1:27 know that the mole (mol) is the unit for the amount of a substance

In Chemistry, the mole is a measure of amount of substance (n).

The abbreviation for mole is mol.

The mass of 1 mole of a substance is the relative formula mass (Mr) of the substance in grams.

Example:

The Mr of water is 18.

Therefore the mass of 1 mol of water equals 18 g.