版权所有：华东理工大学物理化学教研室 12 0-2 Matter A substance is a distinct, pure form of matter. The amount of substance, n, in a sample is reported in terms of a unit called a mole (mol). The formal definition of 1 mol is that it is the amount of substance that contains as many objects as there are atoms in exactly 12 g of carbon-12. This number is found experimentally to be around 6.02×1023. If a sample contains N entities, the amount of substance it contains is n = N/NA, where NA is the Avogadro constant: NA = 6.02 × 1 0 2 3 mol - 1 . N o t e that NA is not a pure number. 1). Substance: 0. Basic concepts版权所有：华东理工大学物理化学教研室 12 0-2 Matter A substance is a distinct, pure form of matter. The amount of substance, n, in a sample is reported in terms of a unit called a mole (mol). The formal definition of 1 mol is that it is the amount of substance that contains as many objects as there are atoms in exactly 12 g of carbon-12. This number is found experimentally to be around 6.02×1023. If a sample contains N entities, the amount of substance it contains is n = N/NA, where NA is the Avogadro constant: NA = 6.02 × 1 0 2 3 mol - 1 . N o t e that NA is not a pure number. 1). Substance: 0. Basic concepts