John Cuthber

People do inhale hydrogen. http://en.wikipedia.org/wiki/Breathing_gas With clean hydrogen and proper precautions it is safe.* I'ts also pointless; stick to helium if you want to sound like Donald Duck, or better yet, don't bother. * This is "safe" in the rather unusual sense of "less risky than oxygen toxicity or nitrogen narcosis", rather than the usual meaning.

"I too am interested in this (the soda lime is no where near basic enough to abstract a proton from toluene, unless I am mistaken?). " So what? the reaction doesn't involve toluene, its the decarboxylation of benzoic acid that gives benzene. The hofman degradation would convert benzamide to aniline, potentially a useful reaction, but not for making benzene unless you want the trouble of diazotizing it the reducing that .

I think you have rediscovered photosensitisation. You can indeed produce singlet oxygen with visible light and a dye. The dye absorbs the light and forms an excited state. This then transfers energy to an oxygen molecule and promotes it to the singlet.

"Would it be at all possible that the sodium carbonate would react with the calcium hydroxide in the concrete thus forming sodium hydroxide again? " Yes, and no. If there wre any exposed (CaOH)2 it would have been converted to CaCO3 by exposure to CO2 in the air. With very fresh lime mortar there might be enough Ca(OH)2 to convert sodium carbonate to the hydroxide but it wouldn't last anyway.

I'd probably call the one in the middle a bead. The point is that if you were to thread the bead/ ring/whatever else you might want to call it onto a tight fitting string then it would hide six inches of that string.

It's not a reduction, it's a decarboxylation. The classic method is to heat with soda lime. RCOOH--> RH +CO2 In principle, there's another way, react it with a strong lewis acid catalyst and a little of a methyl halide like CH3Br and AlBr3 You get a series of friedel crafts type reactions which are reversible. If you fractionally distill the mixture slowly you should get benzene and a whole bunch of dimethyl and trimethyl benzenes etc left behind. I don't know if this has ever been used as a synthetic method.

Oops! I should have spotted that too.

It may just be me, but I think if you are going to talk about a "proper equation" you shouldn't have fractions in th coefficients.

"Transpiration is the process of loss of water from the aerial parts of the body in the form of water droplets." No, it's not. http://en.wikipedia.org/wiki/Transpiration Gutation is the process of forcing out water as a liquid (here's a nice picture as well as some text) http://www.darklightimagery.net/52-6.html Transpiration is losing water as a vapour. "Animals have just two nostrils or pores because the concentration of oxygen was quite high when they appeared on land." Er, no again. Numerically, most animals are insects, which generally have a large number of pores called spiracles for breathing. http://en.wikipedia.org/wiki/Spiracle We humans also have a vast number of pores for sweating (I believe humans are some of the sweatiest animals on earth) but they couldn't do the job of keeping us supplied with air. It's a safe bet that different plants have vastly different transpiration rates that suit their environments. Xerophytic plants, in particular, would have slow rates of water loss. Many plants are able to actively control the rate at which they transpire by opening and closing stomata, so it's hardly as if they have some fixed rate and have to put up with it.

Interesting question this. There have been various points put forward along the line that, if it's lying it's unethical. Personally I think that's debateable (lying about the monster in the lake to stop your kids drowning might be perfectly ethical if that is what keeps them alive, please don't start to debate that here) but I'm not sure it's always relevant. Another point made was "The problem with the placebo effect as treatment, is that for it to work, the patient can't know it's a placebo effect. " Again, I'm rather unconvinced. When I get a sore throat or cough I take cough medications that I know don't work better than a placebo in clinical trials. I'm well enough qualified as a chemist and a pharmacist to fully understand that result, just to make it clear, here's the edited highlights. It means I'm taking a medicine with no real effect, and I know it. However I also know that the placebo effect is much stronger than most people give it credit for, so I believe (and God knows how you would test this) it gives some relief from symptoms. Is it ethical for me to do this?

"Despite what John Cuthber says, in my example the cylinder is 6 inches deep (not zero), and 6 inches wide, so that the entire sphere would be contained in the cylinder. If that seems wrong to you, imagine a sphere infinitesimally larger than 6 in diameter, so that there would be an arbitrarily small ring and endcaps left." If you put a drill through something at least one of the "endcaps" is removed; generally both. Without the endcaps what you have is an arbitrarily small ring which isn't six inches high. I accept it's a sloppy definition, but I'd usually think that if someone says they put a cylinder through a point (like the centre of a sphere) they meant the axis of the cylinder went through the point. The reason I'd think that was that otherwise, it doesn't really tell you much.

No it won't. The potential difference is large enough but an electron set free will be acelerated over a short distance before it hits an air molecule. It won't get to cover the whole distance from 1.1MV to ground so it won't get that much energy. You would need to put the voltage across a vacuum tube to get a high enough energy to generate antimatter. Even then you would need to get the right sort of collision to get antimatter.

NH3 is ammonia, NH2OH is hydroxylamine NH4OH doesn't really exist, but it would be ammonium hydroxide; NH3OH is nonsense.

I think that saying you drill a six inch long hole in it already says the shpere must have been more than six inches in diameter; explicitly saying so should be redundant. and thanks, btw to Mr Mongoose for doing the maths. And, for Mr skeptic's benefit "Perhaps you can tell me what part of the problem forbids my solution?" The fact that a cylinder of zero height is not a cylinder with a height of six inches as specified in the question. (I'm sure I mentioned that before.)

"You should mix something with nitric acid" Why?

Since the length of the cylinder is specified as six inches "A six inch high cylindrical hole" your idea, a cylinder of zero length, is excluded so it's not a valid criticism. I read the book so I won't tell you what the answer is but I can assure you it exists and is unique.

You mised a few zeros too.

OK, In the first question the measured pressure is 740mmHg but that's a mixture of water vapour and oxygen. The table at the end says that the water vapour is 23.76 mm so the true pressure of oxygen is only 740-23.76 ie 716.24 mmHg So you really only have 155 * 716.24/740 =150 ml of oxygen measured at 740mm. Does that help?

I'm an atheist; it doesn't stop me taking holidays- after all most of the predate Christianity anyway.

The annoyoing answer is probably "it depends". If there is a lot of plant life in the water then the area will have more oxygen. If the water is stagnant and dead then there will be less. It's possible that some bodies of water will change depending on whether the sun is shining.

Blah Blah toxicity blah blah berylium in old phosphors blah blah safely blah blah accept no responsibillity blah blah. But that should work. BTW, I don't represent ebay or the seller here but http://cgi.ebay.co.uk/anti-static-Heavy-Duty-Darkroom-film-changing-bag-58X61_W0QQitemZ280192119957QQihZ018QQcategoryZ29993QQssPageNameZWDVWQQrdZ1QQcmdZViewItem will let you use ordinary film which is fast and cheap.

It's difficult to know without seeing what you did. I think that not taking account of the volume would make a difference about that big. If you add 75ml of NaOH soln to 1 litre of Acid you end up with 1.075 litres; if you forgot about that and just assumed a final volume of 1 litre I think the difference would be about that big. On the other hand, I guess it's easier to ask whoever set the question.

The energy, I can calculate (and are you sure about the value of 932MeV? It seems rather high). The rate of transfer of energy, ie power as in the original question, I don't know.

I really don't think the lengths of the words will help you. They seem to have been bunched into five letter strings (except at the ends of sentences).

Such cynicisnm in one so young. I just wonder how they got on when the people realised that the judge had just officially declared April 1 to be a public holiday. Do you think the employers might have been a teeny bit upset?