The alchemists' experiments that tried to change base metals into gold led to the discovery and description of the properties of various elements and substances. Their "trial and error" approach to studying the reactions of various substances formed the basis of the modern science of chemistry. In this exercise the students heat copper coins (pennies) in a solution of a strong base (NaOH) and zinc shavings, which puts a silver-like coating on the coin. They then rinse the coin and heat it in a flame where it develops a "golden" appearance. Students are asked to "research" what is actually happening in this reaction.
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| Brian and Ethan are heating the pennies in the NaOH and zinc solution, carefully turning the coins to trying to ensure that both sides of the coins can be exposed to the mixture |
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| Catherine and Pablo are turning their coins in the solution. |
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| Morgan is heating the "silvered" penny in the flame to try to turn it "golden". |
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| A "golden" penny with two "base" copper coins. |
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| Michael tranfers his and Estelle's silvered coins to a beaker of water to rinse them before they heat them in the flame to turn them into gold coins. |
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| Silvered coins removed from the crucible in which they were heated in the NaOH and zinc powder solution. |
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