A Penny Green

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During this project, the group will be attempting to turn a penny green. Needed in this experiment will be pennies dated before 1982 because that was when pennies were made of copper. During this experiment, the group will be mixing together different chemical reactions in order to get the penny to turn green. The group is trying to create a patina coating on the penny. Patina is referring to the blue-green layer of corrosion that expands on the surface of copper when it is exposed to oxygen and sulfur compounds. However, instead of using simply sulfur and oxide compounds, like the Statue of Liberty, the experimenters will be using a vinegar substitute. The vinegar is being substituted for the acid rain, the acid is the
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The patina is preserving the statue, it is protecting the Statue of Liberty from further deterioration. Another result of patina, besides the blue-green color, is the mass change of the Statue of Liberty.
Studies have shown that only the top 5% of the skin has oxidized in the first one hundred years since it was built. Most of this occurred in the first ten to twenty-five years because of early oxidization. It took about thirty-four years for the very top layer of the skin on the Statue of Liberty to become completely blue-green.
First of all copper must oxidize in order for the process to start. It’s a basic reaction of copper to oxygen. The chemical formula is: 2Cu + O2 --> 2CuO. The vinegar is very similar to acetate acid. Together the vinegar and copper would form Copper (II) Acetate. The formula would be Cu(C2H3O2)2. Also, the patina growth varies dramatically with location and how much copper sulfate (CuSO4) the object contains. The Statue of Liberty has been exposed to acid rain and oxygen which forms (over time) patina. The acid rain is the combination of rain and the pollution in the atmosphere which solidifies enough for form acid rain. The sulfate comes from sulfuric acid in the acid rain and the sulfate is bound to other components in patina. This is because the copper sulfate is normally soluble in water. Also, copper carbonate Cu(HCO3)2 does not exist in a solid state, so when the rain
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