Mary Lou's Diamond

    On this balmy Friday afternoon, Mary Lou found herself among the small group of students waiting outside the door of the chemistry stockroom. Prof. Bengston was busy inside preparing a solution for them to separate into components. But her heart was not in lab that afternoon. During lunch, she had gone across the street to collect some sand in a small bucket to use in one of her floral creations. After running her fingers through the sand for several minutes to pick out stray pebbles and grass, she discovered that the small diamond in her ring was gone! She remembered distinctly seeing it twinkle in the sunlight moments before plunging her hand into the sand. "It must be somewhere mixed in with the sand. I can't lose it: it was my grandmother's ring. Mother will kill me!" So my dear readers, you can see why her mind was elsewhere rather than on the unknown solution.

   When Prof. Bengston finally reappeared, he handed them a screw-capped bottle containing a blue liquid. They were told that there were two components in the bottle.

   At first they thought it might be a good idea to determine what the major component was. It didn't smell like anything unusual - not gasoline or something like that. But still it might be flammable. They dipped a strip of paper into the liquid and saw that it soaked into the paper. Then, using a test-tube holder they brought the moistened paper near a flame, but the paper did not burn until the heat dried it out. It seemed the major component, the diluent, was probably water - probably.

   Since it was nonflammable, this made it easy to heat, and they found that a small sample of the blue liquid boiled very close to 100c (water?), but it lost its color. "Humm - seems to be an aqueous solution of something that is thermolabile," muttered Wilbie using his usual esoteric science-speak. "Perhaps it will get blue again when cool." After waiting, for awhile, it did NOT get blue again.

   "Well, that rules out our distilling the water away to recover the blue stuff," thought Cheryl out loud, and getting an admiring glance from Jimmy, who was just beginning to understand.

   They then each took small aliquotes from the bottle, and split up with each person trying one of the several alternative ways they agreed on might be useful. Jason added some NaOH to raise the pH and make it basic hoping that the blue would precipitate either as a solid or float to the top. Wilbie did just the opposite and added some HCl to lower the pH and make it acidic. Jimmy added some sodium carbonate hoping that a common anionic precipitator might work (hopefully making "blue carbonate"), and Cheryl tried adding some barium chloride to hers hoping a common cationic precipitator might work (making barium blue-ate"). Mary Lou begged to be secretary as she was totally incapable of thinking straight. The results were unanimous - nothing worked!

   The group parted promising each other that they'd put a lot of weekend thinking into various ways, but the only thing Mary Lou could think of was the diamond lost in the sand now sitting atop her lab bench back at school.

   Not wishing to tell her brother Jason that she had lost the diamond, she tried very obliquely to ask him how he might extract a diamond from sand. Fortunately for her, he was busy getting ready for soccer practice, and only off-handedly told her to surf the web. It wasn't long before she saw deBeers rock crushers pulverizing kimberlite and then how the gravels were sluiced through rivers of water for awhile. Then the bottoms of the sluices were lifted up, and some gooey grease was scraped off with big putty-knives. This was melted and floated to the top of the cauldron, while diamonds - even very small ones - collected at the bottom of the kettle.

   On Monday, while the others discussed any ideas they had gotten over the weekend, Mary Lou was busy spreading vasoline all over the bottom of a short length of eave trough (aka "roof gutter"). She then continued to make wet messes by making a slury of her small amount of sand in water and allowing it to run down the tilted, gooey trough.

   Of course, all her wet-and-sloshing commotion attracted the attention of the others, but she wouldn't confess to what she was really up to. "I'm busy!" is all she said.

   Finally, after sloshing the sand slurry from one end of the trough to the other many times, she dumped the slurry into a big bucket just in case the diamond was still in the slurry.

   She then poured boiling water down the trough to melt the vasoline, and collected it in a bucket. Soon the molten vasoline separated from the hot water and formed a liquid layer atop the water. At the bottom of the bucket were a few granules of sand (and hopefully the diamond also!). She dumped off the liquids into another bucket and poured the granules onto a paper towel to dry and then carefully dumped the dried granules onto her black bench top.

   "Wilbie, got yer magnifying glass?" she begged knowing he carried a wide assortment of such exploratory tools in his outlandishly large backpack.

   Almost immediately, she let out a shriek, and let Cheryl take a peek. One of the granules was a nicely faceted bit of crystalline substance - the diamond.

   With a great sigh, she settled back with the diamond now safely inside a small screw-top test tube and in her purse.

   She was about to confess to all what had been worrying her, when her brother suddenly let out a whoop and ran off to the stockroom, and soon returned with a bottle ether. "Please turn off any flames! My sister just gave me the idea that I think'll work."

   They all clustered around Jason - with, of course, Mary Lou trying to nudge between Cheryl and Jimmy. Jason filled a test tube a third full of the blue mystery solution and then added about an inch of ether, which, being both immiscible in water, and less dense than water, floated on top. He covered the top of the tube and shook it. As the mix slowly began separating back into the ether and aqueous layers, it was now the upper ether layer that was blue, while the aqueous layer was colorless. "Now if we use a suction bulb to take out the blue layer and put it in another tube, we'll be almost there," instructed Wilbie.

   Cheryl had gone over to the fume hood, turned its fan on and gotten a large beaker of hot water from the faucet. Into that was set the blue ether tube and soon it was boiling (ether's bp = 37c [body temperature]), and quickly was containing less and less ether and more and more intense blue. Soon they had one tube of water, and one tube of dried blue dye. The separation was completed!

    EXPLAIN in 50 words or less the reason(s) the diamond (but not the sand) got caught in the vasoline AND the reason the blue dye went from the water to the ether. (The members of the first two groups to answer this properly will get an extra 5 pts on the next quiz.) (Hint #1: "chromatography"; hint #2: this might or might not have to do with the "teflon experiment" mentioned on one of the first green sheets you were given at the beginning of the semester.)