The Gold Penny Lab
In this lab, you will be converting a regular penny into a “gold”
penny. In doing so, you are following a tradition that goes
back to the earliest days of chemistry.
The modern practice of chemistry started with the study of alchemy in
medieval Europe and the Middle East. Alchemists believed that by doing
certain chemical reactions, you could turn cheap metals into gold. Some
of them did, anyway- the others would convince people that they could
do this and sell them the secret.
Safety:
In this lab, it is very important that you wear your goggles,
appropriate footwear, and aprons at all times! The chemicals
that we are working with are extremely dangerous and can
cause serious injury.
Materials:
Two bright, shiny pennies
Steel Wool
Sodium Hydroxide (3M)
Bunsen Burner & Sparker
Zinc (granular)
Graduated Cylinder (25 mL)
Spatula
Evaporating dish
Hot plate
Crucible tongs
Beaker (250 mL)
Part One- Preparing the Penny
You need a shiny penny to do this lab!
1. Clean your penny with steel wool. Wash with water and use a paper
towel to dry.
2. What does the penny look like? Record your observations in your
data table.
Part Two: Making a Silver Penny
1) Place enough zinc filings in a 100 mL beaker to cover the bottom
2) Carefully add 20 mL of 3M sodium hydroxide (NaOH) to the same
beaker
3) Place the beaker on a hot plate. Your teacher will tell you the
setting. If the liquid begins to boil, turn down the hot plate a little.
4) Use your tongs to pick up the penny and place it in the beaker. After
1 minute, use tongs to turn the penny over and allow it to simmer for
another minute or until it is coated.
5) Once the penny is coated, remove it with the tweezers. Make sure
your partner uses the tongs to hold the beaker still while the penny is
removed.
6) Put the hot penny in the 250 mL beaker, which is half-filled with
water. This serves to cool and rinse the penny.
7) With tongs, remove the penny from the water and dry it with a paper
towel.
8) Record your observations of this penny in your data table.
Part Three: Making a Gold Penny
1) Using the tongs, hold the penny (by its edges)
heads up in the flame of the Bunsen burner for 3
seconds.
2) Remove from heat, flip the penny and re-heat
tails side up for another 3 seconds.
3) Repeat carefully until you see a color change. WARNING: Pennies
will melt if left in the fire too long! The zinc core of a penny melts
easily!
4) Set the penny on the bench top to cool. Rinse the penny a second
time.
Cleaning Up
Disposal of Sodium Hydroxide: After it has cooled, carefully pour the sodium
hydroxide into the sink. Rinse down the drain with water.
Disposal of Zinc: Once sodium hydroxide is out of the dish, pour a little water
into the dish, swirl, and drain. Rinse with water again, drain. Use paper towels
to wipe the zinc into the trash can.
Equipment/Glassware: Wash everything and return it to where you got it.
Table: Wash the table with soap, water, and a sponge.
Chemistry
Name_________________________
LAB: A Penny For Your Thoughts
Date_______________ Pd._______
Answer the following questions:
1.
Data:
Table: Penny Observations
Penny
Observations
Part 1: Before Lab
Part 2: After Zn and NaOH bath
Part 3: After heating in flame
2. Outline the safety rules you observed today.
3. What do you think happened to turn the penny silver? What was the silvery
coating?
4. What do you think happened to turn the penny gold? What is the gold
substance?
5. Do you think you made real gold? Why or why not?