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When Metals Eat Each Other

Galvanic Oxidation in the Home


Author(s)

Jacqueline C. Ruiz Harewood
Mathematics and Natural Sciences
National University
jruiz@nu.edu

Abstract

This case study was written to help students understand metal reactivity and metal incompatibility before they start learning about redox reactions. The storyline is based on a real-life situation in which two children are interrupted by a power failure in the middle of watching their favorite television show. Visual examination of the electrical panel in the cellar soon makes it clear that they need the help of a professional. The electrician who arrives recommends that the entire electrical panel should be replaced because the metals are “eating each other.” The description is apt, for what is really involved is the phenomenon of galvanic oxidation or corrosion; in fact the word corrosion traces back to the Latin corrodere, which means to “gnaw through.” In addition to exploring the safety impacts of galvanic oxidation in the external environment, students will also have an opportunity to discuss where metal corrosion might occur in the body (e.g., dental amalgam fillings). The case was designed for high school or undergraduate students taking introductory general chemistry courses.


Objectives

  • Identify safety issues related to galvanic oxidation in household electrical panels.
  • Explain how to avoid or promote galvanic oxidation.
  • Use galvanic series to predict which metal will corrode when physically joined to another metal.
  • Define cathode, anode, oxidation and reduction.
  • Explain how a redox reaction can be used to generate electricity.
  • Analyze a redox reaction into half reactions of oxidation and reduction.

Keywords

Metal reactivity; metal corrosion; galvanic oxidation; galvanic series; metal compatibility; noble metals; electrochemistry; galvanic cells

Topical Areas

N/A

Educational Level

High school, Undergraduate lower division

Format

PDF

Type / Methods

Directed

Language

English

Subject Headings

Chemistry (General)  |   Dental Medicine  |   Environmental Engineering  |   Science (General)  |  


Date Posted

5/29/2018

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