MBB 222 Study Guide - Midterm Guide: Gibbs Free Energy, Equilibrium Constant

• School: Simon Fraser University
• Department: Molec Biol & Biochem
• Course: MBB 222
• Professor: Adam Barlev

Document Summary

For the same reaction under conditions where reactants and products are not at 1 m initial concentrations (as would be true under cellular conditions), gibbs defined the following relationship to determine the actual free energy change: G = g + rt lnq (2. 14) where the mass-action ratio, q, is the ratio of initial concentrations of products over and the subscript i denotes initial concentrations. It is important to note that q reflects the actual initial concentrations of reactants and products and does not equal keq except when the reaction is at equilibrium. When the reaction is at equilibrium, g = 0, and equation 2. 14 becomes. If g < 0, the reaction proceeds spontaneously from left to right as written. If g > 0, the reaction proceeds spontaneously from right to left as written. This is because the actual concentrations of reactants and products are important in determining reaction spontaneity.