Chapter 3: Stoichiometry Vocabulary

A set of vocabulary flashcards covering basic chemical stoichiometry concepts, atomic mass units, mole conversions, chemical formulas, and reaction yields.

Chemical Stoichiometry

The study of the quantities of materials consumed and produced in chemical reactions.

Modern System of Atomic Masses

The system established in 1961 that assigns $^{12}\text{C}$ a mass of exactly $12$ atomic mass units ($u$), serving as the standard for relative atomic masses.

Mass Spectrometer

An instrument used to accurately compare atomic masses and determine isotopic composition by converting atoms or molecules into positive ions with high-speed electrons and accelerating them into a magnetic field.

Average Atomic Mass

Also known as atomic weight, a dimensionless value representing the weighted average mass of an element's naturally occurring isotopes.

IUPAC

International Union of Pure and Applied Chemistry.

Mole

The amount of substance equal to the number of carbon atoms in exactly $12\,g$ of pure $^{12}\text{C}$.

Avogadro's Number

The number of units in one mole of any substance, defined as $6.022 \times 10^{23}$.

Molar Mass

The mass in grams of one mole of a substance, calculated by summing the atomic masses of its component atoms.

Formula Unit

The fundamental unit of an ionic compound, such as $\text{NaCl}$ for sodium chloride.

Mass Percent

Also known as weight percent, calculated as $\frac{\text{mass of element in } 1\,\text{mol}\text{ compound}}{\text{mass of } 1\,\text{mol}\text{ compound}} \times 100\%$.

Empirical Formula

The chemical formula representing the smallest whole-number ratio of atoms in a compound.

Molecular Formula

The exact chemical formula of the molecules present in a substance, given by $(\text{empirical formula})_n$ where $n$ is an integer.

Limiting Reactant

The reactant that is completely consumed first in a reaction, limiting the amount of product formed.

Stoichiometric Mixture

A reaction mixture in which all reactants are entirely consumed at the same time.

Theoretical Yield

The maximum amount of product that can be formed when the limiting reactant is completely consumed.

Percent Yield

The efficiency of a reaction expressed as a percentage: $\frac{\text{Actual yield}}{\text{Theoretical yield}} \times 100\%$.