Lec 27 | MIT 3.091 Introduction to Solid State Chemistry

Organic Chemistry: Basic Concepts, Alkanes, Alkenes, Alkynes, Aromatics, Functional Groups, Alcohols and Ethers, Aldehydes and Ketones, Esters, Amines View the complete course at: ocw.mit.edu License: Creative Commons BY-NC-SA More information at ocw.mit.edu More courses at ocw.mit.edu
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This course is part of a series taught by Kevin Ahern at Oregon State University on General Biochemistry. For more information about online courses go to ecampus.oregonstate.edu www.youtube.com 1. The Gibbs free energy is the energy available to do useful work in reactions. The change in the Gibbs free energy for a reaction is important because it determines whether a reaction is favored, unfavored, or at equilibrium. 2. Thus, when the Gibbs free energy change is negative, the reaction in question goes forward as written, but when the Gibbs free energy change is positive, the reaction goes in reverse. 3. A related term to G is G°', which is the Standard Gibbs Free Energy change. This refers to the Gibbs Free Energy change for a reaction under standard conditions. Since most reactions occur at non-standard conditions, G is much more useful than G°'. In fact, the sign of G°' does NOT tell the direction of a reaction, except under standard conditions. 4. Chemical reactions require activation energy (I'll call it G+ here) in order to get started. Catalysts (both enzymes and non-biological catalysts) act by lowering G+. Catalysts DO NOT CHANGE G. All they do is lower the energy required to activate the reaction. While enzymes speed reactions immensely, they therefore DO NOT CHANGE THE OVERALL REACTION CONCENTRATION AT EQUILIBRIUM. They simply allow the reaction to get to equilibrium faster. 5. G is affected by the concentration of reactants and products of a reaction by the ...