Chemistry Redox Reactions

A series of free High School Chemistry Video Lessons.

In this lesson, we will learn

  • Oxidation Reduction Reactions - Redox
  • Half Reactions
  • Voltaic Cell



Oxidation Reduction Reactions - Redox
Oxidation-Reduction Reactions, also called redox reactions, are reactions for which the driving force is the transfer of electrons. Oxidation is the loss of electrons and the gaining of a positive charge. Reduction is the gain of electrons and the gain of negative charge. Metals are generally oxidized and become cations while non-metals are normally reduced and become anions.

Understanding oxidation-reduction reactions.
Redox Reactions Demonstrations



Oxidation reduction (or redox) reactions



Recognizing Redox Reactions

How to identify a reaction as being redox by assigning oxidation numbers to all elements and checking for elements being oxidized-reduced.



Half Reactions
Half reactions are used for balancing oxidation - reduction reactions that occur in aqueous solutions. The sum of the oxidation and reduction half reactions forms the overall equation for the full reaction. To add half reactions, it is necessary for the number of electrons lost to equal the number of electrons gained.

This video teaches you how to write half-reactions, with an emphasis on how to handle diatomic species.



This lesson walks through how to write half reactions for oxidation and reduction given a particular redox reaction.



Voltaic Cell
A voltaic cell is the device in which the transfer of electrons takes place through an external pathway. The flow of electrons in a voltaic cell enable energy in form of electricity to be produced in redox reaction. The set-up of a voltaic cell includes an anode, a cathode and a salt bridge that is used to neutralize the system.

Voltaic Cells Theory

This video explains how to use the Metal Activities table to determine which species will be oxidized and which will be reduced.



Voltaic Cells Practice

This video shows the construction of a voltaic cell and simple animation overlay that shows what is happening to the species in the reaction.




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