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John Cuthber

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Everything posted by John Cuthber

  1. I was just testing to see if anyone read the list. The RMX should be HMX.
  2. Isn't the answer to this question "Yes, I have one between my ears"? I think we need a definition of computer as well as consious. If my brain (and as much of the nervous/ sensory system as is required) can be mapped onto a turing machine then a computer can be consious (at least as much as I can). If not then it can't (at least for the definition of consious that says it means "acting like a brain"). Is the brain a turing machine? If not, what does it do that a turing machine can't? (and I know that one possible answer to that is that a brain can be consious- but that's begging the question).
  3. You can recrystalise it from salt substitue and that will get you a pure enough product for most things. What do you want it for?
  4. Ironiser, Trust me, it does make sense, and you can just think about it. The problem is that you need a lot of background knowledge before you can do that- not least you need to understand a lot of quantum mechanics. In the meantime, have fun trying to live your life without having to remember stuff.
  5. Aparently about 320% of people have voted in this poll, so I guess there must be a God after all (or the software has screwed up somehow)
  6. He can pay as much attention as he likes in class. That equation is just plain wrong. The product of the reaction is acetic acid, so googling it might not help. There's another way of balancing equations that might help here. Pretend that the Cr(VI) is present as CrO3 (not a million miles out for acid dichromate) and that it's converted to Cr2O3. 4 CrO3 --> 2 Cr2O3 + 3O2 Then write out the oxidation as if its being burned in oxygen C2H5OH + (however many) O2 --> CO2 + H2O Each O2 requires 4/3 CrO3 From that you can get the stoiciometry of the reaction.
  7. Well, you might be a student, but I think you are right. NOC is not a stable compound and it's not a radical I have ever heard of.
  8. "None of the above" would be a good option.
  9. It's difficult to put them in any real order but I wasn't exactly happy working with flurosulphonic acid perchloric acid, HF, bromine, nitroglycerine, PETN, TNT, RDX, picric acid, EGDN, tetryl, RMX, RDX, tetrachlorodibenzodioxin or ricin. On the other hand I think more people are killed by alcohol than by all those "nasty" chemicals put together.
  10. He's going down hill. Even with the engine switched off he would still roll down the hill and accelerate until the wind resistance (etc) was dissipating energy as fast as gravity was providing it. The engine isn't the only power source here.
  11. Sucralose is a calorie free sweetner so its not going to provide energy. Taurine and speed have practically nothing in common. The most likely effect of all these added chemicals is to give you really expensive urine, that's where the end up.
  12. Usually, but not always. At the maximum the change in absorbtivity with wavelength is small so errors in the wavelength don't matter so much. On the other hand, if there's a "valley" in the spectrum you can use that instead. Of course, the sensitivity will be lower, but that might be an advantage sometimes. If the solution is very concentrated you might want to use some wavelength where the stuff absorbs less strongly- that way you don't need to dilute the sample to get it within the linear range of the spectrometer. Also if the solution has some impurity in it that also absorbs at the maximum, but not somewhere else in the spectrum you can sometimes measure the concentration without interference from the impurity.
  13. This has been discussed at some length on another site. http://www.thenakedscientists.com/forum/index.php?topic=17926.0 The problem is not with the physics, but with the poster's interpretation.
  14. Heating copper to red heat in air will coat it with the oxide (mainly CuO, some Cu2O). Quenching it in water will make a lot of the oxide fall off as flakes. With a bit of copper pipe, a gas stove and a bucket of cold water you should be able to make some quite easily. If you want a lot this will get tedious. Adding copper compounds to H2O2 generally makes it decompose to water and O2 - not a lot of use. What do you want the stuff for? If it's for colouring flames then the quality of the product from heating copper in air is probably good enough.
  15. DMSO doesn't smell much but one of its uses is as an oxidant. The by product (the sulphide) really stinks. I think a scrubber with an amine might be a better idea- such scrubbers are used for cleaning up gas streams anyway so the technology isn't new. How fast MeI reacts with, for example, ethanolamine, is another matter.
  16. The heat of neutralisation in water is the the same for all acids so you could do this reaction in solution. Sb(V) is fairly oxidising so I suspect the product would be Fe(III) hexafluoroantimonate, even if you started with Fe(OH)2. If someone said "What happens if I add dilute perchloric acid to Fe(OH)3 ?" would anyone be predicting anything exciting?
  17. I know that people have extracted DNA from old things but that Dinosaur DNA from amber remains in the realms of science fiction. What's the oldedts DNA found and is it reasonable to assume that viruses might last roughly that long?
  18. Not to me. For every positive number there is a negative number and they form a pair whose sum is zero. Then you sum all the zeros and get zero.
  19. I also think that's what the question is about. You might also want to add something about the pros and cons of the various definitions. Incidentally, I never found "electronegativity" to be a very useful concept. As far as I can see, the definition is pretty much circular. It seems to be something like "Fluorine and oxygen behave in such and such a way because they are electronegative; electronegative elements are the ones that behave in such and such a way." Actually, they behave that way because of the way their electrons are organised and the extent to which they shield the nucleus. If their electrons didn't behave that way, they would be a different element.
  20. Thalidomide isn't a hydrocarbon and doesn't contain any chlorine. No hydrocarbon contains chlorine. Very few drugs are hydrocarbons.
  21. A biochemist walks into a bar and says "I'd like a pint of adenosine triphosphate please. The barman says "Certainly sir, that will be 80p." A mosquito was heard to complain, that a chemist had poisoned his brain. The cause of his sorrow was paradichloro diphenyltrichloroethane.
  22. How much of the power from a diesel engine goes into driving the injection system? If you saved all that power by making the stuff superfluid would you save 20%? Looks like balderdash to me. As for "In fact, refinery fuels, such as diesel fuel and gasoline, are made of many different molecules. They can be regarded as liquid suspensions if we take the large molecules as suspended particles, and the base liquid is made of small molecules. " No, they aren't. If your diesel has lots of volatile stuff (small molecules) in then it's dangerously flammable. If there's too much long chain stuf then it waxes in cold weather. They refine diesel to a fairly narrow range of boiling point (and, therfore molecular size). If you put a field across something you tend to induce charges on it, these seek to align so that they atract one another. The forces involved in liquid viscosity are the atractive forces between molecules, and you may have just made them stronger. A lot of the molecules in diesel oil are long chain hydrocarbons. Under the influence of a field these will straigthen out. The long chans will tangle better than the wound up ones. I really don't think much of this idea.
  23. I think it is fair to say that he has indeed both proved, and disproved, exactly zero.
  24. Comparing anything to the compressive strength of bone is a bit misleading since things (not just bones) seldom fail in straight compression.
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