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  1. O

    Splitting of Eu characteristic L gamma radiation in EDX analysis?

    Haven't been able to find the answer anywhere IRL yet, so I thought I'd see if someone in the PhysicsForums could help me with this one. When doing SEM/EDS (EDX/EDXS) (~equivalent to x-ray fluorescence) analysis it looks as if my europium containing samples contain copper as well, which'd...
  2. O

    The Chemistry Of Sweetener

    You could start with heating the different sweeteners in an oven at a certain temperature and note the differences before and after: do they look burnt? No need to taste then. Do they look the same as before? You might try and taste if they still taste sweet. Beware: I don't know anything about...
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    Dodecahedral metal coordination?

    OK, I just calculated for a triply capped trigonal prism that there is just one radius ratio: 0.73 For a dodecahedron I calculate 0.83 as the minimum radius ratio (for cation-anion interactions) but this leaves four out of eight coordinating atoms at almost twice the distance (as described...
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    Dodecahedral metal coordination?

    Is it true that there should be two distances from a dodecahedrally coordinated cation to the two types of coordinating atoms? When I calculate what the octahedron should look like assuming that all anion-anion distances are equal I will get two different cation-anion distances: if all...
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    Teflon and alkoxides?

    Hi! I heard from somebody that teflon might react with some alkoxides, and that this is actually what DuPont uses in some cases to make the teflon coatings stick to cookingware or whatever is coated in these specific cases. This bothers me since I have a cuvette with a teflon stopper...
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    Sleeping late and eating late

    Where did Pengwuino go? I just want to ask you (and maybe Nerro as well) (or Moonbear more scientifically) what will happen if people like Pengwuino and Nerro travel across a time zone? Will you still like the same cycle with regard to the clock or will your cycle be shifted corresponding to...
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    Chemical Nomenclature help

    No, d) Al(H2))6Cl3 should definitely be d) Al(H2O)6Cl3 which means I think it is just hydrated aluminium chloride AlCl3.6H2O (aluminium chloride hexahydrate). But if that's not the same thing, then I'd have to call Al(H2O)6Cl3 hexa-aquaaluminate chloride. I think b) is ammono not amino. amino...
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    Term symbols & degeneracy

    Hi! I've finally made some effort to understand spectroscopic term symbols (^{2S+1}L_J) and after having thought a few times that I'd understood but then running into trouble again, now I'm fairly convinced that I got it right. But some things bother me though. Apparently I was locked too...
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    Ideal Gas HW: Volume of Bubble Rising to Surface

    You first state that P_f >>P_i and then you go on saying that the pressure is decreasing. Which statement is the true one?
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    Natural log of a pressure is ?

    I really don't see the problem. You get an expression P2/P1 that is unitless for obvious reasons - the units cancel out on division. If P2/P1 = x then P2 = x times P1, P1 having a (arbitrary) unit of pressure like bar, kPa, atm, psi etc. and x being unitless. The only thing I wonder about is how...
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    Stuff that attacks materials

    This sounds really good, but also too complicated to find anything specific (/ too extensive to read it all and become almost all-knowing :wink: ) (No chance of you telling me what happens with aluminium on contact with chlorinated solvents? :wink: :wink: ) So they give out "standards" that...
  12. O

    D orbitals 5 or 6?

    kanato! you seem like someone getting the picture with the linear algebra involved in orbital theories! have you seen any different linear combinations of the d orbitals than the usual xy,yz,zx,x2-y2 and z2 set? Hope this is not too OT... but I would like to see what it looked like if one...
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    Interested in nanotubes and nanotechnology

    Also do check if your university subscribes to any e-book! It's an opportunity one shouldn't let pass by.
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    Silicon inert?

    Hi! Is silicon inert? i.e. can I clean it from deposited films with e.g. HNO3 and H2SO4 without etching the silicon itself? What about amorphous carbon?
  15. O

    Grey and White tin

    OK, if the formulation "will convert to grey tin" should be interpreted as over time, maybe not even within some millennia, but it will happen, then the procedure sounds right and you need only thermodynamical data.
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    Nitrogen Organic

    Well, here you spoilt the opportunity to first pedagogically ask why the poster connects the release of CO2 to ionicity, followed by a discussion (trying to make the poster learn by being confused since we ask him/her if he/she really believes in a certain thing - or in the opposite :devil: )...
  17. O

    Stuff that attacks materials

    No, rather something stating: silicon - stable towards ..., ..., ... gold - attacked by aqua regia (formation of soluble complexes) etcetera Not that I checked the book, but your reply as well as the book's title give me the impression that this is more a book about corrosion principles...
  18. O

    Stuff that attacks materials

    Hi! Does anyone know a good reference literature or internet resource regarding what materials are compatible with which acids, solvents etcetera? I'm no good at this at all. I had e.g. no idea that ammonia attacks aluminium. Are silicon and amorphous carbon attacked by anything or are they...
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    Optical Fibers Question

    Well, "explain", hrmm.... but it has something to do with vibration at least. But as I'm writing it seems odd to me that the optical and vibrational energy scales should overlap... I think, however, the solution lies in that "optical" fibers actually don't use visible light (the association...
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    Bonding in Liquids

    I think my experience tells me that sugar dissolves more slowly than salt, but I'm not quite sure. But actually the salt may dissolve faster because of the hydration enthalpies of the ions. But this actually shouldn't explain the kinetics... :confused: 1: I don't think oil is so polar. But I...
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    Grey and White tin

    To me it sounds like one would need more than thermodynamic data. The phase might be metastable at certain temperatures, i.e. thermodynamically white tin should convert to grey tin, but the kinetics are not sufficient for the conversion. Wow, I really wouldn't know how to tackle this one. Do...
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    Chloroform and metals

    Help me!! :grumpy: :grumpy: :grumpy: :grumpy: :grumpy: Aaaaargh!!!!! The :devil: :devil: :devil: at the library have removed the Gmelin Handbook of Inorganic Chemistry from the basement. I just faced lots of empty shelves. :confused: Ok they got rid of CAS, because that can be...
  23. O

    Chloroform and metals

    Chloroform is said to react violently with both metals (Al, Na, Li, Mg, K, Fe, Zn) and e.g. sodium methoxide (CH3ONa). Does anyone know more about this? What happens? Formation of e.g. CCl3Na with release of H2? Or CHCl2Na+NaCl? And how about reaction with alkoxides? Does chloroform react...
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    Normality question

    :eek: No! 1) Na+ is not a proton, so sodium acetate cannot donate a corresponding proton (acetic acid, however, can). 2) As far as I know none of the three hydrogen atoms on the acetate ion are acidic. You cannot just look at the overall formula NaC2H3O2 and think that you can transform it...
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    Question about Experimental Results

    As far as I can see, all water-miscible solvents in your experiment can contribute to hydrogen bonding, and all cyclohexane-miscible solvents cannot. It seems that in this test the possibility of hydrogen bonding is more important than just polarity. But, of course, it doesn't harm to doubt...
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    Still a metal?

    But I guess this has nothing to do with the potential difference over the battery terminals, i.e. what makes the battery a battery, but only with the potential at this one terminal, which makes your point relevant not only to batteries. What makes the electrons flow is 1) the potential...
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    Tetrahedrally adapted d-orbitals?

    Does anyone have a link to a picture of the shapes of tetrahedrally adapted atomic d-orbitals? Aren't the familiar d(z2), d(x2-y2), d(xz), d(xy) and d(yz) orbitals just one of several possible sets of atomic d-orbital shapes? Or have I misunderstood this point? I would like to rationalise why...
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    Gaseous Oxygen = Paramagnetic?

    liquid oxygen hey, this is one thing I didn't think of: what about liquid oxygen, is it possible to attract O2(l) by magnets? Your answers almost seem to imply that...
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    Chemistry group project

    Wow, right above me, I just had a link "Biological oxygen demand", linking to [PLAIN][/url]. Now my second window has been directed to, where it says: Welcome to InterLab Supply, your complete source for BOD testing and home of the "Original"...
  30. O

    Is midnight PM or AM?

    Heck, this sounds unlogical to me, 0:00AM should be midnight and non-existent 12:00AM=0:00PM=midi. Lucky me I don't live in the states, that's for sure! Long live 0:00-lim_{t->24:00}(t) (No offense to the latin language though :wink: )