jdurg

The sodium amalgam creates a much greater surface area for the sodium metal which results in a much more efficient use of the metal. If you take ten grams of sodium and react it, then take ten grams of sodium placed in a sodium amalgam, the sodium amalgam will react MUCH more rapidly and much more effectively due to the much greater surface area of the amalgam. It's like if you try and ignite a pile of lycopodium powder, nothing much happens. However if you try and ignite finely dispersed lycopodium, a fireball breaks out.

I'm not exactly sure what you mean by expansion ratio, but you can use the ideal gas equation to get a rough estimate. Basically, you assume that the pressure of the system remains the same throughout. Then you calculate how much of each gas you have to start out with and with PV=nRT you can calculate the volume of the reactants. Then using the laws of thermodynamics and the enthalpy of the reaction, you can calculate how much energy is given off by the reacting species, then determine what their change in temperature will be as a result of the energy. With this new temperature and number of moles of gases, you'll again use PV=nRT to get a rough estimate of the volume that the products of the reaction will take up.

Yes indeed. That stuff is INREDIBLY neat too! It's a mixture of sodium and potassium metal that actually forms a liquid at room temperature. Then there's also the sodium/mercury amalgam which is actually not something to mess around with. (Due to the toxicity of the mercury, and the high reactivity of the sodium). Anyway, the Na/K alloy is a liquid at room temperature which quickly develops an oxide coating on it. If you disturb the 'puddle', however, the surface is exposed to the atmosphere and will quickly catch fire and burn quite intensely. VERY potent stuff that can quickly get out of hand since it's in a liquid form.

Just a quick little update. The wound has sealed itself off and is no longer an open, festering sore. The injury itself is about the size of a US Nickel in area and is a mixture of a red/white/brown 'chunks'. The skin on top of the wound is leathery tough now as it appears as if my body has regrown the flesh that was ripped off. One thing that can be noticed, however, is that the skin in that area is about 2mm thinner than the surrounding tissue. So there's a bit of a gully in my foot. It doesn't hurt any, but is is REALLY creepy looking. If I move my big toe around, you can kind of see the flesh moving around beneath the skin. This is going to leave one nasty looking scar.

Yes, you are correct. An oxidizing agent will take electrons and form a more negatively charged species. An oxidizing agent gets reduced, and a reducing agent gets oxidized. Remember the phrase LEO-GER. Lose Electrons Oxidized, Gain Electrons Reduced. The tricky part is that a reducing agent is easily oxidized, and an oxidizing agent is easily reduced. In terms of pure elements, fluorine is the strongest oxidizing agent and cesium is the strongest reducing agent. (Francium may indeed by a stronger reducing agent, but there has never been enough of it in existance to prove/deny that). PtF6-, I believe, is a VERY strong oxidizing agent and is what was used to oxidize Xenon for the first time. Many alkali metal borohydrides are incredibly potent reducing agents as well. As for what typically encountered chemical is the strongest reducing agent, I'm not sure. (Though I am certain someone will come in here talking about some random species that doesn't exist in a stable solution that is mathematically considered the strongest reducing agent. Unless you can go into your chemistry supply cabinet and pull down a bottle of the stuff, it doesn't count. )

Remember that the density of a gas is directly related to it's molecular weight. A high molecular weight gas will be much more dense than a low molecular weight gas. So if you assume your gas to be at STP, you can calculate the molar mass of it. Since one mole of oxygen at STP is 32 grams divided by 22.4 liters which equals 1.43x10^-3 g/mL, you know that the density of your unknown gas at that temperature equals 2.77x10^-3 g/mL. If you have one mole, which would take up 22400 mL, you can figure out the molecular mass which is 62.08 grams per mol. You know the gas is binary, so it has a molecular formula of X(y)H(z). The question also tells you that 1.31 grams burned produces 1.21 grams of water. Hydrogen makes up about 11.111% of the mass of water, and we know that the hydrogen had to come from your compound. So if 1.21 grams of water was formed, then 0.1344 grams of hydrogen is in there. (Since 1.21*0.11111 equals 0.1344). We now also know that the rest of the mass of your unknown gas is that 'other' element because the initial question said that an excess of oxygen was used. So Hydrogen makes up 0.1344/1.31 = 10.26% of your unknown gas. You should be able to come up with the rest of the information you need.

No no no no. That is definitely not correct. The sizes of the atoms INCREASES as you move down a group. Cesium is bigger than rubidium which is bigger than potassium which is bigger than sodium which is bigger than lithium. The atomic radius increases because as you move down the group you are adding more electron shells to the atoms which results in a bigger electron cloud. In addition, the nucleus is getting larger too, so the distance between the center of the nucleus and the edge of the outermost electron cloud increases as you move down. When you move left to right, however, the addition of the extra protons actually outdoes the addition of the extra electrons. No new energy levels are added as you move left to right, only subshells. (I.E. you get a 3p and 3d subshell when you move towards the right, but not a 4s). So the combination of the extra protons which add an additional pull on the outer electrons, and by not adding any new electron shells, the radius of the atoms decrease. So fluorine is smaller than oxygen which is smaller than nitrogen which is smaller than carbon etc. etc. Left to right, atomic radius decreases. Top to bottom, atomic radius increases. (Also, these trends exclude the noble gases and their full shells).

Swansont's post was a perfect one. It simply tried to let the original poster think about why a positive ion would be smaller than a neutral atom. If you just go ahead and do homework for people, they won't learn squat and will keep coming back asking us to do their homework for them. Swanson was just trying to stimulate the poster's brain and get them to logically think through the problem and answer the question themselves. (Now to the original poster, please don't take offense if you weren't here trying to get homework help. It's just that when school is in session we always see a LOT of people coming here and posting their homework questions without giving any effort into solving them on their own).

Nope. That's like asking if you can make use of detonating a half pound of TNT as opposed to a full pound. If you use teency little quantities of it, you can control the heat that's given off, but the heat won't last long enough to make any use of it. If you use larger amounts, then you'll get plenty of heat but have no way of using again. You'll also have to be wary of using ANY fissile material because you run a VERY high risk of having it go supercritical as it all is formed in the reaction. It'd be really nice if the thermit reaction could be mastered and controlled to economically produce energy, but that's just not the case.

Benzene, Toluene and Xylene all smell like model paint thinners. It's a VERY distinctive smell and the Testors corporation will forever be associated with that odor in my mind.

Thermit reactions can be used on ANY metal oxide and a reactive pure metal. In each case, the more reactive metal 'rips' the oxygen off of the less reactive metal oxide resulting in the formation of the liquid metal and aluminum oxide. The problem is that the amount of heat generated is so high that it can actually cause some of the metals to boil. If this happens, the resulting liquid metal will explode all over the place and create a lot of damage. The whole reason why thermit reactions AREN'T used is due to the inability to control them and their 'randomness'. It takes a good deal of energy to get the reaction going, and once it has started going there's no way for you to control it. Those aren't very good properties for something that you want to use to generate energy. In addition, if you perform a thermit reaction on a radioactive metal oxide, you run the risk of forming the pure radioactive metal in sufficient quantities to start a nuclear chain reaction. You don't want to be creating a large mass of a liquid, fissile radioactive metal. That would result in a very nasty situation developing.

That demonstration also works with temperature quite nicely. Place it in an ice-water bath and you'll see one color. Then dunk it in a hot water bath and the color rapidly changes. Really neat to see. (Also, I don't know if you could consider 2CH3 => Ethane a dimerization. I consider it more of a reaction because as you said, it's not something that's easily reversible while the 2NO2 <=> N2O4 is quite reversible. Those damn semantics again. hehe. )

Because NaOH and KOH both absorb water from the air in their 'pure' form, and solutions of the bases absorb CO2 from the air to form the bicarbonates. Since the composition of your starting compound changes as soon as you open the bottle, it cannot be used as a standard.

Don't forget that one Liter contains 1000 mL.

NO2, however, VERY easily dimerizes into N2O4. In fact, if you have a sealed tube of NO2, it will dimerize readily and even moreso depending on concentration. NO is VERY reactive and will quite easily oxidize itself to NO2 by reacting with atmospheric oxygen. This NO2 can then dimerize and everything is happy. So NO isn't as ultimately stable as one would make it to be. It's not nearly as unstable as CH3, but not stable like H2O.

Well undoubtedly. I can walk and hike just fine if I'm not wearing my boots. As soon as I put my hiking boots on, however, that's when the pain starts. The only reason I wasn't wearing boots when moving my cabinet is that I foolishly trusted the handles built onto the structure.

Remember that electrons are not static beings. They are constantly moving all over the atom(s) and are not localized. While the oxygen may have the negative charge for a breif moment, just as suddenly it can lose that charge and become more positive. It's just that on a long term basis, the electrons tend to spend more time around oxygen than they do hydrogen.

I've just been going through the routine of putting a germicidal cream and cleansing wash on the wound and then covering it with a bandage to prevent it from sticking to my socks. The wound is beginning to look like it is healing as there's this white film of skin growing over the open area. The area has still not swelled up and is the same temperature as the rest of my foot. It's just incredibly sore and painful at the moment. My plans for mountain hiking this weekend have come to a crashing halt.

Well my feet ALWAYS reek so that's going to be hard to distinguish.

A lot of that has to with side reactions going on. My statement is just countering the one poster's belief that adding salt to a mixture of two 100% miscible liquids will result in the separation of the substances. That's just not true.

Hey everyone. I've got a little question here. Chemistry has always been a topic I'm more familiar with than biology, hence my question. During the day yesterday I was moving some furniture around in my room. I was wearing socks at the time and while moving a heavy cabinet the handle I was holding onto broke off, thus dropping the edge of the cabinet on my right big toe knuckle. Since I was wearing socks, the cabinet slid off of my foot and onto the flooring, but the friction from it sliding down against the sock created a VICIOUS friction burn on my right big knuckle. The area didn't swell up or turn black so I know that there is no bone damage there, but the skin kind of ripped off of the knuckle exposing the tissue underneath. It never bled, but just oozed sebaceous fluid. I walked off the pain and just continued on with my day. Today when I woke up, however, the knuckle area of my right big toe is beginning to hurt. I have applied plenty of antibiotic ointments and sterilizers to the wound and covered it up, but it just feels as if it is throbbing. There is no increase in temperature, the area of my foot isn't swelling, nor is it changing color. It's just really sore and feels like it's throbbing. As a diabetic, I'm always a bit cautious about wounds to my feet. I don't feel as if it is infected, but just want to make sure. I do have a full regimen of amoxicillin at home, however. A while ago I got a nasty bug bite that appeared infected so I went to a clinic and got it checked out. They gave me some antibiotics, but by the time I got the script filled the infection had gone away. I could probably take those antibiotics and hope that it heals soon though.

Cyanide's do dissolve gold because they form a stable Au(CN)2(-) complex. The presence of the Cyanide ion allows atmospheric oxygen to oxidize gold to the Au+1 state. Nitrosyl Chloride (NOCl) will dissolve gold because in solution the NOCl will break down into nitrogen oxides and chloride ions. It's basically a compacted aqua regia.

Glycerol is VERY polar. It has three -OH groups, one on each of the carbons. It is incredibly polar and VERY miscible in water. Glycerol has such a strong affinity to water that if you leave it out it will actually absorb water from the air. There is nothing about it that doesn't cry out 'polar compound miscible with water'. Also, the addition of a salt does nothing to affect a substances solubility in water. If something will mix with water, it will mix with water regardless of whether or not there is salt in there. The salt and the ions aren't what's responsible for the dissolution of another substance.

Yeah, but only a handful of atoms worth. The equillibrium is FAAAAAAAAAAAAAR to the left in that reaction. It's just that when a complexing agent gets involved, then once those gold atoms go into solution they stay there and more will move over to take its place. The net result being the dissolution of gold.