CHEM105 Chapter Notes - Chapter 21: Cathodic Protection, Magnetic Core

• School: University of Alberta
• Department: Chemistry
• Course: CHEM105
• Professor: Yoram Apelblat

Document Summary

Corrosion: natural process which oxidizes metals to their oxides and sulfides, shares many similarities w/ the operation of a voltaic cell. Iron does not rust in dry air; moisture must be present. Iron does not rust in air-free water; oxygen must be present. Iron loss and rust formation occur at different places on the same object. Iron rusts more quickly in contact w/ a less active metal (such as cu) and more slowly in contact with a more active metal (such as zn) 2 separate redox processes occur during corrosion: loss of iron. A strain, ridge, or dent in contact w/ water is typically the site of i ron loss. This site is called an anodic region b/c the following half-rxn occurs there: One the iron atoms lose electrons, the damage to the object has been done, and a pit fors where the iron is lost. At this cathodic region, the electrons released from the iron atoms reduce oxygen: