3.1.7.1 - Oxidation and Reduction

Vocabulary flashcards covering the principles of oxidation, reduction, oxidation states, and the methodology for balancing half equations as presented in the lecture notes.

Oxidation

The loss of electrons.

Reduction

The gain of electrons.

Redox reactions

A combination of reduction and oxidation reactions occurring simultaneously because one species loses electrons which are then donated and gained by the other species.

OILRIG

An acronym used to remember redox rules: oxidation is loss, reduction is gain.

Oxidation Number

A value that gives the oxidation state of an element or ionic substance.

Element Oxidation State Rule

The oxidation state of an element is $0$.

Neutral Compound Oxidation State Rule

The oxidation states in a neutral compound add up to $0$.

Charged Compound Oxidation State Rule

The oxidation states in a charged compound add up to total the charge.

Hydrogen Oxidation State

Hydrogen has an oxidation state of $+1$.

Oxygen Oxidation State

Oxygen has an oxidation state of $-2$.

Halogen Oxidation State

All halogens have an oxidation state of $-1$.

Group I Metals Oxidation State

Group I metals have an oxidation state of $+1$.

Oxidising Agent

A species that accepts electrons from the species that is being oxidised, causing it to be reduced and seen as a reduction in oxidation number.

Reducing Agent

A species that donates electrons to the species being reduced, causing it to be oxidised and seen as an increase in oxidation number.

Half Equations

Equations used to show the separate oxidation and reduction reactions that occur in a redox reaction, balanced by species and charges.

Balancing Step 1 (Half Equations)

Balance all species excluding oxygen and hydrogen.

Balancing Step 2 (Half Equations)

Balance oxygen using $H_2O$.

Balancing Step 3 (Half Equations)

Balance hydrogen using $H^+$ ions.

Balancing Step 4 (Half Equations)

Balance changes using $e^-$ (electrons).

Combining Half Equations

The process of determining the overall redox reaction by ensuring the number of electrons is the same for both half equations, which can be done by scaling up the number of moles.