Avogadro's number

Avogadro's Number is a fundamental constant of chemistry and physics, denoted by the symbol N_A or simply A. It is named after the Italian scientist Amedeo Avogadro, who contributed significantly to the development of molecular theory in the early 19th century.

Definition

Avogadro's Number is defined as the number of constituent particles (usually atoms or molecules) in one mole of a given substance. Its value is approximately 6.02214076 × 10²³ mol⁻¹. This number is used to convert between the mass of a substance and the amount of particles in that substance.

History

The concept of Avogadro's Number was first introduced by Jean Baptiste Perrin in the early 20th century. He named it in honor of Avogadro, who had first proposed that equal volumes of gases, at the same temperature and pressure, contain an equal number of molecules.

Applications

Avogadro's Number is used extensively in chemistry and physics to perform calculations involving the mole, a basic measuring unit in stoichiometry. It is also used in Avogadro's law, which states that the volume of a gas is directly proportional to the number of gas molecules.

See also

• Mole (unit)
• Stoichiometry
• Avogadro's law
• Molecular mass