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Everything posted by hypervalent_iodine

  1. There is more than just hydrogen bonding, but it is an important one.
  2. Worth mentioning that prevention is better than cure. Are you doing this in consultation with a doctor to monitor your health?
  3. Exciting update! IDoNotCare had now been permanently banned for similar offences.
  4. I've noticed that our recommendations are the same, though I'm not sure what they were before (I think they were the same as the CDC's were). We haven't had many cases, though last week a small cluster of about 9 popped up. Given how things have gone in VIC, and how fast our state premier was to close state borders back up, you'd think they're want everyone to get tested who may have been in contact? I had to get tested on Monday as I was showing symptoms and had been in one of the areas with a contact tracing alert, and while the line was very long (it took me two hours), they seemed to be coping and I got my result back within 48 hours (it came back negative). It is very odd for a state (or country) so desperate to avoid a second wave to explicitly tell people not to get tested unless they're symptomatic, given what we know about asymptomatic carriers.
  5. For O, you also need to be aware of drawing conventions with Fischer projections. Namely, the bonds on the left and right are coming out towards you.
  6. Having resonance doesn't mean something is aromatic, you also have to have a fully conjugated system. Have you drawn out the resonance structures?
  7. You mistake appears to be that you are considering the functional group as a whole rather than the atoms individually. When assigning priorities, you are supposed to only look one atom out from the chiral carbon. In your case, the atoms attached to this carbon are C, O, H, and C. Assigning priorities to these, the O is first, the H is last and you cannot yet distinguish between the other two. In this case, you take those two carbons and look at that they are connected to. In the first carbon, you have (in CIP order) O, O, and C (NB with double bonds, the atom is counted twice), and in the second carbon you have H, H, and H. The first place in which these differ is in the first priority, where the first carbon has an O and the second a H. Since the O is higher priority than H, that carbon is given the higher priority. Thus you have this: Since the H is already orientated to the back, we can look at it as is and see that it is R. This is just how they've given the question. The point would be that the student has to know to orientate the H properly to assign stereochemistry.
  8. Staff have recently decided to update the text of Rule 7: ! Moderator Note Advertising and spam is prohibited. We don't mind if you put a link to your noncommercial site (e.g. a blog) in your signature and/or profile, but don't go around making threads to advertise it. Links, pictures and videos in posts should be relevant to the discussion, and members should be able to participate in the discussion without clicking any links or watching any videos. Videos and pictures should be accompanied by enough text to set the tone for the discussion, and should not be posted alone. Users advertising commercial sites will be banned. Attached documents should 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)
  9. essereio has been permanently banned for repeated violations of rule 2.1.
  10. ! Moderator Note No, you're racist because you espouse racist beliefs, the expression of which on this forum (besides being wrong) is also against the rules. Consider yourself banned.
  11. What have you learnt? We can't do your homework for you, so you will need to make some attempt at this yourself before anyone can give you any guidance. Searching by chemical formula won't be helpful in this case. If they have got this far, they should already know how to construct IUPAC names and identify functional groups.
  12. It is a 14 year old thread, so it’s not totally surprising most of the links no longer work.
  13. Moreno has been banned for the rather insistent tendency towards racist rhetoric.
  14. ! Moderator Note We are not in the business of dispensing medical advice. I recommend you see a doctor when you can.
  15. Metal organic frameworks are very popular at the moment. https://en.m.wikipedia.org/wiki/Metal–organic_framework They contain organic components as well obviously, but the area sits much more squarely with inorganic chemistry. I suspect that the examples given by the OP were used to distinguish synthetic and naturally occurring macromolecules, though it is a bit confusing as rubber can also be naturally occurring.
  16. ! Moderator Note A question best answered elsewhere, lest this thread continue to get dragged off topic.
  17. It’s not just limited to proteins either. You can also engineer yeast and bacteria to produce complex chemicals, some requiring several enzymatic steps. For example, I remember a while back there were a couple of papers that did this for the production of codeine and other morphine type compounds. There were problems where some reactions were not compatible with others, so in one paper the authors compartmentalised the enzymatic steps in different organelles yeast, and in the other the authors used two strains of E. coli to complete different halves of the synthesis. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4924617/ https://pubmed.ncbi.nlm.nih.gov/26847395/ Chemoenzymatic synthesis is a very big area. In fact the Chemistry Nobel prize in 2018 was awarded to 3 people, one of whom (Frances Arnold) received it for pioneering the use of something called directed evolution. Essentially, her lab looks at enzymes that are able to perform reactions that are difficult to do outside of enzymes. They take the gene for the enzyme that is able to perform a given reaction that they are interested in, and create a library of mutants that are then transformed into whatever organism. The mutants are screened and the most active selected for the next round of mutagenesis, etc. They’ve used it towards greener syntheses of compounds used in, for example, pharmaceuticals and biofuels.
  18. I can see what you’re maybe getting at here, but it is confusing. The Keq would not be written like that as the equilibrium is not dependant on the concentration of the solid salt. The expression for Ksp is not actually different from how you would write other equilibrium expressions, since you typically don’t include terms for solid or liquid components in any expression for Keq. This is the same in, for example, expressions for Ka, where water is not included. The reasoning is that these components are normally in such large amounts relative to other components, that minor changes to their concentration has no effect on the overall equilibrium. This holds true for Ksp since we assume at a minimum that the solution is at saturation point; adding more salt has no effect on the concentration of ions in solution, and therefore no effect on the equilibrium. The answer to this is simply stoichiometry. If x number of moles of a salt has dissolved, and the ratio of it to one of its ions is 1:1, then x number of moles of that ion is in solution. Note of course that this concentration is not the same as the amount of salt that might have been added to solution, just how much at equilibrium is actually in solution. I think you understand most of the concepts here, so I don’t think you’re necessarily missing anything. Ksp and molar solubility are closely linked - if one is low, so is the other. We might use the numbers for different things or to work out other problems. Practically, molar solubility is a more useful and easily relatable number if you just want to know how soluble something is. However, if you want to know the ion concentration in more complicated scenarios (I’m talking common ion effect) or if you want to say predict whether something will precipitate in complex solutions, you would need to use Ksp. Perhaps have a read of this: https://www.chem.purdue.edu/gchelp/howtosolveit/Equilibrium/Solubility_Products.htm
  19. Inconclusive is one way of putting it. Their first paper with was highly suspect and contained a lot of concerning ethical elements. Their follow ups don't seem to add very much, and is at odds with a lot of the other data that has been published regarding HCQ. Derek Lowe's coverage on it has been quite informative: https://blogs.sciencemag.org/pipeline/archives/2020/04/16/more-small-molecule-clinical-data-against-covid-19-as-of-april-16 https://blogs.sciencemag.org/pipeline/archives/2020/04/11/the-latest-hydroxychloroquine-data-as-of-april-11 https://blogs.sciencemag.org/pipeline/archives/2020/03/29/more-on-cloroquine-azithromycin-and-on-dr-raoult
  20. I don't think there has necessarily been any political meddling. They are working with the data that they have, but I also think that this is where the issue potentially lies, since I don't believe there has been significant testing done in children to know what risk they actually pose to other people. I completely agree with you on your points about school closures - the long term economic effects would be disastrous. In addition to your points I would also comment that universities, which are already struggling with the loss of international student money, would surely go bust if they also lost an entire graduating year of domestic students.
  21. There was a paper circulating a little while ago that caught my attention, published in Nature. https://www.nature.com/articles/s41586-020-2223-y To be honest, I am pretty baffled that it was published in Nature. The top leads identified in their screening assay are known as pan-assay interference compounds (PAINs). IOW, they are nuisance compounds and generally not something you would pursue in a drug design campaign. In fact, the seminal paper that discusses PAINs is a Nature paper (https://www.nature.com/news/chemistry-chemical-con-artists-foil-drug-discovery-1.15991), which makes this even more confusing. I can't imagine anyone with a med chem background would have reviewed this, as the red flags should have been very obvious. In any med chem journal, this paper would have been rejected since you have to screen for PAINs as part of their submission guidelines. I'm worried that this signals a general lowering of the bar when it comes to these sorts of publications, which will only make things more difficult in the long run. Derek Lowe has written some good blog posts on the matter: https://blogs.sciencemag.org/pipeline/archives/2020/04/10/more-on-screening-for-coronavirus-therapies
  22. I’d certainly believe it. A lot of the students I’ve dealt with over the last 5 years in the micro and genetics labs I’ve worked in don’t seem to realise that there is an inherent ambiguity, because that is just how they’ve always interpreted it.
  23. farsideofmoon has been suspended for 2 weeks for repeated thread hijacking.
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