Chemical Reactions and Aqueous Solutions (Chapter 4)

Vocabulary flashcards covering key terms from the lecture notes on chemical reactions and aqueous solutions.

Chemical equation

A symbolic representation of a chemical reaction showing the reactants and products, with coefficients indicating the proportions of each substance.

Reactant

A starting substance in a chemical reaction.

Product

A substance formed as a result of a chemical reaction.

Coefficient

A number placed before a formula to indicate how many moles of that substance participate in the reaction.

Aqueous solution

A solution in which the solute has dissolved in water; ions may be present in solution.

Dissociation

The process by which an ionic compound separates into its ions when dissolved in water.

Electrolyte

A substance that conducts electricity when dissolved in water.

Strong electrolyte

A substance that completely dissociates in water, producing a large current; includes most ionic compounds, strong acids, and strong bases.

Weak electrolyte

A substance that only partially dissociates in water and conducts electricity weakly (weak acids and weak bases).

Nonelectrolyte

A substance that dissolves in water as molecules and does not conduct electricity.

Soluble

A substance that dissolves readily in water to form a homogeneous solution.

Insoluble

A substance that does not dissolve significantly in water and may form a precipitate.

Net ionic equation

An ionic equation showing only the species that actually participate in the reaction; spectator ions are omitted.

Spectator ion

An ion that appears on both sides of a reaction and does not participate in the chemical change.

Precipitation reaction

A reaction in which an insoluble salt forms from mixing two aqueous ionic solutions.

Solubility rules

Guidelines used to predict whether ionic compounds are soluble or insoluble in water (Table 4.5 in the notes).

Acid

A molecular compound that ionizes in water to produce H+ (hydronium) and a counterion; acids conduct electricity when dissolved.

Strong acid

An acid that ionizes completely in water and is a strong electrolyte.

Weak acid

An acid that ionizes only partially in water and is a weak electrolyte.

Base

A substance that increases the OH- concentration in water; strong bases dissociate completely, while weak bases are molecular and only partly ionize.

Strong base

An ionic compound that dissociates completely in water to form OH-, a strong electrolyte.

Weak base

A molecular base that ionizes only partially in water and is a weak electrolyte.

Oxidation state (oxidation number)

A bookkeeping value used to track electron transfer in redox reactions; rules include elements in their elemental form have oxidation state 0, fluorine is -1, oxygen is -2 (except in peroxides), hydrogen is +1 in most covalent compounds; the sum of oxidation states equals the charge of the species.

Redox reaction

A reaction involving transfer of electrons, leading to changes in oxidation states.

Reducing agent

The substance that donates electrons in a redox reaction and is itself oxidized.

Oxidizing agent

The substance that accepts electrons in a redox reaction and is itself reduced.

Combustion

A reaction of a hydrocarbon with oxygen to form carbon dioxide and water.

Synthesis (Combination) reaction

A reaction in which two or more substances combine to form a single product (A + B → AB).

Decomposition reaction

A reaction in which a single compound breaks down into two or more substances (AB → A + B).

Single-replacement reaction

A reaction where an element replaces another element in a compound (A + BC → AC + B).

Double-replacement reaction

A reaction where two ionic compounds exchange partners to form two new compounds (AB + CD → AD + CB).

Net ionic equation

An ionic equation that shows only the species that actually participate in the reaction; spectator ions are removed.