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CHEMICAL PROJECTS Research Ideas for Young Chemists JAY A. YOUNG, King's College, Wilkes-Borre, Penna. JOHN K. TAYLOR, National Bureau of Standards, Washington, D. C.
A Temperature Sensitive Stirring Rod See: Emu, K.D., A N D S C H ~ L ES. S ,R., J r . , J . Chen~.Educ., 35,527-S(19.58). Nitmgen(1V) oxide is prepared and transferred to a small tube, dosed a t one end and immersed in sn ire bath. The top of the small tube is then sealed ofF. The procedure is essentially simple, though good technique is required and a beginner would ~ r o b n h l ynot succeed in his first attempt. At moderately high temperatures the gas confined in the bube is largely NO*; a t Ihw temperatures the dimer, NO4, predominates. Since the momomer is colored and the dimer is colorless, the sealed tube ran be used as a temperature sensitive st,irring rod.
Question: You have two choices if you wish to undertake an investigation in this field, ~~k~ a temperature sensitive stirring rod; or decide llpon some other unique property of some other substance .,mixture of substances and use that property to make n device will have some NOTE: The nitrogen oxides are mildly poisonous; care should be exercised.
Zone Refining See CHRISTIAN, J. D.,J . Chem.Educ., 33,32(1956). Zone refining is a, highly efficient technique far the purification of a variety of materials. The proceas roneists in the gradual transport of an ingot through a narrow molten zone. The slow sulidifiration of the material s t the coaling end of the molten zone results in a crystallization process in which impurities are rejected. Zone refining is ueed for the preparation of highly purified materiels including silicon, tin, germanium, antimony, and various organic materials. The reference cited above describes x, simple procedure that is not only instructive in demonst,mting the principle of eone refining, but should be useful in t,he purification of many lowmelting materials. Essentially, the material is contained in a small-bore Pvrex tube that is named slowlv throueh a hot zone created by an eloctrird heating tape. Colored p-dichlorobenzene cakes and naphthalene are suggested as test materials.
as well as the theory of the technique. The art,icle cites references that should be helpful in bath respects. Questionr: Conatrurt apparatus for purification by zone refining and purify several materials by its use. Look into methods far determination of the purity of the materials selcrted for refining and compare the efficiency of your zone-refiner with other methods of purification, e.g., solvent crystdlizstion. For a selected material, study the variables affecting the efficiency of eone refining, such ss rate of transport through the molten zone. size of molten sane. diameter of "inzot." nosition of t,hetube. The author mints out thst the removal of fluoresrent imourities makes a dramatic demonstration. Could fluorescent impurities be added intpntionxlly as tracers to indicate the efficiency of the
The alert student will want to delve into practical applications
The Extraction of Metals from Ores See KEUBEL,A., J . Chem. Educ., 21,148-9 (1944); GECKLER, R. P. C. H., J.Chem. Educ., 21,350,436, a,nd439(1944). In these articles the authors discuss the extraction of four metals, uranium, indium, lead, and copper, from their ores. Sufficient details are given so that the extractions can be carried out hp interested students. NOTE: Because of the hazard involved, beginning students should not attempt the extraction of uranium from pitchblende. However., the eeneral orincioles which a o d "v to the winnine" of a m&nl fram an ore in which it occurs in small amounts are discussed in the article hy Keubel. This discussion will be helpful t,ostudents who elect to work in the area defined by the questions, helow.
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Questions: Using one of the ores for which an extraction procedure is
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MARCHI, L. E., J . Chem. Edue., 21,407-11 (1944); and STONE, deeeribed in the cited articles, devise a. different method for the extraction of indium, copper, or lead fram the selerted ore. Select another ore containing indium, lead, or copper, but for which an extraction procedure is not described in the cited articles, and devise a suitable procedure for the extraction of metal from this ore. Select an are of some other metal, and devise a procedure far the extraction of the metal, or metals, from this ore. For any question, above, which you have elected to study, what is the efficiency of your process, in terms of the per cent of the metal, present in the ore, which you finally obtain in the metallic state? Far any question, above, which you have elected, can your procedure be improved either to yield the desired metal more economically, or in a state of higher purity?
