12.1 Electrochemical Cells Flashcards
Electrochemical cells
convert between electrical and chemical energies
utilizes redox reactions (transfer of electrons) to harness electricity (flow of electrons)
(either generate electrical energy from chemical reactions or generate chemical energy from electricity)
2 fundamental types of electrochemical cells
galvanic (voltaic) cells
electrolytic cells
3rd: concentration cells (for another time?)
which electrochemical cell types house non spontaneous reactions
electrolytic cells
which electrochemical cell types house spontaneous reactions
galvanic (voltaic) and concentration cells
2 types of electrodes
anode: the electrode where oxidation occurs
cathode: the electrode where reduction occurs
An Ox; Red Cat
anode
electrode where oxidation occurs
cathode
electrode where reduction occurs
purpose of galvanic cells
to collect electrical energy from a spontaneous chemical reaction
purpose of electrolytic cells
to convert electrical energy into chemical energy
a RECHARBEABLE battery
plugging phone into wall to recharge the battery
main difference between galvanic cell and electrolytic cell?
flow of electrons is reversed!!
we are putting the electrons back into the cathode so we can redo the chemical reaction and harness more energy later
which direction is the flow of electrons in a galvanic cell?
anode to cathode
spontaneous flow of electrons… going the the place of reduction
does the flow from anode to cathode change between the 2 cell types?
NO! anode will always be oxidized and cathode will always be reduced!!
what changes is which chemical species is the cathode/anode
which direction is the flow of electrons in an electrolytic cell?
anode to cathode
electrons ALWAYS flow anode to cathode
which direction is the flow of charge in an electrochemical cell?
cathode to anode
the flow of charge is always opposite th flow of electrons
what are the 2 separate compartment of galvanic cells called
half-cells
Salt bridge
the structure which connects the 2 solutions; consists of an inert salt/electrolyte
allows anions and cations to flow into either half-cell to balance newly generated charges so the reaction can continue
[…] is the shorthand notation used to represent the components of a voltaic cell without having to draw a picture of the whole things
Cell Notation / Cell Diagram is the shorthand notation used to represent the components of a voltaic cell without having to draw a picture of the whole things
cell diagram
Anode | anode sol’n (concentration) || cathode sol’n (concentration) | cathode
electrons always flow from —– to —— in ALL electrochemical cells
anode to cathode
Standard Reduction Potential
describes each elements natural tendency to either gain or lose electrons
positive Standard Reduction Potential
element sponteneously GAINS electrons
wants to be reduced
negative Standard Reduction Potential
element sponteneously LOSES electrons
does NOT want to be reduced
Standard Reduction Potential of the entire cell
when SRP is positive
delta G is negative (spontaneous!)
in galvanic cells, the anode is…
charge
negatively charged
anode loses electrons… electrons move away from negative charge
in galvanic cells, the cathode is…
charge
positively charged
cathode gains electrons… electrons move toward the positive charge
the standard cell potential is…
the voltage difference between the anode and cathode
In a galvanic/voltaic cell, the standard cell potential is [positive/negative]
positive
In an electrolyric cell, the standard cell potential is [positive/negative]
negative
Cell potential energy (E cell)
a measure of the spontaneity of the reaction
the larger the cell potential, the more …
… work we get out of the cell
