In electrochemistry, a voltaic cell is a specially prepared system in which an oxidation-reduction reaction occurs spontaneously. This spontaneous reaction produces an electrical potential that can be easily measured using a Voltage Probe. Taking advantage of this fact, students are able to quickly establish the reduction potentials of five unknown metals relative to an arbitrarily chosen metal in “Experiment 28–Establishing a Table of Reduction Potentials: Micro-Voltaic Cells” from Chemistry with Vernier.
When using a Voltage Probe to measure the half-cell potential, you must zero the probe using a specific process before starting the experiment:
- Connect the Voltage Probe to the data-collection interface and start the data-collection program.
- Clip the red and black leads of the Voltage Probe together. The meter reading will drop to a value below ~0.1 V, which is expected behavior.
- Choose Zero from the Experiment menu (Logger Pro) or from the Sensors menu (LabQuest App). After the probe is zeroed, the meter reading will be approximately 0.00 V. You are now ready to measure potential.
- If you exit Logger Pro 3 or LabQuest App and restart the program, you will need to zero the Voltage Probe again.
- Zero the probe only when the red and black leads are connected together.
For troubleshooting information, visit Voltage Probe Troubleshooting and FAQs