6 Measure the potential of the first cell by connecting M 1 to M 2 This is done

6 measure the potential of the first cell by

• Test Prep
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6. Measure the potential of the first cell by connecting M 1 to M 2 . This is done by bringing the positive terminal or lead of the voltmeter into contact with M 1 (copper) and the negative terminal in contact with the other metal M 2 . If the voltage displayed in the meter is negative, then reverse the terminals. Recall that the + terminal is the cathode and that reduction takes place there, thus you are measuring oxidation potentials and will need to change their sign to report them as reduction potentials in Data Table 2. 7. With a positive voltage displayed, wait about five seconds to take a voltage reading and record the value in DATA TABLE 1 . Be sure to press down on the metal piece in order to make good contact. Also record which metal is the positive terminal and which is negative. Use the same procedure to measure the potential of the other three cells , M 1 to M 3 , M 1 to M 4 , and M 1 to M 5 , continuing to use M 1 (copper) as the reference electrode, thus it remains connected to the positive terminal of the voltmeter and negative voltage readings are possible. 8. Analyze your data thus far and arrange the five metals from the highest (most positive) reduction potential to the lowest (most negative) reduction potential. Metal M 1 (copper) will be assigned an arbitrary value of 0.00 V since it is used as a reference electrode. 9. Using the voltmeter, measure the potential of the remaining possible spontaneous cell combinations. If the sodium or potassium nitrate solution has dried (or if any of the other solutions have dried), you may have to re-moisten it. Record each measured spontaneous cell potential in Data Table 3 and identify which metal was the cathode and the anode for the spontaneous cell. 10. Calculate the predicted potentials for the remaining possible spontaneous cell combinations and record each calculated potential in DATA TABLE 3. Show your calculations within the data table. 11. When you have finished collecting data, use forceps to remove each of the pieces of metal from the filter paper. Rinse each piece of metal with tap water. Dry it and return it to the correct container. Remove the filter paper from the Petri dish using forceps and discard it in the trash. Rinse the Petri dish with tap water, making sure that you do not touch the chemicals.