The importance of an element or chemical compound.
Is a quantity that represents the mass per substance amount.
Can also be called also the amount of substance and indicates the number of a substance that is in the crystal phase of the substance.
Refers to the weight of an atom of the substance in question.
Mol is an SI unit used to show how many elements of the substance there are. 1 mole is 6.0221415 * 10 23 .