19.3 Galvanic Cells
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Characteristics of Electrochemical Cells
1. The anode is ALWAYS the site of oxidation. (an ox)
2. The cathode is ALWAYS the site of reduction. (red cat)
3. Electrons ALWAYS flow from anode to cathode.
4. Anions flow to the anode and cations to the cathode through the salt bridge (in galvanic cells).
5. In galvanic/voltaic cells (spontaneous), the cathode is + and the anode is –.In electrolytic cells (nonspontaneous), the cathode is – and the anode is +.
6. Often, the cathode gains mass, while the anode loses mass (for metal/metal salt galvanic cells).
Galvanic vs Electrolytic Cells
|GALVANIC (VOLTAIC) CELLS|
|Spontaneous (ΔG < 0, Ecell > 0)|
|Produce Energy (Electricity)|
|Function as Batteries|
|Nonspontaneous (ΔG > 0, Ecell < 0)|
|Consume Energy (Electricity)|
|Often Used to Produce Elements|