Kotz and Triechel, Chemistry and Chemical Reactivity Chapter 19: Sections 6-8.
- 19.5 The half-cell voltages listed in the previous section are determined under standard conditions. If concentration is not at equlibrium, or if temperature varies from 25°C, then the Nernst equation can be used to determine potentials:
E = E° - (RT/nF) ln Q
R and F are constants.
n is the number of moles transferred.
- 19.6 The maximum work that can be done by the reactions of the half-cells are given as wmax = nFE. This is also the free energy -ΔrG. So E° is related to the equilibrium constant:
ln K = nE° / 0.0257 at 25°C
- 19.7 Electrolysis is the use of electrical current to supply the energy for chemical change. This process is the reverse of that in a voltaic cell, which uses chemical reactions to produce current.
- 19.8 Electrolysis reactions allow us to determine the number of electrons exchanged from the current produced:
current = charge/time
This is an important method for determining the mole relationships in a reaction to verify a molecular formula (mass relationships can only produce an empirical formula).
If you find these study methods useful, visit the Chapter 19 resources at Cengage "Brain" companion site for our text. Click on the chapter dropdown and select Chapter 19 to use the flashcards and glossary.
Use the MindTap reader version of the textbook to view videos and test your understanding with interactive checkpoints. Check OWLv2 for your homework problems.
Videos for Chapter 19: Principles of Chemical Reactivity: Entropy and Free Energy
Review the Videos at Thinkwell Video Lessons.
- Under "ELECTROCHEMISTRY"
- Galvanic Cells
- The Nernst Equation
- Electrochemical Determinants of Equilibria
- Electrolysis and Electrolytic Cells
- Electrolytic Cells
- The Stoichiometry of Electrolysis
Homework problems: See your Moodle assignment!
AP LAB #16 GUIDED INQUIRY — — Building an Electrochemical cell — Phase III
Use your batteries (or commercial batteries) to observe the results of electrolysis on common molecules and rank results. Write and post your formal report.
- AP2009 20 Determination of Electrochemical Series
- AP2009 21 Measurements using electrochemical cells and electroplating
- IGHCE Lab 16.1 OR HSCKM X-1 Produce Hydrogen and Oxygen by Electrolysis of Water
- IGHCE Lab 16.2 OR HSCKM X-2 Observe the Electrochemical Oxidation of Iron
IGHCE Lab 16.3 OR HSCKM X-3 Measure Electrode Potentials
- IGHCE Lab 16.4 Observe Energy Transformation
- IGHCE Lab 16.5 OR HSCKM X-4 Build a Voltaic Cell
- IGHCE Lab 16.6 Build a Battery
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