chemistry
sort by: Relevancy | Title try advanced search for more options
-
It is important that chemists agree on notation and nomenclature in order to communicate molecular constitution and configuration. It is best when a diagram is as faithful as possible to the 3-dimensional shape of a molecule, but the conventional Fischer projection, which has been indispensable in understanding sugar configurations for over a century, involves highly distorted bonds. Ambiguity in diagrams or words has led to multibillion-d...more
-
-
Half a century before direct experimental observation became possible, most structures of organic molecules were assigned by inspired guessing based on plausibility. But Wilhelm Körner developed a strictly logical system for proving the structure of benzene and its derivatives based on isomer counting and chemical transformation. His proof that the six hydrogen positions in benzene are equivalent is the outstanding example of this chemical...more
-
-
-
-
-
Professor Sylvia Ceyer continues her discussion on chemical equilibrium and external effects such as a change in volume, adding inert gas, and a change in temperature. Parameters are set for maximizing the yield of a reaction, and the Principle of Le Chatelier's is returned to. Hemoglobin is used as an example involved in a series of equilibrium reactions in response to oxygen pressure.
-
-
-
-
The lecture opens with tricks ("Z-effective" and "Self Consistent Field") that allow one to correct approximately for the error in using orbitals that is due to electron repulsion. This error is hidden by naming it "correlation energy." Professor McBride introduces molecules by modifying J.J. Thomson's Plum-Pudding model of the atom to rationalize the form of molecular orbitals. There is a close analogy in form between the molecular orbita...more
