Key Concepts1 mole of any substance contains 6.022 x 1023 particles.6.022 x 1023 is known as the Avogadro Number or Avogadro Constant and is given the symbol NA1N = n x NA     where N = number of particles in the substance     and n = amount of substance in moles (mol)     and NA = Avogardro Number = 6.022 x 1023 particles mol-1To find the number of particles, N, in a substance: N = n x NATo find the moles, n, of substance, n = N ÷ NA