Avogadro's number, denoted by the symbol "Nₐ" or "L", is a fundamental constant in chemistry. It represents the number of particles (atoms, molecules, ions, etc.) in one mole of a substance. The value of Avogadro's number is approximately 6.022 x 10^23 particles per mole.
To put it in perspective, one mole of any substance contains the same number of entities as there are atoms in exactly 12 grams of carbon-12. This concept allows chemists to easily convert between the mass of a substance and the number of particles it contains.
Avogadro's number plays a crucial role in various chemical calculations, including:
- Calculating the number of atoms, molecules, or ions in a given amount of substance.
- Determining the molar mass of a substance.
- Converting between mass, moles, and number of particles using the mole concept.
The precise value of Avogadro's number was determined by experiment and is based on a measurement of the charge of an electron. It is named after the Italian scientist Amedeo Avogadro, who proposed in 1811 that equal volumes of gases, under the same conditions of temperature and pressure, contain an equal number of particles. His hypothesis was later refined and became known as Avogadro's law.