Balanced equations tell us what is reacting and in what relative proportions on the molecular level.
The mole (symbol: mol) is the base unit of amount of substance in the International System of Units or System International (SI), defined as exactly 6.02214076×1023 (Avogadro’s number) particles, e.g., atoms, molecules, ions or electrons .
Example: 2 H2(g) + O2(g) 2 H2O(l)
2 moles H2(g) + 1 mole O2(g) 2 moles H2O(l)
This relationship can be made because of Avogadro’s number (NA)