Thursday, September 9, 2010

The Physical and Chemical Properties of a Penny

istockphoto_2992953-lincoln-penny-2007-on-white-background.jpg         The penny, something we use everyday, but never take the time to examine.  A penny has many properties, both chemical and physical, that are not always apparent the the naked eye.  Based on the year the penny was made, there are a couple factors that that could cause different results.  For instance if the penny was made between 1944- 1982, then it is made of 95% copper and 5% zinc, while if made after that, the penny will be made of 2.5% copper and 97.5% zinc.  For experimental purposes, I chose to focus more on the penny made before 1982 that had a larger amount of copper in it.  The penny possibly the most simple and basic form of money has more properties than one would have ever thought.

Physical Properties

All of the properties listed below are physical because the compound itself changes, but nor the chemical composition.
  • Weight:
    • Before 1982: 3.1 g
    • After 1982: 2.5 g
  • Volume: 360 mm3
  • Color: A copper color that loses its sheen over time.
  • Circumference: 19mm
A smashed penny's weight and volume would stay the same, but it circumference would be changed.
  •  Smell: A copper/ iron smell similar to blood

Chemical Properties

All of the following properties are chemical because they involve a chemical reaction that can never be undone.

  • By putting a penny in bleach, along with cleaning the penny and removing some of the rust, dirt, ect., it produced a gritty white material on the penny.

  • By putting a penny in water it will eventually rust causing a chemical reaction.

  • By putting a penny in jewelry cleaner it removed most of the rust, dirt, and made the penny shinier.
The older penny's results were much
more noticable. The cleaner brought the penny
 back closer to its original state.

  • When i put a penny in coke there were signs that corrosion had started.  Based on my research if i had a longer period of time for the penny to sit in the coke the corrosion would be so great that the penny would dwindle down to nothing.
The older penny was the one that had shown the most progress thus far.

  • When I covered the penny with vinegar and left it over night, a green copper acetate formed much like the one on the Statue of Liberty.