12 Oxidation and Reduction - Vocabulary flashcards

Vocabulary flashcards covering key terms and concepts from the Oxidation and Reduction lecture notes, focusing on definitions of oxidation/reduction, redox concepts, oxidizing/reducing agents, half-reactions, and related electrochemical ideas.

Oxidation

Loss of electrons by an atom, ion, or molecule; may involve gain of oxygen or loss of hydrogen; oxidation number increases.

Reduction

Gain of electrons by an atom, ion, or molecule; may involve loss of oxygen or gain of hydrogen; oxidation number decreases.

Redox (oxidation–reduction) reaction

A chemical reaction that involves the transfer of electrons between substances; oxidation and reduction occur together.

Oxidation number

A hypothetical charge assigned to an atom in a compound to track electron flow; used to identify oxidation and reduction.

OIL (Oxidation Is Loss of electrons)

Mnemonic indicating that oxidation involves loss of electrons.

RIG (Reduction Is Gain of electrons)

Mnemonic indicating that reduction involves gain of electrons.

Oxidizing agent

A substance that gains electrons during a reaction and causes another species to oxidize; it is itself reduced.

Reducing agent

A substance that donates electrons during a reaction and causes another species to reduce; it is itself oxidized.

Electron acceptor

A species that gains electrons in a redox reaction (the oxidizing agent).

Electron donor

A species that donates electrons in a redox reaction (the reducing agent).

Standard electrode potential (E°)

A measure of a species’ tendency to gain or lose electrons; more positive E° favors reduction, more negative favors oxidation.

Oxygen (O2) as oxidizing agent

O2 commonly accepts electrons in reactions, causing others to oxidize; a strong oxidant.

Chlorine (Cl2) as oxidizing agent

Cl2 accepts electrons to form Cl⁻ in many redox processes; strong oxidant.

Potassium permanganate (KMnO4) as oxidizing agent

A strong oxidizer in redox reactions; MnO4⁻ is reduced (commonly to Mn²⁺) in acidic solutions.

Hydrogen peroxide (H2O2) as oxidizing agent

Acts as an oxidizer in cleaning/disinfection and other reactions; can be reduced to water or oxygen depending on conditions.

Nitric acid (HNO3) as oxidizing agent

Oxidizes metals such as copper; a common strong oxidant in acids.

Hydrogen gas (H2) as reducing agent

Donates electrons in many reductions; a common reductant in organic and inorganic reactions.

Zinc (Zn) as reducing agent

Donates electrons to reduce other species; a common metal reductant in redox chemistry.

Carbon (C) as reducing agent

Donates electrons to reduce metal oxides (smelting) and other species.

Sodium borohydride (NaBH4) as reducing agent

Donates hydride (H⁻) to reduce carbonyl groups in organic synthesis.

Lithium aluminum hydride (LiAlH4) as reducing agent

Strong hydride donor used to reduce a wide range of functional groups in organic synthesis.

Half-reaction

One side of a redox equation showing either oxidation (loss of electrons) or reduction (gain of electrons).

Oxidation half-reaction

The portion of a redox equation where a species loses electrons.

Reduction half-reaction

The portion of a redox equation where a species gains electrons.

Balancing redox reactions (half-reaction method)

A method that balances redox equations by balancing oxidation and reduction half-reactions separately, then combining them.

Acidic solution balancing

Balancing redox equations in acidic solution by adding H⁺ and H₂O to balance hydrogens and oxygens, then electrons.

Basic solution balancing

Balancing redox equations in basic solution by neutralizing H⁺ with OH⁻ and canceling water where appropriate.

Anode

The electrode where oxidation occurs in an electrochemical cell; electrons flow out of it.

Cathode

The electrode where reduction occurs in an electrochemical cell; electrons flow into it.

Voltaic (galvanic) cell

A spontaneous electrochemical cell that converts chemical energy into electrical energy.

Electrolysis

Non-spontaneous redox process driven by an external electrical current; splits compounds into simpler species at electrodes.

Corrosion

Redox process where metal is oxidized (often at the anode) and a reduction occurs at the cathode, typically forming rust in the presence of water and oxygen.