Download ELECTROCHEMICAL LEMON

ELECTROCHEMICAL LEMON
In this lab we will study oxidation-reduction reactions and electrochemistry by
using a lemon to make a battery. You will use a lemon and a pair of electrodes of your
choice to see how much voltage you can generate.
Materials
lemon
DMM hardware
suitable electrodes
conductivity meter – electrolysis apparatus
Procedure
1.
2.
3.
4.
5.
Using your computer open the PSL Excelerator Program and create a probe for
the DMM Voltage DC. Also set up a digital display and change your experiment
clock to collect data for at least an hour. If the DMM module is not connected the
directions for set up are as follows: Two test leads come with the DMM Module.
One is black; the other is red. Notice that each lead has a clip on one end and a
banana plug on the other. The clip is used to connect the lead to a variety of items.
Take the black test lead and place the banana plug into the common input banana
jack labeled COM on the DMM Module. Take the red test lead and place the
banana plug into the volts input banana jack that is labaled both V and Ω.
Do not use the DMM (digital multi-meter) until after you have tested the lemon
with the conductivity meter (clip alligator clips to the electrodes) to see if your
fruit battery is working. (Extra credit if you bring in other fruits to try: 1 point for
each fruit).
Using a knife make two slits in your lemon so that the electrodes will be able to
be inserted (see diagram below).
After your electrodes have been inserted check the electrochemical circuit with
your conductivity meter to see if there is an electron flow (your LED should
light).
After you are assured your lemon battery is creating “juice” you need to take a
reading using your DMM. Those individuals with the five highest readings will
have a run off at table 1 using that DMM. The three highest voltages generated
receive extra credit (5,4,3 points).
Questions and Summary
1.
One of the electrodes was the cathode where reduction occurs (the electrons flow
from the anode to the cathode in this electrochemical lemon). The other electrode
was the anode where oxidation occurred (the metal here lost electrons to the other
metal). Identify which metal was the anode and which was the cathode. (**Chart
N may help if you are unsure.)
2.
3.
Why do you think there was a difference in the voltage produced by the other
experimenters in class? (In other words what variables are there in this
experiment?)
Does the potental difference (the voltage generated) depend on the fruit used?
Please explain.
*Diagram*