User Guide for “Reaction Mechanism Animation” learning and teaching package

A.  Minimum system requirements

-  PC with Intel Pentium II 450MHz processor

-  128MB RAM

-  SVGA display with Hi-color, 1024 x 768 pixel resolution

-  16x CD-ROM drive

-  Microsoft Windows 98, ME, NT, 2000 or XP

-  Microsoft Internet Explorer 6.0 or above

-  Macromedia Adobe Flash Player 9

-  Microsoft Word 97

B.  Organisation of the content

The content of the package is organised as follows:

  Introduction

  Tutorial

-  Curved arrow notation

-  Homolysis and heterolysis of covalent bonds

-  Reactive species in organic chemistry

-  Three-dimensional formulae

  Animations

-  Electrophilic addition

-  Bimolecular nucleophilic substitution (SN2)

-  Unimolecular nucleophilic substitution (SN1)

-  Free radical substitution

-  Electrophilic substitution

-  Nucleophilic addition

-  Nucleophilic acyl substitution

  Glossary

  Useful Websites

  Quiz

-  Correct use of curly arrows

-  Writing reaction mechanism

-  Questions (Word document)

-  Suggested answers (Word document)

C.  Notes for teachers

The objective of this package is to complement the learning and teaching of topics related to organic reaction mechanisms in the Advanced Level Chemistry curriculum. However, teachers should note that this package may contain materials which are not included in the curriculum. These additional materials are included to provide a more thorough illustration of the concepts. Teachers may select suitable parts for teaching according to their students’ specific needs. The package consists of the following parts:

1.  Tutorial

Essential concepts and conventions for writing organic reaction mechanisms are briefly introduced. In this part, students are provided with a brief review of the curved arrow notations, homolytic and heterolytic cleavage of chemical bonds, chemical species involved in organic reaction mechanisms (e.g. nucleophiles, electrophiles, free radicals, carbocations and carbanions), and the conventions for writing three-dimensional formulae.

2.  Animations

A variety of informative animations are provided to help students visualise and learn the concepts of organic reaction mechanisms. Animations for seven types of organic reaction mechanisms are included: Electrophilic addition, bimolecular nucleophilic substitution, unimolecular nucleophilic substitution, free radical substitution, electrophilic substitution, nucleophilic addition and nucleophilic acyl substitution. For each one, the following basic information is presented:

- general mechanism(s)

- example(s)

- summary

Additional concepts are also illustrated in the animations of some reaction mechanisms, such as the structure of benzene in electrophilic substitution of benzene, comparison of SN1 and SN2 reactions in nucleophilic substitution of haloalkanes, and Markovnikov’s rule in electrophilic addition of alkenes.

Different parts of animations in each reaction mechanism can be viewed continuously or separately. The animations can be paused at anytime, and the starting-point to run the animations can be altered by adjusting the sliding bar at the bottom of the screen. These features can cater for different needs and learning paces of students. Moreover, they provide flexibility for teachers to select some individual parts of the animations for illustration in class.

3.  Glossary

In this section, the terms involved in the seven types of organic reaction mechanisms are listed with their explanations or definitions. The corresponding mechanisms which the terms are related to are also given for easy reference.

4.  Useful websites

Some websites with additional information about organic reaction mechanisms are listed for reference.

If you encounter problems accessing the websites in this part, it may be due to the flash player settings. Please go to http://www.macromedia.com/support/documentation/en/flashplayer/help/settings_manager04.html and click the option “Always allow” in the screen of the “Settings Manager”. This setting allows the flash player to communicate with other locations on the internet.

5.  Quiz

A quiz is provided to help reinforce the learning of concepts in organic reaction mechanisms.

a. Correct use of curly arrows

28 questions are included. In each question, a mechanism step is shown. Students are required to judge whether the step shown is correctly written or not and click the appropriate circle button. Students can immediately check the answers by clicking the “Check” button. For any incorrectly written mechanism step, brief explanations will also be shown after clicking the “Check” button.

b. Writing reaction mechanism

10 comprehensive questions of writing reaction mechanism and the corresponding answers are given as two Microsoft Word documents. These questions are of a more advanced level and can therefore serve as an extension of study in organic reaction mechanism. Teachers can adapt the questions for their students if necessary.

D.  Acknowledgements

We thank Prof YEUNG Lam-lung from the Department of Chemistry, Hong Kong University of Science and Technology, for his advice and his work in reviewing the contents of this package.

E.  Disclaimer and Copyright

a.  This package has been produced for the purpose of supporting the learning and teaching of organic reaction mechanisms in relation to Section 11.6 and 12.1-12.6 of the Advanced Level Chemistry Curriculum prepared by the Curriculum Development Council (2005). While the examples and quizzes included are designed in a way of catering for the whole spectrum of learning differences as far as possible, it should not be interpreted as the depth of treatment of the topic in the curriculum. Moreover, the software is not intended to be the only way to approach the topic of the curriculum. Therefore, teachers are recommended to devise various appropriate strategies to facilitate students’ effective learning of the topic.

b.  Copyright of this package belongs to the Education Bureau, HKSAR. All rights reserved. Any commercial use without prior permission is at risk of legal liability.

F.  References

-  http://www.chem.qmw.ac.uk/iupac/ (accessed in 7 January 2008)

-  http://www.chemguide.co.uk/ (accessed in 7 January 2008)

-  http://en.wikipedia.org/wiki/Main_Page (accessed in 7 January 2008)

-  Solomons, T. W. (1998). Fundamentals of organic chemistry (5th ed.). New York: John Wiley & Sons.

-  Morrison, R. T., Boyd, R. N., & Boyd, R.K. (1992). Organic Chemistry (6th ed.). New Jersey: Prentice Hall.