CHEM 201 Lecture 16: Chem 201 Lab Report 6

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19 Feb 2020
Rebecca Tsarofski 4/18/19
Lab Partner: Olivia Mattos
Chem 201 Experiment 6
Electrochemical Cells
Procedure: Please refer to page 19 of my laboratory notebook for an outline of the steps to be
followed for this experiment. Each group produced about 110 mL of waste and there were no
changes made to the procedure.
Experimental and Calculated Data
Red Lead
Black Lead
Measured Ecell (V)
Calculated Ecell (V)
Percent Error
0.10 M Zn²
0.10 M Cu²
-1.086 V
-1.10 V
0.10 M Zn²
0.0010 M Cu²
-1.050 V
1.04 V
0.0010 M Zn²
0.10 M Cu²
-1.094 V
-1.16 V
0.10 M Cu²
0.0010 M Cu²
0.079 V
0.06 V
0.10 M Cu²
0.010 M Cu²
0.064 V
0.03 V
Cu²⁺ + 2e- Cu
Zn² + 2e- Zn
In this experiment, my partner and I carried out several serial dilutions to get the correct
concentration of each solution. Using different pairs of solutions for the red and black leads, we
determined the measured Ecell with the pH meter value displayed. To find the calculated Ecell,
we used the Nernst equation and plugged numbers in. We used both of those values to solve
for the percent error of each trial.
After solving for the calculated Ecell, I was able to compare the two values to each other.
For the most part, the experimental cell potentials were decently close to the calculated ones.
The largest gap occurred with cell E, with an measured potential of 0.064 V and a calculated
value of 0.03 V. The differences between the two columns of values could be due to errors
made during the experiment, including allowing the salt bridge to touch the electrodes or not
properly cleaning the electrodes between each trial. My partner and I did not have good data for
cells D and E, which led us to obtain data from another group. It is possible that the last two
trials had incorrect values because we did not assign specific electrodes to each concentrated
I noticed that the percent errors of the electrochemical cells containing Zn² were much
closer to zero than those containing C. When we diluted the C solution for the Daniel cell
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