In chemistry, a mole is a standard unit used to measure the amount of a substance. It represents a specific number of particles, such as atoms, molecules, or ions.
One mole is defined as containing exactly 6.022 × 10²³ particles, which is known as Avogadro’s number.
For example:
- 1 mole of oxygen atoms (O) = 6.022 × 10²³ oxygen atoms.
- 1 mole of water molecules (H₂O) = 6.022 × 10²³ water molecules.
The mole helps chemists relate the microscopic world of atoms and molecules to measurable quantities in the laboratory. It also connects the mass of a substance to the number of particles it contains.
👉 For instance:
- 1 mole of carbon-12 atoms has a mass of exactly 12 grams.
- 1 mole of hydrogen gas (H₂) has a mass of about 2 grams.
So, the mole acts as a bridge between atomic scale and laboratory scale.