Pros And Cons Of Lead-Acid Electrochemical Cells Lab Report
Determining Standard Reduction Potentials, Equilibrium Constants and Investigating a Lead-Acid Electrolytic Cell Purpose Experimental Methods All procedures were followed according to the lab manual (experiment 10 – Electrochemistry Laboratory). Data and Observations Part A: Grams of FeSO4 used: 0.759 Voltage during voltmeter and battery check: 9.23V Table 1. Electrochemical Cells Data Part B: Table 2. Lead-Acid Battery Results and Calculations In order to make 5ml of 1M FeSO4(aq) (molar mass = 151.92), we calculated the needed grams according to c= n/V; 1 = n/(0.005), n = 0.005. Since n = m/M, 0.05X151.92 = 0.7596g. Part A: Cu2+ (aq) + Zn (s) Cu (s) + Zn2+ (aq) E°cell = 1.06 V Cu2+ (aq) + 2e-
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0.34 V – 1.06 V E°red (Zn) = -0.72 V E° = RT/nF · lnK; n = 2 as 2 electrons were transferred from Zn to Cu 1.06 = (8.314 · 298)/(2 · 96485) · lnK K = 7.16 · 1035 Zn2+ (aq) + Mg (s) Zn (s) + Mg2+ (aq), E°cell = 0.66 …show more content…
This is indeed similar to the case where hydrogen is taken to be the standard for comparison for all the other elements, given a E°red of 0. From our results, E°red(Cu)> E°red(Fe)> E°red(Zn)> E°red(Mg). Although this relation remains true when we look at the electrochemical series, our experimental values differed from the actual values. In magnesium, the experimental value was -1.38V (actual value: -2.37V). Hence, the percentage error was -41.8%. In iron, the experimental value was -0.14V (actual value: -0.44V), and so the percentage error was -68.1%. In zinc, the experimental value was -0.72 (actual value: -0.76), and the percentage error was the lowest: -5.2%. The difference in values could have resulted from the fact that the temperature was not exactly 298°K, thus altering the calculated reduction potential of the
0.34 V – 1.06 V E°red (Zn) = -0.72 V E° = RT/nF · lnK; n = 2 as 2 electrons were transferred from Zn to Cu 1.06 = (8.314 · 298)/(2 · 96485) · lnK K = 7.16 · 1035 Zn2+ (aq) + Mg (s) Zn (s) + Mg2+ (aq), E°cell = 0.66 …show more content…
This is indeed similar to the case where hydrogen is taken to be the standard for comparison for all the other elements, given a E°red of 0. From our results, E°red(Cu)> E°red(Fe)> E°red(Zn)> E°red(Mg). Although this relation remains true when we look at the electrochemical series, our experimental values differed from the actual values. In magnesium, the experimental value was -1.38V (actual value: -2.37V). Hence, the percentage error was -41.8%. In iron, the experimental value was -0.14V (actual value: -0.44V), and so the percentage error was -68.1%. In zinc, the experimental value was -0.72 (actual value: -0.76), and the percentage error was the lowest: -5.2%. The difference in values could have resulted from the fact that the temperature was not exactly 298°K, thus altering the calculated reduction potential of the