Avogadro's number
represents the number of units in one mole of any substance. This has the value
of 6.022 x 10^23 units / mole. This number can be used to convert the number of
atoms or molecules into number of moles or vice versa.
9.20 mol Cu3(PO4)2 ( 2 mol P / 1 mol Cu3(PO4)2 ) ( 6.022 x 10^23 atoms / mole P ) = 1.11 x 10^25 atoms