Chap 8 - Chemical Composition Practice Flashcards

Vocabulary flashcards covering the key concepts and terms of chemical composition, including atomic masses, the mole, and formulas.

Atomic mass unit (amu)

A unit created by scientists to avoid using very small numbers for atomic masses, where $1\text{ atomic mass unit (amu)} = 1.66 \times 10^{-24}\text{ g}$.

Average atomic mass

The weighted average of the masses of all the isotopes of an element.

The Mole

The amount of a substance that contains the same number of units (such as atoms) as there are in $12.01\text{ grams}$ of carbon; specifically $6.022 \times 10^{23}\text{ units}$.

Avogadro’s number

The number of units in one mole, equal to $6.022 \times 10^{23}$.

Molar Mass

The mass in grams of one mole of a substance, expressed in units of $\text{g/mol}$.

Mass percent of an element

A measure found by taking the mass of an element in one mole of a compound and dividing it by the total mass of one mole of that compound, then multiplying by $100$.

Empirical Formula

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

Molecular Formula

The exact formula of the molecules present in a substance, expressed as an integer multiple of the empirical formula: $(\text{empirical formula})_n$.