Exam 2 Review: Chapters 3 and 4

Vocabulary terms covering stoichiometry, chemical reactions in aqueous solutions, and oxidation-reduction concepts for Chapters 3 and 4.

Percent Composition

The percent by mass of each element in a compound.

Empirical Formula

The simplest whole-number ratio of the atoms of each element present in a compound.

Stoichiometry

The calculation of relative quantities of reactants and products in chemical reactions based on the balanced equation.

Limiting Reagent

The reactant that is completely consumed first in a chemical reaction and limits the amount of product that can be formed.

Strong Electrolyte

A substance that completely dissociates or ionizes into ions when dissolved in water, resulting in a solution that conducts electricity well.

Weak Electrolyte

A substance that only partially ionizes or dissociates in water, resulting in a solution that is a poor conductor of electricity.

Nonelectrolyte

A substance that does not ionize or dissociate into ions in water and does not conduct electricity.

Precipitation Reaction

A chemical reaction in which a solid (precipitate) forms from the mixing of two aqueous solutions.

Brønsted Acid

A substance that acts as a proton ($H^+$) donor.

Brønsted Base

A substance that acts as a proton ($H^+$) acceptor.

Acid-Base Reaction

A reaction involving the transfer of a proton from an acid to a base, typically yielding a salt and water.

Oxidation-Reduction (Redox) Reaction

A chemical reaction involving the transfer of electrons between two species.

Oxidized Species

The species that loses electrons during a redox reaction, resulting in an increase in its oxidation number.

Reduced Species

The species that gains electrons during a redox reaction, resulting in a decrease in its oxidation number.

Oxidation Number

A numerical value assigned to an atom to represent the number of electrons lost or gained by that atom in a compound.

Combination Reaction

A type of oxidation-reduction reaction where two or more substances react to form a single product.

Decomposition Reaction

A type of oxidation-reduction reaction where a single compound breaks down into two or more simpler substances.

Displacement Reaction

A type of oxidation-reduction reaction in which an atom or ion in a compound is replaced by an atom or ion of another element.

Molarity (M)

A unit of concentration defined as the number of moles of solute per liter of solution ($mol/dm^3$).

Dilution Formula

The mathematical relationship used to calculate changes in concentration or volume when a solvent is added to a solution: $M_1 V_1 = M_2 V_2$.