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exchemist

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  1. It’s an antifungal I think. I don’t know if it is used intensively enough to pollute watercourses.
  2. Does it matter? Neither picture is anything like the actual physical arrangement, after all. It’s just a diagram to convey the idea of shells. It does not tell you anything about the real distribution of the electrons in space. (By the way there is something wrong with the atoms, or ions, in your picture. Neither has the right number of electrons.)
  3. There is nothing in QM to suggest observation by a conscious or intelligent observer has anything to do with it. The popular misconception to the contrary is a result of the language used by the developers of the theory in the early days, which talked in terms of observable properties and hence of observers making observations. Pauli, for one, made it clear that ā€œobservationā€ referred just to interaction with the inanimate measuring apparatus employed in the measurement.
  4. So presumably measures to reduce CO2 emission will continue to be implemented in the more enlightened states at least. Trump can’t ban EVs, wind farms and solar arrays.
  5. I thought a lot of climate initiatives took place at state, not federal level, though. Will these be affected by this nonsense?
  6. Encouraging. Though I imagine the fall in cement production may be due to excessive speculative housing developments, which I understand have led to a slump in the Chinese property market and left a number of real estate and construction companies seriously under water. So may be an economically driven fall rather than the result of +ve climate policies.
  7. Yes, in my experience on these forums a lot of relativity eccentrics - I won't say cranks - and QM eccentrics too have an engineering background. I suspect it is because much of engineering is a sort of apotheosis of c.19th physics, seeming to achieve mastery over nature. This view was shaken by the advent of relativity and QM in the early c.20th, which told us a number of uncomfortably counterintuitive things about nature. (I was in fact taught 1st yr 6th form physics by a brilliant teacher who claimed to be agnostic about the existence of molecules! His degree was in engineering and he was great - at classical physics. But we got a different teacher in the 2nd year.) As Feynman said: "You don't like it? Go somewhere else! To another universe where the rules are simpler, philosophically more pleasing, more psychologically easy........I'm not going to fake it. I'm not going to tell you it's something like a ball bearing on a spring when it isn't. " Common sense is not enough.
  8. From what I have read, it seems to me almost all were young women of 18+, with agency as adults. He did get done for underage girls of course but my impression is that there has been an extension, by the media, into implying most of these women were underage girls. But is that true? How many were actually under age?
  9. I’m not sure that knowing Epstein socially even indicates creepiness. Seems just about everybody knew Epstein: he was a vigorous, ubiquitous socialite, by the sound of it. There doesn’t seem to be evidence that most of these people were involved with Epstein’s prostitutes.
  10. Oh yes I don’t mean to suggest it’s wrong or anything like that. Just a bit weird - and in my opinion of doubtful utility to someone trying to learn the principles of chemistry at school level.
  11. Interestingly, all the references to this "abnormal molar mass", including the one you cite, seem to be from Indian source material. I don't recall it from my own undergraduate studies (in the UK), there is no reference to it in my old Moore Physical Chemistry, nor it seems in the Chemistry Libretexts, or in Wikipedia or the other sources I habitually consult when revising chemistry.
  12. I think it may be expressing this in terms of molar mass that is causing you the confusion. Think first of all in terms of the numbers of molecules, i.e. the number of moles of substance. Then i makes obvious sense as the ratio of the "effective" number of moles of particles (i.e. how the substance actually behaves in practice) to the "theoretical" number of moles of the substance (i.e. as it appears on paper from the chemical formula). I must say I think the idea of "abnormal molar mass" is a fairly unhelpful way of thinking about what that is going on. It could almost be designed to get you in a muddle. Nevertheless, see if the following explanation helps. For example if you consider a solution of a partially dissociated substance, its effective molarity would be less than the theoretical value. But the number of moles of a substance = mass of substance present/molar mass. So then an "effective" molarity < "theoretical" molarity could be interpreted to mean the "effective" molar mass > "theoretical" molar mass. This I think is what @KJW is getting at. Personally, I struggle to think of any situation in which the concept of an "abnormal molar mass" is at all useful. (But if other readers can think of a use for it, I'll be interested to learn). I much prefer to leave the molar mass as standard, and think of effective concentrations differing from that predicted by the (standard) molar mass.
  13. This is ridiculous. I attended 4 different schools over 13 years, the last 5 of which were at one in which pupils moved from classroom to classroom for each different subject. As far as I know this is common practice (and essential in science subjects, due to use of laboratories).

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