Horza2002

Well obviously yes they can exist...the Wiki article tells you that and give the references which describes the bonds. As it says in the article, these species are normaly observed at reduced temperature; they say dimolybdenum was observed at 7K (-264oC). They are just rare and difficult to observe is all. In chemistry, there are a lot of weird and wonderful molecules that only exist in extremly low temperatures or for the smallest amount of time. Mississippichem, are they more common with the latter metals because the orbitals are bigger and just allow for a better overlap?

Of course, it is not only the use of land required for people ot live on, you also need a lot of land to support the people already there. Modern agricultural technology is an very important today will be in the future so that we can maximise food product from any given amount of land possible. SMF, all lemur said was that people who suggest population control say that the other group of people should be the ones to do it not the people around them; and in the majority of cases I have heard people talk about that, it is exactly true. It makes sence that with reducing resources, that families limit themselves to having one or two children. HOWEVER, you can't force people to only have one/two children (unless you live in China)...you made the decission to only have two children and in my opinion is a valid and good reason...you obviously thought about the future problems with overpopulation at the like. But if another family decide that they want 4 children, then nobody can force them not too. I agree, people should be educated in this area of concern, resources are rapidly running out and so people need to be aware of problems futuer generations are going to face. But as I said, if even given this information, people decide they want more than two children, you can;t stop them.

The reactions you can do will mainly depend on which alcohols you have. You could try these reactions I've picked because they should, in theory, be easy to do without specalised equipment: Dehydration reaction - if you relux your alcohol with the acid (this will require a secondary or tertiary alcohol and may take a while as HCl might not be strong enough, you usually use sulphuric acid for this reaction), you will get an alkene Esterification - so the reverse of one of the experiments I suggested above, have your alcohol and a carboxylic acid together with a catalytic amount of acid Epoxidation - if you have a 1,2-diol you could try and make an epoxide by heating with acid (WARNING: epoxides are very reactive towards nucleophiles are therefore carcinogenic); not sure this will work very well as the water you remove could simply attack the epoxide under the acidic conditions to give back the starting material Acetal - you could attempt to make an acetal by reacting your alcohol with an aldehyde or a ketone (vanilla is a commonly found aldehyde) and a drop of acid Oxidation - you could try oxidisng you alcohols to carboxylic acids. Primary alcohols will go to the corresponding carboxylic aicd where as secondary will go to the ketone. Tertiary alcohols won't be oxidised. I've attached a PDF file showing what could happen. Alcohol reactions.pdf

Well, that is a very broad question. There are literally thousands of dyes and are all based on a different strucutre to the molecule that give rise to the colour. If you look at that wiki link below, it has pages and pages of information about all the different dyes there are: http://en.wikipedia.org/wiki/Dye For an example, I just picked azo dyes to talk about here as I've used some of these before. These dyes usually contain an azo linkage (-N=N-) between aromatic rings to give a highly conjugated pi-system. By subtley chaning the properties of this pi-system, you can alter the colour of dye is. According to Wiki, there are at least 60 different dyes, all with different colours that contain this azo group; ranging from blue all through the spetrum to red. There are also several methods in which to apply the dye to the material as well; reactive dyes that form chemical bonds to the material, dispersion and others. So in anwser to your question, the chances are there is a dye that will dye the material you want the desried colour without you having to mix several together. Also, depending on the functional groups present in the seperate due molecules, mixing them together might not be a good idea as they can react and loose their colour, alter the colour or simple just degrade.

I think its fair to say that it will be a while before these Lilypads are even possible to let alone a plausible for them to be built. I do quiet like the idea of having them as resorts...a floating holiday destination in the middle of an ocean/sea/lagoon could be a good idea...especially for a water sports based holiday.

Angkor Wat is not a city put a temple complex technically...and it has a moat not a floating. Lemur has made a point I had considered before. If the coast line and low lieing land is flooded, then the price of the remaining land will increase...the people who own it will therefore get even richer and would then be able to afford to at least live somewhere as expensive as a Lilypad would be.

InigoMontoya, I see your point that you could spend the money required to build a Lilypad on moving people inland...but there is a limit on how many people you can squeeze into an area. City centres are pretty crowded as it is (at least here in the UK), so trying to force people who have been forced away from the coast into them is just going to cause problems. I do agree though, maybe smaller versions would make for a nice resort to go visit. I do, however, have to disgaree with you saying that it being just a paper study is not progress towards anything. It may only be the beginning of a VERY long process but it is at least the beginning. And it has prompted another plausible solution to a problem...instead of making more people live in less land...why not move them onto the ocean instead. A radically new idea has to start somewhere, even if its just some idea that someones scribbled down on a bit of scrap paper. I do agree though that it would be very ambitious to attempt to try and build one. I've heard about those floating houses before...they seem a good idea, especially when buildings are built on flood plains. They could save alot of money in the long run.

For the first one, think about the chemical reactions that are important to life and what might happen if you start changing the pH of the solution. Enzymes, extent of prononation of amino acids and a whole range of other things are depndant on pH

Ester hydrolysis is an esay experiment to do. Simple get an ester, stir it with hydroxide overnight and then work up the reaction. The work up should be easy and you can seperate the resulting acid and alcohol very easily simply by washes. For this experiment you would only need a flask, two containter, hydroxide and some organic solvents. E.g. Do the reaction and after it has finsihed, add a lot of water. Extract with an organic solvent and you'll have seperated your alcohol out. Now acidify the aqueous layer and your carboxylic acid should either crystalise out of the water or form a gum that you can then extract with another organic solvent. Another simple experiment I did as a 1st year undergraduate was extract natural product from nutmeg and extract citric acid from orange's. Heres what you could do to isolate citric acid. Basically, you deprotonate the citric acid with Calcium hydroxide to give calcium citrate. This is soluble in hot water but not in cold. So you add the calcium hydroxide to hot orange juice in water, then cool it down with ice, filter it and you'll have calcium citrate. Once that is done, dissolve the calcium citrate back up into hot water, add a dilute acid that will give you citric acid and calcium sulphate (which is insoluble and you can simply filter to remove) and this will leave your citric acid in the water which you can then evapourate to give you citric acid. If you cant to check the purity, the melting point of citric acid is 153oC; the closer you are to this value, the purer your sample is.

To be honest, you shouldn't use ChemDraw to name your compounds. We have three versions of ChemDraw here and each one gave a different name for each of the compounds. And ChemDraw is far from perfect.

Thanks for that Sisyphus. I guess there would have to be some kind of desalinisation system on board...it would make sence if it just took water from the ocean it was on, cleaned it up and then people wud be able to drink, wash, etc with it as well. I like that idea...have several of those cities spread out, say in the Atlantic, like islands that you simply went between each of them to get across. Although, that would be an extremely expensive way to do it...I can;t image builidng one of those things would be cheap...I wonder how'd you'd pay for it? I assume tax the people who live on it as you would anywhere else I guess. Wasn't there talk of being a rail network built under/through the Atlantic at one point to connect America with Europe? Maybe that was another idea I've seen about getting people around the world.

It appears that america is following the way of most of Europe. There has been a downward trend in churches for a while now. I guess though, people still have their beliefs but don;t go to church/active in the ideas anymore. This could be the future for religion.

While reading this article about the potential for building floating cities (http://www.gizmag.com/lilypad-floating-city-concept/17697/), I was wondering if there is any research into floating structures for people to use?

What is related to the wavelenght of a photon?

Yes, if a quantum system is unobserved it is a superpsoition of all its possible states......however, you are NOT a quantum system. Once you leave the atomic scale, quantum effects begin to become far less important until you get the microscopic level where they are no longer used as the effects are immeasurbly small. And just because you are not observing yourself, doesn't mean you are not being observed by something else. And of course you atomic structure exists...if it didn't you'd cease to be at all! Your atomic structure can't just disappear!

It is much much MUCH better to learn the currly arrow mechanism than using abbreviations. If you want to do a degree in chemistry, at some point you are going to have to learn to do curlly arrow mechanism at some point so I'd learn it now, while its easy, before you have to think about all the other things as well. I have also had the moment in exams, not being able to remember the mechanism and just playing around with the arrows until I got something that worked.

Yer, I often use the handheld UV light (my compounds containg a pyrrole that shines quiet nicely). And the old school technqiues are sooo cheap as well! In out lab, a 200ml permanganate stain last 4 of us about 2months using it everyday! I have often found using a variety of the stains is amazing for analysising the reactions. Especially amide coupling reactions...get a general permanganate stain to show all the spots, then ninhydrin to see if your starting amines presnent, then Bromocresol green to see if you acids still there. One of the best stains I've found is the DNP one...the plate is stained yellow while aldehydes and ketones change colour...but go a different colour depending on their identity...aldehydes and unconjugated ketones are orange, conjugated ketones are dark orange/red, benzylic ketones are red/pink.... I should also note that there are hundreds of other stains that can be used that selectively show a specific group (I've used one that only stains primary alcohols over secondary ones) but the link is to the commonly used ones

There are many more classes of polymers than just those two...and it does depend on how you want to class a polymer. If you go with physical properties then thermoplastics and thermosets are good catergories; if you go by composition then you can copolymers, monopolymers; if you go how the polymer was formed you can have radical, living polymerisation, anionic, metathesis; you could also class them according to their functional groups poly-esters, poly-amides, poly-sulphonamids etc. It all simply depends on what you want to class them into

What evidence do you base this idea on? You can't just come up with an idea if there is nothing before it leading you to this new conclusion. Yes, while dreaming, you do think it is reality...until you wake up and realise it was a dream...

Its easy to forget the humble TLC when faced with todays analytical equipment (LC-MS, GC-MS, etc). To this end, I though it would be useful for people to have access to the range of stains that you can use on TLC to reveal a whole range of functional groups. Even now, doing a PhD in a department with plenty of analytical machines, TLC is still usually my first port of call when analysing a reaction mixture. http://pcwww.liv.ac.uk/~jxiao/TLC%20Stain.pdf

Every cell in your body (brain cell, muscle cell etc) has exactly the same set of DNA as all the other cells...what makes them different is which genes are "turned-on" and which are not. In this case, the proteins that are formed control the properties of the cell and what it will do etc. And as NTettamanti said, the Human Genome Project identidifed several thousand genes and what theire role in the human body. With respect to eye colour, there are several different "kinds" of the gene that code for eye colour; called allele's. The different eye colours that you have depend on which allele's you recieved from you parents.

If your looking in a molecule that only has one carbonyl (be it an aldehyde, ketone, ester, aminde, etc) you normally just refer to it as the carbonyl group. However, if you have more than one group in your molecule (as it typical in undergraduate organic exam questions normally asking you to pick between the reacive of a cetome over and ester type), I would then be specific about which carbonyl your talking about (i.e. the methanol attacks the ketone and not the ester). In several PhD thesis I have read, it is simply refered to as a carbonyl group, so I'm sure that is an accept way to talk about them.

Yer I've used SeO2 to oxidise a benzylic position before...thats how I know its really bad for you. Im sure that the safe concentration of selenium is pretty low even though it is essential for healthy biological functions. Its used in some very rare amino acids selenocysteine (used in some enzymes) and selenomethionine.

Arr yes, thanks I Me. That is what I was trying to say but you've managed to say it far better than I did!

I'd like to reenforce what Mississippichem has said, the useful window of a selenium is pretty small. I'm not sure what happens to selenium once you ingest it, but if it acts as an anti-oxidant, then I'd be very worried about the build up of selenium dioxide in your body. http://www.sigmaaldrich.com/catalog/DisplayMSDSContent.do The general message from the MSDS is that selenium diozide is very toxic. There are some vitamins that are actually very very toxic if you have them in high enough concentration. For example, Vitamin A is extremely bad if you manage to exceed your livers capability to deal with it. In addition to causing extensive liver damage, it is really dangerous for unborn children (obviously only applicable if your a woman). http://en.wikipedia.org/wiki/Hypervitaminosis_A