CHEM 154 Lecture Notes - Lecture 26: Gibbs Free Energy, Nernst Equation, Pourbaix Diagram
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Like gibb"s energy, cell potential depends on reaction conditions. the nernst equation allows us to determine cell potential under non-standard conditions: What will happen to the value of measured cell potential and the spontaneity of the reaction if the [zn 2+ ] is decreased? a) Increase, less spontaneous: decrease, more spontaneous, decrease, less spontaneous, does not change. One half-cell provides a references while the other half cell measures the concentration of h + ph = -log[h + ] An external source of electricity is used to drive a non-spontaneous reaction. Commonly used to accomplish chemical change (such as plating of metals). The amount of chemical changes produced depends on the charge passed (and quantity of electrons) Use stoichiometry to relate quantity of electrons with amount of chemical change. Automatic acid/base titrators work using electrochemical principles earned in chem 154. Ii. oh- ions neutralize h+ ions in the acidic solution:
