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February 23 2012 5 23 /02 /February /2012 18:52

Be sure to only dig up the interesting parts of this rather boring diary. Use Control + F to find what you want in here.

1-11

Chemistry Experiments paper: I started this and am beginning to fill it up.

1-12

Bismuth production: Pepto-Bismol is mixed with hydrochloric acid. This results in destruction of the subsalicylate complex. Zinc is added. Very slow hydrogen emission occurs. No bismuth is produced.

Bismuth production 2: I have a piece of high temp solder that has bismuth, tin, silver, and copper in it. When placed in hydrochloric acid, the tin will dissolve, leaving silver, bismuth, and copper behind. When the residue is placed in hydrochloric acid/hydrogen peroxide, the bismuth and the copper will dissolve, leaving the silver behind. The bismuth can be hydrolyzed out of solution or copper’s monovalent oxidation state can be taken advantage of. The solder has begun dissolving in HCl at the speed of tin.

Manganese extraction: A manganese(II) chloride solution was partially neutralized with sodium carbonate and reduced with magnesium. It appears that some manganese was precipitated out, although the magnesium is also in shaving form. The “manganese” sinks, while the magnesium shavings float; the “manganese” vigorously decomposes hydrogen peroxide, while the magnesium does not. This precipitate appears to be quite pure manganese metal.

Iodine oxidation: Tincture of iodine is reacted with sodium hypochlorite. Initially, the solution turns brown as triiodide is oxidized to iodide. Then, the solution immediately turns colorless. It seems that iodate is produced. A small amount of hydrochloric acid was added. Only chlorine was produced, and the solution remained practically colorless. A new batch of tincture of iodine was acidified with hydrochloric acid and reacted with a small amount of sodium hypochlorite, leftover in the vial. A dark reddish liquid (iodine monochloride) seems to have formed, immiscible in water but not decomposed by it. Upon addition of more bleach, the solution lightened and the iodine monochloride liquid turns bluish and solidified as iodine crystals. Two crystals are visible in the vial. The top paper inset was much bleached by the iodine monochloride.

Bismuth production 2: A residue is being formed as the tin is dissolving away.

1-13

Iodine oxidation: Tincture of iodine is a nice deep red when concentrated, although it turns ugly brownish when diluted. First, I acidified tincture of iodine with hydrochloric acid in the ratio 1:1. One drop of sodium hypochlorite solution was added. The solution darkened to brown and became cloudy, evidence of the formation of iodine crystals. Another single drop was added. The solution lightened up to yellow, showing that iodine monochloride solution was formed. (The amount of tincture of iodine was about 10 drops.)  Sodium bicarbonate was then added to neutralize the hydrochloric acid but not make the solution basic as the sodium hypochlorite would have. The iodine monochloride darkened amid vigorous carbon dioxide emission. The solution’s appearance turned to dark brown. Excess water was added, and the solution seemed to explode with precipitate. Iodine crystals fell out. So, it appears that too much hydrochloric acid produces iodine monochloride, while too much hypochlorite produces iodates. A neutral solution performs best at producing iodine crystals, which is why bubbling chlorine through the solution produces them best. This is the dark solution from which the iodine crystals fell out of. Reactions are: 2 NaI3 + Cl2 (formed by NaClO + 2 HCl -> H2O + Cl2 + NaCl) -> 3 I2 + 2 NaCl; I2 + Cl2 -> 2 ICl. I’m not sure of the exact stoichiometry for the final iodine production.

[redacted]

Bromine formation: Sodium bromide was mixed with water to form a paste on one side of a petri dish. On the other side, 1 mL of bleach was placed. About 0.2 mL of hydrochloric acid was added. Chlorine was produced, and it turned the sodium bromide orange. However, not enough bromine was produced, even after replenishing the chlorine, to really make the solution red. I neutralized the halogens with ascorbic acid before disposal.

Iodine oxidation: I removed most of the supernatant liquid and added water to the iodine. Just like the boron prepared earlier, the iodine seems to be in a very fine state of subdivision and forms a colloid with the water. Some settled out over time, although it takes a significant amount of time to get all of the iodine to settle out. The iodine was most definitely iodine, as a sample of it on filter paper almost completely evaporated in air in about 45 minutes, leaving a purplish stain on a nearby piece of paper.

Bromine bleach work: The bromine bleach has finally begun to crystallize. Because NaBrO3 is less soluble than NaBr, the first crystals will be NaBrO3. If I had any use for them, I would take them.

Bromate reactions: I decided to do one thing with the sodium bromate crystals so they do not just go to waste. Sodium chlorate reacts with hydrochloric acid to make chlorine dioxide, chlorine, and sodium chloride. What does sodium bromate do? Addition of a drip of hydrochloric acid produced a vigorous reaction. 2NaBrO3 + 2 NaBr + 4 HCl -> 4 NaCl + 2 Br2 + 2 O2 + 2 H2O The large amounts of gas produced did not have the extremely potent smell of chlorine. (To me, bromine has a sweetish smell, while chlorine has a more bitter smell.)

1-14

Magnet work: An unknown magnet from a landline phone’s speakerphone’s speaker was tested. First, it broke under a hammer, yielding a patched inside. A comparative alnico magnet resisted much stronger blows. The magnet must be a rare earth magnet. Then, it was placed in vinegar. If no iron in solution is produced, then it is a samarium-cobalt magnet. If the yellow-brown of iron is visible, it is an ordinary neodymium – iron – boron magnet. After 12 hours of dissolving, the solution is beginning to look yellow-brown; it must be just an ordinary neodymium magnet.

Tin production: Tin(II) oxychloride is dissolved in hydrochloric acid and zinc is placed in the turbid solution. A large amount of spongy tin formed on the zinc, probably because of the hydrogen bubbling. The sponge becomes crumbly upon drying, and small amounts of the dioxide are produced.

 

 

Bismuth production: The solder appears to have almost completely dissolved. Only small amounts of tin are left out of solution.

1-16

Bismuth separation: The tin-containing solution was decanted and a 1:1 mixture of hydrogen peroxide and hydrochloric acid was added. The solution immediately turned greenish, showing that copper is dissolving. It is very likely that bismuth is also dissolving. The silver should be left behind as its chloride is insoluble. However, just about the entire blackish residue has dissolved, and the solution is not much greener than before. A way to separate the bismuth is copper and silver’s formation of ammine complexes. Bismuth only precipitates the hydroxide under these circumstances. So an excess of ammonia was added (the solution was not neutralized) and then sodium bicarbonate was added. Neutralization occurred with the blue copper ammine complex clearly showing. A precipitate formed and gave off carbon dioxide. This is probably bismuth forming its oxy-carbonate. The bismuth precipitate seems to have occluded copper, which is not removed even by an ammonia washing. So the precipitate is light blue and looks just like copper carbonate. Reaction with bleach only produces some noxious gases as a result of the occluded ammonia and no perceptible oxidation of the bismuth. It seems that there is not much bismuth present, so extraction is difficult.

1-17

Tin(II) iodide production: The tin(II) chloride solution seen just above this was reacted with sodium iodide solution (made by adding ascorbic acid to tincture of iodine) to produce the orange tin(II) iodide. However, tin(II) iodide is partially soluble in water, tin(II) chloride solution, and alkali chloride solution. Unfortunately, all of these were present, so no tin(II) iodide precipitated. A small amount of white precipitate, however, fell out. This could be the result of the hydrolysis of the tin(II) chloride or iodide by the addition of extra water. Here is the whitish solution before the precipitate fell out. Next is tin(II) iodide produced by adding clumps of potassium iodide to tin(II) chloride solution (with excess tin present) at another lab. This higher concentration of reagents allowed the iodide to form and be seen.

Tin(II) iodide part 2: The solution of tin(II) iodide is cooled in a freezer. Nothing is precipitated. My iodide solution is not concentrated enough.

Sodium iodate/periodate production: Tincture of iodine is reacted with bleach. The iodine produced dissolves to form an almost colorless solution. Additional bleach seems to have no action, but it does; crystals of sodium periodate are slowly crystallizing out. Eventually half of the brownish solution is crystals. They are washed with ice cold water (losing about half of them). The first picture is the initial solution; the second is the initial solution upon standing; and the third is the solution after washing.

Cobalt precipitation: Another of my two micro-vials of cobalt(II) chloride solution was reduced by magnesium. Because this one was less acidic, less fizzing was visible, and the cobalt precipitated much more slowly. A video was taken regarding the resulting magnetism of the magnesium because of the precipitated cobalt. Another side effect of the lack of acidity is the formation of a green layer of cobalt(II) hydroxide on the pieces of cobalt metal. They are oxidized by the dissolved oxygen of the water to turn green.

Bismuth dissolution: Bismuth is placed in a hydrogen peroxide/hydrochloric acid mixture, ratio 2:1. No action is observed because trivalent bismuth is colorless in solution. When bismuth is cut with wire cutters, it feels soft like tin, but there is a strange crunching sound and the bismuth often shatters. While bismuth is soft like most of the poor metals, it is also very brittle. This is what causes the crunching sound. Here is a picture of the bismuth shortly after the beginning of dissolution.

Spoon dissolution: An 18/0 stainless steel spoon is placed as the anode of an electrolytic cell. The cathode is an ordinary carbon steel screw. The electrolyte is sodium chloride solution. 24 volts produces enough current to trip the built-in circuit breaker on my power supply, so I waited until it reset before using 5 volts, which works fine. Initially, hydrogen is produced at the cathode, while a green solution flows out of the spoon at the anode. After a while, the normal iron(II) hydroxide is formed throughout the container. After about one hour, the stainless steel is severely corroded and the electrolyte is a paste of iron(II) hydroxide. This is what the stainless steel looks like (right side). Below is the precipitate.

Cobalt production and oxidation: The cobalt(II) hydroxide did not turn reddish when immersed in a hot water bath. It remains green.

 

Bismuth reactions: The bismuth solution, in which a significant amount of bismuth was dissolved, was neutralized with baking soda. A pure white precipitate of bismuth(III) hydroxide, after much fizzing, was thrown down, which turned slightly yellow. The precipitate is washed and filtered. It is a good source of bismuth.

Zn      Sn

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