Types of Chemical Reactions and Solution Stoichiometry

Vocabulary flashcards covering the key terms, definitions, and concepts of aqueous solutions, reaction classifications, stoichiometry, acids and bases, and redox chemistry from Chapter 4.

Aqueous Solution

A solution formed when water acts as the solvent.

Polarity

The property of having distinct positive and negative regions within a molecule as a result of an unequal sharing of electrons.

Solution

A homogeneous mixture in which two or more components mix freely with one another.

Solvent

The component of a solution present in the largest amount.

Solute

Any substance dissolved in the solvent.

Solvation

The process of dissolving, wherein solvent molecules surround and stabilize solute particles, such as water molecules hydrating separated ions.

Dissociation

The separation of a soluble ionic compound into its individual constituent ions when dissolved in water.

Electrolyte

A substance that dissociates into ions in aqueous solution, thereby conducting an electric current.

Strong Electrolyte

A solute that dissociates completely in water and exists in solution almost exclusively as ions, including strong acids, strong bases, and most soluble ionic compounds.

Weak Electrolyte

A solute that dissociates only partially in water, producing a relatively small concentration of ions and resulting in poor electrical conductivity (e.g., weak acids and weak bases).

Nonelectrolyte

A substance that does not dissociate into ions when dissolved in water and is present in solution almost exclusively as intact neutral molecules.

Molarity ($M$)

A measure of solution concentration defined as the moles of solute per liter of solution ($\text{Molarity}\,(M) = \frac{\text{moles of solute}}{\text{liters of solution}}$).

Dilution

The procedure of preparing a less concentrated solution from a concentrated solution by adding solvent, described by the conservation of solute mass equation $V_1 \times M_1 = V_2 \times M_2$.

Single Displacement Reaction

A reaction with the general equation $A + BC \rightarrow AC + B$, in which a more active free element replaces a less active element in a compound.

Activity Series

A series that ranks metals according to their ease of oxidation, determining whether a metal will displace another metal or hydrogen from aqueous solutions or acids.

Insoluble Solute

A substance whose maximum equilibrium solubility in water is less than approximately $0.01\,M$.

Precipitate

An insoluble solid substance that forms and separates out of a solution during a chemical reaction.

Precipitation Reaction

A reaction occurring in aqueous solution in which soluble reactants combine to form one or more insoluble solid products.

Metathesis Reaction

A double replacement reaction with the general form $AB + CD \rightarrow AD + CB$, where cations exchange partners; it occurs when driven by the formation of a precipitate, a weak electrolyte, or a gas.

Molecular Equation

A balanced chemical equation in which all reactants and products are written as neutral, undissociated chemical formulas along with their physical states.

Complete Ionic Equation

A balanced equation representing all strong electrolytes as separated, individual dissolved ions, while insoluble substances, weak electrolytes, gases, and liquids remain as whole molecular formulas.

Net Ionic Equation

A chemical equation obtained by omitting all spectator ions from the complete ionic equation, leaving only the chemical species directly participating in the chemical change.

Spectator Ions

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

Arrhenius Acid

A substance that produces or increases the concentration of hydrogen ions ($H^+$) when dissolved in water.

Arrhenius Base

A substance that produces or increases the concentration of hydroxide ions ($OH^-$) when dissolved in water.

Brønsted–Lowry Acid

A chemical species that donates a proton ($H^+$) to another substance.

Brønsted–Lowry Base

A chemical species that accepts a proton ($H^+$) from another substance.

Neutralization Reaction

A chemical reaction between an acid and a base that typically produces water and a salt, cancelling out the identifying characteristics of each reactant.

Titration

A quantitative analytical technique where a solution of known concentration (titrant) is dispensed from a buret into an analyte solution (titrand) until the reaction reaches completion.

Equivalence Point

The exact stage in a titration where the quantity of titrant added is chemically equivalent to the amount of analyte according to the reaction stoichiometry.

Endpoint

The point in a titration where an added indicator changes color, signaling that the equivalence point has been reached.

Acid-Base Indicator

A dye substance added to a solution that changes color across specific pH changes, used to detect the endpoint of a titration.

Oxidation-Reduction (Redox) Reaction

A chemical reaction involving the transfer of electrons between reactants, identified by changes in the oxidation numbers of the participating atoms.

Oxidation

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

Reduction

The gain of one or more electrons by a chemical species, resulting in a decrease in its oxidation number.

Reducing Agent

The reactant that loses electrons (undergoes oxidation) in a redox reaction and thereby causes another substance to be reduced.

Oxidizing Agent

The reactant that gains electrons (undergoes reduction) in a redox reaction and thereby causes another substance to be oxidized.

Oxidation Number

A formal charge assigned to an atom in a molecule or ion according to a set of bookkeeping rules to track electron transfers.

Disproportionation Reaction

A specialized redox reaction in which a single substance acts simultaneously as both the oxidizing agent and the reducing agent, undergoing oxidation and reduction at the same time.