A redox reaction split into two half-cells. The Daniell cell, standard electrode potentials and the electrochemical series. Then how to predict whether a reaction will happen and which metals displace which.
3 lessons, about 1 h 15 min3 simulations11 problems3 practice questionsPython in every lesson
Created by StemPy LabA zinc rod can push electrons into a wire if its half-reaction is kept in a beaker of its own. Join the zinc half-cell and the copper half-cell with a wire and a salt bridge, and the electrons do work on the way: this is the Daniell cell. The zinc rod is the anode, the copper rod is the cathode, and the cell diagram writes it all down.
Each half-cell has its own tendency to gain electrons, but only the difference between two can be measured. So the standard hydrogen electrode is given the value zero, and every other couple is measured against it. This gives the standard electrode potential . The potential of a cell is of the cathode minus of the anode.
Put the couples in order of their and you have the electrochemical series. A metal reduces the ions of any couple with a higher , so a positive cell potential tells you that a reaction can happen. It gives , which is negative. The series also explains which metals dissolve in acid, and why zinc protects iron from rusting.
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