John Cuthber

Do you understand that smoke rises?

How much does the atmosphere of Paris weigh? Here's a hint; atmospheric pressure is 14.7 pounds per square inch.

It's important to recognise that smelters were exposed to lead fumes 8 hrs a day, 5 days a week for years or decades. The one-off exposure of Parisians (residents and firefighters) would be less of an issue. So, you need to look at the vapour pressure, the dilution, the acceptable concentration and the duration to assess the risk. Enjoy.

Plausible denial.

Well, you can use gas filled tubes as voltage regulators and also as transient suppressors https://en.wikipedia.org/wiki/Voltage-regulator_tube https://en.wikipedia.org/wiki/Transient_voltage_suppressor

Apparently, he thinks not.

Nor can I, but I can quote you.

Unless they carefully say otherwise, you can assume they are working with aqueous solutions. Why would it form NaCl? All the chloride ions fall out of solution as AgCl. Otherwise, you seem to be on the right track.

Once in 800 years or so, the sprinkler saves the building. How often does it go off by accident and destroy priceless artifacts?

OK [Makes note in diary for the year 2819]

Nobody had.

Unless it's the right sort of vacuum cleaner (and domestic ones are not) then all that does is move the dust around. https://www.toolstop.co.uk/blog/m-class-dust-extraction-why-you-need-it-and-what-it-means/

So, it would rain across Paris, but not actually put out a fire. Let me know how that helps. Thanks. Maybe I'm biassed, but I think that the essential reason for the whole existence of analytical chemistry is that you can't tell what compounds something is made of by looking at it. You can, I guess, rule out the bright red forms of Pb3O4. I have seen similar smoke from a garden bonfire burning plant waste. I'm pretty sure that the lead content was sub ppm. When helicopter type drones were first invented one of the more interesting uses I heard of was flying air sampling kit through plumes from fires and chemical leaks. Unless someone did that near Notre Dame, we will never actually know what was in the smoke. It's pretty much pointless to speculate. I will make the observation that lead melts when hot and tends to run down into the ashes of fires. I'm interested to see the suggestions that it should be rebuilt with modern materials- at least in part for safety reasons. As far as I can tell, the important thing about old buildings is that they are OLD buildings. If you replaced the cathedral with a modern titanium clad skyscraper you wouldn't have Notre Dame any more. Why not use fire retardant fibre glass resin. You can make that any colour you like. Perhaps part of the cost could be recovered by having advertising painted on it? Or we could do the best job we can of restoring the original. Call me old + grumpy, but that's what I'd prefer. The building has been there for something like 800 years. and (at least according to wiki ) has only caught fire once. That's not a bad safety record. The people who were playing the exciting, but dangerous, game of speculating ahead of the facts were all saying it was caused by hot work near timber. Not a bad guess, but, it seems, wrong. The latest reports are blaming an electrical fault. How does that sit with the idea that we should make it safer by adding modern stuff? My understanding, from talking to professionals who, for example, investigated the Kings cross and Grenfell tower blazes can be summed up as "Fires do exactly as they damned well please".

Srsly? That's the sort of thing Trump would say. That question is " in Seine "

That's right. And one component of the mixture that makes up a lemon is a volatile liquid which give the odour.

No beer; no bacon. No thanks.

Physiotherapy, psychotherapy, surgery, radiotherapy, phototherapy, Extracorporeal shockwave therapy. Infrasound therapy, music therapy, ice packs, hot water bottles, pets, And, of course, death (Not a favoured choice, but a common one in the developing world) If you are considering 'flu, it's important to recognise just how poor the drug therapies are. Most people get 'flu, so it's a modern health disorder. But if you could magically cure every case with a single tablet, it wouldn't make much odds to human longevity. However, if you are looking at "cause of death", infections are pretty low down the list in the Western world (well- sort of- we don't really know to what extent the microbiome affects things like obesity and cancer risk).

OK, so is a lemon a mixture or a compound? Is polypropylene a mixture or a compound? The reason you can smell a lemon is that one component of it is limonene which is a volatile liquid (with a characteristic odour). ( For the benefit of those who want to complicate things: Yes, I know it's more complex than that but, let's stick to the basics for now)

Do you know the difference between a mixture and a compound?

It never was "death", but it is dead; and it has been since the Michelson Morley experiment about 130 years ago.

The same OP seems to have been posted on at least half a dozen websites. As far as I can tell, that result comes from here https://iopscience.iop.org/article/10.1088/1367-2630/aa7e73 where they report on having 30,000,000 antiprotons stored If you reacted those with normal protons you would get energy equivalent to the destruction of twice that mass of matter. If I have done the maths right (and not lost track of all the zeroes) it's 5.4 mJ Roughly the energy released if I drop a paracetamol (acetaminophen) tablet as I take it out of the package (while standing up). We are not launching spaceships with it any time soon. On a tangentially related not, that paper also wins the understatement of the year award. " the lifetime of the proton has been one of the subjects of investigation. In direct measurements stringent limits up to a have been derived, .... However, experimental limits on the antiproton lifetime are much lower. " Yes. The estimated life of the proton is at least 210000000000000000000000000000 years The estimate they have published based on this work is 10 years, two months and ten days. which is indeed, "much lower".

I think some wrestlers would object to that. They have relevant skills and training...

Fundamentally, polypropylene is not volatile. Anything you can smell is, therefore, an impurity. So the question is "what impurities have been introduced to this particular piece of polypropylene?". To which the only scientific answer is "your guess is as good as mine.". If you don't like the smell, leave them outside until it dissipates, or contact the supplier and take it up with them.

"Recent searches reveal that polypropylene may release two highly toxic substances, quaternary ammonium biocides and oleamide." No they don't. How can something made entirely from carbon and hydrogen release something that contains nitrogen?

How can we possibly know if your mum's judgement on this is correct? No. It does not. It can't. Polypropylene does not contain nitrogen but "quaternary ammonium biocides and oleamide" do. How do you know what propylene smells like?