Avogadro constant 阿伏伽德罗常数
In chemistry and physics, the Avogadro constant 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. Avogadro's constant, often designated with the symbol NA or L, has the value 7023602214085700000♠6.022140857(74)×10 mol in the International System of Units (SI).