exchemist

Fair enough, but the link I provided also includes reaction such as : 3Mg2SiO4 + SiO2 + 4H2O → 2Mg3Si2O5(OH)4.

If you have oxides you don't have to generate free hydrogen. For example CaO + H2O -> Ca(OH)2. A quick internet search yielded this: https://www.liquisearch.com/serpentinite/formation_and_petrology/serpentinite_reactions. which suggests several suites of reactions, some of which generate hydrogen and others not. I imagine free hydrogen could contribute to some of the apparently reducing conditions in some volcanism, e.g. when H2S is evolved. (The link also mentions possible reduction of carbon from carbonate to methane.

This is a really interesting article. Thanks for posting. I'm going out now but will read it when I get back. But from initially scanning it, it looks as if you are quite right: they do seem to suggest a gradual net absorption, with a cycle superimposed on it.

Are they being depleted, though? Volcanism returns water to the surface, after all. I would have expected that there would be equilibrium, over some sort of long term cycle.

I'm not watching YouTube videos, as videos take up a lot of time to watch, compared with reading the printed word, and so many are full of crap. What are the key points the videos make? Perhaps we can discuss those.

I can't think of a specific effect of the pressure of the oceans on the oceanic crust, but I have read that water may play a very important role in the convection cycle responsible for plate tectonics. My understanding is that many hydrated minerals are mechanically relatively weak (e.g. "soapy" minerals like serpentine) and that "wet" rocks can get a degree of lubrication from the presence of water as they slide past one another in faults. So it may be that water facilitates the convective motion. I have also read that the volcanism behind subduction zones is at least partly due to the water entrained by the descending slab of lithosphere, which is chemically altered by it, producing lower melting point minerals which expand and rise towards the surface, as "diapirs" of magma. I suspect it's a big subject, actually. I'm not a geologist, I'm afraid.

Interesting. It seems to have quite a lot in common with the Dead Sea. Though I'm not sure whether there are geothermal springs there. What I also found interesting was to read that much of the world's lithium for batteries comes from a spodumene mine in Australia. Spodumene, apparently, is an igneous pyroxene mineral with formula LiAl(SiO3)2, (i.e. 2 silicate tetrahedra with one shared edge). Other sources - or potential sources - are brines in Chile, Bolivia and Argentina. So at least the world is not currently dependent on China or Russia for it. Furthermore it occurred to me that perhaps it could be a good mineral money-spinner for Australia, which might help some of their (numerous) dinosaur politicians to get their heads round the need to stop extracting coal. But more diversified sources would certainly seem prudent, given the difficulty in replacing Li in battery technology. Li seems unique in this role. I imagine this will be due to the small size of the Li+ ion (only the 1s shell is filled) allowing it to form intercalated compounds with carbon, CoO2 etc, reversibly.

Sort of, yes. So it gives you the idea of losing electrons during oxidation. The caveat (sorry if this is teaching grandmother to suck eggs) is oxidation state is not the same as the charge on an actual ion. It's a book-keeping convention that ascribes a number and sign according to what would apply if a given compound were fully ionic. So for example in SiO2, which of course is covalent rather than ionic, Si has an oxidation state of +4 and O has one of -2. And in the present case of the sulphate ion, S has an oxidation state of +6 and the 4 O atoms -2 each. Sulphate reducing bacteria can take S from +6 all the way down to -2 in H2S.

I imagine that would be due to the presence of sulphate-reducing micro-organisms in the manure, wouldn't it? I find the concept of oxidation states helps. The higher the +ve number, the more oxidised the species, which signifies the removal (whether real or notional) of more electrons.

Davy, and others at the time, seem to have used a variety of names, Davy initially proposing alumium. Subsequently both aluminium and aluminum were used, both by him and others, though it's true did write a textbook using the aluminum spelling: https://en.wikipedia.org/wiki/Aluminium#Etymology It seems to have been a choice by a North American called Noah Webster, when compiling his eponymous dictionary in 1828, that settled the American spelling.

I collect some in a water butt connected to a gutter downpipe, for watering calcifuge plants, that's all. But then I live in an area that is not short of water, as do many people. Statistics on who collects and who doesn't are only really relevant if they relate to areas that are short of water or projected to become so. As for sewage, what we need here in the UK is an initiative to separate sewage from rainwater runoff. Sewage is processed in sewage farms, not discharged to the sea (unless there's a problem with the treatment plant, which happens too often). Adding the volume of rainwater runoff to it, as we have done since the Victorian sewers were built, just magnifies the volume that has to be treated. It's a thoroughly bad idea. We ought to be able to run rainwater into the rivers and process sewage alone in the treatment plants.

This is not exactly news, though, is it? People have done this for millennia. What's the issue for discussion here?

OK I see what you mean. These nodules contain transition metal ions in low oxidation states, apparently, e.g. Mn (II).

Enlighten me.

There are micro-organisms that use sulphate to oxidise carbohydrates or hydrogen to obtain energy for their metabolism, so there are circumstances in which ΔG is -ve for a reaction scheme in which it behaves as an oxidiser, being reduced to H2S in the process. But as an oxidiser for what we would regard as a chemical fuel, not really. Concentrated (i.e. not ionised) sulphuric acid is another story however: that can be a powerful oxidising agent.

This post looks barking mad to me. A giant pot of tea? I don't see much point in attempting a serious answer to this nonsense.

In your previous thread on this subject, the possibility of organic origin was mentioned several times. If the pyrite is of organic origin, you would expect it to contain traces of other materials. If the sample is not a pure substance, you can't expect its composition to be exactly that of a pure compound. It doesn't mean there is anything "wrong" with the chemistry of the pyrite portion of it, just that there are substances present in the sample other than pyrite. I should have thought that was obvious. I don't see anything surprising here.

Sure, though that's a rather different point. Though I suppose that if the denial of abortions mainly affects ethnic minorities, that would explain why it cause huge opposition from the women. In a way the most interesting part of all this is how an issue that was originally only a Catholic position came to be adopted by evangelical Protestants as well.

They look like bits of plants or something. Considering the organic origin of these pyrites, I don't think I would find that surprising. Though difficult to confirm of course, in view of the chemical alteration involving in the fossilisation process.

That's very interesting indeed, about how the Religious Right became a political bloc. However, the way I read it, the article does not suggest the preoccupation with abortion was, or is, merely a flag to mask another agenda. It seems to say that while it was opposition to racial desegregation that originally caused the Religious Right to coalesce politically, it was actually the spike in abortions following Roe v. Wade that made it a key issue for them subsequently. So one can't infer from this article that the current preoccupation with abortion is a smokescreen disguising a racial agenda, it seems to me.

That might fit with what I was saying about an organic origin for the pyrite.

I was wondering that. If states try to make it illegal to travel to another state for abortion, I would expect that part of the state law to be challenged - in the Supreme Court! I don't see, on the face of it, how it can be acceptable to deny people the right to travel, within their own country, to take advantage of differences in law between different parts of it. Are there no precedents from other state legislation that can be cited? Drinking? Gun ownership? Age of marriage?

Jolly good. I'm not sure we ought to be offering to check all your answers, quite apart from the effort it requires (at least speaking for myself). If you've got specific queries, we can try to help with those.

Yes, undoubtedly it seems likely that phase changes play a big role, both due to latent heat effects and changes in specific volume/density.

Not as such, but there are a number of instincts that have the effect of leading to reproduction, the most obvious being the mating instinct that is the basis of sexual attraction. Another is the instinct to form partnerships with a member of the opposite sex, which is helpful for child-rearing. But of course, as we are sentient beings, there is a host of other factors that consciously or unconsciously modify our instincts, and may override them. Now that, in most societies, we can control our fertility, conscious calculations about having children play a predominant role.