exchemist

Yeah but how are you going to get Cr (0) up to Cr(+6) without a strong oxidising agent? Salt water and a bit of atmospheric oxygen is never going to do that, surely, is it?

A yellowish tinge would be consistent with iron, certainly. I would not expect any health concerns. Iron itself is not a problem and I would have thought the makers of cooking pans would avoid any alloy components that might give health issues if they were to leach out through corrosion. The main other constituent of stainless steel is Cr. It seems to be Cr +6 that is hazardous, but the product of any corrosion due to salt (NaCl) will be lower oxidation states that are apparently not a problem. I found this link which may provide some reassurance: https://bssa.org.uk/bssa_articles/does-the-chromium-in-stainless-steel-contain-chrome-6-cr6-and-is-this-a-potential-health-hazard/

A "jar of pure electrons" would mean an accumulation of -ve charge. You can do this to some degree with something like a Leyden Jar, in other words a capacitor. And you can use those to produce an electric discharge, which involves an arc. But you would not use the photoelectric effect for that, I don't think. You would need something that can "push" the electrons together, against their mutual repulsion, in other words a high voltage. You won't get that from the photoelectric effect.

Not hydrogen atoms. You want a conducting solid material, such as a metal plate, because the idea - at least as I recall it - is that with light above a certain frequency a current flows in a circuit, due to the emitted electrons, whereas below that frequency it doesn't. The experimental setup to "catch" the emitted electrons is shown in this diagram from the Wiki page: https://en.wikipedia.org/wiki/Photoelectric_effect#/media/File:Photoelectric_effect_measurement_apparatus_-_microscopic_picture.svg You can certainly ionise hydrogen or other gases with light with energy above the ionisation energy for the gas, but this is not what people mean when they talk about the photoelectric effect. As for capturing and containing them, you will struggle because they will repel one another and a bulk -ve charge will accumulate.

There is a useful article here about the care needed when interpreting raw numbers from VAERS: https://www.ibtimes.com/over-900-died-after-receiving-covid-19-vaccine-experts-say-data-misinterpreted-3153820 So the answer I think is no, they have not been investigated for possible causality, nor are there necessarily grounds for doing so. By the look of it, it may be the old post hoc ergo propter hoc trap. It seems quite hard to find the data you are looking for viz. the risk of fatal side effects of the vaccine in fit and healthy under 30yr olds. I have been able to find the relative risk due to the virus of death, hospitalisation by age bands in the US, but this does not filter out the fit and healthy from the others: https://www.cdc.gov/coronavirus/2019-ncov/covid-data/investigations-discovery/hospitalization-death-by-age.html I suspect that, for the cohort you are interested in, the main issues will be (i) the risk to them of Long Covid from the virus, and (ii) the increased spreading of the virus in the population by this group if they are not vaccinated - and hence the potential for further variants to arise. I also suspect we simply do not have data on all this, given that the disease has only been with us for 18 months and given the huge number of variables, e.g. there are more than 5 vaccines in widespread use, there are half a dozen variants of the virus, all with their own characteristics, etc. The only further thing I can contribute is that, in the UK, people under 30 are recommended not to have the Astra/Zeneca vaccine but one of the others, due to the low but finite risk of blood clots. I would think the same applies to the Johnson & Johnson one, as that, I gather, uses similar technology. So Pfizer and Moderna seem to be fine for younger people. And by being vaccinated you do your bit for society by stopping the spread and reducing the chance of further lockdowns due to new variants. Plus you avoid the risk of long Covid, like my 25yr old nephew, and which I myself have had a brush with, as a fittish 65yr old.

Unaccountably, this film does not seem to been reviewed in Nature.😁 I did find this: https://www.imdb.com/title/tt2124189/?ref_=fn_al_tt_1

Can you provide a reference to somebody authoritative who says this? It is not my understanding of how this machine works.

Why do you think they should have been carried out in theory? In theory, surely, a Wimshurst machine will work perfectly well in a vacuum, won't it? I can't see that it relies on the atmosphere in order to function. Or do you see it differently?

I don't think anyone says dark matter is incomprehensible. In fact there is a fair amount of work going on to enable us to comprehend it. It seems to be an unknown form of matter, but that doesn't make it incomprehensible.

Suppose the trouble with that is that YOU then get death threats, from blokes with beards and MAGA hats!

Could be the latter if the rate of generation of new variants exceeds the ability of vaccines to keep up. We are years from vaccinating the whole population.

I'm not sure about citric acid. With free amines you may get ammonium citrates I suppose, but then you would have got ammonium acetates with vinegar. I've a feeling whatever is creating the odour - and it may not just be amines - may have penetrated into the plastic. Some of these things smell very strong so your nose may detect even traces. (I once had to get rid of an old fridge that had failed 6 months previously, with some frozen shellfish in the freezer compartment! It was in a family holiday house on an island in Brittany, that was not used in the winter months. I had to talk to myself about the chemistry of amines all the time I was cleaning it out, just to avoid gagging.)

Well, actually, checking homework is not my absolute favourite pastime....... This all looks fine to me. You are not doing a reaction with an excess of one of the reactants here, so don't worry about that. I assume from your comments at the end that 2.68 metric tonnes of coal is burnt per person per year in your country. I assume this is the US, as you have had to convert to the old Imperial units at the end - something we gave up in Britain when I was at school in the 1970s. And yes you have one mole of carbon reacting with one mole of diatomic oxygen molecules to make one mole of CO2. My only comment on your working is that you may find it better, soon, to start getting used to standard form (exponential or scientific notation) to express the numbers, to get rid of all these zeros which can become easy to miscount. So 2680kg = 2.68 x 10³ kg = 2.68 x 10⁶ g. But maybe you have not come to that yet. You seem to know what you are doing so have confidence in your other calculations. I expect you have got them right.

Well of course they are not tetrahedra. They have a square base.So like any square pyramid they have 5 sides. A tetrahedron has a triangular base. But this film is worthless. I quote Wikipedia: "The Revelation of the Pyramids (French: La révélation des pyramides) is a conspiracy theory pseudo-scientific documentary directed by Patrice Pooyard and released in 2010."

I suspect some of the hydrocarbon-soluble species, perhaps amines etc., have become adsorbed or even partly dissolved into the plastic material. I've always found this sort of thing very hard to remove. You may have to get a new one. Or you could try leaving it out in the sun for a month or something, to see if sunlight can break down the odour-creating species. But I don't have any suggestions for a quick fix if you have tried both ozone and chlorine based bleaches...unless possibly hydrogen peroxide might help. But I'm just guessing.

I'm not expert on this but don't you need to do some geometry to work out how the path length changes with the off-axis distance of the sound reflector. As the reflector moves in towards the axis and this distance decreases, the difference in path length will decrease so your receiver will encounter successive maxima and minima in the sound, as the direct and reflected beams reinforce or cancel. (The reflected sound will be phase-shifted by π as well, I think.) Unless I've misunderstood the scenario.......

OK, so you maintain they did know π, contrary to what most Egyptologists say. That's fine, I just wasn't clear what you were saying earlier.

Looks OK to me. Just remember the -1 superscript means "per" whatever the unit is. You may find if you rewrite it as a "/" it is easier to see what cancels. And try not to just follow the formula you have been given mechanically, but think what you are trying to do, i.e. the number of moles in a certain volume of solution and then then the number of grams that corresponds to.

I agree it seems a strange* question in some ways but I found this which seems to help: https://www.thoughtco.com/definition-of-conversion-factor-604954 So it says a conversion factor is between different units for the same quantity. In the case of the mole, it is a unit for numbers of particles, expressing them in more convenient form for use in chemistry, so I think I would agree Avogadro's number can be considered a conversion factor. But grams to moles?........ *actually damned silly , in my view. What's the point of tripping students up with pedantry like this, that has no impact on their understanding of physical science? Just puts students off, in my view. But don't tell anyone I said that.

Again you refuse to address the simple case of you jumping in the air. Until you do so, there is no point whatsoever in moving on to more complicated systems that are more challenging to analyse. I suspect @swansont is on the money when he refers to the Gish gallop. You did the same thing on the previous thread. Whenever we got to a position in which you had no option but to understand what we were saying, you switched the subject by introducing a new aspect, to prevent us bottoming it out properly. I don't know whether you do this deliberately, as a form of trolling to wind us all up here for your amusement, or whether it is a psychologically motivated thing you do without being aware of it, because you can't bear to face the fact that your ideas are wrong. You've been at this for around a decade now so I would not be surprised if it is the latter. If you want, you can go your grave believing your have proved Newton wrong, but guess what will be your epitaph. So can we please sort out what happens when you jump in the air, then we can apply that to the vibrating ring and then we can see what is making it move on the table? In that order. Otherwise, I'll assume you are not interested in analysing your experiments properly.

mol/litre x g/mol DOES cancel. And gives you an answer in g/litre. Which actually is OK since you've been asked to work this out for a litre, i.e. on a per litre basis. But in fact, to be pedantic, I asked you to consider how many moles there would be in one litre, the answer to which is "0.025 moles", not "0.025mol/l". So you can plug that into your equation, can't you? You've nearly got this, so don't fall at the last fence. Have confidence!

No dice. I am still trying to get you to be clear about what happens when you jump in the air. So far, you are not managing even that.

OK, so does that mean you recognise your body, when you jump into the air, is not an isolated system? And that, when a system is not isolated, internal forces can cause it to move?

Because, unlike you, we like to get one thing at a time straight, instead of continually lobbing in yet more complicating factors in order to obscure the analysis of the problem.

How can the centre of gravity of your body move, just by the action of internal forces? Haven't you spent the last fortnight telling us Newton's laws say that can't happen?