Chem 200
Christmas Redox Lab
Name:___________________________________________________________
Purpose: plate a piece of galvanized metal with copper (Cu) through redox chemistry to make a decorative Christmas ornament. You
will make three ornaments: one for your family, one for Mrs. Chott, and one for the SLUH faculty silent auction that benefits the
Honduras trip.
Your grade will include the completion of three ornaments.
Background: Galvanized metal is made of iron (Fe) coated with a layer of zinc (Zn). The zinc provides protection against rusting
(oxidation of the metals by water and oxygen in the air.) Redox chemistry can be used to remove the zinc layer that covers the iron and
replace the iron with copper.
Pre-lab work: You will be given three 2 ½” x 2 ½” pieces of galvanized metal covered with masking tape. Create designs for each
side of the squares of metal (6 designs total). You may have the same design on each side, or two different designs. Simple designs are
easiest to prepare. Keep in mind where the hole is located for hanging. If you are not artistically inclined, and feel the need to trace
your design from a template, feel free to trace an outline using a small cookie cutter or other object. The inner portion of the design
will be copper-colored on the finished ornament.
Copper (Cu)
Zinc (Zn)
Procedure:
1. Draw your designs with pencil on the masking tape of both sides of each of the galvanized metal squares.
2. CAREFULLY use a scalpel or razor blade to cut along the pencil marks. Remove the masking tape inside the drawing so that the
design is uncovered.
3. Using a pair of tongs, submerge one piece of metal at a time in 50-mL of 6M hydrochloric acid in a 1-L beaker. Lay the ornament
flat on the bottom of the beaker so that it is completely submerged.
4. As soon as the rapid bubbling stops, remove the ornament from the HCl solution with the tongs. Rinse the ornament with tap
water and dry it with a paper towel.
5. Carefully clean the exposed area of the design by rubbing it with an eraser. Do not remove the masking tape. Wipe off excess eraser
pieces.
6. Dip a cotton swab into the copper(II) nitrate solution (3 grams of copper(II) nitrate trihydrate,
Cu(NO3)23H2O, in 250 mL of a 0.25 M hydrochloric acid solution) and gently rub the swab over the exposed parts of the design. Redip the cotton swab in the solution as necessary. The exposed parts of the design should be wet with the solution.
7. Once the entire design area on that side is coated with the copper solution, turn the metal over and rub the copper(II) nitrate
solution over that exposed design area as done in step #6.
8. Rinse both sides of the metal with tap water and dry with a paper towel. Remove the masking tape from both sides of the piece of
metal. For each ornament, attach an ornament hanger, write your name on a piece of masking tape, and attach the tape to the hanger.
Mrs. Chott will spray both sides of the metal with acrylic sealer to slow the tarnishing of the copper. Once the sealer is dry, you will
choose one ornament to keep.
Post-Lab Work:
1. Name the metal that coats the exterior of galvanized metal (hint: read the background information).
2. Write the balanced chemical equation that occurs in steps #3 and #4 (the metal is placed in a solution of HCl and bubbles rise from
the metal.) Remember that the acid is reacting with the exterior of the galvanized metal. (Hint: you’ve seen this reaction in a previous
lab.) Be sure to include the states of matter.
3a. In the above chemical reaction, a metal changes from solid to aqueous states through the loss or gain of electrons. Write the halfreaction that shows this change. Remember to include electrons so that the charges on both sides of the equation are equal.
3b. State whether the above reaction is an oxidation or reduction. ________________________________
4. The inner core of the galvanized metal is iron. Write the balanced chemical equation that shows how iron metal reacts with the
copper(II) nitrate solution. Based on what you observe after applying the copper(II) nitrate solution, you should be able to predict
one of the products of this reaction. You can also predict this product by using the metal activity series.
5. There is an exchange of electrons in the equation you wrote in #4. Write the two half-reactions and indicate which one is an
oxidation and which is a reduction.
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