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John Cuthber

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Everything posted by John Cuthber

  1. Since AgSCN is practically insoluble you can't really do a titration with it. You can use it as part of an indicator system (in the presence of Fe). Titrating with HCl then trying to measure Cl would be ill advised- it's much easier not to add lots of the stuff you are trying to measure. There's nothing to stop you doing the titration with HNO3 to as exact an end point as you can get for the determination of the base then adding excess acid and titrating with AgNO3 to measure the chloride, again to as good an end point as you can get. Warming the solution isn't going to help a lot either.
  2. Since many elements show multiple oxidation states the table is ambiguous. If it's meant to me highest oxidation states then copper is wrong; if it's meant to be most common then iron is wrong. If the asignment is arbitrary then it's all wrong. It also fails to convey any information about the underlying reason for the periodic nature. It springs from the arangement of the electrons in what for simplicity's sake are usually called shells.
  3. "Believing in creationism is kind of like one scientest believing in a certain scientific threory and another one disagreeing with the theory. " Bollocks! In the end the evidence of further experiments should get the 2 scientists to agreee. That's the whole point of science. The creationists will (and do) continue to believe in their "faith" even after it has ben shown to be, at best, unreliable. Believing in fairy tales is not, directly, a bad thing. But if it leads to killing your neighbour because he eats boiled eggs blunt end first then it's very clearly a bad thing. If we stopped tollerating the myth that "it's OK to believe stuff with no evidence" then at least some of the causes of conflict in society would be addressed. Racism, for example, has just as much scientific validity as creationism. Stamp out the idea that "people should be permitted to believe rubbish if they want" and you get rid of both evils. Of course, I'm not saying that religion is the sole source of trouble in the world, just that it's one of the biggest and that most of the others (nationalism for example) are similar in that they rely on a belief (my God/ my country is better than yours) which is invalid.
  4. I know that wiki is not always reliable but, in this case, it is correct. Why bother to raise the matter of wiki's editabillity? it doesn't make any difference to the error you made in the first place.
  5. I don't think anyone has synthesised hexaphenyl ethane yet; there are plenty of similar examples where steric considerations make the molecule impossible. Still the question is a bit odd, I think that several hundred million different compounds have been synthesised. Which ones do you want big ones, smelly ones, left handed ones?
  6. OK, thanks to the incompleteness theorem there are at least some things for which there is no answer. There are quite a lot of things for which, at least in principle, science can give the answer. Is there anything that can give an answer to (at least some) questions that fall outside the first 2 groups?
  7. The point I was making was that whatever the cause; real or related to diagnostic criteria, there is a pressing neeed to do the research to check which it is. The idea the the NIH were looking into autism therefore there must be a link as expressed here "Also, why would NIH put so much effort towards this disorder if they did not feel it was truly on the rise?" is the idea I was trying to question. The other point being that the reported rise (whether it's different reporting or a higher true incidence) predated the use of the vaccine. That's a killer point against the "vaccine causes autism" argument. Whatever the cause may be, it could never have been a vaccine that hadn't been used yet.
  8. Well, I think I know what a non Newtonian fluid is and I don't think you are right about it. http://en.wikipedia.org/wiki/Non-Newtonian_fluid There are plenty of thixotropic varnishes on the market, I don't know if they are clear before they dry. You might be able to find a dilatant mixture of a solid and liquid (that behaves like cornstarch and water) where the 2 components have the same refractive index. Even then you will have problems because the optical dispersions of the 2 materials are likely to differ. I might try powdered glass in glycerine if I were looking for such a mixture.
  9. How does onion help? Is there any evidence that onion does help?
  10. The true rate of autism (whatever that means) may be rising or it may be steady- it may even be falling. The reported rate is definitely rising. For the NIH and its equivalents round the world to ignore the rise in reported cases would be negligent; it falls to them to try to establish what the rise is due to. If it better diagnosis then we should rejoice; Autism isn't the easiest disease to treat but the first step is certainly to diagnose it. If there is a real rise in the rate of the disease then we need to know about it. If nothing else it would, in the long term, have an effect on healthcare spending. More importantly if it becomes more common then there is a greater need for research into the disease. We need to know what causes it and we need to know what we can do about it. The utter bollocks that was talked about measles and mercury does nothing to help those who are affected by the problem. It offers false hope to their families and it fills the pockets of those who, at the most charitable interpretation, have deluded themselves. Worse, it does this at the expense of real research into a real problem. Don't get me wrong, I know that sometimes you have to consider weird theories in order to find the true cause of things. H pylori and its role in ulcers is the classic example. The point is that the research should be judged in a scientific forum, not in court or (God help us) in the media. Distraught parents are not usually well placed to make judgements on such things. We really shouldn't let them get involved in that aspect of the work.
  11. Why do people mix up homosexuallity with pedophillia? I understand that some peopel feel they are both "forbidden by my religion" and therefore equally wrong (though even that seems a strange opinion to me) but even then "equally wrong" doesn't mean "the same thing as". Most religious groups who condemn both of these groups also condemn infidelity in the same way. Yet the followers of those faiths don't generally mix up people who sleep with someone else's wife with pedopiles. Even the most devout (or deranged depending on your point of view) can tell that homosexuallity is not actually the same as eating shellfish even if they are both an abomination. So what is it? Why the blind spot? (BTW, just in case anyone's wondering- no I'm not a member of any of those groups but I'm hopelessly prejudiced against irrationallity)
  12. John Cuthber

    gas mixing?

    When I was at school we were taught that one of the poperties of a gas was that it filled the container it was placed in. The He hardly knows about the CO2 so it will fill the container. So will the CO2. It would be a challenge to measure the difference in concentration with any sensible size of container. You have got the equation; why not use it and see what the answer is.
  13. Nice gadget, what's the frequency response like?
  14. Sepiraph, why do you say "At the very least it allows you to practice to be ambidextrous in writing"? Anyway, I gave up taking notes when I was a student. I realised that I was better off listening to the lecture and trying to understand it. In some cases the lecture was little more than the guy at the front writing out the textbook he had written, from memory, on the blackboard. Well, by simply buying the book I could avoid 2 sets of transcription errors and (more importantly) I could stay in bed rather than going to the lecture.
  15. That's pretty nearly what I said except that 1) I don't think you will get the carbonate to decompose quantitatively to the oxide at any temperature low enough that you don't get significat loss of Na2O as the vapour. 2) I would have given the right formula for Na2O 3) you cannot do that titration with AgNO3 until you have acidified the mixture.
  16. Oops! Sorry. You are quite right. What I should have said was that the reported rate of autism rose first.
  17. Is it me or is it not just this "The Canadian F1 is about to start." that is going round in circles very fast? Anyway, for the benefit of "I Need Help" and his family I' try to help. Unfortunately I can't do anything much without a sample of the stuff to work with. The one thing I can say is that if a tenth of this were ture it would be all over the scientific press- it would be one of the biggest breakthrougs of the new millennium. Well, I'm a professional analytical chemist and I hadn't heard jack about this except on this thread. I don't know where you are based but here in the UK the chemists professional organisation is the RSC Here's the website. http://www.rsc.org/ There's nothing about ormes. Across the pond the equivalent body is here http://www.chemistry.org/portal/a/c/s/1/home.html Again- not a word about it. It's a fake- at best these people have deluded themselves.
  18. On the other hand, nuclear fission actually works. To be fair so does fusion. It works fine in the lab where the fact that it takes more power than it generates doesn't matter. It works fine in H bombs and it works fine in the sun. The process of fusion generates fast neutrons. The interaction of these with other materials (like the containment vessel) will generally render them radioactive. The idea that there is no radioactive waste from fusion is simply not true.
  19. While it may be fair to say that "Greepeace is not blameless in this, and appear to be one of the main drivers keeping the whaling going. Again, national pride, and a refusal to do what Greenpeace tell them. In this, Greenpeace is especially guilty because they choose tactics that are provocative and aggressive. Greenpeace is one of the main reasons the Japanese still kill whales." you really ought to remember that without greenpeace's involvement there would be many more countries whaling and the whales would be worse off. If greenpeace decided to give up on whaling and concentrate it's efforts elsewhere do you really think Japan would stop killing whales? Incidentally, if we are going to take any country to task over their dealings with Greenpeace, shouldn't it be France? http://en.wikipedia.org/wiki/Sinking_of_the_Rainbow_Warrior One dead man seems more important to me than quite a lot of dead whales.
  20. I guess most employers who use illegal labour do it because it's cheap. What happens if you enforce a minimum wage?
  21. Q How much energy in Kilowatts are present in a spinning mass weighing 2 tons (4,400 lbs) and spinning at 8,000 RPMs? A Provided that the mass is a very long thin wire spinning on its long axis, the answer can be made as close to zero as you like. OTOH, if it's spinning round an axis other than the long one then the answer can be as high as you like.
  22. "OK.. let's say I'm in a ship that accelerates away from Earth at an acceleration of 20m/s/s and then maintained that same thrust forever... " Oops! You cannot assume that because it's not possible. Please read up on relativity.
  23. What's that still doing in the news? It should have been dead and buried ages ago. http://www.channel4.com/health/microsites/M/mmr/index.html I understand that about a zillion subsequent studies have found 1 there is no statistical link; if there is an effect it is very small. 2 The rise in autism rates predates the use of the MMR vaccine- it would have had to go backwards in time to be responsible. 3 Dr Wakefield has a patent on a rival product. The word "exploitation" springs to mind here.
  24. The whole point of the titration is that you add acid until the pH is 7 then calculate the amount of NaHCO3 from the ammount of acid. Incidentally, you could take a known mass of the original mixture, heat it to convert it to the carbonae to get the weight loss and hence the amount of NaHCO3, then you could titrate this (after disolving it in water) with dilute nitric acid to get a second measurement of the NaHCO3. Then you could (using an absorbtion indicator or an ion selective electrode as an indicator) titrate with silver nitrate to get a measurement of the chloride. Then you could filter off the AgCl, wash, dry and weigh it and get a second determination of the chloride. 2 pairs of results from just one portion of mixture. And I'd still like to know what use the mass spec would be.
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