Electrochemistry Flashcards
Steps of Balancing a Redox Reaction
- Oxidation States
- Half Reactions
- Mass
H2O, H+
Basic Solution
OH- - Charge
More positive side - Multiply both sides of rxn
- Add/Cancel Out
- Verify
Voltaic Cell
the electrochemical cell that produces electrical current from a spont. chemical rxn
Electromotive Force (force that results in the motion of electrons)
driven by a change in potential energy between anode and cathode
How do electrons flow?
From the anode (negative charged electrode) to the cathode (positive charged electrode)
What are the potential energies for a anode and cathode?
High P.E. to low P.E.
@ which site does oxdiation occur?
Anode
@ which site does reduction occur
Cathode
What neutralizes the charge buildup in the solution?
Salt Bridge
What is used to determine Ecat and Eano?
Standard Hydrogen Electrode (SHE)
What is the formula for calculating the overall cell potential?
Ecell = Ecat - Eano
NIO?
More negative is oxidation
PIR?
More positive is reduction
Standard Potentials for Half-Rxns
All half reactions are written as reductions
Ecell are relative to the SHE (0.00V)
Ecell (+) = reduction is favored
Ecell (-) = reduction is not favored
What will an oxidizing agent do to a reducing agent below it?
Oxidize
What will a reducing agent do to a oxidizing agent above it?
Reduce
Spontaneous Redox Rxn
DeltaG = negative
Ecell = positive
K > 1
Nonspontatnoues Redox Rxn
DeltaG = positive
Ecell = negative
K < 1
Delta G = -nfEcell
F = 96,458
n = moles of electrons
Write the electrochemical cell notation for copper and silver.
Draw voltaic cell
E cell = (+)
Spontaneous Redox Rxn
E cell = (-)
Nonspontaneous Redox Rxn
What are the standards for CU and Ag?
Cu/Cu2+ potential = 0.337V
Ag/AgCl potential = 0.197V
What acts as the electrode in a voltaic cell?
Metal strip (conductive surface)
What happens to the mass of metals in a voltaic cell?
Mass of anode metal decreases and mass of cathode metal increases
What charge would an electrode potential be, with a greater potential energy of an electron at that electrode?
The charge would be more negative because anodes (NIO) have a higher potential energy.
Electron w/greater tendency for reduction is charged relative to SHE?
positive charge and positive Ecell
Electron w/lesser tendency for reduction is charged relative to SHE?
negative charge and negative Ecell
