Chemistry - The Mole, Molar Mass, and Concentrations

Vocabulary flashcards covering core concepts of chemistry including the mole, Avogadro's constant, atomic and molecular molar mass, molar volume, mass density, concentration, dissolution, and dilution.

Constante d'Avogadro ($N_A$)

A fundamental constant equal to $N_A = 6.02 \times 10^{23}\text{ mol}^{-1}$, representing the number of elementary entities contained in one mole.

Quantité de matière ($n$)

A physical quantity expressed in moles ($\text{mol}$) corresponding to the number of entities in a sample, determined by $n = \frac{N}{N_A}$ or $n = \frac{m}{M}$.

Mole ($\text{mol}$)

The unit of quantity of matter, corresponding to a packet of $6.02 \times 10^{23}$ entities such as atoms, ions, or molecules.

Masse molaire ($M$)

The mass of one mole of an entity (atom, ion, or molecule), expressed in $\text{g}\text{ mol}^{-1}$.

Masse molaire atomique

The mass of one mole of atoms of a given element, expressed in $\text{g}\text{ mol}^{-1}$ (e.g., $M(C) = 12.0\text{ g}\text{ mol}^{-1}$, $M(H) = 1.0\text{ g}\text{ mol}^{-1}$, $M(O) = 16.0\text{ g}\text{ mol}^{-1}$, $M(N) = 14.0\text{ g}\text{ mol}^{-1}$).

Masse molaire moléculaire

The mass of one mole of molecules, calculated as the sum of the atomic molar masses of all constituent atoms (e.g., $M(H_2O) = 2 \times M(H) + M(O) = 18\text{ g}\text{ mol}^{-1}$).

Volume molaire ($V_m$)

The volume occupied by one mole of gas, calculated as $V_m = \frac{V}{n}$ in $\text{L}\text{ mol}^{-1}$, equal to $V_m = 24.0\text{ L}\text{ mol}^{-1}$ at $20\text{ }^\text{o}\text{C}$ and $1013\text{ hPa}$.

Concentration molaire ($C$)

The amount of solute per unit volume of solution, defined as $C = \frac{n}{V}$ and expressed in $\text{mol}\text{ L}^{-1}$.

Concentration massique ($t$)

The mass of solute per unit volume of solution, defined as $t = \frac{m_{\text{soluté}}}{V}$ in $\text{g}\text{ L}^{-1}$, related to molar concentration by $t = C \times M$.

Masse volumique ($\rho$)

The ratio of the mass of a sample to its total volume, defined as $\rho = \frac{m}{V}$ and expressed in $\text{g}\text{ L}^{-1}$.

Densité ($d$)

A dimensionless ratio comparing the mass density of a substance to that of water, calculated as $d = \frac{\rho}{\rho_{\text{eau}}}$ where $\rho_{\text{eau}} = 1000\text{ g}\text{ L}^{-1}$.

Facteur de dilution ($F$)

The ratio indicating how many times a solution is diluted, expressed as $F = \frac{t_{\text{mère}}}{t_{\text{fille}}} = \frac{C_{\text{mère}}}{C_{\text{fille}}} = \frac{V_{\text{fille}}}{V_{\text{mère}}}$.

Dissolution

The procedure of dissolving a specific mass $m$ of a solute into a solvent to obtain a targeted solution volume $V$.

Dilution

The procedure of preparing a less concentrated solution (solution fille) from a stock solution (solution mère) using lab tools such as a pipette jaugée, poire à pipeter, fiole jaugée, and eau distillée.

Béryllium ($Be$)

A chemical element with atomic number $Z = 4$ and a molar mass of $9.0\text{ g}\text{ mol}^{-1}$.