Avogadro’s number

Definition

Avogadro's number is the number of constituent particles (usually atoms or molecules) in one mole of a substance, equal to approximately $6.022 \times 10^{23}$. It is a fundamental constant used in chemistry and physics to relate macroscopic and microscopic properties.

5 Must Know Facts For Your Next Test

1. Avogadro's number is $6.022 \times 10^{23}$ particles per mole.
2. It allows for the conversion between moles and number of particles.
3. In the kinetic theory of gases, it helps relate macroscopic gas properties to molecular behavior.
4. Avogadro's number is essential for calculating the molar volume of an ideal gas at standard temperature and pressure (STP).
5. It plays a key role in determining quantities like Boltzmann's constant when dealing with individual molecules.

Review Questions

• What is Avogadro's number and how is it used in the context of an ideal gas?
• How does Avogadro's number facilitate conversions between moles and individual molecules?
• Why is Avogadro's number important for understanding the kinetic theory of gases?

Related terms

Mole: A unit that measures the amount of substance, defined as containing exactly $6.022 \times 10^{23}$ constituent particles.

Ideal Gas Law: $PV = nRT$, which describes the relationship between pressure (P), volume (V), temperature (T), and moles of gas (n).

Boltzmann Constant: $k_B$ relates the average kinetic energy of particles in a gas with the temperature, calculated as $R/N_A$ where $R$ is the gas constant and $N_A$ is Avogadro’s number.