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April 11 2012 4 11 /04 /April /2012 15:59

2-2 - Use Control + F to find what you want in here

Antimony oxidation: Antimony powder is placed in hydrochloric acid. No reaction occurs since antimony is not reactive enough to dissolve in hydrochloric acid. When hydrogen peroxide is added, however, the antimony dissolves, forming either a colorless solution of antimony trichloride or a white precipitate of the trioxide. The reaction was recorded.

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Calcium reactions: I recently obtained 10 grams of calcium for $13.00 from Gallium Source LLC (shipping included). The calcium is golden-colored and dry. Some of this calcium is placed in warm and cold water. The warm water reaction is faster than the cold. Addition of acetic acid rapidly speeds up reaction. A 1% solution of acetic acid reacts vigorously with calcium. Here are some small calcium chunks in the solution.

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Indium properties: When indium is hammered, it easily picks up dirt. Granules of indium were hammered into a foil, and then folded to demonstrate flexibility. With one tap of a hammer, a granule completely flattens. By the way, the line in the indium granule is a gentle fingernail press.

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Alkaline earth metals in acid: Beryllium does not react with 5% acetic acid, while calcium reacts vigorously. Beryllium, however, reacts vigorously with concentrated hydrochloric acid, just like calcium. The resulting piece of etched beryllium is blackish with pronounced crystal structure. It has a strange sweetish smell. I was sure to wash my hands after handling. Here is the piece of beryllium.

Galinstan alloying: This is a very haphazard experiment. Galinstan is first cleaned by a hydrochloric acid bath. Then the galinstan is washed with water and applied to a scratch in a wad of aluminium foil. Some bubbling is observed as the galinstan removes the passivation layer on the aluminium, allowing it to react with the residual water. Most of the water is pipetted away. Another bit of galinstan on unscratched aluminium foil did not absorb in the time interval of this experiment. The galinstan bead forms a thick gray coating containing a mix of galinstan and aluminium oxides. This floats to the top of the bead and can be scraped off, although it begins reforming instantly. Then the galinstan bead was mixed with the aluminium oxide paste. A golden-colored paste was formed, probably as the result of an oxide film. Then all the powder and paste was tossed in hydrochloric acid. A galinstan bead immediately reforms and the aluminium oxide, along with the galinstan content, dissolves. The galinstan bead is removed to another lid and zinc is tossed in the container. Violent fizzing erupts which quickly slows. For some reason, galinstan-impregnated zinc reacts about 10 times slower with hydrochloric acid than normal zinc, a good indication of the alloy’s formation. When the fizzing has sufficiently slowed, the zinc is placed on the lid where the galinstan bead is residing, hungrily awaiting the next bite of metal, be it zinc (I did not know that) or aluminium. When a large, unresisting, and recently cleaned (by the acid bath) piece of zinc already weakened by gallium reduction from the hydrochloric acid is added, the temptation to the galinstan is too great to resist. My first inkling that an invasion was occurring was the creeping of a silver-colored area on the opposite side of the zinc metal. This caught my attention and it was videotaped as it grew. It grew to about two-thirds of the zinc’s surface area before I lifted the zinc. Half of the galinstan was absorbed into the zinc, while the other half was flattened against the zinc in the process of being absorbed. However, the zinc was becoming saturated with galinstan. When the metal was tilted, a pocket of liquid galinstan formed on the lower side. By this time, the metal was being held by pliers in a location that was intentionally spared from the acid bath and was farthest from the site of the invasion by the next door neighbor. These various features of the metal were taped, using the last of my tiny memory card. I accidentally touched part of the zinc that did not appear to be amalgamated and the piece instantly fractured. I quickly placed the zinc in a Petri dish to prevent it from cracking out of the pliers and shattering on the floor. The end that was being held broke off. I can only imagine how brittle the silvery galinstan-saturated section is. Meanwhile, a thin oxide coating has begun forming on the zinc, turning it a milky yellow of Tyndale effect lore. Here are the pictures: Top is the zinc-galinstan alloy. In the flashbulb light, the shiny galinstan-soaked portion appears dark, probably because reflection is more specular (learn physics). Below, the difference between normal zinc and galinstan-impregnated zinc in reaction with hydrochloric acid is seen. Bottom left is the galinstan-aluminium oxide paste that was a golden color, along with the powder. Bottom right is the appearance of the galinstan in the cleaning bath.

Indium: I stepped on a stray indium bead. It prostrated itself so completely to the ground that it never rose again. No other stable metal is so submissive and shapeable.

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Calcium burning: Small pieces of calcium are burnt in a wire loop and the results are videotaped.

Aluminium alloying: A bead of galinstan is placed on lightly scratched beverage can aluminium. The scratching was not enough to remove the thin transparent protective layer on the inside of the can. More vigorous scratching at a new location and moving the bead of galinstan to that location begins the alloy process. A shell of aluminium oxide forms around the liquid galinstan. The aluminium is manifesting evidence of corrosion on an edge about ¾ inch from the original introduction of the galinstan, showing that the aluminium is probably thoroughly impregnated.  The red dashed arrow shows the aluminium oxide shell. The blue circles show the galinstan bead in its shell, top view (bottom) and bottom view (top). The red solid arrow and red circle both show evidence of corrosion in areas of aluminium exposed to the air.

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Indium dissolution: A small piece of indium foil is placed in hydrochloric acid. It is completely dissolved within 12 hours. The dissolution begins extremely slowly but evidently increases in speed as any oxide layers are removed from the metal. Two short videos are taken. Later, sodium bicarbonate is added to the solution. A white precipitate forms which easily passes through filter paper. This is most likely indium(III) hydroxide. Like aluminium(III) hydroxide it is very gelatinous.

3-1

Indium reactions: A piece of In is placed in CuCl2solution. The indium gets covered by a spongy Cu layer immediately. The Cu thickens quickly, and a dilute solution of CuCl2 is cleared of Cu in about 1 minute (when the indium is shaken, the reaction is much quicker). Here are some pictures of the reaction.    

The first picture shows the piece of indium foil. The second shows the indium foil floating on the copper(II) chloride solution. The solution has touched the edges and the underside, turning them both reddish-brown. The third shows the indium foil immediately after submersion. The copper layer is thin and dark. The fourth picture shows the indium foil about 10 seconds later. The copper layer has grown in thickness, although the solution has not experienced any significant de-coloration. (The difference in solution color is fluorescent vs. flashbulb light.) The fifth picture shows the thickness of the copper around the indium piece. The last picture shows the solution after the reaction has run to completion and been agitated. Pieces of spongy copper have broken from the indium piece, leaving the blackish-looking indium partially exposed. The solution has decolorized, turning into indium(III) chloride. The reaction that has occurred is 2 In + 3 CuCl2 à 2 InCl3 + 3 Cu. Indium is a quite reactive metal.

Indium reduction: The resulting indium chloride solution from the above experiment is reacted with zinc. Initially, no reaction is apparent, but a layer of indium later is seen to be forming on the zinc. It appears spongy, though not as spongy as the copper layer above. When the indium sponge is later compressed, it behaves like a metal, just like the lead sponge previously made, which also compresses to a solid metal. However, it was lost. These are pictures of the reaction. The first (left) is the zinc just after immersion in the indium chloride solution. The second shows the zinc about 8 hours afterwards. So with the third (the indium sponge is visible on the edges) and the fourth (compare to the first). The fifth shows the indium powder and the zinc outside of the solution. Some of this powder was pressed into the pellet which soon was lost.

3-2

Iron comproportionation: Iron(III) oxide is dissolved in an excess of hydrochloric acid to create a yellow solution. A machine bolt is then placed in the solution. A brief and swift dissolution of the electroplated zinc coat occurs, and the hydrogen production stops. It seems as if all of the iron is undergoing this reaction (Fe + 2 FeCl3 à 3 FeCl2) instead of the typical Fe + 2 HCl àH2 + FeCl2. The solution, after 30 minutes, has noticeably turned greener. The reaction will be left overnight. Here is the first set of pictures. The first picture shows the iron(III) oxide completing its dissolution in hydrochloric acid. The second picture shows the machine screw 30 seconds after starting. The third picture shows the solution after 30 minutes.

Beryllium copper(II) chloride reaction: Because of beryllium’s many similarities to aluminium (relatively high melting point, dissolution in alkalis, protective oxide coating), I wondered whether beryllium would undergo the same vigorous reaction that aluminium undergoes with copper(II) chloride. However, I did not want to exhaust, contaminate, or ruin my beryllium, so I only used a highly dilute copper(II) chloride solution (boring). The beryllium reacted more vigorously than the aluminium would under similar circumstances, forming hydrogen gas, beryllium chloride (somehow it stays in solution from the copper(II) chloride’s excess acidity), and copper metal. The beryllium was covered in a layer of dark brown copper, which smeared as it washed off, giving the impression that the beryllium was corroding. However, upon rubbing, the strange dark luster of corroded beryllium metal shone again. The brief (to prevent excess beryllium dissolution) reaction was videotaped.

3-3

 

Iron comproportionation: The reaction was deemed complete by morning, after about 10 hours. The solution was neutralized with sodium bicarbonate to precipitate the iron. A white precipitate formed. This white precipitate is iron(II) carbonate, which is white when pure and oxygen-free as a result of the vigorous carbon dioxide bubbling through the solution. Some of the solution not in contact with the iron was smeared near to the top of the vial, and it retains the brown color of iron(III) oxide (iron+++ doesn’t form a carbonate). This shows that the comproportionation reaction was completely successful and the resulting solution only contained ferrous, not ferric, ions. After a few minutes, the edges and top of the iron(II) carbonate had turned either brown or dark green, the products of aerial oxidation. Ordinary tap water, which contains dissolved oxygen, was added to the solution, and the iron(II) carbonate darkened to a greenish color. Addition of hydrogen peroxide turned it brownish amid fizzing. The left picture shows the resulting iron(II) chloride solution, containing excess hydrochloric acid. The center picture shows the white iron(II) carbonate precipitate. The brown spot at the top is the iron(III) oxide from the unreacted iron(III) chloride solution. The right picture shows the iron(II) carbonate after standing a few minutes.

 

 

Titanium reactions: Titanium foil piece from GalliumSource is placed in hydrochloric acid. A vigorous reaction occurs and the titanium dissolves as fast as a piece of aluminium would. Sodium bicarbonate is added. A precipitate occurs even in a strongly acidic solution (much fumes, pH < 1). Wasn’t titanium supposed to dissolve slowly in even boiling hydrochloric acid? Well, the heat produced by this reaction was enough to boil away the hydrochloric acid. The translucent gel on the side of the vial in the picture below is similar to aluminium hydroxide, which would not exist in such a strongly acid solution. The precipitate, however, is curdy and relatively heavy.

 

 

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“Titanium” reactions: The foil reacts slowly with water, forming small bubbles of hydrogen gas and a white precipitate. This is definitely magnesium.

 

 

3-5

 

Metal and copper reactions: The reactions of magnesium, aluminium, and beryllium with copper sulfate and copper chloride solutions are compared. Aluminium does not react with copper sulfate, while it reacts vigorously with copper chloride. Magnesium and beryllium only exhibit slightly increased signs of reactivity with my excess-acid copper chloride; the excess acid is in all likelihood the only reason for the increased reaction rate. Therefore, only aluminium exhibits the strange phenomenon of being so much more reactive with the chloride than with the sulfate. The pictures are of Al-chloride (top left), Al-sulfate (top center), Be-chloride (top right), Be-sulfate (center left), Mg-chloride (center right), and Mg-sulfate (bottom).

 

 

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Magnesium reactions: Magnesium reacts vigorously with concentrated copper sulfate solution, just like its reaction with copper chloride minus the acidity. Magnesium also reacts violently with a copper sulfate-ascorbic acid mixture, which turns green for some reason (complex formation?). Brown copper mud is produced in the reaction. Magnesium reacts moderately with plain ascorbic acid, showing a rare instance where ascorbic acid functions as an oxidizing agent. Top left is the magnesium-copper sulfate reaction. Top right is the magnesium-copper sulfate-ascorbic acid reaction. Bottom is the magnesium-ascorbic acid reaction, with small bubbles escaping along the sides.

 

 

 

Copper sulfate – ascorbic acid reaction: This try was not good. Too much ascorbic acid was present.

 

 

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Copper sulfate – ascorbic acid reaction: Copper sulfate solution, which is sky blue, reacted with ascorbic acid to form a green solution. A tiny amount of fine copper metal dust has precipitated.

 

 

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