Single-replacement Reaction

Create silver decorations with chemistry

In this activity students perform a redox reaction in which silver take the place of copper in copper wire. The copper changes from its elemental form to its aqueous ionic form. During the course of the reaction, the silver ions are reduced and are removed from the solution. The silver ions are deposited on the copper wire as elemental silver. The copper metal is oxidized and forms ions in the solution, changing the solution from colorless to light blue. The following reaction occurs:

2AgNO₃(aq) + Cu(s) → Cu(NO₃)₂(aq) + 2Ag(s)

Topics covered: oxidation-reduction reactions, single-replacement reactions, activity series.

Materials (per student)

• 0.1 M Silver Nitrate, 50 mL

• Copper Wire

• Beaker, 50 mL

• Scissors

• String, 20 cm

• Craft Stick

Procedure

1. Shape a piece of copper wire into an object of your choosing, such as a star, snowflake, Christmas tree, or other shape. This shape must be small enough to hang suspended in the beaker without touching the sides or bottom.

2. Tie 1 end of the string to the wire shape.

3. Tie the other end of the string to the craft stick.

4. Place the wire shape in the beaker and rest the craft stick on top of the beaker. Rotate the craft stick, winding the string around it, until the wire shape is suspended.

5. Pour silver nitrate into the beaker until the shape is covered.

6. Allow the shape and solution to remain undisturbed. Examine it after half an hour has passed. If you leave the shape in the silver overnight, the shape may disintegrate.

Additional Reading: Classifying Chemical Reactions