Battery Laboratory

You should read Batteries under the Chemistry section of this module before coming to the lab. You will investigate six different batteries in this exercise. You will be led through the procedure once by the instructor, using a copper electrode.

Equipment:

  1. Wires with alligator clips
  2. One voltmeter/multimeter
  3. One porous cup
  4. One Beaker
  5. Several of the following electrodes - Copper, Iron, Tin, Zinc, Ni
  6. Sandpaper or emory cloth.
  7. Several of the following solutions (.1M) - Fe2(SO4)3, FeCl3, CuSO4, SnSO4, ZnSO4, NiSO4, Zn(NO3)2.

Procedure:

Demonstration Battery

The instructor will connect a voltmeter to the demonstration cell and a straight wire will also be connected to the terminals to allow the "free" flow of current. Each group should record the time and voltage reading of this cell about once every 20 to 30 minutes during the duration of the lab. Make note of any changes you observe in the copper sulfate solution and copper electrode.

Single Cell Batteries

  1. Choose two of the electrodes provided. (For example, Cu and Fe)

  2. Fill the porous cup to about 3/4 full with the .1M solution corresponding to the electrode that will be placed in the cup. (For example, use CuSO4 for the Cu electrode or Fe(SO4)3 or FeCl3 for the Fe electrode.) Place the porous cup inside the beaker and fill the beaker to the same level with the other solution. The choice of which electrode goes into the beaker and which goes into the porous cup is not important. The beaker and porous cups, with their electrodes, are referred to as half cells. In combination, they form a single-cell battery.

  3. Place each electrode into the corresponding solution. You may need to lightly sand the electrodes with sandpaper or emory cloth to remove any corrosion or oxidation.

  4. Attach the leads of the voltmeter to the electrodes. Note the following:

    1. Record the value of the potential difference. Be sure to note which electrode is positive relative to the other.

    2. Determine in which direction electrons are flowing outside the battery (through the voltmeter).

    3. What reaction is taking place at each electrode within the solution? Which electrode is being oxidized and which is being reduced?

    4. Identify the cations and anions in the solution and state in what direction they migrate during the reactions.

    5. In a diagram of your battery, identify the electrodes as either the anode or the cathode and show how the ions move through the walls of the pourous cup.

  5. Take your battery to the sink and remove the electrodes. Rinse the inner pourous cup thoroughly. Your instructor may wish you to use the solution in the beaker for the other combinations.

Repeat the above procedure for all possible combinations of electrodes and their corresponding solutions. (If there are four different electrodes available, there will be a total of 6 combinations.) Save the final battery for the next section.

Multiple Cell Battery

In this section, each group in the laboratory will provide their last single-cell battery for the construction of a multicell battery. First, label each of the single-cell batteries and record their individual voltages. Begin connecting the batteries in series, positive to negative. Record the total voltage, from the negative terminal of the first cell to the positive terminal of the last cell, at each stage of the construction. All members of the class will use the same data for their report.

Report

RETURN