CHEM 125a - Lecture 35 - Understanding Molecular Structure and Energy through Standard Bonds

Lecture 35 - Understanding Molecular Structure and Energy through Standard Bonds

Overview

Although molecular mechanics is imperfect, it is useful for discussing molecular structure and energy in terms of standard covalent bonds. Analysis of the Cambridge Structural Database shows that predicting bond distances to within 1% required detailed categorization of bond types. Early attempts to predict heats of combustion in terms of composition proved adequate for physiology, but not for chemistry. Group- or bond-additivity schemes are useful for understanding heats of formation, especially when corrected for strain. Heat of atomization is the natural target for bond energy schemes, but experimental measurement requires spectroscopic determination of the heat of atomization of elements in their standard states.

Resources

Professor McBride's web resources for CHEM 125 (Fall 2008)

http://webspace.yale.edu/chem125_oyc/#L35

This website may include third-party materials pertaining to relevant topics, provided for the user's convenience. Yale does not control or take responsibility for the content of any off-site pages or linked sites.

Assignment

Reading assignments, problem sets, PowerPoint presentations, and other resources for this lecture can be accessed from Professor McBride's on-campus course website, which was developed for his Fall 2008 students. Please see Resources section below.

Course Media

Transcript

html

Audio

mp3

Low Bandwidth Video

mov [100MB]

High Bandwidth Video

mov [500MB]