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Unformatted text preview: Page 1 of 3 Name: Quiz Section: AM Total Points = 60 Standard Potentials vs. Silver/Silver Chloride Reference Electrode Cell Numbers Potential, V Potential, V Experimental Literature (page 37) vs. Silver vs. Silver See Help Box below. (Black Lead on Ag/AgCl) (reverse leads) Values Values 1 (Ag) - Reference 0.556-0.56 0.776 0.80 10 pts 2 (Zn) - Reference-0.762 0.76-0.542-0.76 3 (Pb) - Reference-0.370 0.37-0.150-0.13 4 (Cu) - Reference 0.123-0.12 0.343 0.34 E o E o EXPERIMENT 5 Electrochemistry Part I: Standard Potentials Purpose and Method The first goal is to measure the standard reduction potentials of Ag/Ag + , Pb/Pb 2+ , Cu/Cu 2+ and Zn/Zn 2+ . How is this accomplished? ( 5 pts ) We will construct electrodes using some cellulose film, rubber band, metal ion solution, glass tube and metal electrode. These will be put together to construct a half-cell. The Ecell of each of the half cells will be measured relative to the Ag-AgCl electrode. When we are measuring the standard reduction potential of each of these, we take into consideration that the literature values were values of Ecell relative to the standard hydrogen electrode. To account for this difference, we will use the equation: Ecell= Ecathode + Eanode. Ecathode would be half-cell potentials, while the Eanode would be considered the reference cell. The Ecell comes from our observed values. The Eanode value is given to us in the prelab as 0.20V. To get the Ecathode, we would then use the following equation: Ecathode= Ecell (observed)- Eanode or Ecathode= Ecell (observed)- 0.20 The second goal is to construct a cell with E cel = 0.50V. How is this accomplished? ( 5 pts ) To construct a cell with an Ecell of 0.50 volts, we can look at the table of standard potentials and determine which two equations, when combined, would make a total Ecell of 0.50 volts.First thing we realize is that when copper (with a standard potential of 0.34) is combined with lead (with a would make a total Ecell of 0....
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