Explain why, in galvanic cells, the cathode is positive? Galvanic cells spontaneously produce electricity. The negative electrode acquires electrons that are lost from metal atoms as they become positive ions. This is oxidation (LEO). Thus, the negative electrode is the anode (the anode, by definition is the site of oxidation). If the negative electrode is the anode, then the positive electrode must be the cathode. Diagram the Zn-Cu galvanic cell. List all important aspects of the cell. Zn(s) → Zn 2+ (aq) + 2e – Cu 2+ (aq) + 2e – → Cu(s) Cell reaction: Zn(s) + Cu 2+ (aq) → Zn 2+ (aq) + Cu(s) What is a salt bridge? What is its function? A salt bridge is a connection between the two half cells of a galvanic cell. It contains ions (e.g. K + and NO 3 – ). The ions are essential to the function of the galvanic cell. As the half-cell ions decrease or build up, the ions of the salt bridge move into the half-cells to maintain electric neutrality. 17.6
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This note was uploaded on 04/12/2011 for the course CHEM 1010 taught by Professor Marshall during the Spring '11 term at North Texas.