woelen

Yes, Xeluc, I am interested in this. If you can make new pictures after a week or even later, then still this would be great. Such things are very nice and it is even better if you show them to the world . I also intend to do something like this myself with CuCl2, although I already have several hundreds of grams of this compound. I did not know that such nice large crystals could be obtained. Another very interesting suggestion for you. If you have a heat resistant glass beaker (e.g. Schott Duran or Pyrex glass) or a corrosion resistant crucible, then it may be very interesting for you to carefully heat the CuCl2.2H2O crystals, such that they loose their water. If the heating is done carefully, then they do not hydrolyse and loose HCl, but then you get pure anhydrous CuCl2. That latter stuff opens up a whole new world of copper chemistry in non-aqueous solvents. I just started exploring that. CuCl2 is mostly covalent and it dissolves in methanol, ethanol, acetone, DMSO. It dissolves with all kinds of colors (green, yellow/green, brown, yellow, blue). You even can get very weird precipitation reactions, such as CuCl2 + H2SO4 --> CuSO4(s) + 2HCl, where white CuSO4 precipitates. Also complex formation is very different in non-aqueous solvents.

I've done the experiment by adding freshly cut sodium metal to bromine. Surprisingly, no reaction at all. The sodium is completely wetted by the bromine and then remains floating on the bromine. Next, I added a very small drop of water. If that is done, then the sodium reacts very violently, with fire-like things and little explosions. Probably the bromine makes the reaction between sodium and water more violent. But, very surprising to see that sodium and bromine do not react at all.

Beware, many people don't smell HCN (including me). I once on purpose made HCN by dripping some dilute HCl on solid NaCN and then carefully sniffing (no, don't worry, quantities were well below 20 mg). No smell at all. I did the same test by taking 20 mg of Ca(ClO)2 and dripping some HCl on it. I immediately noticed the smell of chlorine very clearly. I can smell chlorine very well, but I do not particularly dislike that smell (nor do I like it very much). Finally I did such a test with 20 mg of NaN3 and adding dil. HCl to that. When I do that all alarms in my body start ringing, due to the smell of HN3. For me that definitely is the worst smell I've ever noticed . Not the smell itself, but when smelling it, it gives a really alarming feeling, a sense of fear, just as if you've seen a very horrorful scene in a movie or have seen something terribly happening. I cannot explain this, but it is really strange that a smell can do something like that in such low quantities (well below lethal and also well below physical discomfort). This sense of fear, I do not have with Cl2, Br2, NH3, SO2 and many other pungent compounds, but I have it very strongly when smelling HN3. It has nothing to do with real fear.

If you are tight on budget, then indeed I would go for a cheap computer power supply. With the 12 Volts output you can do many things. However, you also need to be able to regulate the voltage output (between say 1 volts and 10 volts). Even better would be to make a current source of say 0.5 A to 2 A, which automatically adjusts its output voltage in order to keep current constant. These are really great for electrolysis. With an LM317 you can make an adjustable voltage source, ranging from 1.2 V and upwards to appr. the raw voltage minus 3 volts. These are perfect in combination with a computer power supply. If you have a little more budget, then you can buy a lab power supply in an electronics store. I do not know American prices, but over here in The Netherlands I can buy one for $150 to $200 with the following specification: Adjustable max. output current 0 .. 5 A Ajustable output voltage 3 .. 30 V With these you can implement a current source and a voltage source. If the current limiting is set to 3A and your circuit draws less than 3 A then the selected voltage will be output. If you want a current source, then set the voltage to 30 V and adjust the max current at e.g. 1 A. Now, the power supply adjusts its voltage, such that the current drawn is 1 A. The latter works perfectly for more concentrated liquids when they are electrolysed. When you want a device with a lower adjustable output voltage, then you need to spend more money, but such a shortcoming can easily be adjusted for. Buy a few power diodes and place these in series with the voltage output. Each power diode takes around 0.6 V, so with three of these your Vmin will be 1.2 Volts. the specs I have given are just indicative. With some searching you might be able to find better devices for that price. Especially the lowest voltage setting is important. Electrolysis can be done at voltages as low as 1.5 Volts.

Wow, that really is great. The reagent grade CuCl2.2H2O I have has tiny crystals, just around 1 mm of length and 0.1 mm thickness or so. Doesn't your camera have a macro-feature? The crystal of FeCl2.4H2O I had has a maximum diameter of approximately 1 cm and I could obtain a sharp picture of that, so with so many crystals of the mentioned size you should be able make a real stunning picture.

Try to find drain cleaner. Drain cleaners come in two "tastes", the alkali one and the acid one. The alkali one is NaOH. This is interesting to have on its own. The acid one is 92 .. 97% H2SO4 with some organic impurities, but for many experiments it is perfectly suitable. There also are some other drain cleaners with diluted acids or bases and all kinds of soap added. Avoid those. You need the real stuff. "Caustic soda" or "lye" or "sodium hydroxide" for the basic stuff. Beware, however, with concentrated H2SO4 and NaOH. Both are capable of eating holes in your skin at quite a high rate. Besides that, both produce a lot of heat when diluted with water. Always add the acid (or NaOH) to water, not the other way around. If you use 35% H2SO4, then you cannot make HCl as gas. The acid simply contains too much water and the gas will remain dissolved. At most your liquid may give off a little amount of fume, but that's all.

Well done Xeluc ! You have done a VERY good job of making such pure CuCl2.2H2O. The color looks very good and it is an indication of high purity. This is very nice stuff for further experiments. What is the length of one such a needle-like crystal? Now there is one thing left. Make a better picture with your Minolta camera .

Here is the point where a current source instead of a voltage source comes into play. If you use a current source for your cell, then you'll see that the voltage, needed to maintain the same current slowly rises. The lowest voltage is needed for conversion of your Cl(-) to Cl2, a higher voltage is needed for conversion of ClO3(-) to Cl2O6 and yet another voltage is needed for electrolysis of the water, forming O2. Unfortunately, the bumps are not sharp, the observed voltage is increasing slowly. Determining when to stop best is not easy and depends on what you want. The problem is that at no point in time there is only chlorate and nothing else. You see a decrease in chloride concentration, an increase in chlorate concentration and even, when still a lot of chloride is present, you also will have some perchlorate in solution already. So, an answer to this question is not easy. I would work as follows: Take a solution of well-known concentration. Start electrolysis and measure the voltage with a given current from a current source. Every now and then sample the amount of chlorate in the solution and keep track of the voltage at that point. From these measurements, you can keep a record and use that in future electrolysis systems. You can even automate it with a current source, which is switched off, when a certain threshold voltage (with some hysteresis built in) is exceeded. No, you'll not end up with the metal hydroxide. Ideally, for each 2OH(-) produced on the cathode either 2H(+) is produced at the anode, or a Cl2 molecule is produced. In practice, due to losses of chlorine gas (bubbling out of solution) and due to losses of OH(-), due to absorbtion of CO2 and due to losses of small bubbles around the cathode, things are more complicated, but when no chlorine gas is lost into the air and no OH(-) is lost due to droplets being lost into the air, the mix finally will contain mostly ClO4(-) with some ClO3(-), ClO(-), Cl(-) and an equilibrium is reached. At the cathode, H2, OH(-) and back-reduced Cl(-) are formed and at the anode, O2, H(+), Cl2, ClO4(-) are formed keeping the system in equilibrium. In the meantime there also always will be some ClO2 in solution, which with OH(-) forms ClO3(-) and ClO2(-). ClO2(-) in turn is converted to ClO3(-) and Cl(-) again: 3ClO2(-) --> Cl(-) + 2ClO3(-), very similar to reaction of ClO(-) So, the final outcome will be (assuming no gasses are lost to the air, except H2 and O2, and water is replenished): - moderate amounts of Cl(-), due to back-reduction at anode - moderate amounts of ClO(-), due to reaction of Cl2 and OH(-) - small amounts of OH(-), due to small excess of OH(-), formation of ClO2 takes H(+) - small amounts of ClO2, due to presence of Cl(-) and ClO3(-) - small amounts of ClO2(-), due to reaction between ClO2 and OH(-) - moderate amounts of ClO3(-), due to disproportionation of ClO(-) and ClO2(-) - large amount of ClO4(-), due to final oxidation of ClO3(-)

I agree with YT. I have a few liters of 30% HCl and I also have one liter of 37...38% HCl. The latter is a REAL pain on storage. It is somewhat pressurized and when I open the bottle an immensely thick and choking white fume is produced, as soon as the cap is loosened somewhat. Till now I have not found a single experiment, which I could not do with my 30% HCl and which needed 37%. The only reason for me, having that 37% bottle is that it is reagent grade from a chemical supply house, while my 30% acid is technical grade from hardware stores. Some of my experiments require very pure reagents and then I use the reagent grade.

Again, it is a matter of quantum mechanics. The energy levels are so close to each other that sometimes Cu(+) is more stable and another time Cu(2+) is more stable. The stability strongly depends on the ligands which are coordinated to the copper core: Water ligands: Cu(2+) is stable, Cu(+) disproportionates to Cu and Cu(2+) Ammonia ligands: Both Cu(2+) and Cu(+) are stable. Chloride ligands: Cu(+) is more stable, in the presence of both Cu and Cu(2+) they comproportionate to Cu(+) So you cannot say that Cu(+) is more stable, it really depends on the compounds in which it is incorporated.

Electrolysis of chlorides gives the following reaction: anode: 2Cl(-) --> Cl2 + 2e cathode: 2H2O + 2e--> H2 + 2OH(-) When the liquid is mixed, you get the following secondary reaction: Cl2 + 2OH(-) --> Cl(-) + ClO(-) + H2O On heating and long standing you get the following reaction: 3ClO(-) --> 2Cl(-) + ClO3(-) So, the chlorate does not form at the anode, it forms indirectly through the intermediate hypochlorite. As you see, Cl(-) is produced from all these reactions again and that Cl(-) also is used up again at the anode. Finally, only ClO3(-) is left. Before that happens, however, a new net reaction comes into play at the anode: H2O + ClO3(-) --> H(+) + HClO4 + 2e Probably the intermediate reaction is as follows: 2ClO3(-) --> Cl2O6 + 2e Cl2O6 + H2O --> HClO3 + HClO4 --> 2H(+) + ClO3(-) + ClO4(-) The H(+) is neatralized by OH(-) from the cathode. There also is a side reaction at the anode during the entire electrolysis process: 2H2O + 4e --> 4H(+) + O2 + 4e As long as chloride, Cl(-) is present, the formation of Cl2 is strongly favoured. When Cl(-) is depleted, then the conversion of ClO3(-) to ClO4(-) via the Cl2O6 intermediate is favoured, but with increasing relative concentration of ClO4(-), nothing but the water is left and finally only water is oxidized at the anode, giving oxygen and acid. But the oxygen and acid-forming reaction also occurs already when quite some chloride is present and also when quite some chlorate is present. This causes the yellow color in chlorate electrolysis cells. When ClO3(-), Cl(-) and H(+) are present at the same time, then a complicated reaction occurs, in which ClO2 (deep yellow) is formed.

You will not end up with pure iron hydroxide. What Xeluc states is an extreme form of the hydrolysis reaction. In reality you'll end up with a compound, which is best described by [math]FeCl_{x}(OH)_{3-x} . yH_2O[/math] Here x is a (possibly non-integer) number between 1 and 3 and y is some (possibly non-integer) number. This compound is a bad non-stoichiometric compound, whose precise composition hardly can be determined. That depends on how fast it is heated, the amount of HCl present in the liquid, humidity of the air, etc.

Making pure HCl gas is not difficult to do at all. Just add some table salt to concentrated H2SO4 and the stuff starts bubbling and foaming. Dry HCl gas is colorless and not that corrosive, but as soon as it comes in contact with air, it starts fuming increadibly, picking up moisture and forming small droplets. This fume IS corrosive. It eats metal things and accelerates rusting of iron objects a lot. Pressurizing the gas, until it is a liquid, forget about that at home, unless you have some really advanced equipment.

Indeed, raivo mentioned it already. Many metals have small impurities, most notably the phosphorous impurity. This gives rise to formation of PH3, which is a very toxic (though non-accumulative) poison. Personally, I would not worry too much, but just to be sure, assure that the room has good ventilation. As long as you only dissolve metals in HCl, things are not that bad, even if traces of PH3 or AsH3 are formed. What you should do, however, is covering the vessels, test tubes and so on with a paper tissue. Not closing them completely, allowing air/gas to escape. This paper absorbs small droplets, thrown in the air, when the acids are bubbling. These droplets enter the air, the water and HCl evaporate and what remains is very fine dust of metal salts and that is a thing which you should worry about. Especially if the metals are toxic (copper, nickel, cobalt). With zinc, aluminium, iron the risks are less. With lead, silver, cadmium and mercury the risks are even larger. Just a little piece of paper tissue over the reaction vessel is a VERY good safeguard against these droplets. For fumes of HCl and NH3, I would not worry too much as long as they do not irritate too much. They are broken down to harmless chloride salts anyway quickly.

Solid iron (III) chloride has a mustard-like yellow/brown color. The stuff you buy at electronics stores is the hexahydrate, FeCl3.6H2O. Solutions of FeCl3.6H2O are yellow, when acidified. They become brown when not acidified, due to hydrolysis of the iron (III) and subsequent formation of hydroxo-complexes of iron (III). When you boil down a solution of ferric chloride in water, then you'll end up with some basic compound. On heating it looses HCl and you end up with a ferric compound, containing chloride, but also hydroxide. Iron (III) chloride is a good printed circuit board etchant and is sold as such in electronics parts stores. It dissolves copper with ease, especially if a small amount of hydrochloric acid is added. It is quite specific for dissolving copper. Dissolving other metals is much more combersome. The reason for this is quite complex. Ferric chloride forms the complex ion FeCl4(-), which is a reasonable oxidizer, but equally important is that copper (II) formed is complexed by the chloride: 2FeCl4(-) + Cu --> 2Fe(2+) + CuCl4(2-) + 4Cl(-)

I have used up some more bromine in an experiment with phosphorous . Really spectacular. http://woelen.scheikunde.net/science/chem/exps/P+Br2/index.html I now have 0.5 ml left. I'll consider the sodium experiment.

The cold you feel only occurs when some gas is allowed to escape from the canister. Evaporation of a gas (liquid --> gas) costs quite a lot of energy and that causes the cold feeling. When the gas is not liquid, but merely under high pressure, then the expansion, due to the release of the gas, also costs energy. That also makes the canister feel cold. If you have canister with a liquid gas or a high-pressure gas and you do not do anything with it, then it does not feel cold. A nice observation is when you take a bottle of beer and you remove the cap. Then at once the pressurized carbon dioxide expands and it cools down considerably. You see a little cloud, due to expansion (and consequent cooling down) and condensation of water droplets in the cold gas.

Last week I made some KBrO3 by means of electrolysis of NaBr and crystallizing this with KCl. See this thread on SFN: http://www.scienceforums.net/forums/showthread.php?t=16254 This stuff is too violent for pyro-experiments, so I searched for another use of this. I converted this stuff to pure bromine by adding NaBr and hydrochloric acid and the resulting bromine I collected in a small vial: http://woelen.scheikunde.net/science/chem/compounds/bromine.html Unfortunately I see no good way to store it for any length of time, so I used it for experiments. One of the experiments is so nice, that I want to share it with others: http://woelen.scheikunde.net/science/chem/exps/Al+Br2/index.html If you attempt to repeat this experiment, please be VERY careful. It is a dangerous experiment, if not performed in the right way. You are warned. Safety info is added in the experiment description on the page.

Sorry if I was not clear. I did not say that these detectors contain tritium, what I meant was making tritium with the help of the material from these detectors.

I did not anything special at all. I dissolved the iron in the acid. In order to have it all dissolved in an acceptable time, I heated close to boiling. When (almost) all iron was dissolved, I stopped heating and put the test tube aside. Two days later, the large crystalline mass was at the bottom of the test tube.

It is possible to define a non-integer positive base B > 1 as follows: Given a base B, then digits 0 ... dmax can be defined with dmax the largest integer value less than B. For B equals 4, the digits 0, 1, 2, 3 are allowed. For B equal to pi, also digits 0, 1, 2, 3 are allowed. Any number can be written as a (possibly infinite) series of powers of B, with the terms multiplied by digits. In base pi, the number 0 is written as 0, the number 1 is written as 1, the number pi is written as 10, the number pi^2 is written as 100. This definition is compatible with integer bases and is a reasonable extension. This definition, however, has a very peculiar property. If you approach a power of pi from below, then the digits do not all go to 3333.... after the period, but they make a jump. For base 4, if you go towards 16 from below, then you'll see the following in base 4: 33.3333......... When the number 16 (decimal) is reached, then in base 4 you get 100.0000... For base pi the behavior is quite different: When pi*pi is reached from below, you get 30.1102111002022113... and many more irregular digits at the .... and then suddenly the digits jump to 100.00000..... when pi*pi is reached. This is a consequence of the base not being integer. Just for fun, I made a small C++-program, which converts numbers in base 10 to numbers in base pi. Here follows the source. It is not a robust well-designed program (e.g. the input could be much better), but it nicely demonstrates the base pi numbers. Input must be given in decimal notation, e.g. 10 or 3.1415 etc. Wrong input causes the program go astray, as i said, input handling could be much better . The source and executable program are attached to this post as zip file. Have fun with your PI-base. It can easily be modified to create any base. pi.zip

If I were you, I would leave it by a nice experiment in your head or on paper. You will NEVER see a visible amount of tritium. The americium samples you are talking about (in fire detectors) are increadibly small (microgram quantities). Taking into account all losses, inefficiencies and so on, do not expect to make more than a few nanogrammes of tritium. Indeed, there is a (small) risk of being exposed to radiation. I personally would not mess with radioactive materials, not even with the small quantities. It is not worth the risk. No, there will be no smoke, no fire, no smells, nothing spectacular to be excited about, not even the tiniest bubble of gas, but you will receive a certain dose of radiation.