Redox Reactions & Electrode Potentials – Lecture Review

Vocabulary flashcards summarizing key redox-chemistry terms, electrode-potential concepts, and balancing techniques presented in the lecture.

Redox Reaction

A chemical process in which oxidation and reduction occur simultaneously, involving the transfer of electrons between species.

Oxidation

The loss of electrons by a species, resulting in an increase in its oxidation number.

Reduction

The gain of electrons by a species, leading to a decrease in its oxidation number.

Oxidizing Agent

A substance that accepts electrons (is reduced) and thereby causes another species to be oxidized.

Reducing Agent

A substance that donates electrons (is oxidized) and thus causes another species to be reduced.

Standard Reduction Potential (E°)

A quantitative measure (in volts) of a species’ tendency to gain electrons under standard conditions; more positive E° indicates a stronger oxidizing agent.

Activity Series

An empirical list that ranks metals (or other elements) by their ability to displace other species in redox reactions, predicting reaction feasibility.

Feasible Redox Reaction

A reaction that proceeds spontaneously because the overall cell potential (E°cell) is positive, or the oxidizing agent’s E° exceeds that of the reducing agent.

Disproportionation

A special redox process in which the same element undergoes simultaneous oxidation and reduction, forming two different oxidation states.

Half-Reaction

Either the oxidation or reduction part of a redox equation, written to show electron transfer explicitly.

Ion-Electron (Half-Reaction) Method

Systematic procedure for balancing redox equations: separate into half-reactions, balance atoms and charge, then combine so electrons cancel.

Acidic Medium Balancing Rule

When balancing in acid, add H₂O to balance O, H⁺ to balance H, and finally electrons to balance charge.

Basic Medium Balancing Rule

When balancing in base, first balance as if acidic, then add equal OH⁻ to both sides to neutralize H⁺, forming H₂O, and simplify.

Cross-Multiplication Charge Balance

A shortcut step in some balancing methods where electron counts from oxidation and reduction halves are cross-multiplied to ensure total charge cancellation.