Jump to content


Senior Members
  • Posts

  • Joined

  • Last visited

Everything posted by woelen

  1. Keep in mind that tin does not dissolve in hydrochlorid acid at any appreciable rate. A mix of tin and lead probably also does not dissolve easily. PbCl2 is quite insoluble and tin does not react at all with HCl. I tried personally dissolving tin and it is really slow The following may be interesting info: Google groups -- thread on tin Testing whether a piece of metal is lead or tin is easy. Dissolve in conc. HNO3 and then dilute 10 to 20 times. If there is tin in the liquid, then a white precipitate is formed of SnO2. Add a solution of KI to the diluted liquid (whether this contains white precipitate or not does not matter for the test on lead). If there is lead in the liquid, then a beautiful bright yellow precipitate is formed of PbI2. So, in one go you can detect the presence of tin and the presence of lead.
  2. Didn't you learn any arithmatic on primary school?
  3. Both indium and tin can be obtained easily from http://www.emovendo.net. Not particlularly cheap, but very very pure samples can be obtained from them. I have tin at 99.99% purity and indium at 99.99% purity. They also have gallium, but international shipping of gallium may be a problem, as it eats away aluminium and is wetting very much. A good source of gallium also is eBay. Personally, I think it is best to buy some tin from such a company. Given the price of very pure tin I would not even think of messing with solder and removing the very toxic lead salts in this process. This company also sells 1 lb amounts of tin, albeit at somewhat lower purity, but also at a much lower price. TIN Metal Element 1lb Shot 99.96% $16.99 TIN Metal Element 30 grams 99.99% $5.99 INDIUM Metal Element Teardrops 10 grams 99.999% $19.99 INDIUM Metal Element Teardrops 25 grams 99.99% $28.99 From this company, I purchased the 30 grams of tin and the 25 grams of indium (I also ordered 30 grams of Se-shot and 30 grams of Ag-shot). Combined shipping to Europe was around $6 as far as I remember. The samples are really nice and pure! They can ship all these elements internationally, because of the fact that they are in shot format or bulk format. This makes them much less dangerous. Only iodine, cadmium and gallium from their list are not shipped internationally as far as I remember.
  4. I did a nice experiment, in which I made two interhalogen compounds. Making one of them react with magnesium metal also is quite spectacular. I did the experiment last weekend and below follows a report with pictures of the experiment: If you want to perform the experiment yourself, be very careful. Carefully read the info on safety in the experiment's description. Have fun, but keep things safe and healthy!
  5. This is fun! What is remarkable is that in the second experiment in the new vial, you did not get copious amounts of I2-vapor. I have done such an experiment with magnesium and iodine. I also want to try with calcium and iodine. I have 75 grams of pea-sized granules of Ca-metal, so this experiment should be possible quite well with the little granules. The latter may be more dangerous, so I have to think carefully about how to do this. The Mg/I2 reaction was initiated by water, can the calcium reaction also be initiated with water?
  6. The third product is water. Net reaction: (NH4)2SO4 + CaO --> 2NH3 + H2O + CaSO4
  7. That sounds terrible! It must be ugly and very impure. The stuff I buy is white or very light grey and its solutions are almost clear and colorless.
  8. That's funny to read. Over here we buy it in 5 kg or 25 kg amounts, almost 100% pure as 'zwavelzure ammoniak', which means something like 'ammonia of sulphuric acid'. It is in the form of small-pea-sized pellets, which are used dry. I've never seen this being sold as a solution. So, this differs from country to country.
  9. I did not say that you are one of these people. I was only annoyed about this CO2-bomb stuff. I still think that that kind of things is not very funny and does not add much to the hobby of chemistry. But of course, you may have your opinion and I'm certainly not intending to insult or discomfort other members of this forum. Indeed, I agree with you that this kind of things can spark people's interest in chemistry (and in fact, I also sometimes do boom/smoke/light things with my kids, just for fun), but to my opinion such things must not be discussed on an internet forum, but have to be conducted personally with the less experienced persons. While you and your audience have fun about the noises, smoke or whatever, you also can explain things, warn for risks, etc. That makes the things even more fun and that really sparks people's interest.
  10. woelen


    There are three types of bleach: 1) Plain household bleach, which contains an alkaline solution of sodium hypochlorite, often also containing quite some sodium chloride. 2) Bleach powder, which is CaCl(OCl), half hypochlorite, half chloride. This is made by leading chlorine gas through a suspension of calcium hydroxide. 3) Swimming pool bleach, which is almost pure Ca(ClO)2.2H2O. Bleach type (1) always is liquid, the other two forms are more stable in the solid form. When you heat bleach of type (1), then it mostly decomposes, giving oxygen and NaCl. Indeed, there also is some disproportionation to chloride and chlorate. When it is boiled, then the decomposition to chloride and oxygen is favored, when it is heated to appr. 70C for a longer time, then the disproportionation is favored. I've never seen a liquid bleach, containing Ca(ClO)2. Of course, this is possible, but I doubt whether this makes any sense, because Ca(ClO)2 is much more stable on storage in the solid state and there is no benefit of having this dissolved over having dissolved NaClO (in fact, even less favorable, because the calcium would give all kinds of undesirable precipitates with many domestic water sources). NaClO is much less stable in the solid state, but solutions of NaClO are equally stable as solutions of Ca(ClO)2.
  11. I would say, don't do that with the CO2 bottle. This is a typical thing for a kewl and not fun at all .
  12. I used a long match and I still have both my hands and all my fingers.... another reason to start with small quantities .
  13. Why not try on-line photography raw chemical suppliers? They sell quite some chems to the general public. I know of a supplier in the UK, who ships internationally, but I do not post the address here (kewls also read this). If you really are interested, send a private message to me.
  14. This is because you want to keep the bubbles when they reach the surface. Any soap, which preserves the bubbles at the surface for a reasonable time works, but in my experience, dish-washing soap is best. PLEASE do not use more. Even 10 ml of gas gives a frightening impressive BOOM. I'm not joking, this really is true. If you use 100 ml of gas mixture, then I'm afraid that the glass from your house will be blown away, but at least you'll damage your ears. PLEASE believe me! You know the name, it is called detonating gas.
  15. That's a very nice setup you made' date=' I never did it that nice way, I just took two electrodes, wound some copper wire around one end, put some cello-tape around it and then put that side (tape and wire) all in a big drop of glue. In that way, only the carbon part is in contact with water and the isolated part of the copper wire. Your setup, however, is much nicer. You must have a lot of minerals in your tap water if you can obtain so much H2 and O2 in just an hour. The experiments I did with tap water simply were too slow to be useful. As others already mentioned, if you want to make H2 and O2, there are other faster and more convenient ways. My personal preferred way of making hydrogen gas in large amounts quickly at very low cost with easy to obtain chems is the following: Dissolve just a pinch of copper sulfate in dilute hydrochloric acid (appr. 7% HCl, 10% at most). Copper oxide or copper carbonate from a ceramics supplier also is OK. You can also make such a solution by electrolyzing dilute HCl for a while with a copper anode. The anode will dissolve. Having made this solution, you have prepared something with which you can dissolve Al-household foil in a matter of seconds and you produce LOTS of H2-gas in a vigorous reaction, which is not too violent (that's why the concentration of HCl must not be too high). The copper/chloride combination is essential. Leaving out one of these makes the reaction much slower and introduces large induction times. See also the following experiment on my website with Al-foil and copper+chloride mixtures: Experiment with al and copper+chloride mixture. Making oxygen gas is even easier. Take some H2O2 (3%) and put in this some mangenese dioxide (from pottery/ceramics stores). Putting in a little piece of raw flesh also works, but this looks quite ugly and unpleasant. The AA-cells, you took apart also contain a lot of MnO2, that's the black powdery stuff. It is not 100% pure what you take out of these batteries but it is perfectly suitable for making oxygen out of H2O2.
  16. Electrolysing directly into a balloon of the gas mixture H2 and O2 I would strongly advice against. If for whatever reason you get a spark (e.g. because the two electrodes touch each other inside the balloon), then the complete setup will be scattered and you'll have lots of glass and other stuff flying around. If you use two balloons, one for H2 and one for O2, then it may work, but the problem with balloons is that they are quite porous and especially the H2 will escape from the balloon quickly. Besides that, doing electrolysis with the balloons seems very cumbersome to me.
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.