Avogadro number

The Avogadro number NAN_{A} is a constant that expresses the number of particles in a mole of matter:

NA=RkB=6.022⋅1023 particlesN_{A}=\frac{R}{k_{B}}=6.022\cdot10^{23}\text{ particles}

RR is the Ideal gas constant and kBk_{B} is the Boltzmann constant.