woelen

Manganese peroxide is a catalyst for decomposition of H2O2. It is not used up at all in the reaction.

Some of the Mn will be oxidized by the H2O2 to MnO2 and this MnO2 will catalyse decomposition of H2O2 much more than plain Mn. Indeed, many things catalyse decomposition of H2O2, but MnO2 is particularly powerful in this catalysis.

Hydrogen is a gas at room temperature and I do not believe that you have access to liquid H2. That would require temps of -260 C or something like that. Anyways, manganese is a metal and is fairly dense, so it simply sinks to the bottom in aqueous solutions. It, however, dissolves fairly easily in acidic solutions, and then gives hydrogen gas, itself being converted to the (almost) colorless manganese (II) ions.

Try to determine whether this compound dissolves in slightly acidic liquids. I do not know this particular compound, but the polyphosphate part makes me think that it is more soluble in slightly acidic liquids. Try an acid, which forms highly soluble salts with Mg. I would start trying with very dilute HCl, or dilute NaOAc with some acetic acid in it (buffer).

Copper nitrate is not Cu(NO3), but Cu(NO3)2. Copper is a +2 ion. As darkblade wrote, determine, which is the most electropositive metal.

Can you provide some online pointers to this kind of information? That would be very interesting. I, unfortunately, have no means of accessing all those paid subscriptions of papers. If you happen to know some freely accessible papers on this subject (especially, Werner's work on Iridium compounds), then I would be very pleased. I know of Werner's work on the carbonate/ammine/cobalt complexes, but I did not know that he also published work on iridium complexes.

Perchlorate and chloride do not react, not even when the perchlorate is quite concentrated. I have perchloric acid (60%) and I added solid NaCl to this and heated it a little. The NaCl dissolves, but no chlorine at all. Even a solution of KI is not oxidized by perchloric acid in aqueous solution. Perchlorates are remarkably inert in aqueous solution, comparable to sulfate ion. I have not found any soluble reductor, capable of reducing perchlorate in aqueous solution at room temperature in reasonable time. Things totally change, when the temperature is rising (e.g. in pyrotechnics) or when the concentration of the perchloric acid rises to above 70% by weight. Then perchlorate becomes a powerful oxidizer, which even can react explosively.

Tartaglia, isn't this expressed a little negatively ? Of course, sometimes accidents happen (sadly enough) and there also are people, who misuse other people (that happens everywhere, so it also happens in science). I, however, have worked for many years at a university and what you describe about "egoistic self serving glory hunters "I have never seen personally . Also, I think you are too negative about this forum and people moving towards their own dooming. People, performing experiments at home, indeed impose a certain risk upon themselves, but isn't that true with many other activities in life?

When copper rusts, then no copper oxide is formed, but a basic copper carbonate and/or a basic copper sulfate (depending on the precise nature of pollutants of the air). This mix of basic copper salts indeed is green with a somewhat blue hue (green/cyan). It is the well know copper patina. ------------------------------------------------------------ I do not have any experience with plutonium (my sample did not yet arrive ), but I do have experience with iridium salts. I ordered 3 grams of "IrCl4" and I will soon make a page about the different colors of solutions of Ir-salts. One thing I can say already, the number of colors, which can be made with solutions of iridium salts really is great and the colors are very intense. IrCl4 certainly is as intense as KMnO4 when it is dissolved in water and gives a dull purple color to the solution (not the bright purple of KMnO4). On standing this solution turns brown. When the solution is acidified and a reductor is added, then the solution turns yellow (color of iridium (III) ???). When an oxidizer is added in the presence of hydrochloric acid to this yellow solution, then it becomes dark red (like red wine, but a brighter color). The colors are a mystery to me, I need more research and I'll try to find out more about that. There unfortunately is only little literature about this. Also, the "IrCl4" has net formula IrCl4, but it is not simply iridium (IV) chloride (according to many textbooks, that compound is of doubtfull existence). Probably "IrCl4" is some complex compound, with Ir and Cl atoms in it at a ratio 1 : 4.

Sure, there will be a reaction. OK, I'll give them here: Chloric acid is HClO3. NaCl contains chloride in solution. So, such a solution contains H(+), Na(+), ClO3(-), Cl(-). Reaction 1: ClO3(-) + 6H(+) + 5Cl(-) --> 3Cl2 + 3H2O Reaction 2: 5ClO3(-) + 6H(+) + Cl(-) --> 6ClO2 + 3H2O Both reactions occur at the same time. I did the experiment, by adding NaClO3 to HCl, but this is equivalent to adding NaCl to HClO3 (all are ionic in water and then there is no difference). The result is as follows: http://woelen.scheikunde.net/science/chem/exps/clo2/index.html

It is the same as http://www.kno3.com. This is a somewhat questionable supplier, but my personal experience with them is quite good. There has been a lot of debate about them on the Internet. Some people believe it is a Texas-based anti-meth organization, which sells chemicals (red P!) to individuals and uses the shipping info for finding potential meth-labs. I myself do not believe this story, I'm quite sure this company is UK-based and not Texas-based, but it is true that the web-page is hosted by a Texas-based hosting company.

What do you think yourself? Think about the reaction which can occur. Chlorate is an oxidizer, especially in acidic environments, chloride can be oxidized (to what?). One of the reaction products will be ClO2, the other will be Cl2. I'll leave it as an exercise for you to try to find out what remains for the largest part after evaporation.

If you really want to do rocketry, then first do some more research and try to understand what is important. Just putting some stuff in a tube and hoping it will work as a rocket is not a wise thing to do. Also, perform a search on this forum, there already is quite some info about this subject.

When copper is oxidized by a combination of air, humid and finely divided acid and salts in the air, then a so-called patina of copper is formed. This is a basic copper (II) carbonate/sulfate mix, which has a cyan color. The reason that the color changes is that a chemical compound of copper is formed. Copper itself is a metallic element. Compounds of elements can have totally different properties than the elements themselves (e.g. look at hydrogen and oxygen, these are gasses at room temperature, while the compound water, made of both elements is a liquid at room temperature). A similar thing you see with iron. When iron is oxidized, then rust is formed, which is brown. This is a mixed oxide/hydroxide of iron (III).

At the cathode the following reaction occurs: 2H2O + 2e --> 2OH(-) + H2 So, you get hydroxide at the cathode. At the anode you have the reaction: 2Cl(-) - 2e --> Cl2 (I use "- 2e", because electrons are taken away at the anode). Summing up both reactions gives the following net reaction: 2Cl(-) + 2H2O --> Cl2 + H2 + OH(-) So, with the correct technical setup, such as preventing the mixing of OH(-) and Cl(-) the final compound, remaining in solution is NaOH.

If you never come closer to the balloon than 20 feet, how do you want to fill it with the two gases and how would you want to make your construction, which should ignite the gasses? Again, I would say, don't do it. There are so many other fun experiments. Try what RyanJ suggested. Make approximately 10 ml of the mix of gases, take a tub, full of water and some soap in it and bubble the gas under water. Light the bubbles with a match or cigarette lighter at the surface and be surprised about the really loud bang from even this small amount of detonating gas. This experiment is safe and does not require ear-protection. But still, I promise you, you'll be really surprised with the loud noise if you really have a 2 : 1 mix of H2 and O2.

It is not bromine at all!!! It is a compound of bromine, but not elemental bromine. Elemental bromine is a red/brown liquid, which gives off thick red fumes: http://woelen.scheikunde.net/science/chem/compounds/bromine.html http://woelen.scheikunde.net/science/chem/pics/bromine.html

In the Netherlands, bromine releasing compounds are prohibited in public swimming pools. It is not just because of the money, I think it has to do with concerns about health. Some people seem to react allergically on bromine and certain compounds, made of this. A few years ago, an accident happened on a high school, where some experiments were conducted with bromine. A little accident happened, which caused a bad smell outside. Many people noticed the smell, but there was not a real alarm, because the amount released was only small. However, one person's body was reacting extremely violently on the presence of the bromine and this person had to be taken away by ambulance, while all other people at the same place just noticed a certain unpleasant smell.

Indeed, iron metal in concentrated nitric acid, colored afterwards with Gimp. You can even make blue gases in that way .

You didn't learn anything from your experience with the exploding 120V electrolysis cell. Did you? If a balloon, filled with H2 and O2 in a 2 : 1 ratio explodes near you, especially when you are inside a room, then there is a reasonable chance that it will be the last thing you will ever hear. The BOOM is extremely loud and may well damage or destroy your sense of hearing! What is so funny of this? Are you the next k3wl on this forum ? Please do not do this experiment!

Well, in fact, formally you are right, but the reaction of WillTheNewf also can be regarded as right. If you dissolve NaF in plain water (without added acid), then the solution becomes quite alkaline. Enough to make litmus blue and if sufficient NaF is dissolved, phenolphtalein becomes red. So, you get free OH(-) ions in solution at quite a high concentration. There are multiple equlibria: H2O <--> H(+) + OH(-) (very weak, mostly at the left) F(-) + H(+) <--> HF (mostly at the right) The acid HF is so weak, that indeed F(-) takes up most H(+) and this drives the equlibirium for water more to the right. The H(+) is consumed and the OH(-) remains behind. The net equlibrium indeed is: H2O + F(-) <--> OH(-) + HF, being mostly to the right. So, Jdurg and WillTheNewf, you both are right.

This is not a simple question at all. Of course, by means of sieve methods, you can enumerate all primes of the form x*x+2, and hence find x. Some possible values for x are: 0, 1, 3, 9, ... However, there is not a closed arithmetic or analytic expression for x, e.g. as function of an index (natural number). There also is not a closed arithmetic or analytic expression for the prime numbers themselves, i.e. for the question: find all x, such that x is prime.

This is quite a good explanation, however, we see quite some HF. The majority of all H(+) ions and F(-) ions are combined to HF. HF only is a weak acid.

Well, you are totally wrong. Suppose you would have a combination of fluorine and hydrogen gas, then it would explode at once. In fact, fluorine is so increadibly reactive, it even reacts with glass. With some difficulty you can water make burn in an atmosphere of fluorine.

The HF will not appear as a gas. It will be dissolved in the water. When the liquid is heated, it will not be driven off as the pure gas. HF forms an azeotrope with water. When the solution is dilute, then first water will be driven away and when the concentration of the HF has risen to the azeotropic value, then a constant ratio mix of HF and H2O is boiled away. Pure HF is borderline between gas an liquid. It boils just under 20C at normal atmospheric pressure.