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hypervalent_iodine

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Everything posted by hypervalent_iodine

  1. Unfortunately, since this is an assignment it would be wrong of a member here to do that (speaking of which, I am moving this thread to homework). The task is up to you. I understand your confusion, but perhaps you might be best emailing your professor and asking him for some clarification as he would be more aware of the exact requirements for your work.
  2. It will take you some time, but it won't be hard. That's the crystal structure that they've given you an example of.
  3. Ah. So it sounds more like they're asking for you to give a molecular formula, coupled with a drawing of its structure. So for instance, your polyethylene would have an empirical formula of CH3(CH2CH2)nCH3 and its structure would be drawn like this: Or like this: (images from wikipedia) I don't think they want you to actually draw a diagram of the atoms, including all the electrons, protons, etc. Similarly, I think that drawing the crystal structures might not be what they are asking of you, as it would be a long and tedious thing to have to do, but I would definitely check that if possible. Even still, you might run into some difficulties with the fibre glass and memory polymers, since they incorporate a lot of different polymers, but I'm sure you can work around it.
  4. I'm not too sure what you want when you ask for the atomic structure. More importantly, why do you want it for? If you can explain the purpose, I/we can possibly point you in the right direction. Since the majority of what you have listed are organic polymers or inorganic complexes, the Bohr models you are trying to find aren't going to be of any use. Also, you will need to be more specific with the type of glass. The crystal structure of tungsten is a body centred cubic and, IIRC, can have a number of space groups. The question I have for you is, do you want tungsten by itself or a tungsten containing complex, such as the tungsten carbide in the lattice structure picture that you linked? First one is definitely wrong. Even ignoring the fact that the numbers of protons and neutrons (and electrons, really) are all out of whack, these sorts of images are kind of pointless when you start involving compounds beyond 1 atom. This brings me back to the question of why you need such a thing in the first place? The last image isn't a lattice/crystal structure, it is simply the molecular structure. Polyethylene will have varying crystal structures depending on what type of polyethylene it is (high-density, low-density, high-molecular weight, cross-linked, etc., etc.). I looked this one up and found that there are over 250 different types of crystal structure for this compound. Do you only need an example of one? The Bohr diagram you have there is only for the silicon atom. Again, I have to ask why you need this? This is fibre glass, yes? If so, there are a lot of different materials used for fibre glass, so you again need to be more specific. Quartz is made up of a continuous SiO4 lattice. There are actually two different crystal structures for it, one for alpha quartz and one for beta-quartz. The one you have linked is alpha. These are a class of polymers, rather than a specific one. Which one are you talking about? What you seem to be after is simply the molecular structure, which is what you linked as the lattice structure for the polyethylene in your OP, as well as the crystal structure. The molecular structure will show you what one molecule of your compound looks like, what kind of bonds it has and the molecular geometry. The crystal structure will show how a group of these molecules pack together in 3D space. You have linked a number of these types of pictures, the tungsten carbide you linked being one such example. You are going to find it very difficult to gather this information for some of the materials you have listed. Fibre glass, for instance, is a combination of some kind of polymer (thermopolyers and epoxy resins, etc.) with fine glass fibres embedded within the crystal structure - so you have two different compounds, not just one.
  5. You should tell us the long story.
  6. The way I remembered the difference between anions and cations in high school was by realising that anion sounds like onion and since onions make you cry (which is bad), anions are negatively charged. Most people tend to relate cations to fluffy cats, but I came to the conclusion early on that my hatred of cats would cause some confusion when trying to apply that logic. These days whenever I see or use the word anion, I still think of onions. There are worse things, I suppose.
  7. Being a water waster is nothing to be proud of when you live in Australia (as you do, IIRC), where water conservation happens to be extremely important. Perhaps not as much as it was a few years ago, but nevertheless, using what works out to be approximately 3 times the recommended daily limit for one person in one day (in QLD, at least) in a single shower is really and truly nothing you should be boasting about.
  8. I've read about this practice several times over the last few years and it never fails to baffle me that people actually fall for such absolute nonsense. It is, according to most crackpots who use it, a cure for cancer and every other disease known to man (and probably the ones we don't know about as well). As an example,I know that in the treatment of cancer, the reasons I've seen cited are because it supplies a source of oxygen to cancerous cells. They think that because a great number of cells display the Warburg affect (a metabolic shift from cellular respiration to glycolosis for energy production), overloading your body with oxygen will cause that shift to reverse and hey presto, cancer is gone. In keeping with the definition of the crackpot moniker, it does not matter how many ways or how many times you tell such people that the premise of their idea is fundamentally flawed, the government is still trying to keep the 'real' knowledge from the general populus for the purposes of keping the money in the right wallets. And of course, we scientists are collectively in on the deal (seriously, even my grad student pay cheque is monumentally huge), but I don't have time to explain as I have a government funded gravy train to be catching.
  9. If you were to go that way, doing it on whole algal cells would not work and you would have to purify them, which of course leads to the issue of product loss and results that are less than they should be. As well, your yields won't be 100%, as stated above, and you will likely get a very wide array of byproducts, which will again not translate well in your results; and this is ignoring the fact that some of the fatty acids you extract will already have double bonds in them (some of them will have multiple). I would go with what Suxomethonium suggested and try and find other protocols for quantifying the lipids. I can't imagine it would be too difficult to find one, given all the recent interest in algae as biofuel feedstocks.
  10. Suzuki reaction can work for those sorts of systems, but as you say the yields will likely be low and you will get byproducts. OP, is there any reason you can't purchase these compounds as you want them? The process for doing this and purifying your product is going to be arduous and expensive for you in the long run and you'll most likely have to do it a few times before you get the hang of it. If you can buy it, I would try go for that route.
  11. If SFN has a character limit for its posts, I'm 99% sure it is something around the region of 'smaller than the IUPAC guidelines'. There are simplified versions for organic chemistry that you find taught in lower level courses or in highschool, but all of the stipulations combined amount to quite a hefty amount of information to be copying into a thread post. There is this website, I forget its name...Gaggle? Giggle? I don't know. Anyway, there are four books: the blue book (organic), the purple book (macromolecular), the orange book (analytical) and some nondescript one for biochemistry. There is also a series of E-resources, published by IUPAC, which contain a whole wealth of information. This is the link for the organic chemistry nomenclature guidelines; however if this is for lower level learning, wikipedia might be a better place to start.
  12. Perhaps I'm missing something here, but the ideal gas equation I've always seen is written as PV=nRT.
  13. Technically not a reaction, but it certainly is endothermic. Firstly, acetotnitrile doesn't have dipole interactions with itself because -CH bonds are not polar. Other than that, I'm a little ost with what you were saying. The reasons behind endothermic mixing are a little complex and the exact mechanism, not really known too well. Water-acetonitrile is an example of a binary mixture that deviates from ideality. The other one you encounter a lot is water-methanol, which shows exothermic mixing. It is thought to be explained mostly by entropic considerations, since endothermic processes are typically associated with an increase in entropy, as well as the clustering structures of water and how solvents interact with them. It doesn't change anything. What changes whether you can call something a hydrogen bond or not is the atoms involved, which will change the properties of the interaction. Hydrogen bonding occurs between a hydrogen bound to some electronegative atom and the lone pair of electrons on either nitrogen, oxygen or fluorine. The strong electrostatic attraction between these atoms makes the distance between them (i.e. the length of the H-bond) smaller and the dissociation energies higher than a typical dipole bond.
  14. There is no difference between the two, since hydrogen bonding is essentially just a specific term for a particularly strong dipole type interaction.
  15. Khan academy is always a good place to start. MIT also has a nice series of free lectures, though this may be more advanced than you're looking for.
  16. All this time I'd been reading it as Miss is sip pi chem. In other words, I took you for a female who enjoys tea, math and chemistry. It's a compliment, really. My name comes from a class of chemical reagents that have been the focus of my work for the past year. Somewhat uninteresting and certainly lacking a witty back story (I'm sure I could come up with one, though), but it gets the point across.
  17. Firstly, I love your avatar. We have that printed and stuck to the lab door with, 'Carol, the patron saint of chemistry' written on it. I have no real experience in pharmacy courses, so I can't give you an in-depth answer to your question, but I will try to do what I can. All pharmacy degrees I know of include lab work, so I don't think your university is unique in that. I also know that such degrees can lead into doing both research and clinical careers. How helpful it it is really depends on how you use it. My advise would be to try and get a hand in doing some research in one of your professor's labs early on and get a feel for whether or not you like it. The easiest way to do that is to make appointments to see the people who do something you like and speak to them face to face. The other way you can get into pharmaceutical based research is with a chemistry or even a biology degree, depending on what you want to do. However, since you are still undecided on whether or not you want to do research, I would stick with the pharmacy degree and go from there.
  18. Essay, can you start making sense and can you do so on topic?
  19. Do you understand what [math]\frac{d}{d x}[/math] actually means in mathematics?
  20. Prussian blue is the first thing I thought of too; and yes, I think that sort of case is what he's talking about.
  21. I have mixed feelings about that name. If for no other reason than the fact that I now have a Gotye song stuck in my head.

  22. People said that about the third reich once too, you know. But seriously, the suspense is killing me. What is my new nickname?

  23. Well, for that particular calculation I was saying that your answer is not in the correct units. It shouldn't have any. I then also said that you should try do your work in SI units. You shoul dbe able to find various distance conversion calculators, etc. online.
  24. I didn't read too much into your OP, but I did notice this, which is dimensionally unsound. If you're dividing miles/year by miles/year what you end up with is a dimensionless number. Also, you should try working in SI units. I have no doubt that this is quite likely true.
  25. That isn't going to be much help without knowing what the ligands are. And if the PIXE results are anything to go by, the metals involved are already known and appear to be iron and calcium. I am not an inorganic chemist myself (JohnCuthber or mississippichem might be more help in this than I am going to be), but you might want to see if you can get some IR and, if possible, an X-Ray crystal structure. There are also various other electronic spectroscopic methods, which I know of only very vaguely, but may be of some help to you.
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