

exchemist
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What is the correct way to use a science based forum ?
exchemist replied to Ned's topic in Suggestions, Comments and Support
If you talk nonsensical crap, you must expect to get closed down. You have been banned over and over agin, from so many forums, that this message must have sunk in by now. The only explanation for you continuing as you do must be either that you have some insane compulsion to talk crap or that you are doing it for fun, as a wind-up. I incline to the latter view, as you know. -
But on this forum you need to express yourself in words, unfortunately, or at any rate without sending us off-site to click on on links of unknown provenance. It's been ages since we had a perpetual motion machine, so if you an explain it without sending us off-site to a link, it would be fun to identify the flaw.
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I'm afraid I am not au fait with what may have been tried recently in this area but I'd have thought there are reasons to expect Fe VIII not to exist, chiefly the effect of increasing nuclear charge as one goes across the period which will lower the energy of the valence shell orbitals, raising the ionisation energy and pulling them in, making them less available for covalent bonding as well. How recent is the work you cite that suggests Fe VIII ? I imagine Ru VIII and Os VIII might be expected to be similar to one another (due the effect of the lanthanide contraction on Os), and both of them to form high oxidation states more readily than Fe, due to having more diffuse (less strongly bound) valence orbitals. But I can't claim any practical knowledge of this. Maybe someone else here can.
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No, you need to take a more nuanced approach to this. Nobody is saying the 3-4 alkene is "not stable". It's more subtle than that. What we've been saying, and what the Zaitsev (or Saytzeff) Rule is saying [suggest you look it up], is that these elimination reactions, where there is more than one possible product, tend to favour the option with the more highly alkyl-substituted double bond. You will in general get a mixture of products containing both options, but there will be a higher yield of the one with the methyl substituted double bond. The reason is that alkyl groups are slightly electron-donating. You may be aware that alkyl groups are ortho/para directing in aromatic substitutions for instance. (F, by contrast, will be somewhat electron withdrawing.) More highly alkyl-substituted alkenes have greater stability (stronger bonds) than unsubstituted ones, as a result. How this occurs is a bit complicated, involving something called hyperconjugation, which gets into MO theory: you may or may not be covering this kind of thing in your course. But the question of "stability" is also worth thinking through a bit further, from the point of view of kinetics vs. thermodynamics. Both products are, so far as I can see, thermodynamically stable, albeit the Me-substituted one is of somewhat lower energy - the more stable of the two. So that answers the direct question you asked. But which product is favoured in the course of a synthesis reaction can be a question of kinetics as well as thermodynamics. The explanation of the Zaitsev or Saytzeff rule given in my old synthesis textbook is that the electron-donating (hyperconjugation) character of the alkyl group stabilises the transition state, thus lowering the activation energy and causing that product to form faster than the other one. This may be something to argue out with your prof.
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They elected the people who made such decisions. That is how modern democracy works. We can't make the decisions of government: we have not the skill, knowledge or time to do it. So we choose, periodically, who to entrust these decisions to, on our behalf, and then we periodically review their performance and decide whether to renew their mandate or give it to someone else. (This is pretty basic stuff, surely?)
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Reminds me of one of the funniest passages in "The Life and Extraordinary Adventures of Private Ivan Chonkin", by Vladimir Voinovich, in which his neighbour enthusiastically recounts to his guest, Chonkin, the number of things he can do with chicken shit, of which he has plenty. He concludes his peroration with: "Even this vodka, for instance........", only to be interrupted by Chonkin diving for the door and throwing up outside.
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To what? Their vaccine doesn't work very well and people don't trust it, so much of the population is exposed to significant risk if they catch the virus. They would need to import gwailo vaccines and convince people to get vaccinated, which is a massive undertaking, or else just accept the deaths and strain on their medical system. Even after the elections, Xi would risk a tsunami of public wrath if that happened. There is nothing they can do about the demographic time bomb, so far as I can see.
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Look it up: it's an enzyme that breaks cellulose down, I think into monomer or dimer units.
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Silverfish use cellulase, I think.
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And what do you think of the answers you have been given here? Do you now understand?
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You are right: I stand corrected. My full version of the OED gives two meanings for the verb (summarised by me) as: to render intricate, or to entangle or ensnare. The OED however describes it as "now rare" and all but one of the examples of its use are from before 1750 (the exception being a Dundee journal, in 1900). So using it as a verb today is a fairly bizarre choice, liable to confuse.
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But with E1 it will be a carbocation, surely, which Me can stabilise as alkyl groups are slightly electron-donating? (I admit it's many years since I did this stuff.)
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If it's E2, surely there is no charged intermediate, is there? If it's E1, I think I'd expect Cl- to leave and the resulting carbocation to be stabilised by Me. Or am I getting mixed up?
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That's because it's been eliminated in the formation of the double bond.
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OK but won't the Me group influence the proportions of 2-3 vs. 3-4 double bonds? What effect do you expect it to have?
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Ah, is this about the Zaitsev Rule?
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What does "do an E2 with NH3 on the 2-metyl-3R-Cl-4S-F pentane"mean? E2 I assume means an elimination reaction, somehow involving ammonia, but what are the substituents on pentane and what were the 2 products? There seems to be a .jpg file attached which we can't see. If you use a few more words, it may help to clarify what this is about.
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This is so idiotic I burst out laughing.