jdurg

Not really, but there are a few rules to follow. One is that when filling in the electrons only put one electron per side to start out. Treat it like you are dealing cards in a game of poker. One electron (card) per side (person) at a time. Do this until all electrons have been used up and ensuring that all bonds (single bonds, that is) have two electrons there. So you should start out by filling in the bonding electrons first, then evenly dispersing the other electrons.

Did you have any type of flux going with your soldering? Fluxes typically contain some type of chloride or fluoride salt which will readily attack gold at higher temperatures.

I kind of wish I could get a sample of Po-209. It has a 100+ year half-life so it would be keepable as a sample in an element collection. In addition, the lack of gamma radiation means that it could be kept in a glass ampoule and put on display. However, the somewhat elevated decay energy and the process of electron capture and positron decay modes might make it tough to keep a sample at temperature that won't melt the glass. Still, if I had enough money it would be nice to have.

Yes, but wouldn't that put undue strain on the carbons in the benzene ring? You'd have the electrons kind of "squished" on one side of the carbon atom and "free" on the opposite side. As a result, it would wind up wanting to flatten out again and you'd run into that hinderance once more.

Another reason for the difficulty in full ring substitution is steric hinderance. The benzene ring is basically a flat structure and the attachments to the ring will wind up on the same plane as well. As you increase the size of the attachments, you decrease the ability of other substituents to attack the central ring and latch on.

Here we go, step-by-step: 1): Figure out the volume of the Earth's atmosphere. This will let you know how much, by volume, is H2O. 2): Find the density of H2O gas so that you can determine the mass of H2O. You will need to have a starting temperature of the H2O(g) in order to get the proper density. 3): Calculate the mass of water vapor in the atmosphere. 4): Using the enthalpy of vaporization for water, calculate how many kJ of energy it would take to condense that mass of H2O(g) into H2O(l) based on the starting temperature of your gas. 5): Determine how much energy (in kJ) a Capital City uses in one day. 6): Derive the amount of energy used (in kJ) by a Capital City in one hour. 7): Finally, calculate the number of hours the city could run based on the energy you calculated earlier. As you can see, there is still some research and work that you'll need to do in order to get the proper values since the question as presented doesn't provide all the values you need.

Could be that the really easily oxidized metals already had a protective layer of oxide on them which prevented any further reaction.

The solubility won't be altered by the centrifugation. NaCl will dissolve in water if water is present. What you will do is move the denser NaCl solution to the bottom of the vessel and relatively pure water will be at the top. However just like having two different gases in the same vessel, eventually it will all mix back together again.

Corn is a good example of genetically modified food. Corn is simply the result of wheat and other grass plants which normally should not have been able to crossbreed doing just that.

Formaldehyde has been known to be added to various alcoholic beverages because it was VERY cheap compared to the ethanol and apparently the taste isn't all that different from regular fermented beverages.

The classic version of this reaction is taking a pyrex test-tube and putting some anhydrous KClO3 in there. Place this over a bunsen burner until the salt becomes liquid. Then you drop some sugar in there (usually in the form of a gummy bear) and it immediately ignites and burns as the liberated oxygen combusts the sugars.

The metabolism of acetic acid takes some time so some of it does get distributed through the body. Lactic acid builds up during extreme exercise which is why muscles get sore that next day. With alcohol, you get the combination of both as alcohol metabolism results in higher lactic acid concentrations and the acetic acid that builds up takes a bit of time to metabolize away.

Yes, but thermodynamics classes typically have the most interesting and exciting demos.

Beer, as do all fermented beverages, contain a naturally substantial amount of methanol in it. I don't recall the actual percentage, but I believe it's around 0.2%. It is generated in the same way that ethanol is made during the fermentation process. In your body, just as ethanol is dehydrogenated into acetaldehyde and later acetic acid (which causes your muscles to hurt that next day if you've had a lot to drink), methanol is dehydrogenated into formaldehyde and later formic acid. The thing is, ethanol and methanol compete for the same enzyme; alcohol dehydrogenase. Because of the relatively high amounts of ethanol present in fermented beverages compared to methanol, the methanol cannot get converted into formaldehyde before it is excreted from your body. A treatment for suspected methanol ingestion is to administer a great deal of ethanol to the individual. This will prevent the conversion of methanol into formaldehyde. Methanol itself is not any more toxic to the human body than ethanol is. It's just that the liver has a really bad habit of converting methanol to formaldehyde which is horrifically toxic. In brewed beverages you may find methanol concentrations, but you won't find formaldehyde concentrations as there's nothing in the beer/wine/liquor to convert methanol to formaldehyde.

It is, but not every place on earth is full of oxygen. Remove the oxygen and it can't combust.

Exactly. In order to get mercury vapor to give off the REQUIRED UV light to make the bulb fluoresce, you need to have an incredibly low concentration of mercury. This is so that it won't conduct the high voltage electricity but will instead absorb most of it and excite its outer level electrons. This is what results in the creation of UV light. Each individual bulb contains very little mercury vapor. The gigantic, four foot long bulbs do contain up to a few mg of Hg vapor, but the standard light bulb that we all see and use every day contains very little. A one time breakage in a non-confined area isn't going to harm anyone. As I alluded to in my previous post, the massive number that break and/or are illegally disposed of each year to have a cumulative bad effect on the environment. The instance described in this thread, however, is meaningless in terms of acute exposure.

If there was enough mercury vapor in there to be a problem, then the bulb would be useless. (As the mercury vapor would conduct electricity and you wouldn't get the discharge which creates the UV rays which cause the powder on the glass to fluoresce). You only hear about the so-called "dangers" because if you repeatedly dump a large number of these bulbs into general trash then over time enough mercury residue WILL build up to cause environmental damage. A dozen broken bulbs, however, won't do you much harm. The bigger harm is getting cut by the shards of glass.

Formaldehyde is indeed horribly nasty stuff. As a senior (or was it sophomore?) in high school I was in my biology/anatomy class and we were disecting a giant clam. (A clam that is the size of a dinner plate). Anyway, my teacher at the time was a very old school individual. He didn't believe in the new preservatives and didn't feel like replacing his entire stock of specimens. So everything we had was still preserved in high percentage formaldehyde solutions. Anyway, we were disecting the clam and thankfully I was wearing my safety goggles. I was standing near the mouth of the clam (didn't know it) when my lab partner did something that compressed the stomach of the clam. A giant stream of formaldehyde shot out of the clam and right onto my face. At first I was completely stunned. I couldn't believe what just happened. I went over to the sink and used a paper towel to wipe the still dripping CH2O off of my face. I then took my goggles off and rinsed my face in a stream of water and dried it. A little while later, my face started itching really badly and I scratched the itchy skin only to see sheets of dead skin fall off of my face. My skin was bright red and raw for weeks and itched like hell. Thankfully, it never scarred and I wiped all the formaldehyde off ASAP. Still, it was probably one of the worst chemical incidents I've ever had. Also, formaledhyde is why methanol is so toxic. Methanol itself is relatively non-toxic. It's similar to ethanol but will make you intoxicated far more quickly and far more intensely. The problem is that your body metabolized CH3OH into CH2O so you wind up with formaldehyde created inside your body. It is the formaldehyde that goes on to kill you, not the methanol. In all alcoholic beverages there is a measureable amount of methanol. In your body, the alcohol dehydrogenase molecule prefers ethanol over methanol so the ethanol is metabolized while the methanol is excreted. Treatment for suspected methanol ingestion is an addition of ethanol into your system.

Quite true. The alkali metals are only really interesting in their pure form and the various compounds they can form. (All the different oxides and other unusual compounds). Though it is kind of neat using some not so common chemicals to get them to precipiate. Things like Uranyl Acetate being used to ppt Na+ out of solution is always fun because you get to use an organic/metallic/actinoid combination to get a simple alkali to settle out of solution. Right now I'm sitting at work in my office looking at the wall behind me where I have a poster I got printed out of my element collection. (It's basically the same idea as the one Theodore Gray put out, but I had mine done a long time before that but never made it available for sale since I'm using a good deal of photos that aren't mine for the radioactive elements I don't have). Looking at all these elements, it's amazing when you think about how just one extra proton can make an element so completely different. Look at gold. If you add one little proton to gold you go from a comparitively unreactive, beautiful yellow metal to a highly toxic, fairly reactive liquid metal in mercury. Going from fluorine to neon you go from an INSANELY reactive, light yellow colored gas to a completely colorless and completely unreactive gas. Going from Xenon to Cesium you go from a barely reactive, colorless gas to an absolutely insanely reactive, golden colored liquid metal. (Well liquid at just a teency bit above room temperature). The sad thing about collecting elements is that once you've got a sample of everything there really isn't much more to do. I mean, I can always upgrade and I do plan on getting larger samples of thallium, molybdenum, hafnium, osmium, vanadium, germainum, arsenic, zirconium and a few of the lanthanoids, but aside from that I'm done. Perhaps in the future i'll start a collection of element oxides. This will be fairly tough for things like sulfur, carbon and the halogens, but for the regular metals it would be kind of neat. For the really reactive metals I could just get a tiny sample of them and let them react with atmospheric oxygen leaving me with just the oxides.

It's kind of funny how once you get an element collection going and you've finally gotten a sample of everything, it's difficult to point out your "favorite". Every element to me has something about it that makes it interesting, but there are some that are just kind of "boring" because either not much is done with them or they are so similar to the other ones. (I think the right side of the Lanthanoid series is like that). I'm kind of going through a spell right now where I've been kind of observing my elements in "groups". Taking out all my Lanthanoids and observing them. Looking at my alkali and alkaline earth metals. Photographing my radioactive metals or my platinum group metals. I can't wait until a couple of weeks from now when I get to see all of my halogens again. (They are currently being sealed in thicker glass ampoules and then getting placed in a large resin casting as an extra barrier and a way to display them all. Once the resin casting comes back I'll paint the back side of it white to really show off the colors of the halogens).

Still, if you have all the equipment it's easiest to just distill urine and drink that.

Yes, it is possible but where would you find the fuel needed for the fire that would be required to boil the blood? In addition, urine would be readily available and could be used for the water content quite a bit easier since it has a higher percentage of water in it.

After learning that they were made with an NC based material, I had some fun with a not-so-bright buddy of mine. We had a black-out on campus due to a hurricane, and at night I told my buddy that ping-pong balls were filled with methane and made out of an explosive. He had a box of them for some reason but didn't believe me. I remember him going out in the hall and then hearing a big "WHOOSH" and a bright flash followed by some vulgarities and a rolling ball of fire going past the door to my room. The carpet had a nice singe-mark on it from the burning ball. hehe.

It really depends on how the atom rearranges its interior electrons. Some will move an S-block electron into the outer d-blocks to make a more stable outer configuration, while some will not go and do that. (If you look at gold, it takes one of its inner s-block electrons and moves it into its outer d-block to gain more stability. This, as a result, affects the valency that it is likely to form).

Yes, it is very important to understand what boiling actually is. Boiling is when the vapor pressure of the liquid (that is, the pressure of the molecules of vapor that it is constantly giving off) is equal to the atmospheric pressure. A liquid is normally a liquid because the atmospheric pressure around the liquid is higher than the pressure of the vapor that the liquid gives off. This causes the molecules to remain in the liquid. However, there is an equilibrium that sets up between the liquid phase and the vapor phase. There are constantly molecules of the liquid that will escape from the surface of the liquid and form a vapor. As the temperature rises, the number of molecules that have the energy needed to escape the liquid rises as well. Therefore, the vapor pressure of the liquid rises as more vapor is formed. When you reach the boiling point of the liquid, the pressure that the escaping vapor is providing is equal to the atmospheric pressure. As a result, there is no real push against the liquid to keep it as a liquid. The molecules within have enough energy and they rapidly leave the surface of the liquid. If you lower the pressure around the liquid, then you alter the equillibrium of the liquid/vapor relationship and allow more molecules to escape as vapor. As a result, the boiling point drops because now you don't need as much energy to leave the surface of the liquid.