exchemist

No. The reason is to do with oxidations states. Ca2+ cations are already "oxidised", in that they have a +2 oxidation state, which is the highest possible for them in normal chemistry. (Ca metal, in an oxidation state of 0, reacts vigorously with oxygen.) Another way to think of it is that CaO is comprised of Ca cations with a charge of 2+ and oxide anions with a charge of 2-. In the course of the reaction between a Ca metal atom and and an oxygen molecule, two electrons are transferred from Ca, which binds them weakly, to O which binds them strongly. This results in a net release of energy, leading to a compound has lower chemical energy than the starting materials - which is the direction all spontaneous chemical reactions take. Whereas if you try to react Ca2+ cations with oxygen, they have no more electrons to give up, so nothing happens.

Recital of this victory for England always reminds me of the curious fact that at school we learned about this battle, Crecy and Poitiers, but were never told that England lost the Hundred Years War, to France. It's one example of how history is often taught, or recollected, in a partial way, in order to bolster national myths. These national myths can have real consequences.

My son is, and I try to keep up, a bit. His main interest is the ancient world, but not exclusively so. I would certainly be interested in reading threads on that subject, anyway.

Any fool can ask questions. Providing answers that are valid is a little harder, considering that imagination does not help much with that.

In principle yes, the body's processes for regulating pH, e.g. the operation of the kidneys which transport substances against a concentration gradient, or breathing more rapidly to reduce the CO2 in the blood, can involve some energy expenditure. But only to a very minor degree and certainly not in the range it would need to be as a factor in dietary calorie control.

Then the reaction has not yet reached equilibrium. Equilibrium is when the forward and reverse reactions are in balance, i.e. the rates are the same.

I have no experience with this myself but my general understanding is that the adsorption capacity of activated carbon goes up with molecular weight of the substance to be adsorbed, and goes down with the degree of solubility of the substance in water. On this basis I would not expect it to be very effective at removing alkali metal cations or carbonate anions. But there may be someone else here who knows more about this in practice.

That's interesting. What's the evidence for these allegations?

Er, no it isn't, actually. But this is too bonkers for me. I'm out.

But that is not evidence that the experiment was biased. He may simply have hoped, or expected, that a fair experiment would make his point for him. Plenty of scientists carry out experiments in the hope or expectation that their hypothesis will be confirmed by it. It's one of the most normal motives for doing science. What, in your opinion, is the evidence that the experiment itself was biased?

What makes you think the diameter of the moon has any relation to the distance between Tierra del Fuego and the tip of Antarctica?

Hmm, well done...but this looks like an amateur site and possibly pirated. I wonder if the site owner has got copyright licence from CRC to do this.

Very interesting. In the case of Brazil, there should be access to gypsum, I'd have thought.

Where are the "locals", if I may ask? I have not read about many places with strongly alkaline soil. I suppose parts of the African Rift Valley would be one of them. But in most places where pH needs adjustment, it seems that the issue is the soil becoming too acid.

A further thought on this: H-bonds seem to need to be linear, i.e. Do-H............Ac, in a line. Also, they are directional, requiring the participation of a lone pair on the Ac atom. In o-nitrobenzoic acid, it seems to be geometrically impossible to get (CO)O-H........O(-ON-Ph) in a line, with one of the nitro group oxygen lone pairs lined up the right way. So I wonder if, in fact, there is any H-bond at all in this molecule!

There is breakdown here of CO2 emissions by economic sector:https://www.statista.com/statistics/276480/world-carbon-dioxide-emissions-by-sector/ And here is a split of powergen by type of generation: https://en.wikipedia.org/wiki/World_energy_consumption You could use this to see what the impact would be if most electricity generation were nuclear. You can see from these figures that power generation is a very large contributor to CO2, so it would make quite a large difference. But I'm not going to go through the number crunching on this: you can do that.😉

I have to say this whole exercise strikes me as pointless. A factor of 2 is not going to make a material difference to how an expression is seen, to anybody who is even remotely used to algebra. As you yourself say, 2π pops all over the place. So "2π" is read and recognised as a familiar symbol already, in its own right. Replacing it by τ won't reveal anything. It may in fact momentarily confuse people who are not used to seeing τ used in this way, as it has other meanings in physics.

Thanks for the information - very interesting to see how you have approached this. You have clearly gone to a lot of trouble. I don't pretend to be expert on agricultural chemistry, unfortunately. Also, it's a little hard to know what would meet your needs, as you have not indicated any cost per tonne limit, where the sites of concern to you are in the world, or what materials you, or they, have to hand. However, shooting in the dark a bit, elemental sulphur and gypsum seem both to be used to reduce soil alkalinity. I also use FeSO4 in my garden (to grow calcifuge plants such as camellias), but I have no idea whether it is used on large scales. But you may already know this and have dismissed these for one reason or another. Bulk sulphur is quite cheap, being a byproduct of oil refinery desulphurisation of fuel. Current price seems to be < $100/mt in sacks, though it will be more by the time someone has shipped it to a useful destination. P.S. Just found this, which discusses sulphur - and FeSO4, so evidently that can have applications at the agricultural scale: https://www.canr.msu.edu/uploads/files/Lowering_Soil_pH_with_Sulfur.pdf

Curiouser and curiouser...... It seems very strange indeed to seal it at the top and only have a 2mm diameter vent low down. That looks distinctly unsafe, if you ever got any bumping in the solvent being distilled. But, from your latest picture, the shorter tube looks to me as if it has been cut. Notice the other one has a nicely rounded end, which the shorter one does not have . The two ends have quite different appearance. Mind you, even if it was originally longer that would do nothing to overcome your objection that the liquid would have to rise up through the joint in order to start the syphon action!

You may be onto something there. If there were any +ve charged oil drops, they would not be held suspended by the electric field but would be accelerated downwards. So the design of the experiment would have effectively filtered out any +ve charged droplets, allowing the experimenter to concentrate on those with -ve charge. But as I said in my first reply, my suspicion is there would have been relatively few +ve charged droplets anyway.

That looks like an oblique and rough edge. Are you sure something has not been broken off from there? It looks far too narrow to be any kind of effective pressure relief, to me. But my question was about the top end of the condenser. Does that vent to atmosphere as well, or is the long tube sealed to it at the top? I'm beginning to wonder now if this is a Soxhlet apparatus at all or whether you have picked up a chunk of someone's vacuum line, designed perhaps for quite another purpose.

It's a good question. I suspect it is to do with speed of motion. The electrons ejected from the oxygen and nitrogen molecules are light and move fast compared to the molecular cations left behind, so they will tend to encounter the oil droplets more quickly and more often, I imagine.

I think this is quite tricky, at least for somebody as rusty as I am. 🙂 If it were not for the H bonding, I think one would expect the ortho- substituted nitro group to increase the acidity the most, being closer. The H bonding will, I should have thought, tend to weaken the acidity, by providing additional binding of the H atom. In orthonitrophenol the H bond setup is close to ideal, as it forms a 6 membered ring, so it can be a strong H-bond. So that could explain why the acidity is anomalously lower than the para version. In orthobenzoic acid however, you have 7 atoms jostling to form the H-bonded ring, which will bend it out of planar and may make the H bond weaker. So perhaps the H bonding effect is not strong enough to disturb the usual order of effectiveness of the electron-withdrawing group. But I have to say, this looks like one of those things in chemistry that can be rationalised either way after the event, but can't really be reliably predicted just from theory. All a bit hand-wavy. But maybe @John Cuthber will have something to add (or tell me I'm wrong).

Yeah I remember him. Stroppy git, he was.😁 I rather think the relativity issue you refer to would be to do with the physicists' dismissal of the notion of time "passing", as in relativity it is just a coordinate axis and therefore doesn't have a "direction". Anyway I don't think it's related to this QM issue of interactions being what make reality tangible.

Sticking with the original mystery glassware, can you confirm whether the condenser is open to the air, at the "top" end, where the long tube loops over and down into it?