Electrochemical Cell

• zinc strip

• copper strip

• 250 mL beakers (2)

• 500 mL beaker

• 2 connecting wires with alligator clips

• tiny LED light bulb

• 1.0 M CuSO₄, 100 mL

• 1.0 M zinc sulfate solution, ZnSO₄, 100 mL

• saturated potassium nitrate (KNO₃) solution, 20 mL—for salt bridge

• filter paper approximately 1 in wide and 6 in long—for salt bridge

• gloves for handling salt bridge

1. Make a salt bridge. Place a piece of folded-up filter paper in the bottom of an empty 500 mL beaker. Soak it thoroughly with KNO₃. Set aside for later.

2. Carefully pour 100 mL of CuSO₄ into one beaker and 100 mL of ZnSO₄ into another beaker.

3. Set up the zinc strip in the ZnSO₄ solution and the copper strip in the CuSO₄ solution. Use a wire with alligator clips to connect the two metal strips. The clips should not touch the solutions.

4. Use gloves to place the salt bridge between the two beakers as shown.

1. What do you observe?

2. Why is it necessary to have an ionic solution in the salt bridge?

3. Which substance is being oxidized? Which substance is being reduced? How do you know?

4. Connect the tiny LED light into your circuit using both sets of alligator clips. What do you observe? What does that prove?

5. Explain how you might reverse this reaction.

6. Making Sense Explain where the electricity in the electrochemical cell is coming from.