1.1—1.3

A set of vocabulary flashcards based on the fundamental chemistry concepts of the mole, atomic mass, and dimensional analysis.

atomic mass units

A unit of mass used to express the mass of individual atoms or molecules, where one amu is defined relative to carbon-12.

Elemental composition by mass

The percentage or proportion of each element present in a substance,expressed as a mass fraction or mass percentage

Empirical formula

The chemical formula that represents the lowest whole number ratio of atoms of the elements in a compound

Formula unit

The smallest unit of a compound that shows the fixed proportions of atoms or ions held together

Law of definite proportions

The principle that the ratio of the masses of the constituent elements in any pure sample of a compound is always the same

Pure Substance

A material with a fixed, definite composition and consistent properties throughout

Constituent elements

The individual elements that make up a compound in fixed proportions

Average Atomic Mass

The weighted average of the masses of all isotopes of an element, based on their relative abundances in nature

Isotopes

Atoms of the same element that have different numbers of neutrons and therefore different mass numbers

Isotopic masses

The mass of individual isotopes of an element, typically expressed in atomic mass units

Mass spectrum

A graphical representation showing the masses of isotopes of an element and their relative abundances

Weighted average

A calculation method that accounts for the relative abundance of each isotope when determining the average Atomic Mass of an element

Relative abundance

The percentage or proportion of each isotope present in a naturally occurring sample of an element.

Avogadro's number

The constant $6.022 \times 10^{23}\,mol^{-1}$ that represents the number of particles (atoms, molecules, or formula units) in one mole of a substance.

constituent particles

The individual atoms, molecules, or ions that make up a substance.

dimensional analysis

A mathematical technique for converting between different units of measurement by using conversion factors and canceling units.

formula unit

The smallest unit of a compound that shows the fixed proportions of atoms or ions held together.

molar mass

The mass in grams of one mole of a substance, numerically equal to the average mass of one particle in atomic mass units.

mole concept

A fundamental chemistry concept that relates the number of particles (atoms, molecules, or ions) to measurable quantities through Avogadro's number.