Chapter 5: Chemical Reactions

Vocabulary flashcards covering chemical equations, reaction classifications, redox processes, aqueous reactions, solubility rules, and acid-base neutralization.

Chemical Equation

A written representation used to describe chemical and physical changes.

Reactants

The starting substances used in a reaction, written on the left side of a chemical equation.

Products

The substances formed during a chemical reaction, written on the right side of a chemical equation.

Law of Conservation of Mass

The principle stating that matter cannot gain or lose atoms during a reaction, meaning equations must have the same number of each atom on both sides.

Subscript

The number within a chemical formula that indicates the number of times an atom participates in a compound, which cannot be changed when balancing an equation.

Coefficient

The leading number placed in front of a chemical formula that indicates the number of times a compound or molecule participates in a reaction, which is the only value adjusted to balance an equation.

Combination Reaction

A reaction classification (also called synthesis) where two or more reactants combine to form one product ($A + B \rightarrow AB$).

Decomposition Reaction

A reaction classification where a single reactant breaks down into two or more products ($AB \rightarrow A + B$).

Single Replacement Reaction

A reaction classification (also called single displacement) in which one element displaces another element within a compound ($A + BC \rightarrow B + AC$).

Double Displacement Reaction

A reaction classification where two compounds exchange cations or anions, which includes precipitation and acid-base neutralization reactions.

Precipitation Reaction

A double displacement reaction in which two soluble aqueous solutions ($AB(aq) + CD(aq)$) react to form an insoluble solid product ($CB(s)$) and a soluble product ($AD(aq)$).

Combustion Reaction

An exothermic reaction involving elemental oxygen ($O_2$) that releases a significant amount of heat, such as hydrocarbons reacting with oxygen to produce $CO_2$ and $H_2O$.

Exothermic

A term describing a reaction or process that releases a significant amount of heat.

REDOX Reactions

Reactions in which electrons are transferred from one chemical species to another.

Oxidation

The reaction process in which a chemical species loses electrons, resulting in a more positive charge.

Reduction

The reaction process in which a chemical species gains electrons, resulting in a more negative charge.

OIL RIG

A mnemonic used to remember oxidation and reduction: "Oxidation Is Loss, Reduction Is Gain" of electrons.

Aqueous Solution

A homogeneous mixture formed when a substance dissolves in water, designated by the state symbol $(aq)$.

Dissolve

The process of a substance entering the solution phase.

Dissociate

The process by which an ionic compound or acid breaks apart into smaller individual ions in solution.

Soluble Salt

An ionic compound that dissolves and enters the solution phase when placed into water.

Insoluble Salt

An ionic compound that does not dissolve appreciably in water and remains or forms as a solid precipitate.

Molecular Equation

A chemical equation in which compounds in solution are written as neutral formula units without explicit ionic character.

Complete Ionic Equation

A chemical equation in which all compounds that dissociate in aqueous solution are explicitly written as separate dissolved ions.

Net Ionic Equation

A chemical equation in which spectator ions are omitted, showing only the specific ions and substances directly involved in forming the product.

Spectator Ions

Ions that remain unchanged in solution on both sides of a chemical equation and do not directly participate in forming the product.

Acid

A covalent compound that donates $H^+$ (protons) when dissolved in aqueous solution, typically represented as $HA$.

Base

An ionic compound that donates $OH^-$ (hydroxide ions) in solution, typically represented as $MOH$ or $M(OH)_2$.

Acid-Base Neutralization

A double displacement reaction between an acid and a base that produces a salt and water ($acid + base \rightarrow salt + water$).