In order to determine the mass of a copper atom, students in William Green’s AP Chemistry class at E.O. Smith High School, Storrs, CT, follow a procedure similar to the lab “Determining Avagadro’s Number” found in Advanced Chemistry with Vernier. His students use an electrolytic cell having copper wire for both the anode and the cathode. During data collection, the current passing through the cell is measured using a Vernier Current Probe.

Using the average current, the students determine the number of electrons liberated during the reaction. Knowing the mass of copper lost by the anode and the number of electrons liberated, the students are able to determine the number of copper atoms removed from the anode, which they use to determine the mass of a single copper atom. One lab group’s results are shown.