Molar Calculations, Avogadro's Law, and Isotopes

Vocabulary flashcards covering the mole concept, Avogadro's hypothesis, molar volume of gases, germanium atom calculations, and isotopic abundances.

Avogadro constant ($N_A$)

The number of atoms per mole of the carbon-12 isotope, valued at $6.02 \times 10^{23}\,\text{particles per mole}$ (or more precisely $6.02214076 \times 10^{23}$).

Avogadro's hypothesis

A hypothesis proposed in 1811 stating that equal volumes of gases at the same temperature and pressure contain the same number of molecules.

Molar gas volume at room temperature

The volume occupied by one mole of any gas at room temperature, which is equal to $24\,\text{dm}^3$ (for example, $32\,\text{grams}$ of $O_2$ occupies $24\,\text{dm}^3$).

Number of moles

A measure of chemical amount calculated by dividing the actual mass of a sample by its relative atomic or molecular mass.

Wilhelm Ostwald

The German chemist who introduced the term "mole" at the end of the nineteenth century due to its relationship to the word molecule.

Molar mass of germanium

The mass of one mole of germanium atoms, given as $72.63\,\text{g}\,\text{mol}^{-1}$.

Isotopes

Different forms of the same chemical element; for example, chlorine-35 and chlorine-37 (which contains 17 protons and 20 neutrons).

Relative atomic mass of chlorine

The average mass of natural chlorine, which is approximately $35.5$ because it is composed of roughly three-quarters chlorine-35 and one-quarter chlorine-37.

Relative atomic mass

The weighted average mass of an element's isotopes, calculated by dividing the sum of the products of each isotope's mass and its percentage abundance by $100$.

Relative mass of aluminum

The atomic mass value of aluminum cited in the lecture as $26.982$.