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woelen

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Everything posted by woelen

  1. It's a long time ago that I have posted here. Some of you may remember me from one year ago (or something like that) and the time that I have been very active on this forum, especially in the chemistry and also in the math sections. I can only draw the conclusion from all my reading of the last few months that SFN has become the militant atheists platform, despite the effort of the moderators to make things different. Is this a science forum? I more and more doubt this. I just want to express my sadness on how SFN has developed the last year. Less science, more extreme POV's. The attitude and taste of this makes me sad. You take away the fun of being a scientist for many people. Do you really think YOU have the truth and all those religious people are retarded. I don't expect an answer, I only post this in the hope that some of you will reflect on what they write. The attitude I see over here on SFN does harm to the image of science. I already have met a few people, who were scared away by what they have been reading over here. Not because of scientific contents (which unfortunately is slowly going to a lower level), but because of the arrogant attitude of "we all know what is best for the world, and all those religious persons are poor souls who still did not see the light". What I am writing certainly does not apply to all of you. I especially want to tell this to the moderator team. But I simply could not resist to express my sad feelings which I have after lurking this forum for the past 8 months.
  2. There are paints (waterpaints, used for children's painting on paper), which easily can be rinsed away with water and a brush. These paints should not be confused with water-based permanent paints. The latter are considerably harder to remove. So, be sure to obtain the stuff, used by children.
  3. Look at the place of the central atom in the periodic table. Halogens are at the last row (-1) before the inert gases, sulphur, selenium and tellurium are two rows (-2) before the inert gases, and phosphorus and arsenic are three rows (-3) before the inert gases. Exceptions are nitrate and nitrite, carbonate. These are -1, -2 instead of -3, -4. Also, keep in mind that phosphate has charge -3, but phosphite has charge -2 (you say -3). But this is not an exeption to the 'rule' I gave above. Phosphite only can give up two hydrogens, so the acid H3PO3 is diprotic and not triprotic. Hypophosporous acid is H3PO2, and that only can give up 1 hydrogen ion, so hypophosphite ion is H2PO2(-).
  4. Why not use blue paint?
  5. If any copper sulfate were formed, then it would not stick to the statue for a long time. Copper sulfate is water-soluble. Any rain, or any attempt to clean the statue, would remove the copper sulfate. Adding zinc to the copper sulfate does make copper, but don't expect that to stick to the statue.
  6. But now I have another question. Do you do this, just for fun or for educational purposes, or do you really want to have K4Fe(CN)6. For almost all people in the world, obtaining K4Fe(CN)6 is quite easy, it even is mentioned on eBay every now and then. On the other hand, obtaining KCN is VERY hard (and for good reasons). I know of a few people who do their best to make KCN (or NaCN) from K4Fe(CN)6 and hence I find it funny to read that you want to go the other way around.
  7. What you suggest certainly will make the hexacyanoferrate (II) ion in solution, but you need excess of KCN in solution. Initially, you'll get a precipitate, but on addition of more solution of KCN, this precipitate will dissolve. Adding acid does not seem like a wise idea to me, especially if you are heating as well, this may be extremely dangerous, due to the creation of HCN. The hexacyanoferrate ion is stable, even to moderately concentrated acid, but the free cyanide of the excess KCN definitely will form HCN. If your goal is making prussian blue, then there is no need to isolate the hexacyanoferrate (II). In this case, simply add acid (in a fume hood!) and add an iron (III) salt. The dark blue prussian blue will precipitate from the solution.
  8. The HNO3 will attack the tubing, albeit slowly. But in the long run it will be eaten, and I would certainly not use 90% HNO3 in aluminium apparatus.
  9. All of you know burning, and also even exploding of gas/air mixtures. Burning also is possible in chlorine gas. The following experiment does not require any exotic chemicals and can be carried out at home. http://woelen.scheikunde.net/science/chem/exps/cl2_c2h2/index.html If you do this experiment, please do not scale up, and make the chlorine gas outside or in a fume hood.
  10. Indeed, you don't need to reach escape velocity. The escape velocity is the initial velocity, needed for a passive object without own driving force, to escape earth. E.g. if you shoot a bullet vertically, then you need escape velocity (somewhat more, due to atmospheric hindrance). If an object has its own driving force (e.g. a rocket with fuel), then a lower velocity can be used to escape earth. The driving force just needs to be larger than the graviational pull in the opposite direction.
  11. You want a religion-based forum? In order to do religion bashing over here? Your previous post does not indicate an openminded attitude towards religion and it gives me the impression that you just want to show how superior you (and science) are, relative to religious people (and religion).
  12. Indeed, I agree with YT. I regard this just as a nice curiousity, and it has nothing to do with drugs (chlorobutanol is not even classified as a drug, and it can be purchased without prescription for relieving people from travelling illness). Your initial product also was chloroform, but the smell probably was mixed with an acrid chlorine/hypochlorite smell. The so-called haloform reaction is unique in its property, that only CHCl3 can be formed (or CHBr3 or CHI3 if hypobromite/hypoiodite is used) and not any other halogenated hydrocarbon. So, formation of CH2Cl2 cannot be the case. Search the net for "haloform reaction" and a lot of information pops up. This is quite an interesting reaction on its own. That makes chloral, CH3C(=O)Cl. When you add some water to this, you get chloral hydrate. Chloral has properties, similar to chlorobutanol, it also makes you numb. But it does not have that nice smell. You will also have side reactions, but the main product will be chloral.
  13. woelen

    Magnesium

    Such household items do not exist. If you want Mg-metal, then you have to buy it. Now you have sufficient suggestions for where to look.
  14. woelen

    Magnesium

    You want magnesium without buying it? Then you'll have a hard time. Making it from other (household)items is very hard. Magnesium is not easy to make at all from magnesium salts and it also is not worth the effort. Have a look at eBay. There are quite a few sellers, who sell magnesium ribbon and sometimes also larger chunks of magnesium are offered. Just search for magnesium metal. Finding powdered magnesium will be MUCH harder. Powdered metals are something which officials do not like you to have. Those can be used for making flash powders and in most countries that is regarded a socially less accepted act.
  15. It is better not to smell the chloroform too much. Chloroform is a carcinogen. Chlorobutanol is safe, and acetone also is only slightly toxic. That is the reason, why I suggest to use such a large excess amount of acetone, such that the end product certainly will not contain left-over chloroform (otherwise I would not instruct you to sniff the chlorobutanol). But yes, I agree that chloroform has a fairly pleasant odour. I, btw, also found a synth for chloroform, based on calcium hypochlorite: Synth of chloroform with Ca(ClO)2 I must admin, I have NOT tested this myself, I just found this, searching the net for chloroform calcium hypochlorite synthesis.
  16. No, that is not possible. The very dilute (0.008 M) acid acts just like plain water. The reaction only can be initiated with concentrated (>90%) H2SO4.
  17. The blue residue is a copper(II) compound. Most likely it is copper hydroxide, or some copper hydroxochloride. It can best be represented as [math]CuCl_{2-x}(OH)_x[/math], where x can be anything between 1 and 2.
  18. With 5% NaOCl you can double the quantity, but I'm afraid that the yield of chloroform will be much less. Chloroform is quite soluble in water, and with such dilute solutions, you may find that most of it dissolves in the aqueous solution. Of course you could distill off the chloroform, but that takes away the nice simplicity of this experiment. First try if working with 5% NaOCl gives sufficient chloroform. If not, you could try making a 5% solution of NaOH, and add Ca(ClO)2 to it. The trouble with that solution, however, is the turbidity of all the calcium in it. A better alternative may be the following: - Take some of your 5% solution of NaOCl - Dissolve some additional NaOH in it (add 5% or so). - Bubble chlorine gas through this solution, until hardly any chlorine is absorbed anymore - Finally, dissolve another 2% of NaOH in order to make it alkaline again. The chlorine you can make with HCl and MnO2, or HCl and TCCA. Only a few hundreds of mg is needed. If you use ethanol, denatured with MEK, then you'll end up with a compound, very similar to chlorobutanol. I also did the experiment with MEK instead of ethanol, and the result is very similar (similar smell, similar appearance), but I'm not sure about the toxicity of the MEK-derived compound. MEK is close to acetone, it is CH3COCH2CH3 instead of CH3COCH3, and the product formed will be CH3C(CCl3)(OH)CH2CH3, instead of CH3C(CCl3)(OH)CH3. I would be careful sniffing the stuff when it contains CH3C(CCl3)(OH)CH2CH3. That single added -CH2- group can make a lot of difference in toxicity.
  19. No, dilute HCl will not liberate ammonia. It even is the other way around. If you have free ammonia, and add dilute HCl, then it will be converted to ammonium ion, according to the following reaction/equilibrium, which is far to the right: H(+) + NH3 <--->>>>> NH4(+) In order to free ammonia from ammonium ion, you need something, which can pick up the associated H(+). Hydroxide can do that, if you add even more H(+), then ammonium ion definitely cannot be split up.
  20. A problem with many scientists (not science, but scientists) is that they claim to have TRUTH, and that only they have TRUTH and no one else. That is a big misconception. Science reveals truth, only about a part of the world around us, but much more remains unexplainable, unknowable and will ever remain so. So, yes, I agree that science is a powerfool tool in revealing truth, but at the same time I also think that we should not overestimate the power of that truth, truth is just a small subset of TRUTH. Right now we live in a demystified society, where science is our new religion, and many people run behind the priests of that religion, without even understanding most of what those priests are telling them. How will society look after a few centuries, maybe it will be full of mysticism? Our society will collapse, just as any society did in the past. Maybe we will see that happen, otherwise our children, grandchildren or grand-grandchildren will see that happen, and in the new upcoming society people will look at the poor few leftover scientists who think science has exclusive access to TRUTH, in a similar way that many people nowadays look at the minority of religious people.
  21. YT, this answer is not correct. You indeed will obtain calcium sulfate, but that is not relevant here. The use of sodium hydroxide would equally work for liberating ammonia. The real reason for expelling ammonia is that lime water contains hydroxide ions. Ammonium ion, NH4(+) is an acid (albeit a weak one). It reacts with hydroxide as follows: NH4(+) + OH(-) <--->>>> NH3 + H2O The equilibrium is far to the right. So, with any soluble hydroxide, you will get liberation of ammonia from the ammonium ion.
  22. This is a funny experiment, I want to share here. This is not because of beautiful colors, but of a very pleasant smell. There is some aftereffect, which can be described as being numb, somewhat floating feeling. It has no adverse effects, if not done too often. First chloroform is made, through the so-called haloform reaction: Take some chlorine bleach and add acetone. Add 3 ml of acetone to 50 ml of 10% active chlorine bleach. Use the bleach without perfumes or other additives. This will make chloroform. This step may take some time. Just let the chloroform settle at the bottom, until a few blobs are obtained. Collect them with a pipette. No need to purify them, their main impurities are acetone and water. These blobs are used in another reaction, requiring more acetone. The net reaction is as follows, the mechanism behind the reaction is more complex: CH3COCH3 + 3ClO(-) ---> CH3COO(-) + CHCl3 + 2OH(-) Next, dissolve some NaOH (or easier, some KOH) in a few ml of ethanol (96%, not denatured). Set this aside. Mix your chloroform with four times its volume of acetone and then add a small amount of the ethanol with NaOH or KOH to this mix of acetone and chloroform. Shake very well and cool the mix. Shake well. You will notice a strong rise of temperature, the chloroform and acetone react exothermically, producing a compound, called chlorobutanol, a.k.a. chlorbutol. Pour the liquid into 20 ml of ice cold water. You will see formation of an oily liquid and needle like long crystals on top of the water. Take away as much of the water as possible with a pipette, without taking away the oil and crystals (if they are there) and add new water again. Some of the oil may float on the water, some of it may form a blob at the bottom. The net reaction is: CHCl3 + CH3COCH3 ---> CH3C(CCl3)(OH)CH3 The mechanism behind the reaction is that the OH(-) ion in alcohol takes away the H from the CHCl3: CHCl3 + OH(-) ---> H2O + CCl3(-) The latter ion is extremely reactive. It attacks the acetone, it attaches to the middle C, where the O is connected and charge shifts towards the more electronegave O-atom: CH3COCH3 + CCl3(-) --> CH3C(CCl3)(O(-))CH3 The middle negative charge is compensated by picking a H(+) from water: CH3C(CCl3)(O(-))CH3 + H2O ---> CH3C(CCl3)(OH)CH3 + OH(-) The net effect is that no hydroxide is consumed, it hence is a catalyst. What you now have has a really strong and very good smell. It gives a strong cooling sensation and seems to open up your throat and makes you breathe more easily. This is quite a pleasant sensation. If you inhale too much of the compound, then you start to feel numb, and you get a "floating" feeling. So, don't breathe too much, unless you want to sleep. This compound is used in medicine, as a travelling aid for people, who get sick on car or boat trips. They eat the compound in the form of an encapsulated pill. PLEASE DO NOT DO THAT WITH THE MATERIAL YOU MAKE. IT STILL CONTAINS NaOH OR KOH AND ACETONE, WHICH ARE NOT GOOD AT ALL! Sniffing the stuff is fine, and quite pleasant, but DON'T EAT IT. Also don't drive a car or use heavy machines after sniffing this material too much! This is a funny experiment, but don't do foolish things with it.
  23. The more posts you have, the larger the particle .
  24. The person, who wrote the webpage probably did not know very much about chemistry. Dichromium sulfate does not exist. But, given his description (orange powder), I'm almost 100% sure that he means ammonium dichromate. Ammonium dichromate is an orange powder, which easily is ignited. Mixing this with sulphur will make the 'lava' more realistic. Ammonium dichromate on its own will result in formation of a very fluffy green and very voluminous powder, while it is 'burning'. The mix with sulphur will yield a dark colored more lava-like substance, when it is 'burning'. Be careful with ammonium dichromate though. It is a carcinogen. The volcano-experiment used to be quite popular, because it makes a fairly safe, yet spectacular, demonstraton. Besides that, ammonium dichromate is a nice and interesting chemical, which seemed not to be dangerous (e.g. it is not explosive, extremely corrosive, or otherwise immediately dangerous). But unfortunately, it is a carcinogen, and since that is known, the use of this funny chemical has diminished quite a lot.
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