Avogadro’s number

Definition

Avogadro's number, $6.022 \times 10^{23}$, is the number of atoms, ions, or molecules in one mole of a substance. It is a fundamental constant used to relate macroscopic measurements to microscopic quantities.

5 Must Know Facts For Your Next Test

1. Avogadro's number is $6.022 \times 10^{23}$ and is denoted by $N_A$.
2. It allows the conversion between the number of particles and the amount of substance in moles.
3. In the ideal gas law, it helps relate the volume of gas to the number of gas molecules when using \( n \) (number of moles).
4. It provides a bridge between atomic scale measurements and macroscopic quantities observed in experiments.
5. Avogadro's number is crucial for calculating quantities like molar mass and for stoichiometric calculations in chemical reactions.

Review Questions

• What is Avogadro's number and what does it represent?
• How does Avogadro's number facilitate conversions between microscopic and macroscopic quantities?
• Why is Avogadro's number important in the context of the ideal gas law?

Related terms

Ideal Gas Law:

$PV = nRT$, an equation that describes the state of an ideal gas by relating pressure ($P$), volume ($V$), temperature ($T$), and amount of substance ($n$) with the universal gas constant ($R$).

Mole:

A unit representing $6.022 \times 10^{23}$ entities (atoms, molecules, etc.). It allows chemists to count particles by weighing them.

Boltzmann Constant: $k_B = 1.38 \times 10^{-23} \text{J/K}$, a physical constant relating average kinetic energy of particles in a gas with temperature.