1. Lab 12 Copper to Silver to Gold Purpose To change the appearance of a copper penny to ‘silver’ and then to ‘gold.’ Date:

2. Experiment 1. Dip a pre-1982 penny in vinegar, scrub shiny with steel wool 2. Mass of clean and dried pre 1982 penny = _________ g 3. Heat solution to a gentle boil, turn off heat. 4. Place penny in dish 5. Place penny in beaker of water (tongs!) 6. Mass of dried ‘silvered’ penny = ________ g 15 mL NaOH 1 g Zn powder

3. 7. Use tongs to pass the ‘silvered’ penny back and forth through the burner flame until it turns to ‘gold’ 8. Mass of ‘gold penny = _______ g 9. Leave the dish out for the next class

4. Analysis 1.Calculate the mass of the ‘silvered’ penny. 2.Calculate the mass of the ‘gold’ penny. 3. Calculate the mass of zinc added to the penny. This space is for YOUR statement that should summarize what an alloy is AND how this lab made an alloy. Results

5. Questions 1.Explain what caused the penny to turn ‘silver.’ 2.Explain what caused the penny to turn ‘gold.’ 3.If you had used tin instead of zinc, what alloy would you have made?