John Cuthber

Nether the nail, nor the magnet are paramagnetic, so Curie's law doesn't apply.

The graph only needs to be fairly accurate to illustrate the point. There are three values of x where x^7- x^5 = -0.05 How do you invert that? Which one do you choose?

There have never been any thunderstorms on the moon, yet it has gravity. So you are wrong.

Thanks for drawing the graphs. If you look at the blue line (which indicates what would be the "inverse function") at x= about -0.05, the blue line has 3 different values. So, if I asked you what's the value of f^-1 of -0.05, which answer would you give? The function isn't monotonic, so there's no reliable way to invert it. If you do the same with y=x^5+ x^7 you will see what the difference is.

Are we talking about "competent to get elected" or "competent to run a government"? Clearly they sometimes manage the former so that's a pointless question. It follows that we need to establish whether Republicans are competent to run a government. So the next question is "What are governments meant to do?". Well, there are obviously lots of answers to that. Here's just one observation. Generally, the rich will get richer and the poor will get poorer. There are zillions of reasons for that; the simplest is that the rich can afford to buy wholesale and sell retail. I contend that one of the fundamental roles of government is to ensure that this tendency does not become exploitation. It is the purpose of government to maintain some degree of "fairness" such that one's chances in life are not solely determined by the accident of birth that one enters into this world in a a rich family or a poor one. To do that you need a mechanism by which the "natural" process is held in check. On a practical basis that means taxation of the rich and benefits for the poor. So it is a requirement of any government that, in order to provide basic fairness, there need to be taxes and benefits. I can't see how you can have a just government that doesn't do this. And, since the republicans want to abolish them, they are, by that very fact, not competent to form a government. It's not an issue of whether Cruz or Bush is competent. Nobody who puts forward the idea of reducing benefits in circumstances where those benefits are already inadequate, is competent to govern. Thus no Republican is competent.

That's not quite what I meant. There is a general solution to quadratic equations "minus b pluss or minus the square root of b squared minus four a c all divided by two a" There is no general solution for 8th order polynomial. But there is an inverse for the particular instance of y=x^8. the solution is that y is the 8th root of x and you can calculate it by pressing the "square root" button on your calculator a few times. (OK, it's messy for negative numbers, but that's not the point) What I don't know is whether X^7+X^5 falls into the group of 7th order polynomials that dos have an analytical solution. I can show, graphically, that x^7 - x^5 does not have an inverse.

That's not unreasonable. https://en.wikipedia.org/wiki/Celluloid

In general, you can't. But what about this specific case?

I don't know if it's soluble or not. But I know that the inverse function exists.

I can "brute force"it by simply swapping the axes. So, there is an inverse; there might not be an analytic one.

Violins are, as you say, resonant, and they will exhibit "frequency pulling" effects. And fireflies don't, and won't. That's why I said they were different. The (firefly) phenomenon I referred to isn't anything to do with resonance. So there's no way you could use it to judge whether I understand resonance or not. Why did you pretend that you could? Since there's, at best, some difficulty getting the two violins exactly in synchronisation- if nothing else because the players will move and the Doppler shift will change the observed frequency- it makes sense to eliminate that and feed the same signal to two loudspeakers.

I didn't do any. The word "we" has a wider meaning than you seem to imply. And whoever did the tests they wouldn't be doing them "as a chemist" so that's just silly.

It could be. The reactions involved are complicated- and it's entirely possible that the solubility in, for example, 65% H2SO4 might be higher if you add some salt like KHSO4 It's really very difficult to try to calculate this sort of thing. You have to rely on experiments. Which makes the idea of "count the moles" look very naive.

At lest part of the reason might be that a zoo is a very unnatural environment.

In my opinion, and, I think that of others, you should stop doing this. You should stop asking for an explanation of things that don't exist and claims that have no basis. You have been told about this before. Why do you keep doing it?

I'm not sure, but I think I'd start by taking logs of both sides and seeing if that got anywhere.

Part of the reason for using excess H2SO4 is that it's also the solvent in which the reaction takes place. And this "H2SO4 + HNO3 => HSO4(−) + NO2(+) + H2O" isn't realistic because H2O reacts with H2SO4.

Nice of you to mention it- after the event. As I said, a clumsy mistake which it would have been better to just admit to. And do you actually believe that it's always 91%- never 90 or 92? Do you, for example, think that the water content doesn't depend on the local temperature and humidity? So, it is a figure with, as I said here (and explained in my PM I think) spurious accuracy. https://en.wikipedia.org/wiki/False_precision Again, a clumsy mistake you were too busy pretending that you didn't make, to learn from it.

I cited both a source and a reason for assuming that cotton is 100% cellulose You, on the other hand, have pulled a spuriously accurate figure of 91% out of thin air. YOu say you don't understand how the amount of nitrogen is important, well, you are trying to work out how much of the nitrogen source- KNO3 you need. Don't you see how one tells you the other? If I need 1 gram of nitrogen and the KNO3 contains x % of it then I need 100/x grams of it. "ps. 72+80+10 = 162 You said, it's not even closer to that value." I never said what that value was (though I divided 78 by it) I did say (in a PM for those who are struggling to follow this) that the molecular mass of cellulose is nowhere near 162, and that statement is perfectly correct isn't it? It's about 162 n where n is the degree of polymerisation. Typically that's about 1000 to 10,000. according to this https://en.wikipedia.org/wiki/Cellulose ​So your estimate of the number of moles is wrong by a factor of about 1000 or 10,000. "I was not talking about mass of whole long chain compound, but single monomer unit." That's not what you said. You said moles of cellulose. You never actually said what you were talking about and that's part of the problem. But the number of moles of a substance is perfectly well defined and you got it very badly wrong. Once again, you are failing to accept that you made a clumsy mistake. https://en.wikipedia.org/wiki/Law_of_holes

-That's right. The number of moles of cotton is essentially not possible to know- because we don't know the molecular weight. In fact, because the cotton has lots of different sized cellulose molecules, there isn't even a single "average" molecular weight. There are three commonly used ones and the details are here https://en.wikipedia.org/wiki/Molar_mass_distribution though they don't matter much to the problem of nitrating cotton. (the difference is a bit like the joke about the butcher who makes cheap meat pies. He says the pies are a 50 ;50 mix of lamb and horse. He mixes 1 horse and one lamb.) Anyway, as I say that doesn't really matter here. The first thing you need to do is say what you mean by making "nitrocellulose". You say you test it by seeing how fast it burns so I'm guessing that you want the version with a lot of nitrate groups, but if you want it to use as a plastic, you would probably want a less nitrated version. Without deciding on that, you can't really do a lot with the "number of moles" thing that Sensei was so keen on. Let's assume - just to be different, that you are making nominally "dinitrocellulose". That means that for each glucose unit in the cellulose you want to add two nitrate groups. It has a molecular formula that roughly corresponds to C6H8(NO2)2O5 And let's at least work through the calculation- though in this case it's not as helpful as you might expect. So, for each 6 carbon atoms there are 2 nitrogen atoms. And so the nitrogen weighs (2*14)/(6*12) times as much as the carbon. There's 38.9% as much nitrogen there as carbon. Now we need to know how much carbon there is in 5g of cotton. Well, according to wiki https://en.wikipedia.org/wiki/Cotton "The fiber is almost pure cellulose." and I'm prepared to believe it for this sort of thing. So how much carbon is there in 5 g of cellulose? Well, again, we have a molecular formula (C6O5H10)n And from that we can see that the proportions of the weights are 12*6 : 5*16 : 10*1 or 72 : 80 : 10 and so the proportion of carbon is 72/ (72+80+10) = 44.4% so 5 grams of it has 2.22 grams of carbon. And that would need 2.22/ 0.389 = 5.7 grams of nitrogen It's getting late, so I will let you work out how much potassium nitrate you need to get that much nitrogen. But now I'm going to break the bad news to you. The reaction doesn't go nicely according to the equation you might write out for it. At least some of the nitrogen is lost by oxidising the cellulose (and some of the impurities in it) which converts it to a mixture of oxides of nitrogen. So, you can calculate the number of moles (as long as you know what the molar mass is). And you can calculate the mass of sulphuric acid needed to convert that many moles of nitrate to nitric acid. And it won't help much. Partly because the sulphuric acid is also the solvent, and partly because it's purpose isn't just to make nitric acid. There are at least two possible pathways for the reaction and which one happens probably depends on temperature, concentration etc. Either the sulphuric acid reacts with the nitric acid to produce nitronium ions that attack the cellulose 2 H2SO4 + HNO3 => 2 HSO4(−) + NO2(+) + H3O(+) or the acid protonates they hydroxyl groups on the cellulose, and those react with the nitric acid. Indeed, it's possible that both reactions happen. But, in any case you need an excess of the sulphuric acid. How much of an excess do you need? I don't know; I never tried. I gather that, for making gun-cotton a mixture of about 2 parts of sulphuric to one of nitric is about right. And with that sort of "precision" you can understand why I didn't bother using accurate atomic weights for N,C, H and O or worry very much about the purity of the cellulose.

"What do we want: time travel!" "When do we want it: it doesn't really matter!"

Do you know what the word psychosomatic means? Since the best available estimate is that practically everyone does it, where do these "scientific" studies find their control group? well, as you point out, there isn't one. And yet you pretend that there are studies. How? You already agreed that it's impossible.

And you made the same mistake that he did (in his PM). Did he "help" you?

No I probably wouldn't. And yes, you can assume what you want. But to post it here as if it is important tags you as arrogant

I do. Now, why not answer the question?