# UC

Senior Members

547

1. ## crucible cleaning

Try heating some concentrated NaOH or KOH solution up in the crucible, and keep the alumina submerged. This won't attack the iron, but will dissolve the alumina as sodium (or potassium) aluminate. You might try molten NaOH if hot concentrated aqueous solution won't get rid of it. You may get a thin skin of rust where the hydroxide is, but it buffs out very easily.
2. ## Fractional distillation of NaCl and KCl

Look up solubility curves of NaCl and KCl. You'll find that NaCl has very little swing in solubility from 100C to 0C while KCl is quite a bit more soluble at 100C than 0C. So yes, dissolving in boiling water, filtering (if there is other gunk in the mix), and cooling will give a crop of crystals rich in KCl. It is possible that there will be no NaCl, but that depends largely on how much of each is in the original sample.
3. ## Area of contact between two spheres/size of 'point'

This depends entirely on if you want to operate in a system of pure mathematics or in the real world. In a system of pure mathematics, then yes. The contact between the two would be a single point. If you want to operate in the real world, but want to use two perfect spheres of an infinitely incompressible material (not quite the real world), you still have to contend with the fact that atoms aren't quite as definite as mathematical objects. The aren't hard, sharply defined, closely packed spheres.
4. ## Disposing of packing peanuts?

Use a small amount of acetone in a cup. Adding the peanuts releases their blowing agent and reduces them to styrene (I assume) scented goo. There is no reaction, just a weak solubility that allows the filler gas to escape. Polystyrene is used to make all sorts of things and most end up in the trash, so at least it'll be low-volume trash.
5. ## how to make kno3

First of all, proper sentence structure and capitalization will get you far in life. A better question would have been, "Is it possible to make KNO3 from urea or NH4NO3, and how would I go about doing this?" People tend to assume you're a 14 year old kid who wants to make big explosions in your backyard if you ask about things like KNO3 the way you did. Urea could be made into nitrates by using it as food for nitrobacter bacteria or by decomposing it into ammonia and leading it through heated catalyst tubes with just the right proportion of oxygen to convert it to nitrogen oxides, which are absorbed in water, forming nitric acid, and then neutralized to nitrates. Then again, I dont know of anyone who can do that on a hobby scale. I certainly hope you don't have NH4O4. I've never even heard of such a compound. It's probably really dangerous. No, what you have is NH4NO3. ammonium nitrate. Boil with a stoichiometric amount of potassium carbonate or potassium hydroxide until ammonia stops coming off, concentrate and chill the solution, disturbing it as little as possible. Long, needle-like crystals of KNO3 deposit, which can be filtered from the solution, rinsed with ice cold water, and dried. If you shake it up or move the beaker too much, you get lots of extremely fine crystals which trap the solution between them, dissolve rapidly when you try to wash them, and take eternity to dry out. Why do you need KNO3 so urgently? If this has anything at all to do with the anarchist's cookbook, please delete or throw out your copy right now. It is garbage and you will hurt yourself. Pick up an inorganic chemistry textbook at the library. Learn it. Bonding, Ions, stoichiometry, double displacement/metathesis reactions, redox chemistry (this one is absolutely vital but you won't understand without the other material). The only way you will be able to make any kind of pyrotechnics properly and responsibly is if you understand what exactly is happening. I'm sorry if I've gone on a tirade there for no reason, since I have no idea why you want potassium nitrate anyway. Have fun making it if you do. Cheers
6. ## Gas and colors?????

NO2. It's a unpleasant, toxic, reactive red-brown gas. A reduction in temperature pushes the equilibrium in a closed vessel toward it's colorless dimer, dinitrogen tetroxide. http://en.wikipedia.org/wiki/File:NO2-N2O4.jpg
7. ## Sodium metal production questions

Hey there's plenty of stuff you can do with a furnace that can melt steel. Do your own alloying, melt down aluminum cans into ingots. smelt your own metals. If you have a taste for the dangerous and can afford a quartz reaction vessel, it can probably be used to make sulfur trioxide en-masse from sodium bisulfate. If you don't know what to do with this material neat, you can always dissolve it in sulfuric acid and make your own oleum or dilute that and make clean, reagent grade sulfuric acid without spending a fortune. That is also discussed in the forum I linked. Cheers! -UC
8. ## Sodium metal production questions

You're better off using the hydroxide. It has a lower melting point and no several hundred degree chlorine gas to deal with. Thermal reduction of carbonate with carbon sounds sketchy. I suspect you won't make anything, but If it does work, the sodium will be vapor at those temperatures. Carbon is not a magic bullet for reduction. If you have a piece of sodium, please sink it in some dry mineral oil before you try to melt it. Doing it outside without inert atmosphere will give you a UV-rich, blindingly white fireball, which is cool, but not what you want, I suspect On molten state electrochemical approaches: http://www.sciencemadness.org/talk/viewthread.php?tid=2103 Actual success with a castner cell: http://www.sciencemadness.org/talk/viewthread.php?tid=9797
9. ## Very strange reaction between cinnamon and alcohol

Try boiling some cinnamon in water. If I remember correctly, it turns to "gooey snot" from hydrolysis of starches and such present in the inner bark. What seems to have happened is the same thing, just over a much longer period of time since heating was not used.
10. ## synthesis of chlorine dioxide

http://81.207.88.128/science/chem/exps/clo2/index.html Based upon the equations presented there, using, say, 5eq of chlorate and one of chloride, finely ground and intimitely mixed, then acidifying with sulfuric acid should give you a good percentage of the dioxide in the gas.
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