CHEM 1A Lecture Notes - Lecture 30: Standard Hydrogen Electrode, Galvanic Cell, Reduction Potential
Document Summary
Redox reacions involve electron transfer between an electron donor (a reduced species, oten an elemental metal) and an acceptor (an oxidized species). For reacions with favorable g, the reacion proceeds to products when the electron donor and the electron acceptor are mixed together in a soluion. In such cases, the energy is released as heat. However, there is another way of carrying out the same redox reacion. We can place each redox couple into a separate container called a half--cell. Each half--cell contains half of the reactants and half of the products (such as zn in a soluion of zn ions). The two half--cells can be combined to build a galvanic cell by connecing two metal electrodes with a wire. The two half--cells must be connected with an ionically conducing salt bridge to ensure charge neutrality of the system. Each half--cell has an electrode potenial which is an expression of the electron energy.
