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John Cuthber

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John Cuthber last won the day on April 18

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About John Cuthber

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    Chemistry Expert
  • Birthday 11/10/1965

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  1. How could salt have a boiling point of 883C if it fell apart when it melts at 801?
  2. My analysis is that you just invented the pavement cafe.
  3. Is this related to your interest in musical instrumnts?
  4. "Is that the kind of example you want people to follow" is a question about epidemiology, not politics. It's obvious that the scientists, like any sensible people, would say "No, it isn't". That's got nothing to do with politics. There would have been no loss of "impartiality" involved in answering it. But Boris didn't let them answer because it made his friend look like an idiot.
  5. I'm not sure what you are looking for, but would something like this work https://en.wikipedia.org/wiki/Ternary_plot if you colour coded sleep duration?
  6. It's certainly odd. I'd have expected the opposite effect. I can think of one possibility. If the unfiltered juice contained intact cells and those were broken during the filtration process then it's possible that their contents were less conductive than the surrounding liquid. That's possible, but seems unlikely- I'm not sure how you would test it. Does it get hot during filtration? Is it being filtered on an industrial scale- could you try with a smaller rig- say a laboratory scale with a flask, funnel and filter paper?
  7. Is anyone actually extracting juice from potato fruit?
  8. A fog in a vacuum is impossible. There's nothing to hold it up.
  9. It might be worth explaining the bizarre unit- the "inch of vacuum". It is, as I said, like trying to describe the thickness of a coin by measuring the difference between that thickness and the width of your thumb. The original idea was fairly simple. You got a mercury filled barometer. http://www-mdp.eng.cam.ac.uk/web/library/enginfo/aerothermal_dvd_only/aero/fprops/statics/node15.html, Then you connected the top of it to your apparatus. The better your pump was, the more it pulled the mercury up. And if your use for a pump was pulling water out of a mine shaft, that's probably as good as it needed to be. You could pull water roughly 13 times further , because it's 13 )or so) times denser than water. The problem is that the pump doesn't pull the mercury up- the atmosphere pushes it up- and the atmosphere is variable.. Well, that's still OK if you need to know if your pump is pulling water out of a mine, because the head of water is also affected by the atmosphere. But, if you want to get a reasonably accurate measurement, you can't use the atmosphere as a reference point. (OK, technically, you can- if you measure it accurately). If the actual atmospheric pressure varies by an inch of mercury, that isn't going to make much difference to the mine pump. A change between 20 inches and 21 isn't worth worrying about. But, if you are actually working with a pressure that's less than an inch of mercury, your "reference" point varies so much that you can't tell if your pressure is positive or negative (well- it' can't really be negative, but that';s what the gauge.would show). None of that will actually help answer the OP's question. Because the question is like saying "my antique clock keeps time to +/- 30 minutes a day. IS that good enough?" Good enough for what? If the OP ever actually tells us what question they want to answer, we might be able to answer it.
  10. Interesting question of definition; does a diamond count as organic, or inorganic? Some definitions include CH bonds... Anyway, I think quartz is probably the commonest inorganic macromolecule. Molybdenum blue is one of the oddest https://pubs.acs.org/doi/pdf/10.1021/ja512758j
  11. And the answer is that it depends what you are trying to do. How did you imagine that we could answer the question without knowing that? It's worse than that. It's like asking how thick a coin is by expressing is as "How much thinner than a thumb is it?". Which part of "impossible" did you not understand?
  12. If the atmospheric pressure is the so called "standard" of 760 mmHg it is impossible to get 30 inches of vacuum.
  13. If you are an insect in the jar it matters very little- you are dead either way. Both are far too low.. If you are trying to do things that need a good vacuum- like build a mass spectrometer, there's no meaningful difference between 29 inches of vacuum and atmospheric pressure. Both are millions of times too high Well, do you now realise that you were wrong?
  14. OK Thredbarron, It's going to work better if you start at the beginning. I doubt that you woke up one morning and thought "Just for kicks, I will hook a vacuum pump and gauge to a jar". What are you trying to do or find out?
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