exchemist

Yes the dissociation constants are known for thousands of acidic compounds. OK I won't say google them, but the fact is you need to look them up somewhere. When I was doing this sort of thing back in the day, we used what was known as the "Rubber Book", a huge telephone directory size book that sat on the bookshelf in every chemical laboratory. Details here: https://en.wikipedia.org/wiki/CRC_Handbook_of_Chemistry_and_Physics I have no doubt that similar compendia of this data exist in on-line form. Checking briefly on-line just now, it looks as though most of the tables one finds actually still reference the Rubber Book. Re temperature dependence, I gave a formula for how equilibrium constants depend on temperature, in an earlier post: ΔG = -RTlnK. The snag, as @John Cuthberpoints out, is you need to know ΔG for the reaction in question, which means looking up the relevant thermodynamic data for the reaction. You will find this ......in the Rubber Book.

You are still using the wrong formula for k.e. Do you bother to read the replies to your threads? Why do you not check it? The second term should not be +mc², but -mc². That's MINUS. I've highlighted it for you in red. That way, when v = 0, k.e. = 0 which makes sense. Rework your maths using the correct formula and see what you get.

What about the π phase shift of the reflected wave. Have you taken that into consideration when working out where the maxima and minima will be?

You are still using a wrong sign in the formula for relativistic k.e. In your formula, if you set v to zero, you get a kinetic energy of 2mc², which is an obvious nonsense. This has already been pointed out to you. If you fix that, you have a chance of making sense, at least.

If you use a wrong formula, you can expect to get a nonsensical outcome. As @Ghideon is gently hinting, that is what you have done here.

I see. I'm not sure how bringing it here helps, if your antagonists are on Twitter, but that's your affair I suppose.

Don't we already know that epigenetics partially rehabilitates some of Lamarck's ideas even though in a very limited way)? What is new here?

...by which you mean you didn't get an infection, I suppose.

Hmm, if it has 2g/l of dissolved substances, that does not look to me like anything one could derive from tap water alone. This all feels a bit scammy to me.

You need a salt (NaCl) solution for that, as you are making hypochlorous acid (HOCl).

I'm a bit mystified by all this. Surely the chloralkali process yields NaOH, not acid, doesn't it? And when you speak of carboxylic acids, which ones are you talking about and what are you digesting anaerobically to produce them? And what are you using mother of vinegar with, to convert it to acetic acid? Sorry for so many questions.

Piezoelectric crystals. But this is off-topic for this thread so I'll shut up.

No, that's wrong. You can, if you know the dissociation constant as well. (A dissociation constant is just the equilibrium constant for a dissociation reaction.) You can't know the pH just from the chemical equation for the dissociation, since that does not tell you where the equilibrium lies between the left hand side and the right hand side. That's the missing piece of information that the dissociation constant (or the ionic product in the case of water) tells you. To make life easier for you, if you have a strong acid, such as HCl or HNO3, you can assume that it is fully dissociated (unless you are dealing with very high concentrations). So for these, if you know the concentration of acid from the amount you added, you can set [H+] equal to that, since every molecule of acid gives you one H+ ion in solution. So knowing the acid concentration you can just work out the pH from that. If you have a weak acid, like acetic acid, then you need to look up Ka for the acid and work out [H+] using that, knowing the concentration of acid you have added. If you have a more complex mixture, involving and acid and a base together, then if it is a strong acid with a strong base, you can assume full neutralisation occurs and that the pH will be determined just by what is left over. If you have a weak acid, or a weak base, then you will need to know the equilibrium constant for the neutralisation reaction involved. So it is doable in all these cases, so long as you know the molecular concentrations AND the relevant equilibrium constant.

OK, you still have the same confusion as originally, it seems. In my original reply to you, I mentioned that you seemed to be treating water as fully ionised, when it is in fact barely ionised at all. It looks as if we need to go back and revisit what dissociation into ions involves. (Forgive me if you know all this, but it looks from your posts as if you may not.) Water consists of H-O-H molecules, right? H is bonded to O, by means of a covalent bond. You do not have lots of free "H" and "OH" floating around. However, what happens to a tiny fraction of the molecules is that they split, or dissociate, into ions. The covalent bond involves two electrons, one from H and one from O, being shared between the two atoms. In the dissociation of a water molecule, both electrons go to the O atom, leaving H without an electron. So you get H+, because it is one electron short and OH-, because it has one extra. In bulk water, there is a dynamic equilibrium, in which molecules are continually dissociating into ions and ions are continually recombining into neutral molecules again. But, and this is important to understand, the dissociated state requires more energy than the neutral state, so only a tiny fraction of the molecules are dissociated into ions at any given moment. Whereas what you have been doing, in effect, is counting all the H atoms present, bonded or not, towards your "[H]" figure. That's why it's wrong. You need to know the proportion of the molecules that is ionised at any given moment. This is extra information. You can't calculate it just from the chemical formula You get this from Kw, which is an experimentally determined figure.

There's a rather perfunctory entry in Wiki about this: https://en.wikipedia.org/wiki/Extinction_threshold It's not very good, but possibly some of the links and references could be informative.

If you know the concentration of H+ or H3O+, you are home and dry. You take the log of the value and take the negative of what you get (the logs are almost invariably -ve, so this procedure gives you a +ve value for the pH.) If you want to find the pH without knowing the concentration of H+ (or H3O+), you need to know the dissociation constant for the species present. For pure water we know this, of course. For other solutions, it depends what you've got. They are documented for many molecules. For example you can find values of Ka for all the commonly encountered acids. It is also possible to calculate equilibrium constants, in principle including dissociation constants, from the thermodynamics of the species involved: ΔG = -RT lnK, where ΔG is the change in Gibbs free energy for the dissociation.

That's a fair point, certainly.

From measurement, [H3O+] and [OH-] are each 10⁻⁷ mol/l in pure water at room temp, hence you get a pH of 7 and an ionic product, Kw of 10⁻¹⁴. It looks as if you have calculated the number of moles of pure H3O+and OH- you would have in a litre, if water were 100% ionised. But, as it is only very slightly ionised, so you will get wrong numbers that way. At least, this is how it looks to me at first glance.

Aha, that's interesting. But this must be a universal issue, then, in cooking with stainless steel vessels, since salt is an essential ingredient in cooking almost anything. Why are we not all poisoned?

We have a stainless steel cooking pot, some salt and some water. Where would ferricyanide come from?

No. I've had with you, pal. You're a timewaster.

To me, this has the hallmarks of someone with an idée fixe who is trying to preserve it by deliberate misunderstanding, i.e. arguing in bad faith. I don't see the point in carrying on with this, now.

Well we can rule out the latter in this context, but some MgCO₃ could be present in hard water I suppose. Does that mean you discount the reassurance given in the link in my first post on this thread?

A vibrating object is just the same as your body, just doing it faster.

Well, still a bit wrong, but you seem at least to be accepting that internal forces within the body (of the muscles acting on the bones of the skeleton) cause the centre of gravity of the body to move up and down, in reaction to contact with the floor. Do we agree on that?