Chung Chieh
Department of Chemistry, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1
cchieh@uwaterloo.ca
Websites can store texts, articles, figures, computer simulations, multimedia segments, assignments, quiz and test questions, student records, discussion records and other materials. Information can be in the form of textbooks with the added flexibility of being hyper-linked for dynamic access. Because browsers are easily available, websites offer many benefits for educators and students. Websites have replaced posters, loudspeaker announcements, and notice boards.
I have developed a website for students at the University of Waterloo, and it has been in operation for a few years. Files for the website reside on a twin-CPU SUN Ultra Enterprises Unix server, but many pages have links to other internet sites. It can be accessed by anyone using a browser anywhere at any time, thus, it serves as a cyber office. Students registered in our courses can write quizzes over the internet using a proper browser, their marks are recorded on the same server. A locally developed program is used for this operation. While it is functioning, the website is constantly maintained, developed, and updated.
This website evolved from an earlier design of a Computer Assisted Chemistry Tutorial (CACT) system on a local computer network of IBM PCs. Our students used CACT for several years before we adopted the Internet technology.
In this article I will share my experiences in implementation, design, development, operation, and maintenance, comment on future uses of websites for teaching and learning, and discuss our quiz design and operation. The CACT website address is http://www.science.uwaterloo.ca/~cchieh/cact/.
Dr Robert John Lancashire
Department of Chemistry, University of the West Indies, Mona Campus, Kingston 7, JAMAICA
rjlanc@uwimona.edu.jm
Introductory courses on coordination chemistry traditionally introduce Crystal Field Theory as a useful model for simple interpretation of spectra and magnetic properties of first-row transition metal complexes. In addition, Crystal Field Stabilisation Energy (CFSE) calculations are often used to explain the variation of their radii and various thermodynamic properties. Such calculations predict that for octahedral systems d3 and d8 should be the most stable and for tetrahedral systems d2 and d7 would be favoured.
A more detailed interpretation of spectra relies on the development of the concept of multi-electron energy states and Russell-Saunders coupling. Most textbooks [1,9] pictorially present the expected electronic transitions by the use of Orgel diagrams or Tanabe-Sugano diagrams [10], or a combination of both. To this end, nearly all inorganic textbooks include Tanabe-Sugano diagrams, often as an Appendix.
At UWI in the past, we have used Orgel diagrams to cover high-spin octahedral and tetrahedral configurations, except those with a d2 octahedral configuration or d5 ions (either stereochemistry). For d5, no spin-allowed transitions are possible and the Tanabe-Sugano diagram is introduced to help interpret the spin-forbidden bands. For d2 octahedral, where interpretation is made difficult since generally only 2 of the 3 expected transitions are observed and the lines due to 3A2g and 3T1g(P) cross, we have once again used a Tanabe-Sugano diagram.
To make use of the Tanabe-Sugano diagrams provided in textbooks for all configurations, it would be expected that they should at least be able to cope with typical spectra for d3, d8 octahedral and d2, d7 tetrahedral systems. This is not the case. The diagrams presented are impractical, being far too small. To make matters worse, the diagram for chromium(III) d3 systems is extremely limited (D/B ~ 30) and for simple NH3 or acac complexes would require a small amount of extrapolation, whereas for the [Cr(CN)6]3- ion, D/B corresponds to greater than 50!
No textbooks give Tanabe-Sugano diagrams for tetrahedral systems and any spectral interpretations of cobalt(II) d7 tetrahedral systems revert to using Orgel diagrams. (Examples of d2 tetrahedral complexes are not very common.)
A set of UV/Vis spectra (in JCAMP-DX format) as well as spreadsheets and JAVA applets giving the Tanabe-Sugano diagrams will be made available and a comparison of interpretation methods presented.
Bert Ramsay
Chemical Concepts Corporation, 32 North Washington St., Suite 9-B, Ypsilanti, Michigan, 48197-2662
(Emeritus Professor of Chemistry, Eastern Michigan University.)
Bert@chemicalc.com
This paper will discuss how the Chemical Calculator (U.S. patents 5,265,029; 5,604,859; and patents pending) can be used as a learning tool to improve students' basic problem solving skills. The chemical calculator is designed to function as an "electronic" tablet on which the student can write the solution to a problem, and then complete and display the calculation result (with units). In addition, practice in the development of paper-and-pencil problem solving skills is provided to the student via the Personal Tutor mode. The Personal Tutor provides suggestions for correcting both unanticipated-, and commonly encountered incorrect answers. The Personal Tutor can also help with a step-by-step solution to problems. The Learning Curve Monitor tracking of 1) the number and type of incorrect answers, 2) the amount and type of help received, and 3) the time spent on the problem virtually guarantees (*) student success. (*Caveat:: the student must still do the work!)
Iris K. Stovall
Program Coordinator, Illinois Online Network, University of Illinois, Urbana IL 61801-2991
istovall@uillinois.edu
Some times departments need to consider establishing a new computer lab or upgrading an existing lab. Among the issues to be faced are new or upgraded hardware, platform, security, networking, support and applications. The potential choices are almost infinite. This paper will discuss experiences with the Chemistry Learning Center at the University of Illinois at Urbana Champaign. The decision to replace or upgrade hardware depends, in part, on the software applications currently used and on those that are anticipated in the near future. In some cases it is economically sound to upgrade existing hardware. In others, it ultimately costs less to replace old hardware with new. While the hardware is the most visible part of a computer lab, security, which is usually invisible, is the most difficult problem to solve. Students often cause accidental or deliberate harm to the operating system unless they are prevented from making modifications. On the Wintel platform System Policies and operating system provide the means to control student access while providing instructors with the access they need. Without a network many of the benefits of computers are negated and enforcing computer security becomes more difficult and time consuming. A lab of networked computers increases access to shared resources such as printers and data and allows instructors to collect information about a student's performance. Selecting appropriate networking may ultimately prove more important to the success of the lab than the choice of computers the students use.
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