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February 17 2012 6 17 /02 /February /2012 20:17

12-24 - Use Control + F to find what you want in here

Lead iodide reactions: Sodium hypochlorite oxidizes the surface of lead iodide crystals, but not the bulk, making them turn brown. They get darker over time, indicating more oxidation. PbI2 + 2 NaClO -> PbO2 + I2 + 2 NaCl

Rare earth extractions: The brown precipitate has fallen out of solution. It does not have the reddish tinge of iron(III) oxide, but it could just be a different form. However, iron(III) would have been reduced by the zinc, so it must be a lower-valence rare earth compound. The remaining solution is colorless. The brown precipitate redissolved for an unknown reason, turning the solution a pink-brown color. The solution gradually becomes colorless. The rare earth must have been oxidized.

Lead iodide reactions: The blackish precipitate is washed with water. The water is then removed and the precipitate acidified with hydrochloric acid. Chlorine gas is produced as the lead(IV) oxide oxidizes the hydrochloric acid, which then reacts with the iodine present to form a yellow solution of iodine monochloride in hydrochloric acid.

Lead chloride oxidation: When lead(II) chloride is treated with sodium hypochlorite, it turns brown. This appears to be the formation of a minute quantity of lead(IV) oxide.

12-25

Copper chloride crystallization: The evaporation is going well.

Mischmetal solution: It has turned light pink-orange.

Boron extraction: Some iron(III) oxide appeared to appeared from nowhere.

12-26

 [redacted]

Boron extraction: The boron/water mixture filters very slowly through ordinary paper, but hopefully the boron will stay on the surface of the paper. A boron spotted paper is better than no boron. Actually, a rather large amount of boron was collected by the paper and is slowly drying.

Mischmetal hydroxide: The mischmetal acetate solution was reacted with ammonia. A very light green precipitate was formed which gradually turned orange, then dark brown, at least in part of it.

Magnesium-copper chloride reaction: Magnesium turnings react fairly rapidly with copper(II) chloride, forming a mixed oxidation state complex. Aluminium tends to react more vigorously.

Iron separation from mischmetal: Hydrated iron(III) oxide dissolves in acetic acid to form basic iron(III) acetate, which appears soluble in dilute acetic acid. In the mischmetal dissolution, the iron appears to oxidize by air to iron(III) oxide, which dissolves in the acetic acid.

12-27

Cerium dioxide separation: Sodium carbonate was added to the mischmetal hydroxides because cerium dioxide was supposedly soluble in sodium carbonate. Hydrogen peroxide was added some time later. Acidification with hydrochloric acid destroyed the carbonate, while ammonia dropped no precipitate. Acidification of the remaining hydroxide with hydrochloric acid produced no sizable quantity of chlorine gas, showing that the cerium had not really oxidized to cerium dioxide. Next, the hydrochloric acid solution was diluted and magnesium shavings introduced into the solution. They dissolved rather quickly without reducing any of the iron. A piece of zinc is then added. No immediate reaction is observed other than slow hydrogen production. After a while, however, the iron is precipitated and the solution clears. The hydroxide precipitate as formed by ammonia has a light green color (praseodymium) as well as a slight color change in different light (neodymium). The separation of the rare earths from iron has succeeded! JThe hydroxide will probably turn more yellowish as the cerium(III) oxide oxidizes to cerium dioxide. Since lanthanum(III) oxide is more basic than cerium dioxide, it can be dissolved in ammonium chloride solution to furnish lanthanum chloride and ammonia gas (La(OH)3 + 3 NH4Cl -> 3NH3 + 3 H2O + LaCl3) while cerium as a more acidic member does not act in that manner. Even trivalent praseodymium, neodymium, samarium, etc. should not dissolve in ammonium salts in this way.

 

 

Wheel weight dissolution: Pieces of lead previously placed in concentrated hydrochloric acid have developed a rather impermeable coating of lead chloride. After a while, dissolution by acetic acid/hydrogen peroxide can continue, however.

12-28

Rare earth extraction: The mischmetal hydroxide has dried and shows no evidence of iron contamination to the naked eye. The oxidation of the cerium(III) has proceeded, turning it less greenish and more yellowish. This process should work well with isolating neodymium salts from neodymium magnet acetate. However, due to the historical similarity of the rare earths from each other, the ammonium chloride method was unsuccessful in isolating any lanthanum from the hydroxide mixture. The hydroxide mixture is then dissolved in acetic acid. The evidence of some formation of carbonate overnight is seen by the slight bubbling of the hydroxide as it slowly dissolves in the vinegar. The solution was then neutralized by ammonia until a sizable amount of hydroxide precipitated. This was filtered. The resulting solution was completely precipitated with ammonia. The color difference is obvious. One is a cerium-rich section, while the other is lanthanum-rich. They are not pure enough to be entered in the element collection, though, so they were discarded after production.

 

Chemicals from household substances: I began to rewrite this document.

Why I do home chemistry: I wrote a paper on why I perform chemistry at home and why it may be good for you too.

12-29

Lead carbonate production: The lead dissolution in hydrogen peroxide/acetic acid went as planned. The lead solution was pipetted off and neutralized with sodium bicarbonate to form lead carbonate. The precipitate was very heavy. After a washing with water, it was filtered on a tissue from which only a little escaped.

 

Yttrium production: The supposedly yttrium-nickel alloy ground electrode of a spark plug was placed in vinegar to dissolve the yttrium. No immediate reaction is observed, possibly because of a protective coating formed by the nickel, making it impervious to acetic acid. After over an hour, no bubbles are observed to have formed. Yttrium-nickel alloy is impervious to acetic acid.

Antimony production: The black residue from the lead dissolution was dissolved in hydrochloric acid and hydrogen peroxide added. A white precipitate dotted with black dirt (random insoluble junk) was formed. The white precipitate was washed with water to remove the [redacted] and filtered. Hydrochloric acid was then added to the precipitate in the filter paper. It redissolved and fell through the paper into another container, where it hydrolyzed a little as it hit some water. Zinc was added and a moderately vigorous reaction with the acidic solution ensued. Black flecks of antimony were precipitated simultaneously, insoluble in the acidic solution. The antimony was washed with water, dried, and photographed.

Vanadium production: A chrome-vanadium steel screwdriver bit is immersed in hydrochloric acid. The solution turns yellow and small amounts of hydrogen are produced, typical of iron dissolution. After a while, the solution turns nearly colorless and small amounts of insoluble black precipitate are formed. It is difficult to tell whether the precipitate is magnetic as the screwdriver bit is strongly magnetic, but the precipitate does not appear to be magnetic.

Lead production: The previously formed lead carbonate is redissolved in excess acetic acid and zinc is added. A black spongy precipitate, amid the fizzing, begins to form on the zinc. This precipitate is pure spongy lead metal. Some lead carbonate is visible on the bottom of the container in this picture. Once the lead sponge is compressed it becomes much smaller with release of water, just like a real sponge.

 

Nickel reactions: A nickel spark plug ground electrode is placed in a mixture of 30% hydrochloric acid and 3% hydrogen peroxide in the ratio 1:3. Dissolution begins slowly, with a green layer of nickel(II) chloride floating out of the electrode, and continues steadily.

12-30

Vanadium production: More precipitate has formed overnight. It should consist of just carbon and vanadium flecks; no tungsten or molybdenum should be present.

Copper chloride crystallization: The copper chloride appears to be just about crystallized. When a stainless steel knife is inserted into it, it begins corroding immediately, reducing the copper to the very dark mixed oxidation state complex, which gets reoxidized by atmospheric oxygen in the acidic condition.

Nickel reactions: The nickel solution is darkening but very slowly.

Lead dissolution: Here is a picture of the elements insoluble in acetic acid/hydrogen peroxide. These are all of the elements other than lead in the wheel weight pieces.

Copper comproportionation: Copper is placed in an acidic solution of copper(II) chloride. Immediately, the solution begins turning dark at the bottom. After a while, the solution ceases becoming darker. When water is added, it lightens up again instead of precipitating the copper(I) chloride crystals.

Vanadium production: The residue, which mostly appears very light (amorphous carbon), was washed with water. It is nonmagnetic, showing that no iron has been left behind. Since vanadium is 3 times denser than carbon, a drying and then dropping into water should make the vanadium fall to the bottom while the carbon is stuck on the top by surface tension. However, there is not enough vanadium to do this.

Lead sulfate production: The lead solution from the lead dissolution was reacted with magnesium sulfate to produce insoluble heavy powder of lead sulfate. The precipitate was washed with water, filtered, and dried. Like most but not all lead compounds, it is white.

Wheel weight dissolution: The black residue was washed with water and acidified with hydrochloric acid. Not much happened, although undoubtedly the tin was dissolving. Addition of hydrogen peroxide rapidly cleared the black suspension, causing fine crystals [redacted]  to fall down and collect in the bottom. [redacted] Adding water to this mixture did not hydrolyze any antimony. All of the other times the antimony was readily hydrolyzed, but here, a significant amount of sodium bicarbonate was needed to just make a cloudy solution. This has more of the behavior of tin than antimony. I’m not sure why this is. Repetition with new lead is deserved. It is strange that the cutting open of the lead pieces reveals no shine of metal inside, only a dull gray interior.

Nickel reactions: The ammonia turned the nickel solution bluish, but precipitated hardly any hydroxide. When sodium bicarbonate was added, however, a large amount of nickel carbonate precipitated. This was filtered and washed with water. Addition of a large excess of ammonia formed a blue ammine complex.

[redacted]

12-31

Nickel carbonate: It is taking a while to dry, showing that some deliquescence even after washing is present.

[redacted]

Nickel complex and oxidation: Nickel forms a yellow-green chloro complex with excess hydrochloric acid. Nickel carbonate dissolves slowly in acetic acid to form a green solution of nickel acetate. From the amount of bubbling it appears that more hydroxide than carbonate formed. Addition of sodium hypochlorite does not oxidize the nickel(II) to nickel(III), probably because the solution is too acidic.

Antimony trioxide extraction: Lead from a new wheel weight is dissolved in acetic acid/hydrogen peroxide. Some oxidation of the non-lead elements is accomplished by the hydrogen peroxide alone, as evidenced by a whitish film of oxidation products floating above the elemental powders.

Sodium bromide oxidation: Manganese dioxide powder, about 10% pure and contaminated with carbon, ammonium and zinc chlorides, and lower manganese oxides, was added to a solution of sodium bromide acidified with acetic acid. No immediate reaction occurred. Returning after a few hours, the solution is light yellow and smells of halogens.

Hydroxide                Chloride

La          Ce

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