Mole

Definition

A mole is a unit of measurement in chemistry and physics that represents Avogadro's number, approximately $6.022 \times 10^{23}$ particles (atoms, molecules, ions, etc.). It is used to quantify the amount of substance in a given sample.

5 Must Know Facts For Your Next Test

1. One mole of any gas at standard temperature and pressure (STP) occupies 22.4 liters.
2. The Ideal Gas Law can be written as $PV = nRT$, where $n$ is the number of moles.
3. Avogadro's number is crucial for converting between atomic/molecular scale measurements and macroscopic quantities.
4. In kinetic theory, the number of moles helps determine the total number of particles in a gas sample.
5. Moles are used to relate mass to molar mass; the molar mass of a substance is its mass per mole.

Review Questions

• What is Avogadro's number and why is it important?
• How does the concept of a mole apply to the Ideal Gas Law?
• What volume does one mole of an ideal gas occupy at STP?

Related terms

Avogadro's Number: $6.022 \times 10^{23}$, the number of particles in one mole.

Ideal Gas Law:

$PV = nRT$, an equation relating pressure, volume, temperature, and moles of a gas.

Molar Mass: The mass of one mole of a substance, usually expressed in grams per mole (g/mol).