woelen

Interesting, could you give a reference to the place where this is mentioned. I looked up several tables on the Internet with pKa values for many acids, but I did not find reliable data on HSbF6. Anyway, pKa values for very strong acids tend to be unreliable anyway, because in aqueous solution one cannot distinguish between strong, very strong and ultra strong acids, the observed strength is the same for all of them.

Have a look of this page: http://en.wikipedia.org/wiki/Hypochlorite It might be that you still had some NaClO3 in your dried sample. Chlorates give ClO2 with HCl and as the color of that gas is very intense, you might have regarded that as chlorine. Air with a few percents of ClO2 in it looks quite similar to pure Cl2 gas, albeit a little more yellow. See also: http://woelen.scheikunde.net/science/chem/exps/clo2 Here you can see how ClO2 looks like in higher concentration, made from NaClO3.

From your stomach. Just take out something (drinking a lot of booze may help getting some out of it) and carefully distill the nice contents of your stomach. Surely you get some HCl.

YT, keep in mind the remark of Swansont. There is more to this to say than just increase of mass of nucleus. If that were the entire story, then the metal Cs would have a density of approximately 20 times the density of Li, but in fact its density is MUCH less. This is due to the larger size of the atoms. A nice example is the density of KF versus K. Although K atoms have a much higher nuclear mass than F atoms, still KF has a much higher density than K (almost twice the density of the metal). This is due to the different size of the atoms (ions) in the different compounds, and here the effect of larger average nuclear mass in K is by far outbalanced by the increased packing denisty of KF.

No, I don't think so that these are hypochlorite. I on-purpose made a lot of these crystals by letting some bleach evaporate in a petri dish. The crystals I obtained were mainly NaCl. The crystals, when dissolved in water again, hardly are oxidizing anymore and if HCl is added to them, no bubbles of chlorine are formed at all. The reason for this is that solid NaClO.xH2O is very unstable. For this reason, solid NaClO is not available at all. Solid bleaches either are based on Ca(ClO)2 or LiClO or some chloroderivative of isocyanuric acid. Indeed, the solid NaClO.xH2O is known, but it is a laboratory curiousity, which is not easy to make at all.

I expect it to react nicely. Adding a small amount of sulphur makes ignition easier though.

Get some hydrochloric acid (around 30% HCl) from a hardware store and do the following: Dilute the acid to 10% HCl by mixing two parts of water with one part of acid. Add a spatula full of powder to the acid. If it reacts immediately and violently, then most likely it is magnesium or a magnesium-rich alloy (magnalium). If it does not react immediately, but it takes some time, then it may be aluminium. A confirmative test may be to add a spatula of the powder to concentrated 30% HCl. With this it should give a violent reaction, with an induction period of a few seconds. If the powder does not react with concentrated HCl or only very slowly, then it definitely is not aluminium powder. If the solution is not colorless after the powder is dissolved, then another metal may be present as well. Some paint-store aluminium powders contain some copper. A solution of aluminium (and also of magnesium) in hydrochloric acid is colorless. The tests I present here of course are not 100% fool-proof, but with the materials, available for the general public it is the best there is. Given the small number of possibilities for the powder, I also think that this is a fairly complete test in the case of quick dissolving. I do not expect you to have powdered beryllium metal or a powdered lanthanoid around .

Theoretically, steel wool could ignite spontaneously. Very finely divided iron is pyrophoric. But I've never heard of steel wool igniting spontaneously. With oil the chance is reduced, when it is humid, I can imagine that this increases the chance of ignition, but still, I think the chance is VERY low. If this could happen more easily, then certainly in the overly safety-aware US this product would be banned from the shelves.

The blue color indeed is due to copper ions in solution. Cu(2+) ions are nice blue. Your hydrogen peroxide apparently also contains some acid, otherwise you would not obtain a blue solution, not even if the copper metal was somewhat oxidized. Many commercial preparations of hydrogen peroxide contain some phosphoric acid as a stabilizer. Without stabilizer, hydrogen peroxide decomposes too fast to be stored for any length of time.

It is due to a certain volatile compound, a certain essential oil. I do not know which oil, maybe someone else knows. There are quite some compounds which have such a mint-like smell (e.g. chlorbutanol, eucalyptus-oil, also some camphor-derivatives).

It is 0.8 V for: Ag(+) + e --> Ag It is 1.98 V for: Ag(2+) + e --> Ag(+) You will never encounter Ag(2+) ions in your everyday life. This is exceedingly rare and only can be made by oxidation of silver with extreme oxidizers like ClF3, F2 or XeF6. Ordinary silver ions, such as in silver nitrate, are Ag(+) ions. Ag(2+) ions are not stable in water, they oxidize water, forming oxygen gas. Ag(+) ions still are quite strong oxidizers, but not so strong that they oxidize water, but sufficiently strong to oxidize skin, paper, etc. Redox potentials never are for a single compound, they are defined for the transition of one compound into another. So, it has no sense to tell something about the redox potential of e.g. silver metal. It does have sense to tell something about the redox potential of change of silver ion to silver metal.

Of course you can separate small quantities of charge (capacitors also do that), but these are small when expressed in terms of moles. E.g. a 1 F capacitor, which holds 1 Coulomb of charge at 1 V is HUGE in terms of electronics, but still in terms of moles it is tiny: 1 C of charge is only appr. 0.00001 mole of electrons. Electronics capacitors usually are expressed in μF or nF. I still think that e.g. 1 mole of copper ions in a liter of water, would be an extremely unstable thing and would explode, because of the repelling electrostatic forces.

The redox potential for silver only is 0.80 volts, not 1.98. Have a look at http://www.wissensdrang.com/auf1rp.htm for some common half reactions. But still, your cell would make about 3.8 volts. Probably a little less, because of resistive losses. The misunderstanding in your reasoning indeed was between the metal and the ion. The ion really is totally different. The reason why lithium is less reactive than sodium and potassium also has to do with properties of lithium compounds. Lithium hydroxide for instance is not very soluble in water, so this clogs up a free path of water to the lithium metal.

No, this is not possible. Imagine such a solution with H2O and Cu(2+) ions in it with no counter anion like chloride. It would be an extremely highly charged liquid, which would explode at once, due to the strong repelling electrostatic forces. Any macroscopic chemical compound, whether it is pure, a mix, a solution, whatever, is electrically neutral.

Assume that PCl5 and H2O produce H3PO3 and HCl as the sole products. Try to balance the following equation: PCl5 + H2O --> H3PO3 + HCl If you do the same math for PCl3 + H2O --> H3PO3 + HCl then you'll see that this is easily balanced, while for the other one this is impossible. Without any insight in the chemical properties of PCl5 you can see on the basis of plain mathematics that PCl5 simply cannot give H3PO3 and HCl only, when it is added to water. Either different compounds are formed, or additional compounds are formed. Also, if you do similar math for PCl5 + H2O --> H3PO4 + HCl you also see that this is easily balanced. In general you can state that if mathematically an equation cannot be balanced, that the reaction simply cannot occur. If an equation can be balanced, then the reaction might occur, but whether it really occurs or not is the subject of chemistry.

Certain plastics (I'm no expert in this, though) can be made semiconducting. They even have made plastics, which, while conducting current, emit light. These allow one to make large glowing surfaces, something like LED's, but at a much larger surface. Some interesting links on LEP's (Light Emitting Plastics): http://clinton4.nara.gov/WH/EOP/OSTP/Science/html/plastics.html http://researchnews.osu.edu/archive/light.htm A nice link on plastic electronic devices and semiconductors: http://www.sciencenews.org/articles/20030830/fob5.asp

As a computer scientist I expect that massive parallellism in the future will bring more processing power. Imagine processing units consisting of organic molecules. Slow, but versatile, and imagine that there are billions of these things working in parallel, carefully networked for inter-process communication. This is what happens in our brains. They are slow, but hugely parallel. Together, these slow cells form the most powerful processing unit known to man. So, I think that in the (still quite far) future organo-computer will be powerful. Currently, experiments are conducted with "plastic-based" chips. New semiconductor technologies, based on GaAs can be used for ultrafast systems. GaAs based semiconductors can be made much faster, but their manufacture also is much more expensive, but in the future these may become more common. In certain ultra-high frequency applications, GaAs semiconductor devices are used (e.g. multi gigahertz transmitters, ultra high speed DSP's). Yet another important development are optical processing units. With these, light itself is used for processing purposes. Nowadays, optical networks are quite common already, but processing (e.g. routing) still is done by converting optics-->electronics-->routing-->electronics-->optics, but experimental setups exist already, which can do routing directly by means of optical devices, without electronics intermediate. As with many technologies, do not expect a single technology to be the silver bullet. A combination of technologies will give best results and in practice I expect that different technologies will live next to each other, together giving the results we want.

Yes, the black material consists of fine silver particles. This is the idea behind black and white photography. The black parts of an old black and white picture are made of many ultrafine metallic silver particles, immersed in the gelatin of the photo paper. A few links on the oxidizing properties of Ag(+) ions and the black particles of metallic silver, which are formed when the Ag(+) is reduced to Ag: http://www.uni-regensburg.de/Fakultaeten/nat_Fak_IV/Organische_Chemie/Didaktik/Keusch/p14_hyd_ag-e.htm http://www.chemistry.usna.edu/manual/Ex35.pdf ------------------------------------------------------------------------------- Now the second part. When AgNO3 comes in contact with your skin, then the following happens: AgNO3 --> Ag(+) + NO3(-) (dissolving of the salt) Ag(+) + X --> Ag + X(+) Here X is a (possibly large) molecule from your skin, some proteinic particle, whatever organic oxidizable compound. So, the skin is the reductor, and NaCl present on your skin is not important at all. Also, light is not important in this particular situation. Put some AgNO3 on your skin, and even in total darkness it will stain your skin. So, there are two different things to be distinguished: 1) The ease at which Ag(+) ion is excited and made to react with other things by means of light. This is exploited in photography. 2) The ease at which Ag(+) ion is capable of oxidizing organic matter, such as skin, dust, paper, etc. This happens even in the dark. When (1) and (2) are combined, then we enter the area of photography. Photo paper contains AgCl (or AgBr or a mix of both) and this is reduced easily, itself acting as oxidizer: AgCl + dev --> Ag + Cl(-) + dev(+), where dev is a developer molecule. This reaction occurs anyway, whether the AgCl is exposed to light or not. But... where the solid is exposed to light, at those places, there already are some Ag atoms, dissociated from the halogen atom. At these places, the developer acts faster than on other places. So, by adjusting the time that the print is in the development bath, one can control how the image looks like. It is important to keep the photo paper with the AgCl/AgBr for such a long time in the bath, that the exposed areas already are reduced (made black), while the unexposed areas still remain white (not yet reacted AgBr/AgCl). The precise chemistry and physics behind this is amazingly complex, but a simplyfied explanation, quite understandable is given in the link below: http://science.csustan.edu/nhuy/chem1002/photoexp.htm

Silver ion is a strong oxidizer, not silver metal. Silver metal is the reduced form of the oxidizing ionic species. It is essential that the silver is in a salt, because then it is Ag(+), while in the metal it is Ag(0). Think of this, this is a VERY important difference. E.g. Na(+) in table salt is inert and harmless, while Na(0), the metal is a very strong reductor. You cannot simply compare metals and the derived ions with each other, they are TOTALLY different. The effect of nitrate only exists at high temperatures (as in fireworks) or at very high concentration and low pH (as in nitric acid). Nitrate ion without acid at low temperature really is very inert. Just take some NaNO3 or KNO3 and rub your hands with that for minutes. Nothing happens, at least not more than when you rub your hands with e.g. table salt. Also, if you take a concentrated solution of NaNO3 or KNO3, then nothing special happens with your skin. AgNO3 kills your skin, due to the Ag(+) ions, and HNO3 kills your skin, not because of presence of NO3(-) ions, but because of presence of HNO3 molecules. Again, these are very different from nitrate ion. An even more striking example is the perchlorate ion. The ion ClO4(-) is even more inert than the dull chloride ion at low temperature. And this remains so, with concentrations of even up to 60% by weight. Only when the perchlorate becomes covalently bound, then it becomes extremely reactive and corrosive. So, KClO4 (ionic compound) is inert at room temp (not at high temps as in fireworks) and also dilute perchloric acid H(+)/ClO4(-) is "inert" at concentrations up to 72% (only acidic, not strongly oxidizing). Above that concentration, covalent HClO4 molecules are formed and at those concentrations the compound becomes very corrosive (e.g. to skin) and also very reactive and dangerous (liable to cause explosions with reducing agents). Silver metal indeed is not very toxic, but silver ion is among the more toxic ions. Again, ions and free elements cannot simply be compared, they are totally different.

Yes, you're totally right. But this is without acid. Repeat the same experiment with H2O2 + dilute strong acid (any strong acid will do). Then you'll not get bubbling, but the solid iodine is formed instead. In the experiment you describe you get catalysis through the formation of hypoiodite: I(-) + H2O2 ---> IO(-) + H2O IO(-) oxidizes H2O2 (oxygen goes from -1 to 0 oxidation state): IO(-) + H2O2 --> I(-) + H2O + O2 In acidic solutions, however, the hypoiodite ion cannot exist and the acid HIO is so extremely unstable that it in practice cannot be formed. The only alternative then is formation of iodine and there is no catalytic effect.

But still, this is not the strongest acid. The chloro-borane based acids, mentioned in earlier posts are MUCH stronger than the acid you mention. I think that that wikipedia page is exaggerating a little. I always though that HSbF6 is about 10^6 times stronger than sulphuric acid and not 10^16 times stronger, but I might be wrong .

No, no chlorine remains behind, but chloride. AgCl consists of Ag(+) ions and Cl(-) ions. The Ag(+) ions are reduced to metallic Ag and the chloride ions remain behind as Cl(-). The reducing agent is the photographic developer, which frequently is a complex of hydroquinone and sulfite, but compounds like pyrogallol, catechol, or even vitamin C also act as reductor. What remains in solution is chloride ion and some oxidizer species, derived from the developer. These oxidized species are very complicated, often polymeric/condensed organic molecules and cations.