SME
Grade 10 Science · Chemistry
Oxidation-reduction reactions, electrochemistry, electrolysis and corrosion
Follow the electrons in a zinc–copper cell: where oxidation and reduction happen, and what the salt bridge does.
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Zinc gives up electrons more easily than copper, so zinc is the anode.
The electrons leave the zinc and travel along the wire to the copper.
E° = 0.34 − (−0.76) = 1.10 V.
Assumptions
•
Each metal stands in a 1 M solution of its own ion, at 25 °C.
•
A wire joins the metals; a salt bridge of KNO₃ joins the solutions.
•
The metal with the lower reduction potential is the anode: E° = E°cathode − E°anode.
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