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exchemist

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Everything posted by exchemist

  1. And even that varies from ocean to ocean, hence all the markings on the Plimsoll Line on a ship's hull, showing the different limits to which it can be safely loaded:
  2. The density of ice is lower than that of liquid water at the same temperature. Unlike most materials, ice expands upon freezing. Objects that are lower in density than the liquid in which they are immersed will tend to float in it. The reason it expands on freezing is because the molecules in the solid take up orientations that maximise the strength of hydrogen bonds between the molecules. This leads to a more "open" structure than in the liquid. The physics that governs whether and how an object floats is to do with the relative magnitude of the object's weight and the buoyancy force it experiences from the liquid. This is set out in what is known as Archimedes' Principle. There are details here: https://en.wikipedia.org/wiki/Archimedes'_principle
  3. That may be a good strategy, as one of the issues not much discussed as yet is the need to rewire entire neighbourhoods to cope with the higher electricity demand, once most people have EVs. If people can generate at least a proportion themselves it could help a lot.
  4. From what I have read, it is better to keep an old IC vehicle as long as you can, before trading it in for an EV, due to the large and unavoidable carbon footprint of manufacturing a new vehicle, of any type. But your next purchase, whenever it is necessary, should be an EV. The longer you can leave it , the greener the EV will be , since the renewable proportion of the electricity it consumes will grow as the years pass. Also the charging network will get better over time. I'm currently running a 19yr old petrol VW Golf, (the 1.4l one with both supercharger and turbocharger, which performs like a 2l but with much better fuel economy). It still works fine and does what I need it to do, so I intend to hang onto it for another year at least.
  5. Don't be an arsehole. The procedure you were suggesting could easily put someone in hospital.
  6. On the contrary, the countries of Western Europe are by far the best to live in, anywhere on the planet.
  7. Yes. If the rolling road measured the power (torque x revs) output of the engine at the driving wheels, then if you measure the rate of fuel consumption and you know the calorific value of the fuel, you can work out what proportion of the calories burnt end up as mechanical power. It will be 25-30%, I expect. There will be some errors due to frictional losses in the transmission, so you will slightly underestimate the output of the engine itself. In a mechanical transmission those losses are small - <2% if I recall correctly - , but with a torque convertor they may be more significant. There may also be some errors due to the fuel not being 100% burnt to CO2.
  8. Indeed. So you should not suggest hazardous procedures without at least pointing out the hazards.
  9. Then you should not be recommending this procedure to a person whose expertise you do not know, on a public forum.
  10. This strikes me as a terrible idea. Capturing large quantities of these gases is risky enough, but for an amateur to attempt to react them is definitely a recipe for an explosion.
  11. How does this work? When you electrolyse NaCl, you evolve H2 and Cl2, and you are left with NaOH, i.e. an alkaline solution.
  12. Instantaneous consumption is given by the rate of consumption, isn't it? The units of which are volume per unit distance, sure, but it does not seem to me to add anything to express this as an area, even though dimensionally that is what it is.
  13. Yes I think so. What insight does this division provide?
  14. Well the pH shows a value of about 1, with indicator paper, which is very approximate. You would get 1.3 with 0.1M oxalic acid: https://www.aqion.de/site/ph-of-organic-acids. So that doesn't prove much on its own. But it is true that the precipitate looks blue-white, which looks right for copper oxalate. The reaction is referred to here:https://en.wikipedia.org/wiki/Copper_oxalate as a method for making copper oxalate, with sulphuric acid as a byproduct. (This video is by somebody different - a Dutchman by the sound of him. I can't place the earlier one.) If it works with copper sulphate it might work with zinc sulphate, seeing as that too is insoluble in water.
  15. Hmm, a YouTuber who makes a point of trying to get round EU laws. Not sure I approve. But purely from the chemistry point of view, if the oxalate is insoluble and precipitates, then that should drive the equilibrium to the right, for a while. As the acidity increases though, less and less of the oxalic acid will dissociate into oxalate ions, so the thing will slow down and stop at some point.
  16. I tend to agree. Everything has to have some value and the fact that a constant it has the value it does is no more improbable than any alternative value. To give a trivial example, the fact of my personal existence relies on a highly "improbable" chain of coincidences, regarding how my parents were conceived, how they happened to meet and so forth. But nobody feels the need to argue my existence must have been "designed" by some great plan, because of its intrinsically low probability.
  17. OK, understood. Though this seems to be a very roundabout way to make it. Can you supply a link to show us where you are getting this route from? Zn oxalate seems to be insoluble in water so I imagine it might work in the same way.
  18. Ah, possibly not. Regarding whether it works, I was wondering about that. If an insoluble chelated metal oxalate is precipitated from an aqueous solution, I guess you are left with an acidic solution with sulphate ions, i.e. dilute sulphuric acid. But it can't be a way to generate pure sulphuric acid.
  19. Why are you doing this? Sulphuric acid is readily available, surely?
  20. What bothers me is that this looks like a reduction overall, yet I can't see what is being oxidised. Unless it is the methanol.
  21. I don't remember much organic synthesis, I'm afraid. I can see how you will get an enol (or enolate, under alkaline conditions) but how do you think the oxygen is removed?
  22. It's in trouble then. They have no teeth, so how is it going to deal with the tail?
  23. Yes, it is one of my go-to references for this kind of discussion.
  24. A transatlantic ship crossing takes 4 days (on a fast, purpose-built ship), during which each passenger has to be given a cabin and meals, as if in a hotel, with all the associated staffing costs, but at sea, so a lot more expensive than on land. The cost of that has to be compared with a 7hr flight, with 2 in-flight meals provided. Planes can be tuned round in a couple of hours at each end, so a single A340, taking 250 people each flight, can transport 1000 people in each direction during a 4 day period. That's hard for ships to beat. And that's before you take into account of the value of time for the passenger, as others have pointed out.
  25. I think it's the sort of question that people who believe in the "hard problem of consciousness" sometimes ask. It seems to me that if one takes the word "like" literally, the colour red is sui generis - it is what what it is - i.e. it is not "like" anything else - except for another similar colour, perhaps. But I think the question is actually intended to invite an answer to the (to my mind unanswerable) question of how to describe the sensation of experiencing the colour red. Another similar, well-known one is Nagel's: "What is it like to be a bat?" I assume they mean a flying one rather than a cricket bat*, but perhaps it doesn't matter. Massimo Pigliucci has little time for the "hard problem". He doesn't think it is a problem at all, but arises from a category error: https://philosophynow.org/issues/99/What_Hard_Problem I'm inclined to agree. *Reminds me of a scene in one of those 1950s schoolboy books, "How to be Topp" etc, in which a boy is not paying attention in biology class, when hibernation is being discussed:- Teacher: Molesworth! What are you doing? Molesworth: Me sir? Nothing, Sir. Teacher: Molesworth, what does a bat do in winter? Molesworth: Er, er.......er, it splits if you don't oil it, Sir.
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