jdurg

Doesn't count. If you go by that criteria, then I'd say element 119 or element 120 because there is a chance that at one point in time one or two atoms of those elements were created but weren't detected. Therefore, they would be considered "the rarest". In reality, any element that occurs, or can occur, due to natural processes on Earth are considered as possibilities for rarest. Francium currently holds that title since its half-life is so short that even if it were created in bulk you'd never have a large amount of it. Astatine, at least, has an 8-hour half-life so you could theoretically generate a large amount of it and refine it before it decays away. With francium, you just don't have enough time. Some of the trans-uranic elements fall into the rare category as well since only a few trace samples of them have been found on earth due to natural radioactive processes. However, because of all the radioactive fallout caused by nuclear weapons testing and research you can never be sure if they were created by natural methods or because of man.

Well, perhaps dwarfs and babies should be kept out of the area as SO2, as well as Cl2, are fairly dense gases and will tend to hang out in low-lying areas.

Well, first off I realize that the "eka" designations given by Mendelev were for the elements directly BELOW discovered ones and not next to. Secondly, the intention of the eka designation is to denote that an element does exist, but you haven't found it yet. Eka-ununHEPTium would be indicative of an element AFTER, or BELOW element 117, not element 117 itself. Therefore, I am completely correct in my earlier post by stating eka-ununHEXium even though that designation is inherently off. The actual name for element 117 right now should be eka-astatine.

I think we're also still awaiting element 117 to be conclusively discovered. I think the discovery was breifly mentioned recently, but they were unable to reproduce their results so it was withdrawn. I guess for now we'll just have to call it eka-ununhexium.

Actually, we can use a real example of a question like this. Let's say we have a room that is 8 feet high, by 10 feet long, by 14 feet wide. There are 0.3048 meters in one foot, so converting to metrics your room is 2.4384x3.048x4.2672 meters. This is equal to 31.7149 cubic meters. 0.001 cubic meters makes up one liter of volume, so your room has a total volume of 31,714.868 liters. That's a lot of volume. So how many grams of hydrogen at one atmosphere would it take to fill that room up if the hydrogen was an ideal gas and the temperature was 80 degrees Fahrenheit? The first step here is to write out the ideal gas law. PV=nRT. You have the volume (31714.868L), you have the Pressure (1 Atmosphere), you can find the ideal gas constant (R=0.0820574587 L · atm · K-1 · mol-1), and you have the temperature, though it needs to be converted into Kelvin (80F). To convert to Kelvin, you first convert to Celcius and then add 273.15. So to start, you subtract 32 from your Fahreneheit value. 80-32 = 48 Now take this value and multiply by 5/9. 48(5/9) = 26.67 Now take this value and add it to 273.15 26.67+273.15 = 299.82 K. You now have all the values you need to calculate the number of moles of H2 gas needed to fill your room! (1)(31714.868) = n(0.0820574587)(299.82) n = # of moles = 1289.09 moles of gas! One mole of Hydrogen is 2 grams, so you would need 2.57818 kilograms of hydrogen gas to fill up your room.

Remember, if you're using the Ideal Gas Law, ANY gas takes up 22.4 liters of space if it is ONE MOLE of the gas. Doesn't matter if it's an uber heavy gas, or something like hydrogen. One mole of gas at STP takes up 22.4 Liters of space according to the Ideal Gas Law.

You could also do something such as "You have 10.7 liters of SF6 at 45 Degrees Fahrenheit. If the sulfur hexafluoride was decomposed into its elements, how many grams of sulfur and how many grams of fluorine gas would you have. In addition, how many moles would this be?" This would be quite difficult as you have to deal with gas density, the fact that sulfur and fluorine aren't simple one atom molecules, and converting Fahrenheit to Kelvin.

Silver will always be contaminated with copper. They are in the same column in the periodic table so they have somewhat similar chemical properties too. In addition, just the tiniest portions of copper ions in solution will provide a blue color. So while the coloring may be slightly blue, that doesn't mean that it is a very high % of copper.

I'm not stating that the reaction itself is simple, but the equation itself is a simple double replacement reaction. I was a bit confused as to what was actually being asked.

What are you confused about? It's a fairly standard reaction equation.

Please don't flood the message boards with the same question. Your post in the regular chemistry forum is good enough. It will eventually be answered there. This thread will be closed.

All I know is that chocolate does a damned good job of removing garlic breath and onion breath, and that it tastes damned good too.

Almost. If you have 6.25 moles of methane then you have 25 moles of hydrogen since each mole of methane has four moles of hydrogen. (6.25x4=25). Therefore, you have 25 grams of hydrogen in your sample. The other 75 grams is carbon.

Correct. Calcium Carbonate would be written as a solid reactant and not as an ion.

Here's some help. Bleach is a mixture of NaOCl and NaCl in water. Vinegar is CH3COOH (Acetic Acid) in water. When you mix an acidic compound with bleach you get a mixture of HOCl, and Cl2 along with NaCl. When Cl2 mixes with water, you get a mixture of HCl and HOCl and dissolved chlorine gas (Cl2). Steel wool is comprised of Iron Metal (Fe). So knowing what components you're mixing and what their products are, you should be able to come up with the reaction that takes place.

I think the Cl2 will also react back with the water a bit and form some HCl. Granted, it won't be a whole lot, but I think it would be enough to be noticeable in the overall, messy reaction.

It's freaky, isn't it? I didn't know what it was at first, but thinking back it was way to small to be a kid. The problem was that the sun was right in my face so I didn't get a good look and just had to go on instinct. I figured swerving to the side of the road would be safer than swerving into traffic. My car thinks otherwise. Still, it's odd how the brain reacts in situations like that. How it slows everything down and really makes you psychologically screwed up for a while. Yesterday was horrific as I couldn't think straight all day long. Today has been much better, but when I go and drive into work again on Monday I'm sure some nasty flashbacks will happen. Ugggh. Stupid brain biochemistry.

This is a question that I'm just a bit curious about. Yesterday morning, I got into a car accident on my way into work. I was blinded by the sun and saw something dart out in front of my car so instinctually I swerved to the right and wound up hitting a telephone pole. I was perfectly fine and nobody else was involved, but it still kind of sucked. Anyway, what has been really weird is that in my mind I keep replaying the accident and it just appears to be playing in slow motion. In addition, there is this really weird haze about the entire situation. I mean, I was there and remember it happening, but a lot of the details are incredibly fuzzy. Things such as the route I took to get to where the accident took place, the exact street I was on, what it was that darted out in front of me (I believe it was a dog, but at that moment I couldn't tell and didn't want to risk hitting a child), etc. etc. What is the chemical in your brain that makes you have a hazy memory of the situation? Also, what process results in the apparent slowing down of time as everything is happening? Today I feel MUCH better and a lot of the stress and bad feelings have gone away, but damn, I wish it would all go away.

Hehe. I was just about to say the same thing.

Sadly, for every five or six competent and responsible chemists like many of us here, there are thirty or forty complete and total retards who shouldn't be allowed anywhere near chemicals.

When I was instructed on writing net ionic equations and learning solubility rules, I was ALWAYS told to write out each and every compound as an aqueous compound. Do this on both sides of the equation. Then, when you have all your ions written out, use your solubility rules to pair up insoluble ions. As an example, let's say you are mixing Barium Nitrate and Sodium Sulfate. I would write everything out like the following: 2Na+ + SO4(-2) + Ba+2 + 2NO3(-) => 2Na+ + SO4(-2) + Ba+2 + 2NO3(-) Now based upon solubility rules we know that sodium salts and nitrate salts are soluble. So we can remove them from the equation: SO4(-2) + Ba+2 => SO4(-2) + Ba+2 Barium sulfate is one of those compounds that we know is not soluble, so as a result we can rewrite our above equation as follows: Ba+2 + SO4(-2) => BaSO4(s) There. You know have a net ionic equation. This is a fairly simple method to learn about writing net ionic equations as well as learning which compounds are soluble and which are not.

PbI is a beautiful canary yellow color as a solid precipitate, but alas it is not soluble in water so you cannot have a solution of it. (Besides, I believe it would be colorless in solution).

Not a problem. It just might be that you haven't gotten deep enough into orbital theory and other grotesque details about the electrons yet.

That is not correct. You do not assign electrons based on pairs. The electrons are "dealt" one at a time to each side (if you are working with an individual atom) until all electrons are used up. For Oxygen, you have two unpaired electrons on opposing sides of the atom, not three sets of paired electrons. (And when elemental oxygen is properly drawn, you'd see that there are unpaired electrons on each atom in the O2 molecule which helps explain some of the reactivity of the molecule).

To me, it still blows my mind that we've been able to visually see individual atoms thanks to electron microscopy. No matter how many times I see it, I'm still blown away.