Question 3: Electrochemical Cell (1 6 points)
A high school girl was ready for her big date but discovered with horror that her silver necklace was all tarnished. Having just studied about redox reactions and electrochemical cells in chemistry class, she grabbed some aluminum foil, put it in a dish, and placed her necklace on top
of the foil. Then she added some baking soda, a little salt, and hot water. Within a few minutes, her
necklace was bright and shiny again.
The formula for tarnished silver is Ag2S. Use the equation below to answer the following questions.
Ag2S+ Al (s) w AI2S3+ Ag(s) (unbalanced)
a. Balance the equation with coefficients.
(1 point)
b. What makes this an oxidation-reduction reaction? (1 point)
c. Write the half-reactions showing the oxidation and reduction reactions. Identify which is the
oxidation reaction and which is the reduction reaction.
(2 points)d. What is oxidized in the reaction? What is reduced? (2 points)
e. In this simple electrochemical cell, what functions as the anode? What is the cathode? (2
points)
f. Why does the necklace need to touch the aluminum foil? (1 point)
g. What part of an “electrochemical cell” is the baking soda, salt, and water mixture? (1 point)
h. Is this a galvanic cell or electrolytic cell? Explain your answer. (2 points)i. Write the standard cell notation for an electrochemical cell consisting of an anode and cathode of the same types as in this experiment, connected through a salt bridge. (2 points)
j. What would the overall potential for this cell be?(2 points)