John Cuthber

The spam bots have probably harvested your email by now and will send you endless trash. The PM system seems to work perfectly well so I really wouldn't recommend putting your email here. The "lepton" thing is a light hearted way of indicating how much stuff you have posted- "leptons" haven't posted much, "quarks" a bit more and so on. BTW, the lowest oxidation state oxy-acid derived from chlorine is hypochlorous so you end up needing lots of names and prefixes to keep track of them all. hypochlorous/ hypochlorite; chlorous/ chlorite; chloric/chlorate; perchloric perchlorate. I personally think the IUPAC names are ugly, but I can see how they are easier to remember. For what it's worth, the "per" in peroxide means the same as the "per" in perchlorate so the name "perchlorate" is correct. A peroxide contains "more than the usual amount of oxygen"- so does a perchlorate or a persulphate. One could say that persulphate is wrong because it should be peroxysulphate. HClO

The recovery of gold from old computers is often done in very poor countries where labour costs are very low and the environmental impact of the process is simply ignored.

They don't seem to be easy to find out about. This http://www.springerlink.com/content/w60054l7wu642728/ gives some data on the first dye and the last experiment here http://www.mtholyoke.edu/courses/menunez/Chm302OrgIIWeb/Labs1-6.pdf might be interesting too.

Actually, as far as I can see when there's only one possible one they are called -ic acids like carbonic boric and (a bit obscure), silicic but I don't know if there's really a good reason for this- just convention.

My understanding of perfect pitch is that you would be able to connect a microphone to a frequency meter and whistle/ hum "concert pitch A" (without looking at the meter) and the meter would read 440 Hz exactly. Can you do that? Perfect relative pitch is another matter, given the 440 Hz start even I can get pretty close to 880 Hz or 220 Hz (the octave up and down). I'd struggle to do the notes in between the octaves (Hey! I'm a chemist, not a musician)

It looks to me like a matter of definition. "The photon has zero invariant mass " The need to qualify the variety of mass that a photon lacks as invariant implies that there is some other sort of mass (presumably variant) that a photon does have. OK so a photon at rest has no mass. A photon "at rest" does not exist. (Even allowing for "stationary" photons in Bose Einstein condnsates, if it's "at rest" from your point of view it's doing roughly 1000 MPH from mine because I'm on the other side of a spinning plannet.) Can anyone explain why that pair of statements is inconsistent with the assertion that no photon which exists has zero mass? Anyway, the mass or lack of mass of a photon (at rest or otherwise) doesn't matter in terms of answering the question "how can we create a true vacuum (impossible), with something that has mass(that cannot go the speed of light) and go the speed of light (thus a paradox) to accurately measure the speed of light?" We don't need a true vaccuum to measure c. (Though actually I think I may have made a mistake in my answer yesterday; I think you need to plot 1/c vs p and extrapolate to p=0 then calculate c)

A spot of searching for "surface tension" might help you here.

"I think the first one is something simular to an aldol condensation. Actually I'm nearly 100% positive it's related in some manner." I'm pretty certain that it's not (other than that it forma a carbon carbon bond). I also wonder if you actually looked into the chemistry of pinacol. Even a google search on the word might have helped, and I think the 'net's really quite good at that sort of thing.

Is this "Transfusion blood is heated in water, not a microwave oven. Why? Because if heated in a microwave, the blood becomes toxic and more than one patient has died as a result." backed up by any peer reviewed data? If someone died was it due to tocicity or to local overheating causing clotting? Is this just an urban myth?

Actually photons have mass. It's given by E=MC^2 and E=hf. (Energy, mass, speed of light, Planck's constant and frequency) They are atracted by gravitational fields (The effect is usually refered to as "gravitational lensing"). They also carry momentum and exert radiation pressure. There is a cop out on the "nothing can travel at the speed of light" What is forbidden is accelerating anything with a rest mass (ie a mass, even when it's stationary) to the speed of light. Photos have zero rest mass (a slightly meaningless idea since a photon at rest doesn't exist). The fact that we cannot produce a perfect vacuum does not stop us being able to establish the speed of light in a vacuum. That sounds like a paradox, but it isn't. We can measure the speed of light in air at one atmosphere pressure, we can do the same at half an atmosphere, a tenth, a thousandth and so on. Then we can plot a graph of speed vs pressure and draw a straight line through the points. We can carry that line on until it hits the axis for "pressure = zero" and read the value of the speed in a vacuum from that. I hope this answers your question.

ecoli, What aldehyde and what triple bond? The classic method for the first part, IIRC, is reduction by magnesium. Look for stuff about pinacol. I'm not sure abouty the second; perhaps dehydration to the epoxide then reduction?

Try this page (In general, try using a search engine) http://polymer.matscieng.sunysb.edu/OH_handouts/polyFoam.doc.

I think this http://www.mutr.co.uk/prodDetail.aspx?prodID=1194 thing about memory alloys is about as close as you will get.

Quite a lot of chemicals are worth taking the trouble not to get on the skin too. Of course, provided that you don't come into contact with the Br2 it's also safe for experimenting. All chemicals are safe as long as they aren't anywhere near you. (Explosive and radioactive ones can get you at a distance.) Fundamentally, (and this is an important point) there are no dangerous chemicals. There are lots of dangerous things to do with chemicals and for some chemicals there's a bigger choice of dangerous things to do than others, but the danger is a matter of what you chose to do with them- not a property of the chemical itself. A beaker of NH4Br isn't a bigger problem than a beaker of NH4Cl. On the other hand, if I wanted to make some smoke I'd use the chloride unless I had a really good reason to risk the neurotxicity of the bromide (and possibly the carcinogenic bromate too)

I don't think there's enough information to answer the question. As it happens the formula of hydrogen selenide is H2Se This decompses to give H2 and Se. The Se then reacts with the tin I think it will give SnSe- it might be SnSe2 but it doesn't matter because it takes up vrey little space whichever compound is formed. H2Se --> H2 + Se The H2Se and H2 have the same volume because there are the same number of moles of each. However, imagine that you chose H2Se2, the selenium equivalent of hydrogen peroxide. It too will decompose to give H2 and Se (which will be removed by the tin) H2Se2 ---> H2 + 2Se There are still the same number of moles of gas on each side of the equation so the pressure won't change. I'm not sure how stable H2Se2 is- it might not exist (though a web search for hydrogen diselenide does give some results so I think it's real) The point is that it (H2Se2) would give the same result as H2Se. You cannot distinguish the 2 possible formulae by that experiment.

A couple of thoughts. 1 A plane flying in the right direction (heading into the sunrise I think) on the equator is, in effect, on a conveyor belt travelling at about 1000MPH (this conveyor is normally called the earth). This wouldn't make any real difference to its abillity to take off because the air is being dragged along by the earth. Any conveyor that could run under a plane that was trying to take off would drag an enormous amount of air with it. This would create at least some lift. Once the plane starts to rise the friction is reduced. If you raise the belt speed in order to try to compensate for the reduced frictional drag then you will incerase the amount of air dragged over the wings and create more lift. I think that the plane takes off but I wouldn't like to pay for the conveyor or the fuel to run it. 2 Anyone got a vertical take-off plane?

In terms of the LD50 and such the bromides are roughly as toxic as the chlorides but, since bromides are used as drugs acting on the central nervous system, I would sugest steering clear of them.

Since all bromides are toxic I really wouldn't recommend tasting them or inhaling the smoke.

The problem is that, unlike a V de G, it doesn't help you at all. You might as well use a bit of wire connected to the power supply. With a V de G you spray charge onto a belt and the motor drags that charge towards the top sphere- in doing so it has to overcome the electrostatic repulsion between the charges on the belt and that of the top sphere. This means that work is done on the charges and their potential is raised. The current is the same as that sprayed onto the belt by the HT power suuply, but the output voltage is much higher. With an electron beam this doesn't happen so the output voltage is the same as the input.

That mixture of hydrocarbons is fairly good at extracting things from water so, unless you happen to have something very water soluble in it as an impurity, washing with water won't remove the impurity. If on the other hand the stuff is very water soluble then it's unlikely to disolve in the naptha in the first place. Having said that, it looks like you have found a source of pet ether which was the original problem.

Can anyone else see why this "Shellite from the hardware store is generally an ok substitute for backyard extractions" is exactly why this "if you dont trust it's purity wash it with distilled water before use (ie add water, shake, let separate into layers - the shellite floats ... discard water layer from the bottom)" may not work very well.

Yes, if you are eating "the pill". Otherwise the body's feedback mechanisms make sure that the effects are tiny, certainly less than the natural variation in hormone levels from one person to the next. Anyway, the idea that eostrogens make you gay is utter balderdash. Don't forget that all of us, while in utero, were exposed to female hormone levels nearly as high as our pregnant mothers. If that exposure led to homosexuallity then there simply wouldn't be any straight men.

Last time I was doing this I precipitated the silver with sodium acetate and washed off the copper acetate (you lose Ag this way but you can always recover it as chloride). If you want to get the silver then you can heat the acetate carefully so it decomposes. Since the acetate is slightly soluble you should be able to convert it to Ag2O with excess NaOH, wash it then redissolve it in HNO3.

Don't forget that if it looks too good to be true it probably is. IIRC pyruvate is naturally present in the body, created and used up rapidly so adding a little wouldn't have much effect.

Fractals, like those generated using imaginary numbers, are used for data compression which is reasonably important in this www world. I don't know if the particular fractals they use are calculated using imaginary numbers. "I just fail to see how this makes the equation any more solvable. You still can't have the square root of a negative and just because you put an i down doesn't change this." That's a fair point but I think there are 2 answers. Firstly the mathematicians are happy because now they can write down an answer. If they had to keep on making up "strange" numbers in order to answer lots of equations I think they would have given up, but just one weird number i, seems to do the job. The other reason is that ignoring the fact that i doesn't exist and finishing the calculation seems to work in quite a lot of physics. If it makes the equations work, perhaps it must be (in some sense) real.