ma Quiz 8 key

ma Quiz 8 key - cell ( .0592/n) log Q E = 0 (.0592/2) log...

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Chemistry 106 Recitation 3-17 Name: Section: 1. (3pts) The emf generated by the cell of Sn 2+ (aq) + Pb (s) h Sn (s) + Pb 2+ (aq) is 0.25 V when [Sn 2+ ]= 1.5 M. What is the concentration of the Pb 2+ ? Pb reduction = -.126 V Anode Sn reduction= -.136 V Cathode This reaction must have a power source to run in this direction. Using E = E ° cell — ( .0592/n) log Q .25 = -.01 - (.0592/2) log (x/1.5) x = 2.47 E-9 2. (3pts) Electrolysis of MgCl 2 produces magnesium metal. What mass of Mg is formed when a current of 5.80 amps is passed through molten MgCl 2 for 1.34 days? 1.34 days x 24 hours x 3600 sec x 5.8 C x mol e - x mol Mg x 24.3 g Mg = 84.56 g day hr s 96485 C 2 mol e - mol Mg 3. (2pts) What is the emf of a tin concentration cell when [Sn 2+ ]= 0.5 M and 1.1 M? using E = E
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Unformatted text preview: cell ( .0592/n) log Q E = 0 (.0592/2) log (.5/1.1) = .0101 V 4. (2pts) Write in the appropriate word to complete each sentence about a concentration cell . a. The dilute side of the cell acts as the anode . (cathode or anode) b. E cell is zero . (zero or depends on the concentrations) Chemistry 106 Recitation 3-17 c. The concentrated side of the cell acts as the reactant : the dilute acts as the product . (product or reactant) 5. (1pts E.C.) What is the purpose of a salt bridge in both a voltaic and concentration cell? A salt bridge serves to keep the solutions neutral by adding either anions or cations. It allows for the electrons to keep flowing from the anode to the cathode....
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This note was uploaded on 04/07/2011 for the course CHEM 106 taught by Professor Herron,s during the Winter '08 term at BYU.

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ma Quiz 8 key - cell ( .0592/n) log Q E = 0 (.0592/2) log...

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