key term - Oxidation-reduction

Definition

Oxidation-reduction, also known as redox, is a fundamental chemical process that involves the transfer of electrons between two substances. It is a key concept in understanding the behavior of batteries, fuel cells, and other electrochemical systems.

5 Must Know Facts For Your Next Test

1. In a redox reaction, one substance is oxidized (loses electrons) while another substance is reduced (gains electrons).
2. The transfer of electrons is the driving force behind the operation of batteries and fuel cells, where chemical energy is converted into electrical energy.
3. Oxidation numbers are used to keep track of the changes in oxidation states during a redox reaction.
4. Balancing redox equations is a crucial step in understanding and predicting the outcomes of electrochemical processes.
5. Redox reactions are fundamental to many biological processes, such as cellular respiration and photosynthesis.

Review Questions

• Explain the relationship between oxidation and reduction in a redox reaction.
  • In a redox reaction, oxidation and reduction occur simultaneously. One substance is oxidized, meaning it loses electrons, while another substance is reduced, meaning it gains electrons. The transfer of electrons between the two substances is the driving force behind the reaction. This electron transfer is essential for the operation of batteries and fuel cells, where chemical energy is converted into electrical energy.
• Describe how oxidation numbers are used to track changes in oxidation states during a redox reaction.
  • Oxidation numbers are assigned to atoms in a compound based on a set of rules, and they reflect the degree of oxidation or reduction of the atom. During a redox reaction, the oxidation numbers of the atoms involved change as electrons are transferred. By keeping track of the changes in oxidation numbers, you can identify which atoms are being oxidized and which are being reduced. This is a crucial step in balancing redox equations and understanding the overall process.
• Analyze the importance of redox reactions in the context of batteries and fuel cells.
  • Redox reactions are fundamental to the operation of batteries and fuel cells, which are devices that convert chemical energy into electrical energy. In a battery, a redox reaction occurs between the anode and cathode materials, where one is oxidized and the other is reduced. This electron transfer generates a flow of electric current that can be used to power various devices. Similarly, in a fuel cell, a redox reaction occurs between the fuel (e.g., hydrogen) and an oxidizing agent (e.g., oxygen), producing electricity and water as byproducts. Understanding the underlying redox processes is essential for designing and optimizing these electrochemical systems.

Related terms

Oxidation:

The loss of electrons by a molecule, atom, or ion, resulting in an increase in oxidation state.

Reduction:

The gain of electrons by a molecule, atom, or ion, resulting in a decrease in oxidation state.

Oxidation Number:

The charge assigned to an atom in a compound, based on a set of rules, that reflects the degree of oxidation or reduction of the atom.