Electrochemistry2 Flashcards
COMMON FEATURES of Electrochemical Cells
2 ELECTRODES:
ANODE
CATHODE
What do the 2 ELECTRODES do in an Electrochemical Cell?
They conduct electricity between cell and surroundings
What happens at the anode?
oxidation half-reaction (electrons LEAVE half cell at anode) - EXCESS ELECTRONS
What happens at the cathode?
reduction half-reaction (electrons ENTER half cell at
cathode) - ELECTRON DEFICIENT
What is a SALT BRIDGE? What does it do?
A salt bridge is an inverted U tube of inert ions in gel joins half-cells via “liquid
wire” and allows ions to flow into/out of bridge to neutralize electrolyte and
complete circuit
What is an ACTIVE ELECTRODE?
redox active metal electrodes, immersed in electrolyte
What is an INACTIVE ELECTRODE?
inert conductor electrode, immersed in electrolyte
Notation for Voltaic Cells (ie. || , | , , , ( ) ) + orders?
|| physical separation of cells
| different phase as previous
, same phase as previous
( ) concentration, if included
Order same as in half-reactions:
FAR LEFT = anode electrode
FAR RIGHT = cathode electrode
Why Do Voltaic Cells Work?
potential difference between cells (‘CELL POTENTIALS’)
Ecell > 0
- positive potential = spontaneous reaction
- electrons flow
anode to cathode
-application: VOLTAIC CELLS
Ecell = 0
- no potential
- at equilibrium = no electrons flow
Ecell < 0
- negative potential = non-spontaneous reaction
- electrons flow
anode to cathode
WITH input of energy - APPLICATION: ELECTROLYTIC CELLS
Standard Cell Potential, E°cell
energy available to do the work of moving a charge between two electrodes (difference in electrical potential for reduction between the two electrodes)
E°cell = …
E°cathode – E°anode
Strength of oxidizing agent is proportional to
E°half-cell
