Chemical Composition and Reaction Stoichiometry

Vocabulary flashcards covering chemical composition, stoichiometry calculations, molar conversions, aqueous solution reactions, solubility rules, and reaction classifications.

Stoichiometry

The study of the quantitative relationships between reactants and products in chemical reactions, based on the law of conservation of mass.

The Mole

A unit of amount equal to $6.02 \times 10^{23}$ particles (atoms, ions, molecules, etc.) that bridges the microscopic world of atoms and molecules with the macroscopic world.

Avogadro's Number ($N_A$)

The constant defining the number of particles in one mole of a substance, equal to $6.02 \times 10^{23}$ particles or $6.02 \times 10^{23}\,mol^{-1}$.

Molar Mass

The mass of one mole of a substance, often referred to as formula weight, whose value in $g\,mol^{-1}$ is numerically equal to the formula's atomic mass in atomic mass units ($\text{amu}$).

Percentage Composition

The percentage by mass of each element in a compound, calculated by dividing either the total mass of the element in the compound by the compound's molar mass, or the mass of the element in a sample by the total sample mass, then multiplying by $100\%$.

Driving Forces for Chemical Change

The four primary conditions that favor chemical change in aqueous solutions: formation of a solid (precipitate), formation of water, transfer of electrons (oxidation-reduction), and formation of a gas.

Precipitation Reaction

A chemical reaction occurring when two solutions of ionic compounds are mixed, resulting in the formation of an insoluble solid known as a precipitate.

Molecular Equation

A chemical equation that shows the complete chemical formulas of all reactants and products without indicating ionic dissociation.

Complete Ionic Equation

A chemical equation representing all strong electrolytes as separated, dissociated aqueous ions.

Spectator Ions

Ions that appear unchanged on both sides of a chemical equation and do not participate directly in the reaction.

Net Ionic Equation

A chemical equation showing only the specific ions or species that participate directly in the reaction, omitting all spectator ions.

Solubility Rules

Guidelines used to predict whether an ionic compound will dissolve in water (be soluble) or remain insoluble and form a solid precipitate.

Strong Acid (Arrhenius Definition)

An acid that produces $H^+$ ions in water and acts as a strong electrolyte by dissociating completely, such as $HCl$, $HNO_3$, and $H_2SO_4$.

Strong Base (Arrhenius Definition)

A base that produces $OH^-$ ions in water and acts as a strong electrolyte by dissociating completely, such as $NaOH$ and $KOH$.

Oxidation-Reduction (Redox) Reaction

A chemical reaction that involves the transfer of electrons between chemical species, characterized by changes in oxidation states and commonly occurring between metals and nonmetals.

Synthesis (Combination) Reaction

A reaction classification in which simpler substances combine together to produce a single, more complex compound.

Decomposition Reaction

A reaction classification in which a complex chemical compound breaks down into two or more simpler substances.

Combustion Reaction

A rapid reaction involving oxygen ($O_2$) that produces energy in the form of heat and light, frequently involving a hydrocarbon reacting to form carbon dioxide ($CO_2$) and water ($H_2O$).