Electrochemistry (5/16)

E0 measured in volts used to refer to any reduction half-reaction

likes to be reduced, more spontaneous

uses electric energy to make a reduction reaction happen

site of oxidation

site of reduction

A spontaneous reaction is used to generate a positive potential difference that drives a current E0 must always be positive

1: identify which reaction happens at the cathode and which happens at the anode, reverse the half reaction at the anode and flip its sign and add potentials

2: identify which reaction happens at the cathode and which happens at the anode, Ecell= Ecathode- Eanode to find the different in reduction potential

two half cells connected by a wire and a salt bridge ions can travel back and fourth

electrodes must be the same material two regions must have concentration difference anode to cathode

electrical energy is used to drive a non-spontaneous redox reaction negative E0

non-spontaneous reduction of metal ion in solution results in a deposition of solid metal onto cathode mol=IT/nF current*time/ mole e- * Faraday’s constant

Can either discharge (galvanic)spontaneously or recharge (electrolytic), allowing multiple uses

has a relatively low energy density or low energy to mass ratio used in some applications today

cathode and anode

helps account for how electrical potential of a cell is affected by temperature and concentration of reactants E’cell=Ecell-RT/zF*LnQ

E’cell=E0cell-0.05916/z*logQ

lower E, more non-spontaneous

-nFE0cell