Standard Cells & Cell Potential

Standard Cells Standard cell: Galvanic cell at SATP with 1.0 mol/L solutions Standard cell potential (∆E˚): Maximum electric potential difference of a standard cell Standard reduction potential (∆Er˚): Ability of a standard half-cell to attract electrons in a reduction half-reaction ∆E˚ = ∆Er˚ - ∆Er˚ cell cathode anode By convention, hydrogen is chosen as a reference half-cell and is assigned a ∆Er˚ of 0 to be used to determine ∆Er˚ of all other half-cells

Calculating Cell Potentials Although you might multiply the half-reactions by a coefficient to balance the electrons, do NOT multiply the ∆Er˚ value ∆E˚ > 0 indicates a spontaneous reaction, a requirement of galvanic cells E.g. Determine the standard cell potential for a galvanic cell in which the following reaction occurs: Zn(s) + 2AgNO3(aq)  Zn(NO3)2(aq) + 2Ag(s) http://group.chem.iastate.edu/Greenbowe/sections/projectfolder/flashfiles/electroChem/voltaicCell20.html

Electrolytic Cells ∆E˚ < 0, nonspontaneous Requires an external battery or power source Electrolysis is the process of supplying electrical energy for a nonspontaneous reaction to occur Some applications: Rechargeable batteries, production of elements, electroplating

Practice p. 708 #10-12 p. 709 # 2, 6-8 Review: p. 725 # 1-7, 10-14