Dean Skovlin and Bill Harrison of Cal. State University, Northr~dgewho tirst s t a r t e d me thinlung about t h l s problem: and K n s t ~ nW v n n ~ J o n e sfor a copy of the* Instructions for her Nine shution Puzzle. Appendix: Details of Procedure This series of exercises can be carried out on two scales: (a) classical centrifuge
tube semi-micro (181,or
(b) spat plate and dropper, to minimize reagent use lems of waste disposal.
and prob-
(We currently use (a) for most parts, but use (b)to show, for example, that Co2+,Ni2+.and Fe3+can he simultaneously identified in one drop of solution). The concentrations of the unknowns are uniformly 0.1 M (nitrate, sulfate, or chloride in acid medium, as appropriate); the specific reagents are generally 2 M, while the bench reagents are 4 M. These concentrations give good visible precipitates with less than 10 drops of the reactants. We use 5%thioacetamide and follow the standard practice for precipitation of the metal sulfides.
CAUTION:Students always must be informed of the high toxicity of the H,S that is produced.
However, we are totally convinced that the importance of seeing the various colored sulfides far outweighs the slight potential danger of any H2S that is liberated. Generally, the procedures and reagents are minor adaptations of what is in the well-known books (6), especially that by Vogel(18). Waste disposal problems are no different from those encountered in the standard Fresenius scheme (21). Copies of the complete set of instructions for the seven practical sessions are available on request.
Literature Cited 1. Fresenius,C. R. QuolifotiueChemlcolAnolysis:loth ed: Churchill: landan, 1881;pp 291-317 dextipfion of the "claseicalscheme". 2. Maeller 2;Bailar. J. C.: Kleinbelg,J.:Guss,C.O.;CasteUion,M.E.;Meh,C.ChamInorganic Quolitofiue Amlysis; 3rd ed: Harcourt Brace Jovanovich: istry, ~ i l h on 891-964. New York. 1989: ... 3. Jenhs. R A n Infmdudion to X-Ray Specfmmhy;John Wiley: New York. 1983. 4. mug, H. P.;Alexander,L. E.X-rayDl/fmclionPmcedures; J. Wiley: New York, 1954. 5. van Spronsen,J. W The Petidic System of ChemM Ekmmb; Elsevier:Amater dam. 1969:p 137. 6. Bmum, T L.; IeMay,H. E. QuolitdiueImrsanieho1~is:Prentice-Hell:New Jer. sey, 1983. 7. Red, R D.: Cortelou,W P; Calandra , A. J Chrm. Edue. 1940,17,220.See also Bendeni-Pichler, A. A; Sehneider.F.; Steinbach,0. F.;J. Chem. Edue 1951.34,
em
8. Ling. M.J Cham. Edue 1984.66.746. 9. Laing, M. S. A. J kience 1991.87.285-287. 10. MaeUer, T. Inorganic Chrmislgv;John Wiley: New Vork. 1982;p 247. n. ~ouglae.B E.; ~ c ~ a n i eD.l .H.; ~lexander, J. J. concepts ond ~odoisoflnorganic New York. 1983:pp 616617,620-621. Chemistry, 2nd *John W~lw: , 12. Wulfsberg,G. P~incipks ofDosctip.5~ Ino?pg.nir Chamistry; BmokssiCole: Monterey.1987: especially Chapter 3. 13. Davenport,D. A. J. Cham. Educ. lW0,47,271;famoushrtheterrible warningthat ens'.. and for remindins us that alwavs "Silver chlo"de ia a ,ode ereen . %e #rim elknee of facts remainam. 14. Verksde, J. G. J Chrm. Edue 1881.68.911414. 15. Drago, R. S.; Bmwn, T L. Expe?imenls in Oenerd Chamisfry, 3rd ed; Allyn and Bacon: Boston,1970;pp 215-228. 16. (a1 Johnstone,A J C h m . Educ 1984.61.847.ibl 6UI lnternati0n.dConferen- on Chemical Edueation,Maryland,1981;h e e d i n s p 116. 17. Marcus,S.; Sienko, M. J.; Plane, R. A. Ezpetimntol General Chmdry; MMeCrawHill: New Yark, 1988:pp 37742. 18. Voge1.A. I. MacmandSemimicro Quolihtim hoganleAnolysis.4th ed; hqmans Green: Landon, 1954;p 222. 19. (a1 Steig.3.J. Chem. Educ 19&5,65,3M.lbl Finhalt,J. E. J Chem. Educ 1984.61, 849. (cl MacWod, G. E.; Lassetfre, E. N.: Breen, G . J Cham Educ 1940,17,520. (dl Slowinski,E. J.; WolPey. W. C.; MesteMn, W. L. Chamicol Principlas in tha Lobomfogv.4th ad.;Saunders:New Ymk 1985;pp 311319. (el WymneJones,K 11th Internotional Conkmncr on Chemrml Edumtion. York, 1991;Proeeedinga, p 1C9,Abshaet P2.41. 20. Alexander, W.; Street, A. Metals in tha Seruin ofMan 8th ed: Penyio: London, 1982. 21. Petty, J. T J. Cham. Edue. 1991.68,942943,a truncated amawment ofqualitative analwli. which emohadzes the mmimization of the ~rablemsof waste dir-
Nominations Being Solicited for the Fourth Brasted Memorial Award Nominations for this Award, which is adminstered by the ACS Division of Chemical Education through its International Activities Committee, are now being solicited. The fint Brasted Memorial Award was presented to Professor David Waddington (of the United Kingdom) at the Division's Tenth Biennial Conference on Chemical Education, held in West Lafayette, IN, in 1988. The second Brasted Award was presented to Professor Aleksandra Kornhauser (of Yugoslavia)at the Eleventh Biennial, held in Atlanta, GA, in 1990. The third Brasted Award was presented to Professor Ernesto Giesbrecht (of Brazil ) at the Twelfth Biennial, held in Davis, CA, in 1992. The fourth Brasted Award is to be presented at the Thirteenth Biennial, to be held at Bucknell University in Levisburg, PA, in 1994. The primary criterion for eligibility far the award is significant cantribution to the advancement of chemical education internationally-a criterion that clearly described a n important part of Bob Brasted's life. Anyone wishing to nominate an eligible person should send a nominating letter (in English), not t o exceed two typewritten pages in length (single spaced), which describes the candidate's contributions to chemical education, with particular reference to the international aspects of these contributions. A curriculum vitae and other supporting documentation (10 pages, maximum) should be attached to the nominating document, and a seconding letter is required. The nominee must not he a citizen or a resident of the United States, but the nominator and seconder may he from any country. The nominating documents should be sent to the Committee Chair, Rofessor Zafra Lerman, Institute for Science Education and Science Communication, Columbia College, 600 S. Michigan Avenue, Chicago, IL60605 U.S.A., in time to reach her by November 30,1993. She will forward all nominating documents to the Brasted Award Subcommittee of the DIVCHED International Activities Committee. It is intended that the name of the Award recipient shall be announced by March 31,
1994. The Brastrd Mcmonal Award mnsisrs of rconnmy class air farr fmm the recrpltnt's humc city ta the lliennial .Lewisbury, PA, in this rase,, l w n g expenses at the Biennial C'onfrrmrc, n one-yearrnembcrsh~pin r h r D ~ s l o nof Chemical Education, and a one-year subsrr~pr~on to the Journnl ofChpn,,~alEdumlio,,. Thc rcriplrnt is expected to present the Brasted Memorial Award Lecture a t the Biennial Conference on Chemical Education.
670
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