Mole Concept

Vocabulary practice flashcards covering definitions, formulas, and conversions related to the mole concept, molar mass, Avogadro constant, and gas molar volumes.

Mole

The SI unit of amount of substance (symbol: $\text{mol}$). One mole ($1\,\text{mol}$) of a substance consists of $6.02 \times 10^{23}$ particles, or $6.02214076 \times 10^{23}$ elementary entities of the substance.

Avogadro Constant ($N_A$)

Also known as Avogadro number, defined as the value $6.02 \times 10^{23}\,\text{mol}^{-1}$.

Number of Moles from Particles

Calculated using the formula $\text{Number of mole, } n = \frac{\text{Number of particles}}{N_A}$, or by dividing the number of particles by $N_A$.

Molar Mass

The mass of a substance that contains one mole of the substance, expressed in units of $\text{g\,mol}^{-1}$.

Number of Moles from Mass

Calculated using the formula $\text{Number of mole, } n = \frac{\text{Mass (g)}}{\text{Molar mass (g\,mol}^{-1}\text{)}}$.

Molar Volume at Room Temperature and Pressure

The volume occupied by one mole of any gas at room temperature ($25\,^\circ\text{C}$) and a pressure of $1\,\text{atm}$, which is equal to $24\,\text{dm}^3$ (or $24\,000\,\text{cm}^3$).

Molar Volume at Standard Temperature and Pressure (s.t.p.)

The volume occupied by $1\,\text{mole}$ of any gas at standard temperature and pressure ($0\,^\circ\text{C}$ and $1\,\text{atm}$), which is equal to $22.4\,\text{dm}^3$.

Equal Volumes Principle for Gases

The rule stating that at the same temperature and pressure, equal volumes of all gases contain the same number of particles.

Conversion of Number of Moles of A Gas to its Volume

Calculated by multiplying the number of moles by the molar value: $\text{Number of moles} \times \text{Molar value}$.

Conversion of Volume of Gas to Number of Moles

Calculated by dividing the volume of the gas by the molar volume: $\text{Volume of gas} \div \text{Molar volume}$.

Mole Concept Conversion Diagram

A central interconversion diagram showing that the number of moles connects to mass (via multiplying or dividing by molar mass), number of particles (via multiplying or dividing by $N_A$), and volume of gas in $\text{dm}^3$ (via multiplying or dividing by molar volume).