9.7 galvanic (voltaic) and electrolytic cells (ap chem)

components of electrochemical cell

electrodes, solutions in the half cells, salt bridge, voltage/current measuring device

electrodes

solid metals connected to an external circuit that provides an electrical connection between the two parts of the system

anode

where the oxidation half-reaction occurs

cathode

where the reduction half-reaction occurs

galvanic (voltaic) cell

uses the energy released during a spontaneous redox reaction (ΔG < 0) to generate electricity

electrolytic cell

consumes electrical energy from an external source, using it to cause a non-spontaneous redox reaction to occur (ΔG > 0)

electrodes are connected by...

an electrolyte

electrolyte

an ionic substance or solution that allows ions to transfer between the electrode compartments

salt bridge

U-shaped tube inserted into both solutions that contains a concentrated liquid or gelled electrolyte

solutions in the half cells

Ionic compounds that conduct current and/or participate in the redox reactions

voltmeter

a device used to measure voltage

direction of electron flow

anode (-) to cathode (+)

electrolytic cells involve...

a thermodynamically unfavored reaction