Electrochemical Reactions

The purpose of the experiment is to perform five electrochemical reactions using a voltage probe. The overall goal is then to measure the voltage, compare it to the theoretical values, calculate the concentration of the cells, and identify unknown metals in the cells. The theoretical E° of the Cu-Pb voltaic cell was calculated simply by subtracting the E°cathode by the E°anode (E_cell^o=E_cathode^o-E_anode^o), using the given standard reduction potentials. In the reaction, Copper, the cathode, was reduced and Lead, the anode, was oxidized. The E°cathode for Copper had a potential of .34 V. The E°anode Lead had a potential of -.13 V. Thus, the calculated theoretical E° of the cell was determined to be .47 V. The average experimental E° for the Cu-Pb cell was found to be .486 V, giving a 3.404% error when compared to the theoretical value.

Cu-Pb Voltaic Cell:
Reduction Half-Reaction Cu_((aq))^(2+)+2e^-→Cu_((s) )
Oxidation Half-Reaction 〖Pb〗_((s))→〖Pb〗_((aq))^(2+)+2e^-
Balanced Chemical
Equation Pb_((s))+Cu_((aq))^(2+)→Pb_((aq))^(2+)+Cu_((s))
Standard Cell Notation Pb_((s)) |〖Pb〗_((aq))^(2+) ||Cu_((aq))^(2+) |Cu_((s) ) The

E_cell^o was determined to be 0 V since the same metal was used as the electrodes. In doing so, the differences in the standard reduction potentials was 0 V. The R value, the ideal gas constant is given in 8.314 J/(mol K), T is the temperature at standard conditions (298.15 K), n is the number of electrons transferred (2 in this case), and F is the Faraday Constant of 96485.3399 J/(V mol). The reaction quotient, Q, was determined to equal the concentration of the concentrated Copper ion divided by the diluted Copper ion concentration (Q=([Cu_diluted^(2+)])/([Cu_concentrated^(2+)])= .05 M). The average corrected Ecell was found to be .042 V, givng a 10.52% error when compared to the theoretical