High School Chemistry : Help with Galvanic Cells
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Example Question #1 : Electrochemistry
Which statement is true of a galvanic cell?
Electrons travel from cathode to anode, oxidation occurs at the anode, the anode is the negative electrode, and the reaction is spontaneous
Electrons travel from anode to cathode, oxidation occurs at the cathode, the cathode is the negative electrode, and the reaction is spontaneous
Electrons travel from anode to cathode, reduction occurs at the cathode, the anode is the negative electrode, and the reaction is nonspontaneous
Electrons travel from anode to cathode, reduction occurs at the cathode, the anode is the negative electrode, and the reaction is spontaneous
Electrons travel from cathode to anode, reduction occurs at the anode, the cathode is the negative electrode, and the reaction is nonspontaneous
Electrons travel from anode to cathode, reduction occurs at the cathode, the anode is the negative electrode, and the reaction is spontaneous
Galvanic cells always involve spontanous oxidation-reduction reactions. In any electrochemical cell, the electrons always move from anode to cathode. Also, the anode is always the site of oxidation, and the cathode is always the site of reduction. Since the reaction is spontaneous (net release of free energy) it drives the movement of electrons from the anode to the cathode. Remember, oxidation is loss of electrons and reduction is gain of electrons. Since oxidation always occurs at the anode, we are left with an excess of electrons, making it the negative electrode. It should makes sense that the extra electrons from the anode spontaneously travel to the cathode (positive electrode).
To help remember oxidation-reduction processes, consider the mnemonics "OIL RIG" and "An Ox, Red Cat." OIL RIG stands for "oxidation is loss, reduction is gain" in reference to electrons. An Ox, Red Cat tells us that the anode is the site of oxidation, while the cathode is the site of reduction.
Example Question #1 : Help With Galvanic Cells
Which of the following differences between galvanic cells and electrolytic cells is false?
Electrolytic cells have negative voltages
Electrolytic cells are non-spontaneous
Electrolytic cells have oxidation take place at the cathode
Electrolytic cells have a positive Gibb's free energy
Electrolytic cells have oxidation take place at the cathode
Electrolytic cells use non-spontaneous reactions that require an external power source in order to proceed. The values between galvanic and electrolytic cells are opposite of one another. Galvanic cells have positive voltage potentials, while electrolytic voltage potentials are negative. Both types of cell, however, have oxidation occur at the cathode and reduction occur at the anode.
Example Question #3 : Electrochemistry
For the following reaction to occur does the does the electrochemical cell voltaic or galvanic?
Galvanic
Both
Neither
Electrolytic
Galvanic
First we must rearrange the reduction potentials so that when added together, they match the reaction that takes place in the electrochemical cell.
In the overall reaction, 
Use the equation: 
The cell must be galvanic because the 
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