Turning copper into silver then gold

Aim: To turn copper into silver then gold.


Equipment: Bunsen burner, Safety glasses, zinc powder, NaOH solution, Beaker, Tripod, Gauge mat, Heat mat, Scissor tongs, And a copper coin.

 
Method: Pour 20 mL of NaOH solution to the beaker then add the zinc dust in the dish with the NaOH, and gently swirl the mixture together, Set up tripod and bunsen burner + gauge mat, Turn on bunsen burner and put under the tripod, set bunsen burner to a blue flame,Heat for 5 minutes. Do not boil. When the Beaker is hot is hot, place a penny in it. Heat for two minutes or until the penny is coated and becomes silver in appearance, Remove the penny from the dish with tongs and drop it into water. When cool, wipe the penny clean with a cloth to remove any excess zinc, Using tongs, hold the penny in the flame of a Bunsen burner and gently heat. The penny should turn “gold” (brass). (Do not overheat the penny.), Dip the penny in the beaker of water until it is cool to the touch.