Electrolytic vs. Galvanic Cell Worksheet
1.
Identify all similarities between an electrolytic cell and a galvanic cell.
Electrolytic
Anode:
Cathode:
Galvanic
oxidation
reduction
oxidation
reduction
Electrons flow from anode to cathode
2.
Identify all differences between an electrolytic cell and a galvanic cell.
Electrolytic
Anode
Cathode
3.
Galvanic
+
-
+
nonspontaneous
requires electrical input
spontaneous
produces electricity
one solution
requires electrical
2 solutions
requires a salt bridge
Explain why the charge on the anode of an electrolytic cell is the opposite of a
galvanic cell.
In an electrolytic cell, electrons are forcibly pulled away from the anode, and
deposited on the cathode. With fewer electrons on the anode compared to the
cathode, the charge on the anode is positive.
In a galvanic cell, natural competition to undergo oxidation and reduction
results in electrons left on the anode as spontaneous oxidation occurs. These
electrons then flow to the cathode where reduction takes place.
With increasing numbers of electrons on the anode compared to the cathode,
the charge on the anode is negative.
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4.
Identify the direction electrons move within in an electrolytic cell and a galvanic
cell.
In the electrolytic cells, movement of electrons through the adaptor that runs
the electrolytic cell, moves electrons from the anode to the cathode.
In the galvanic cell, spontaneous loss of electrons onto the anode causes
electrons to flow towards the cathode where fewer electrons reside.
5.
Why must the two half-cells in a galvanic cell be kept separate?
If the chemicals in ½ of the cell were to directly interact with those in the other
½ cell, a chemical reaction would results, with no electricity being produced.
By keeping the ½ cells separate, natural competition to lose and gain electrons
results in movement of electrons through an external wire that results in the
production of electricity.
6.
Explain how a salt bridge in a galvanic cell works.
The build-up of positive ions on the anode side will result in repulsion of
additional positive ions. This will prevent more positive ions entering the
solution.
As the concentration of positive ions on the cathode side decreases, the
negative ions in that half-cell will begin pulling th positive ions back into the
solution.
To prevent an imbalance of positive and negative ions in either half-cell
stopping the cell from working, a salt bridge connects the 2 half-cells. With a
free flow of ions from the salt bridge and into the salt bridge on either side of
the galvanic cell, the numbers of these ions remains fairly constant, preventing
the galvanic cell from working.
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