Cell EMF and the Nernst Equation

Name: Cell EMF and the Nernst Equation
Author: StemPy Lab

A galvanic cell built from two half-cells. Cell notation, emf from standard electrode potentials, the link between emf, Gibbs energy and the equilibrium constant, and the Nernst equation for any concentration.

3 lessons, about 1 h 40 min4 simulations11 problems6 practice questionsPython in every lesson

Created by StemPy Lab

Course outline (3 lessons)

Lesson 1about 35 min
Cell notation and cell emf
A torch cell says 1.5 V on its label, and a voltmeter may read less when the torch is on. The label gives the emf of the cell, the voltage when no current flows. This lesson shows how to write any cell in one line, how to read the cell reaction from that line, and how to find the emf from standard electrode potentials.
1 simulation2 practice questions1 Python program4 problems
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Lesson 2about 30 min
Gibbs energy and the equilibrium constant
A cell does electrical work as its reaction runs, and the most work it can do is fixed by the Gibbs energy of the reaction. This gives $\Delta G^\circ = -nFE^\circ$ . Join it to $\Delta G^\circ = -RT\ln K$ and the standard emf of a cell tells you the equilibrium constant of its reaction. A flat battery is a cell that has reached equilibrium.
1 simulation2 practice questions1 Python program4 problems1 Python lab
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Lesson 3about 35 min
The Nernst equation
The standard emf is for ions at 1 mol/L. A real cell has other concentrations, and they change as the cell works. The Nernst equation gives the emf for any concentrations: $E = E^\circ - \dfrac{0.0591\ \text{V}}{n}\log Q$ at 298 K. We find it from $\Delta G = \Delta G^\circ + RT\ln Q$ , write the reaction quotient $Q$ correctly, and use the equation for a cell and for a single electrode.
2 simulations2 practice questions1 Python program3 problems1 Python lab1 question set1 note
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Cell EMF and the Nernst Equation: Practice Paper

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Cell EMF and the Nernst Equation

Course outline (3 lessons)

Cell notation and cell emf

Gibbs energy and the equilibrium constant

The Nernst equation

Test Your Learning

Your teacher

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