In chemistry and physics, the Avogadro constant (named after the scientist Amedeo Avogadro) is the number of constituent particles, usually atoms or molecules, that are contained in the amount of substance given by one mole. Thus, it is the proportionality factor that relates the molar mass of a compound to the mass of a sample. The Avogadro constant, often designated with the symbol NA or L, has the value 6.022140857(74)×1023 mol−1in the International System of Units (SI).
Its standard Value found from experiments