Avogadro's number

noun

, Chemistry.

1. the constant, 6.022 × 10 23 , representing the number of atoms, molecules, or ions in one mole of a substance. : N Compare gram-atom, gram molecule.

Avogadro's number

1. The number of atoms or molecules in a mole of a substance, approximately 6.0225 × 10 ²³. It is based on the number of carbon atoms in 12 grams of carbon 12.

Word History and Origins

Origin of Avogadro's number¹

First recorded in 1925–30; Avogadro's law

Example Sentences

In that case, metrologists were adapting to fit the needs of chemists, who wanted a way to express SI units on the scale of Avogadro’s number—the 6 × 1023 units in a mole, a measure of the quantity of substances.

From Scientific American

The things I do manage to remember bear an inverse relationship to any usefulness: Avogadro’s number, the Fibonacci sequence, the smell of Chanel No. 5.

From New York Times

In effect, Dr. Bettin had devised an experiment that would precisely measure a constant known as Avogadro’s number, which for many years dictated that one mole of a substance contains 6.022 × 10^23 particles such as electrons, atoms, ions, or molecules.

From New York Times

Avogadro’s number had been estimated but, like the speed of light, never precisely measured and agreed upon.

From New York Times

The ampere, the kelvin and the mole will also be redefined based on their relationships to the charge on the electron, Boltzmann’s constant and Avogadro’s number, respectively.

From Nature