Standard Zinc/Copper Cell

A standard cell comprising zinc strip in 1.0 M ZnSO​4 solution, a copper strip in a 1.0 M CuSO4 solution, and a connecting salt bridge are connected to a voltage probe.  The voltage can be projected using the Vernier LabPro interface.

Curriculum Notes 

This is a great demo to introduce the concept of electrochemical cells.  It can be preceded by the "Reaction of Zinc and Copper II Ion" demo to show how an electrochemical cell separates a redox reaction into reduction and oxidation half-reactions.

Lead Time 
One day of lead time is required for this project.
Materials 
  • 2 ea. 400 mL beakers, one containing a strip of zinc metal partially immersed in a 1.0 M ZnSO4 solution, the other containing a strip of copper metal partially immersed in a 1.0 M CuSO4 solution.
  • a salt bridge comprising a u-tube filled with 1 M KNO3 solution.  The ends of the u-tube should be tightly plugged with cotton that has been saturated in the KNO3 solution.
  • a Vernier voltage probe.
  • a Vernier "Go Link" interface.
  • an empty 250 mL beaker to hold the salt bridge upright when not in use.
  • a computer with the Vernier "Logger Lite" program that is capable of projecting the screen image.
Procedure 
  • Place the two beakers side by side.
  • Connect the probe leads to the metal strips where they stick up above the surface of the solutions.
  • Place the salt bridge upside down so that one arm is in each of the solutions.
  • Students should note that no voltage registers until the salt bridge is inserted into the solutions.
Safety Precautions 
  • Always wear goggles when performing chemistry demonstrations.
  • Gloves should be worn to protect your hands from the solutions.

© Copyright 2012 Email: Randy Sullivan, University of Oregon Chemistry Department and UO Libraries Interactive Media Group