Tarnishing is properly considered a chemical change.
What is an oxidized penny?
The copper in a penny, whether it forms the bulk of the coin or merely a surface layer, turns dull when exposed to the air. The reason is that copper atoms combine with oxygen molecules to form copper oxide, in a chemical process called oxidation.
Are corroded pennies worth anything?
Even a corroded 1909-S VDB cent that has been cleaned, bent, and has holes (a pretty ugly-looking 1909-S VDB penny, really…) might be worth $100 to $200 as a filler piece — because demand for the rare Lincoln penny is so high!
What cleans a penny the best?
Vinegar (or Lemon Juice) and Salt This method is the best way to clean your pennies, and it will produce a very bright orangey-copper color on your pennies. It does this by using the low levels of acids that are contained naturally in vinegar and lemon juice to remove the patina (brown oxidation) on the penny.
Why do old pennies tarnish, and how?
A. Hi, Daniel. Old U.S. pennies (before 1982) are made of copper; newer pennies (after 1982) are made of zinc and then electroplated with copper. But in either case the outside surface of the pennies is copper. Copper, like almost all metals except gold and other precious metals, will tarnish.
What does it mean when copper is tarnished?
Copper, like almost all metals except gold and other precious metals, will tarnish. What this means is that copper will slowly react with the oxygen and sulfides in the air to form copper oxide and/or copper sulfide reaction products on the surface.
What kind of metal is a Penny made of?
Old U.S. pennies (before 1982) are made of copper; newer pennies (after 1982) are made of zinc and then electroplated with copper. But in either case the outside surface of the pennies is copper. Copper, like almost all metals except gold and other precious metals, will tarnish.
Why do copper pennies have a dull color?
Pennies get dull and tarnished over time because of the copper that is used in their composition. Copper slowly reacts with oxygen in the air to form copper oxide, which has a dull, greenish color to it, and this is what people see as tarnish on copper pennies.
