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1999 Summer ConfChem
Conference Articles
Abstracts of Papers:
Internet or web sites 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.
This website evolved from an earlier design of a Computer Assisted Chemistry Tutorial (CACT) system, which resided on a server of a local computer network of IBM PCs. Our students used CACT for several years before we adopted the internet technology. Thus, we call the web site Internet CACT, or simply CACT.
One of the important features for the Internet CACT is to conduct quizzes over the internet. Students have the choice of going to small group tutorials and write 5 class-room quizzes or writing 9 to 10 CACT quizzes over the Internet per term. During the Fall term (September-December, 1998), 650 of the 995 students registered in Freshman Chemistry I (CHEM120) have written 9 CACT quizzes each over the Internet site. During the Winter term (January-April), 390 of the 610 students registered in Freshman Chemistry II (CHEM123) have written 10 quizzes each over the Internet. Their marks were recorded on the same server. A locally developed program is used for this operation. While it is functioning, the website is constantly been maintained, developed, and updated.
A counter was placed in the CACT site during the Fall term of 1998. Usually, the numbers of access is about 20 per day. However, a few days before major tests and final examinations, the numbers of access were between 500 to 700 per day, usually at night. When the counter was in place, between 5 to 10 seconds was added to the time required for loading the menu. We have disabled the counter, for the convenience of students.
In this article I will share my experiences in implementation, design, development, operation, and maintenance, comment on the future outlook of using websites for teaching and learning, and will discuss our quiz design and operation. The CACT website address is http://www.science.uwaterloo.ca/~cchieh/cact/cact.html.
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.
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, and take responsibility for their success!)
We are currently trying to locate the remainder of this paper.
We are currently trying to locate the remainder of this paper.
We are currently trying to locate the remainder of this paper.
We are currently trying to locate the remainder of this paper.
The Physical Chemistry On-Line (PCOL) consortium has developed and conducted a series of short-term projects for use in the physical chemistry curriculum. The projects involve faculty and students from geographically dispersed institutions, are short in duration (~4-6 weeks), and use e-mail and the World Wide Web for communication and information distribution. They are designed to enhance physical chemistry at colleges and universities which may have limited resources available for physical chemistry, by offering an alternate pedagogical approach. This paper will highlight the motivations of the participants, outline the specific projects used to date, and provide some evaluation of the pedagogical effectiveness of the approach.
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