Chapter 8: Chemical Quantities Key Terms

Atomic Mass Unit (amu)

A unit of mass used to express atomic and molecular weights, equal to one-twelfth the mass of a carbon-12 atom.

Average Atomic Mass

The weighted average of the atomic masses of the isotopes of an element, based on their natural abundance

Mole (mol)

The SI unit for the amount of a substance, defined as the quantity of matter that contains as many entities (atoms, molecules, or ions) as there are in 12 grams of carbon-12.

Avogadro’s Number

The number of entities in one mole of a substance, equal to 6.022×10236.022 \times 10^{23}6.022×1023.

Conceptual Problem Solving

A problem-solving approach that involves understanding the problem conceptually and applying logic and reasoning to reach a solution.

Molar Mass

The mass of one mole of a substance, expressed in grams per mole (g/mol).

Mass Percent

The percentage by mass of an element in a compound, calculated as:

Mass Percent=(Mass of Compound/Mass of Element​)×100

Empirical Formula

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

Molecular Formula

The formula that gives the actual number of atoms of each element in a molecule of a compound.