper sulfate waste from
the lab? The same question goes with conc. sulphuric acid.
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Hegi
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| Quote: Originally posted by bismuthate | | So I was just wondering: why is it OK for citizens to dump copper sulfate root killer down their toilets yet we can't dump copper sulfate waste from
the lab? The same question goes with conc. sulphuric acid. |
You can´t? ´Cause we can ..  Also interested in this question.
Our webpage has been shut down forever cause nobody was willing to contribute. Shame on you all!!!
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arkoma
Redneck Overlord
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anyone know how to deposit copper on glass? Be a bad ass retro mirror.
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DraconicAcid
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"Chemical Curiosities" states...
30 mL of 1 mol/L copper(II) acetate solution is added to a well-cleaned 500 mL round bottom flask (without a ground glass joint), followed by 5 mL of
80% hydrazine hydrate solution. The blue solution immediately turns a brownish green. The copper mirror is formed when the flask is rotated slowly
while being heated gently in the gas flame.
It does not suggest alternative reducing agents.
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
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bismuthate
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http://www.realscience.breckschool.org/upper/fruen/files/res... check out this paper. It talks a good bit about reducing agents for copper
mirrors.
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Brain&Force
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I've read that ascorbic acid works well for mirror-making as well.
Zwitterion copper-plated his HTC HD2: http://www.sciencemadness.org/talk/viewthread.php?tid=14644&... (the image is missing)
At the end of the day, simulating atoms doesn't beat working with the real things...
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alexleyenda
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I read a lot about KClO3 cells and I have two questions:
1- Most people say the max voltage should be 5.5V, however some say 6V is fine too... Would I be fine with a 6V power supply or would i end up with
perchlorate?
2- I have trouble understanding current density, I have not found clear explanations to it. What does the current density changes in term of
efficiency in reactions? I know for some reactions it has to be really high, while sometime it has to be low.. why? /what is the best current density
in this case (I think I saw it was 0.2A/cm²?)/ at what point does it starts to really damage the MMO electrodes/ How do I calculate the current
density? (I guess Current/ area of the smaller electrode ?)
Thanks !
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jock88
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http://oxidizing.typhoonguitars.com/
Current density at the anode is:
current into cell divided by the area of anode in use (in solution).
x amps per cm squared
Keep cathode area approx. (very approx) the same area to half the area of anode area.
Arranged in a sensible manner. It is good to have a cathode each side of a big flat anode.
Distance between anode and cathode not important as far as making product is concerned but you can vary the distance to suit the power supply voltage
that you are STUCK with.
Stop obsessing over the voltage.
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alexleyenda
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A very random question I wanted to ask for a long time: When I cook instant noodle, as soon as I dump them in the boiling water it starts to boil 3
times stronger, and if I push the block of noodles to the bottom, it boils even 3 times stronger again. Why the heck does it do that? I guess more
area for the bubbles to form like for boiling chips is part of the answer ?
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jock88
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I think noodles are the new boiling chips.
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