Tuesday, July 31, 2012

Olympic Medal Metals

Metallic medals have been awarded to 1st, 2nd and 3rd place Olympic athletes since the 1900 Paris Olympic Games. The medals awarded at the 2012 London Olympic Games are 7mm thick, 85 mm in diameter, and, weigh 400g.
While we happily refer to these olympic medals as gold, silver and bronze, is this chemically accurate?

"Bronze medals" are often made of bronze, an alloy of copper and tin.
At the 2012 London Olympic Games, the bronze medals are made up of a mixture of 97% copper, 2.5% zinc and 0.5% tin. This composition is actually much closer to the composition of brass which is the term used to refer to an alloy of copper and zinc.

"Silver medals" contain at least 92.5% silver. The silver medals awarded in the 2012 Olympic Games were composed of 92.5% silver and 7.5% copper.

"Gold medals" must also contain at least 92.5% silver, but they are plated with at least 6g of gold so they look like "gold" medals. The 2012 Olympic gold medals are made up of 92.5% silver, 6.16% copper and 1.34% gold.


Further Reading
Periodic Table
Percentage Composition
Mass-mole Calculations
Moles-Number of Particle Calculations
Density Calculations

Suggested Study Questions
  1. Give the chemical symbol for each of the following elements:
    • gold
    • silver
    • copper
    • tin
    • zinc
  2. Explain why chemists refer to bronze and brass as alloys.
  3. Calculate the mass of each element present in the bronze olympic medals awarded in 2012.
  4. Calculate the mole of each element present.
  5. For the 2012 Olympic gold medal, calculate the mass of silver present.
  6. Calculate the number of silver atoms present in a 2012 olympic gold medal.
  7. Calculate the mass of gold present in a 2012 olympic gold medal.
  8. Calculate the volume of an olympic medal and use this to calculate the density of an olympic medal.
  9. Calculate the surface area of a 2012 Olympic gold medal.
  10. Assuming the 2012 gold medal is coated evenly with gold, what thickness is the layer of gold?

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