UC

For the first one, you are doing it right, but which measurement (diameter or radius) makes sense? If you stack spheres, isn't their total height going to be the diameters of each added or their radii? For the second one, you need to look up what crystal structure aluminum crystallizes in. Assume that the aluminum atoms are solid spheres with a radius equal to the covalent radius. Wikipedia will tell you that it is face-centered cubic. Then, draw a unit cell and calculate what's called the atomic packing factor. http://en.wikipedia.org/wiki/Atomic_packing_factor This is amount of space that the aluminum atoms occupy per unit volume. FCC crystal structure has an atomic packing factor of 0.74, although I suspect that your homework should show the derivation. This means that 26% of space in any given volume of crystal is empty. From the size of your cube, calculating the volume of "empty space" should be easy. The mass of the cube is irrelevant.

If that's the case, you may want to put quartz sand and the turnings in the mortar and pestle and see if you can grind it directly together. The sand should be a nice abrasive and will probably help get the magnesium much finer.

That largely depends what the unsaponifiables are. They could be an extremely large number of things and are going to depend largely on what kind of oil it is. In oils, the percentage is usually quite low, so I would not suspect any significant effects unless isolated or if a ton of the oil is consumed. Google shows some arthritis treatment with avocado and soybean unsaponifiables. I've no idea if it's actually helpful or another junk health product. It looks to be credible, but I don't have the time to dig through sites and references.

It'd be safe to try a mortar and pestle, but I can almost guarantee you that it wont work. You're going to mash all the bits of metal together and not much else. You could try the magnesium in light mineral oil in a blender for a while, then repeated washings with hexane. I've made very fine aluminum powder with the standard ball-mill method, but I suspect that Mg is far too reactive to be ground for a week and a half and not be all oxide. A little oil in there with it would impede proper grinding by making the powder clump. What is the powder for?

Of course a polymer doesn't have to be all identical molecules. But you need a confined set of possible units. Take DNA (The enzyme that assembles it is called DNA polymerase, so gives you a hint there). There are 4 different monomers. Granted, it is a very precisely assembled polymer, but a polymer none the less. Proteins would also be polymers. They have quite a few options of monomer units, but are all linked with peptide bonds. Generally the number of bond types making up the backbone of the chain (if it's a chain polymer) is small As for inorganic polymers, polydimethylsiloxane walks the line between organic and inorganic. How about red phosphorus? It has a polymeric structure and yet is a pure element. Generally when we think of polymers, we think of long chains, but this is not always the case. How about polycarbynes? These are random network polymers and precursors to synthetic diamond. Each monomer unit attaches to three others and you get a tangled mesh as a result.

I've done this with nu salt brand. The hot solution was filtered through cotton and came out perfectly clear. The cryatals were washed with ice water. Upon heating, they turned brown. bitartrate clinging to them I suspect.

The short answer is that atoms like to have 8 (or 0)valence electrons surrounding them. This is an extremely stable configuration. Carbon has 4 electrons. By forming 4 bonds, it has a total of 8 (2 in each bond) surrounding it. Oxygen has 6 surrounding it. by forming two bonds, it adds 2 to it's collection and has 8. etc. etc. Electronegativities are experimentally derived, but follow a relatively simple pattern. If you get into higher chemistry all these things slip into place. Fluorine gets a -1 because one more electron (with a -1 charge) completes the set of electrons that occupy its 2p atomic orbitals (a 3-dimensional region of probability for the position of an electron around the nucleus defined by quantum mechanics). This probability can be written as an equation on paper, but this is advanced college physics and beyond me even though I understand the basic concepts. The thing that makes this part of chemistry inaccessible and restrains it to memorization in lower level classes is how incredibly complex the equations are. The rules resulting from them are basic principles for chemistry though. The easy way to get around trying to explain such a complex concept early on is to just confine it to memorization. Chemistry walks the fine line, in my opinion, between the impracticality and inapplicability of math and physics to everyday life (beyond basic stuff), and the overly-specific analyses of biology that also lack applicability. It's called oxidation because of it's history. Oxygen being a rather accessible and common oxidant is where the reaction was first observed and only later on was the concept extended to other reactions as well as the mechanism for it. If you continue to complain and call chemistry BS in all your posts I don't think I'm going to take the time to respond anymore. I take it quite seriously.

The easiest way to start these is to look at the ring and what substituents are on it. You need to have a diene and a dieneophile. The dienophile contributes 2 carbons to the ring and is generally equipped with electron withdrawing groups. The diene contributes 4 carbons to the ring and usually has electron releasing groups on it. The final product has one double bond, right between the double bonds on the diene. Hint hint: an enol ether would be a very good electron releasing group and might take care of where that double bond goes. Since you have specific orientation for your substituents, you need to look at the cis principle and endo addition rule. I have no idea how to use 4 carbons, but I see a very easy way to use 5.

Salt substitutes, depending on brand, may only be part KCl and even when mostly KCl, usually contain fumed silica, potassium bitartrate, adipic acid, and whatever constitutes natural flavors. These ingredients are either for flavor modification (it is quite nasty alone and at best poorly improved by the additives in my opinion) or useful as anticaking agents. In some areas, you can buy KCl in 40lb bags as sodium free water softener salt. They will probably be between $15 and $25 but they're much more pure and cheap than an equivalent amount of salt substitute and will last you essentially forever unless you're using them for their intended application.

Your control should probably be distilled water that is boiled immediately before testing to make sure there are no bacteria living in it. If you are going to be growing cultures of each, absolutely nothing should grow on that sample. You may get very few results, since tap water (which ends up in your sinks, water fountains, and toilets) is usually chlorinated which will kill most bacteria. Be prepared to explain your results if every sample ends up with none or very little in the way of bacteria. As a side comparison, you may also want to test the toilet seat/rim, top surface of the water fountain, kitchen sink, outside of a water bottle, which are also useful indicators of cleanliness of certain water sources. More repetitions make your results more credible, so I would take samples from a few different toilets, water fountains, sinks, etc. and present your results as averages.

Yes, but this is rather clearly a homework question. Regardless of how correct the equation in the homework is (which it isn't in this case) the answer is going to reflect the unbalanced equation he was given. Conceptually, it is a fine problem, although the chemistry is wrong. Calculating for O2 and converting to dichromate is extremely roundabout. The two half reactions are a shorter and cleaner way to calculate this. Oxidation states/numbers are vital for understanding redox chemistry. They get muddled a bit since inorganic compounds are more defined in terms of oxidation states than organic molecules, but the assumptions you make for them can correctly predict stoichiometries. Basically, look at how many valence electrons an element has. Then look at the electronegativities of it and the atoms bonded to it. Oxidation number is a crude predictor of the electron density around a nucleus in a compound. First, recognize that a bond represents one electron from each atom coming together. Two of the same element are the same electronegativity and neither steals the other one's electrons away completely. There is perfect sharing and the average density around each nucleus is not going to change. We don't change the count on the oxidation number for this. Something that is all one element, therefore has an oxidation number of 0. If one of the two elements is more electronegative, we pretend that it takes both electrons to itself (stretching the truth except for purely ionic bonds) An electron has a -1 charge, so the more electronegative element gets a -1 for that bond and the less electronegative element gets a +1 for that bond. The oxidation number can never be more than the number of valence electrons, nor less than it's negative: example: oxygen can never be more than +2 and never less than -2. Take methane for example. CH4. Carbon has a higher electronegativity than hydrogen. So, we say that each hydrogen is +1 and the carbon, since it has 4 +1s attached to it must be -4. This is true because methanol doesn't have any charge, so the +s and -s must balance. Now, let's look at methanol. The carbon has three hydrogens and a single bond to an oxygen (which is itself bonded to a hydrogen). the least electronegative thing here is the hydrogen, so they will all give their electrons up and be +1s, while the oxygen being the most electronegative must take electrons from both bonds that it forms. Oxygen is therefore a -2. Now for the carbon. The oxygen is going to take one electron from the bond, making the carbon +1. However, the carbon has those three hydrogens giving 1 electron each for a total of -3. Put together, the overall oxidation number of the carbon in methanol is -2. Redox reactions are a simple balancing of oxidation numbers. If you want to make methanol go to CO2, you need to make the carbon go from -2 to +4. This is a 6 number increase. So, you need something to drop 6 numbers. Lets use Cr2O7(2-). Using the method above, you will find that chromium is in a +6 state and likes to drop down to +3. This is a drop of 3. So, you need 2 times the drop in 3 to make up for the increase in 6. Since there are two Cr(VI) in Cr2O7(2-), one mole of dichromate will oxidize one mole of methanol to CO2. Use google to look up the half reactions method if you didn't learn it in class. This is a way of keeping track of all the other atoms involved while figuring out how to balance the reaction. It will also tell you if the reaction is promoted by acidic or alkaline reaction conditions. Well, Im done with my little essay. If you need better explanation, just ask. I tend to be convoluted sometimes.

insane alien is right about the products of the reaction between NO2 and CH4. Of course, a melange of CO, formaldehyde, formic acid, CO2, H3COH, NO2, NO, N2O, H2O, and N2 is likely depending on stoichiometries. OCN- and CNO- properly describe the cyanate and fulminate anions respectively, but you will not make them by reacting CH4 and NO2.

Here's one that should definetly work. I seriously question if those other preparation (except the lead one) would work, or at the very least are probably very very difficult to get to work. Place some dry ferrous oxalate (yellow) in a test tube and plug the top end loosely with glass wool. Heat the ferrous oxalate until gas ceases to be evolved (CO2), leaving a black, magnetic powder. This powder is probably a mix of extremely finely powdered iron and probably a little FeO. The CO2 acts as a shielding gas and the glass wool prevents pressure from building up, but also stops air from flowing into the tube. When the glass wool is removed and the powder poured into air, the bits of iron rapidly react with oxygen and "ignite" (glow strongly). You could seal the tube off as an ampoule if you really wanted. Cobalt and nickel look like other good candidates. Perhaps manganese. Based on the same principles, your lead tartrate will probably work as well, but as iron is more reactive, it will probably be more impressive. (and not toxic) You may also be interested in this. It isn't quite pyrophoric, but rather impressive: http://www.theodoregray.com/PeriodicTable/PopularScience/2005/10/1/index.html Do I even need to mention to be careful with something like that? It should be obvious.

Let's make this simple. What oxidation state does hydrogen usually take in compounds? (not including hydrides) What oxidation state does oxygen usually take in compounds? (not including peroxides) Since ethanol and CO2 are neutral compounds, the sum of the oxidation states of their atoms must equal 0. The two carbons in ethanol have different oxidation states. Pay attention to what other atoms each is connected to. Both become CO2 in the end. The hydrogens and oxygens are just along for the ride. It's the carbon you need to focus on. Write your half equations for each carbon seperately. Google redox equations and pay better attention in class.

Mmmmm utter rubbish. Since the direction of current constantly changes, the main effect of treating a conducting solution with AC, IIRC is to heat it.

Check your oxidation states. Unless antimony assumes a +1 state that I'm unaware of, definetly not. Perhaps KSb(FeO4)2 is what you meant. A ferrate alum is what I suppose you could call it. It's quite hard to isolate ferrate as it is. Not to mention that the Sb will also have anionic character in strong base, which is where ferrate will be stable. You have it as a cation here. I guess it might be still possible, but my money would be against it. Then again, it all goes in the crapper if 2Fe(VI)+3Sb(III) --> 2Fe(III)+3Sb(V) is favorable.

No, I believe you'e thinking of dimethylsulfide. DMSO by itself is largely harmless. It has a mild, but distinctive smell. The point of using MeBr is that it's a gas and will leave the container after treatment. The route with DMSO leaves a solid, and to effect complete reaction (if it even happens easily at room temp) you'd need an excess. Because it's b.p. is so high, you'll get the aerosol soaked into surfaces and it has no plans of evaporating very fast, possibly ruining the material in the shipping container and giving everything an odd smell.

Mmmm. good old proteases. Meat tenderizer has plenty. These are usually papain or bromelain.

You're not going to be able to do this in water. Note that SbF5 hydrolyzes readily giving some godforsaken mix of antimony(V)fluoride/hydroxide/oxide and HF. The fluorine on the iron compound (FeF3?) is going to be your lewis base. Perhaps the reaction would proceed more easily using a crappier lewis acid than FeF3. Even something like LiSbF6 would be interesting, although it would lack the potential colors of a transition metal compound. I wonder of SbF5 will react with SF6....[sF5][sbF6] anyone? I suspect it would be polymeric though.

I'm not sure what compound you are referring to by prop-2-ene benzene. I suspect you either mean alpha or beta-methyl styrene. NBS will selectively halogenate the methyl position to benzyl bromide (a very unpleasant lachrymator). I believe Br2 can also be effectively used, as long as radical conditions are provided. (light, heat, initiator, etc.) Benzylic and allylic carbons tend to react similarly with radical reactions since both are strongly stabilized by resonance.

Generally, metal plating solutions are acidic and quite a bit more concentrated than 1M. "leveling agents" are the compounds used to help produce coherent, smooth platings. The best ones seem to vary from metal to metal and they are usually organic compounds. I'm sure there's a forum somewhere about this. Plating borders on an art and most of what you'll find are tried and effective "recipes" for plating baths.

Cyclohexanes don't behave at all like benzene rings. The directing groups are only effective on benzene rings because they modify the resonance patterns of the aromatic ring. You should treat them like straight chain alkanes for the most part. There are 4 steps you need for this one. The first is MeLi or MeMgX. What is the product of this reaction? Do you see an easy elimination given the structure you just made? perhaps a certain addition reaction will give you a direct precursor to your desired product after that... You will only halogenate the methyl (allylic position) if you give it free radical conditions by the way. Don't use NBS.

I'd suspect that there are indeed fluoroantimonic salts. Just like there are hexafluorophosphate salts and tetrafluoroborate salts. I'd think the way to go is not to have any hydroxide anywhere near the mix since that'll give water and immediate hydrolysis to clouds of HF. Stoichiometric Anhydrous iron fluoride and antimony pentafluoride in liquid anhydrous HF followed by slow warming under dry argon to remove the HF solvent is probably the only way to do this. X-ray crystallography would be what you'd use to try to show the octahedral SbF6- within the crystal lattice, confirming it as a hexafluoroantimonate salt. You'd need either teflon or copper vessels as glass would probably react rapidly. I believe copper passivates readily with HF around and is used for F2 generation by electrolysis.

You forget however about diffusion. any gas or plasma will very rapidly disperse in space. The exception is when there is so much of it that gravity hold it together, and even then, I'm sure plenty is lost, it's just not enough to matter. The only way to make this work is if what you're proposing is to make a star, which we obvously do not have the capability to do.

It's electron pushing. I suppose you should technically draw an arrow from the Li-C bond to the carbon too. There is a bond between the Lithium and carbon, albeit an extremely polar one. In the reaction products, you see that lithium is a +1 ion with ethoxide. It can't become an ion if it's still bonded to carbon. So the bond (which is made up of 1 electron from the lithium and 1 from the carbon) must disconnect from lithium. Hence the arrows showing the migration of both electrons. Now, carbon has two extra electrons, right? Enough to make an entire bond. if it uses them to attach to the hydrogen and the O-H bond isn't broken, the hydrogen is going to have 4 electrons surrounding it. Does that look like a happy compound? IMPORTANT: If you make a bond (arrow from atom to atom) and have the same number of reactants as products, you also have to break a bond somewhere (arrow from bond to atom). Generally you won't draw the ethoxide attacking the lithium cation since they don't really form much of a bond. If you count them as seperate products, you have three products. If you have two reactants and they combine to make three, another bond has to break somewhere to make up for the difference.