Oxidation-Reduction (Redox) Reactions - Key Concepts

Vocabulary flashcards covering redox basics, oxidation states, agents, half-reactions, and example analyses from the notes.

Redox (oxidation-reduction) reaction

A chemical reaction that involves transfer of electrons between species, causing changes in oxidation states for one or more elements.

Oxidation

Increase in oxidation state of a species; loss of electrons.

Reduction

Decrease in oxidation state of a species; gain of electrons.

Oxidizing agent

The substance that is reduced in a redox reaction; it causes another substance to be oxidized.

Reducing agent

The substance that is oxidized in a redox reaction; it causes another substance to be reduced.

Oxidation state (oxidation number)

A formal charge assigned to atoms in a compound to track electron transfer; rules include: pure elements = 0; H is +1 when bonded to nonmetals; O is usually -2; peroxide = -1; superoxide = -1/2.

Oxidation state of a pure element

Always zero.

Half-reaction

A partial redox equation: oxidation half-reaction has electrons on the right, reduction half-reaction has electrons on the left.

Rule: pure element on one side and same element in a compound on the other side

Indicates a redox reaction due to electron transfer.

Single replacement reaction

A reaction where an element replaces another in a compound; typically involves a redox process.

Double replacement reaction

Two compounds swap partners; typically not a redox reaction (e.g., acid-base, precipitation).

Combustion reaction

A fuel reacts with an oxidizer (often O2) to form products like CO2 and H2O; always a redox reaction.

Synthesis (combination) reaction

Two or more substances combine to form a single product; may or may not be redox.

Decomposition reaction

A compound breaks down into simpler substances; may or may not be redox.

Oxygen oxidation states: oxide, peroxide, superoxide

Oxide = -2; peroxide = -1; superoxide = -1/2.

Hydrogen oxidation state rule

Hydrogen has +1 oxidation state when bonded to non-metals.