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hypervalent_iodine

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Posts posted by hypervalent_iodine

  1. My assumption is that it is asking you for the masses of each individually to make up a litre of solution with those concentrations and that the first number is meant to be in M. The last bit is an assumption though so I would check that. How much is also kind of vague and not stated but the only way I can think to answer it (it isn’t even really a question it’s just a statement) with that information is with masses.

  2. While this thread is closed and (I think) being the only person who identifies as female in this thread, I just wanted to provide a little food for thought. Of all the women in my life with whom I am close to, I can't think of a single one who hasn't been sexually assaulted or raped by a man at some point in her life. I cannot say the same about the men I know wrt to false accusations. Anecdotal I know, but something to think about. 

  3. I think it’s also important to note that we don’t always agree on a particular course of action such as banning every time it is suggested and will make compromises that everyone can agree to regularly. Conferring with one another isn’t merely an exercise in box ticking. 

  4. 2 hours ago, Klaynos said:

    I agree. Having friends who were on short term contracts for 20 years makes me somewhat cynical. 

    What, you don’t like rolling 3 month contracts completely contingent on obtaining a portion of the ever-dwindling pools of grant money available? Weird. 

  5. After some further discussion, staff have updated the above to now read:

    Quote

    Attached documents should be for support material only; material for discussion must be posted. Documents must also be accompanied by a summary, at minimum. Owing to security concerns, documents must be in a format not as vulnerable to security issues (PDF yes, microsoft word or rich text format, no).

     

  6. I’ve met a couple of members IRL when I’ve been in the US and have considered them friends at various points. Others I knew digitally when IRC was a thing, and a few I am friends with on FB. These days I generally avoid crossing streams. 

    On 12/18/2020 at 10:31 AM, MigL said:

    anyone remember Overtone ?

    Difficult to forget that one. 

  7. 1 hour ago, studiot said:

    Reading this more thoroughly I think the bottles must all contain white powders, not solutions as I originally thought.

    So you will have to make you own solutions.

    So you should add two further actions to your table:

    Solubility in water and solubility in dilute HCl.

    Are all the reagents listed going to be soluble in both ?

     

    Solubility in barium chloride as well. 

  8. I agree with Sensei. Get a model kit or even just some tooth picks and blu tack. Make something with four different substituents and make its mirror image, then try and rotate the mirror image so that it is identical to the first molecule. You’ll find that it doesn’t work because they are not superimposable. If you repeat the process but with two substituents that are the same, you should find that you can rotate them to look identical (hence it is not chiral). The example you gave doesn’t work since by your own logic, the two mirror images are superimposable.

  9. 5 hours ago, Anchovyforestbane said:

    How specifically does the direction in which a molecule directs light effect how they fit together?

    It doesn’t. The stereochemistry and how they occupy space is what matters. A good illustration of why this matters in drug design is your feet. They are mirror images of one another but nonsuperimposable in the same way enantiomers are. You will probably know from experience that if you try to put your left shoe on your right foot or vice versa, it won’t fit very well. The same is often true for chiral drug molecules and their molecular targets (eg. enzymes). In the drug world, the quintessential example of why chirality matters a lot is thalidomide, which I’ll let you look up. 

  10. I am unsure of what you are wanting to know here, so forgive me if I am off base. The l and d notation refers to the direction a chiral molecule rotates polarised light. To my knowledge, this property doesn't really affect stereochemistry, it's more that it is a consequence of it (i.e. only chiral molecules are able to do it). The reason molecules are able to exist as either l or d is because two enantiomers will rotate polarised light to the same magnitude, but in opposite directions. For example, if one enantiomer of a molecule rotates light by +10o (d), then the other enantiomer will have an optical rotation of -10o (l). 

     

  11. 54 minutes ago, MasterOgon said:

    There is some new circumstantial evidence and logical justifications, but the main thing is a detailed description of the experiments with which you can establish the fact of this phenomenon. Among these are the simplest experiments that anyone can repeat. This article is being considered for publication in a scientific journal and received a positive review from a respected scientist. It is at the bottom of the page http://sci-article.ru/stat.php?i=1601957819 The reviewer's page contains links to information about him.
    Thus, the fact is substantiated indirectly if there is an above average knowledge of aerohydrodynamics, it is proved experimentally with minimal means, and is confirmed by the opinion of a specialist. The only thing that is missing is links to authoritative sources confirming this fact, since it has not been studied by anyone yet.

    !

    Moderator Note

    I looked at their Google scholar page, and while many of the publications are in Russian, it is pretty clear that this person is not in the business of aerodynamics. Expert? Maybe, but not in the area you are writing in. 

    In any case, as you do not seem to have any new data I see no reason why this should remain open. 

     
  12. 9 hours ago, zapatos said:

    She literally had no idea how to apply, where to apply, how to fill out applications, and could get no help from those in her family as they were just as clueless.

    This is a very good point! I am currently reading a lot in relation to some new (and generally awful) reforms to our higher education sector that were just passed here in Australia. In some of the submissions to parliament, it was highlighted that one the key factors leading to under representation of Indigenous people in universities is that they often don't know what they have available to them. As such, the prospect of enrolling and relocating seems financially daunting and confusing. It is also one of the things that can lead to low levels of retention. Students who live in more metropolitan areas (and more likely to be white) are much more exposed to university life, either through linkages in their school or because someone in their family has been, etc. 

  13. On 9/30/2020 at 2:57 AM, NerdShift said:

    Thanks for your reply.

    Yes i know about the Aufbau principle, but as I've expressed in my first post, Zn, Cd and Hg are exceptions (also 24Cr, 42Mo & 74W);

    For example when an atom has 20 electrons (Ca), its 4s is filled while the 3d is empty, and in an atom with 21 electrons, the 21th e belongs to 3d; so we expect the next atoms to have a filled 4s subshell while their 3d is not filled yet, but when we reach Z=24 (Cr), we'll realize that its electron configuration is:

    24Cr: [Ar] 3d⁵ 4s¹ (instead of [Ar] 3d⁴ 4s²)

    And this is also true for 29Cu; which has a filled 3d but a half filled 4s:

    29Cu: [Ar] 3d¹⁰ 4s¹

    (I think it might happen due to the more stability of filled & half filled subshells...)

    So, I really expect the 30th electron to go to the 4s subshell and fill it, as we see in Zn's electron configuration:

    30Zn: [Ar] 3d¹⁰ 4s²

    Thus, if the last electron of Zn (30th) belongs to s subshell, why does zinc belong to the d-block?!

    (I know about the blocks;

    How elements are separated to s p d f blocks, according to my high school book:

    If the last electron of an atom belongs to a special subshell, the atom would be in the corresponding block.

    (I know it might be simplified, that's a high school book afterall.)

    So I feel a contrast between the subshell to which the 30th electron belongs, and the definition of blocks.

    Please let me know if I am wrong

    & Sorry for non scientific terminology or grammatical mistakes, I am not a native English speaker you know

     

    Yes, sorry, I was writing on my phone so I didn't have time for a full reply. 

    The two exceptions you mention are actually a little misleading. I believe that in reality, they do fill the 4s orbital first, then as electrons start filling up the 3d orbitals one of the 4s electrons moves into the 3d to give 3d54s1 / 3d104s1. It is not a case of only putting one electron into the 4 s and then filling up the 3d orbitals, which is maybe where you are confused with Zn. The reasons for this come down to stability, as you mentioned. It is more favourable to have a completely full or half full set of d orbitals. 

  14. I'm actually not 100% sure how it deals with PMs. I would have thought that those would have been hidden as well since that would fall under the umbrella of "content". However, we have spam posts set to be hidden rather than deleted and hiding posts isn't an option available even to me in PMs. I do know that if it does happen, it doesn't happen immediately. Posts get removed in batches. 

  15. I was more talking about the coverage of the article. However, they discounted the possibility of SO2 because in order to observe the results they got, it would need to be a bit hotter (about double) than what is measured in the upper clouds. Surely the simpler explanation is that they detected SO2 that was a bit hot, as opposed to phosphine? 

  16. I’ll admit this isn’t an area I know much about but the results seem a bit (a lot?) overstated. They aren’t even completely sure it’s phosphine. I read somewhere that the rotational transition they measured could also be within the same region that SO2 might absorb on a planet with H2SO4 clouds. Is this accurate?

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