The number "6.022 × 10²³" is known as Avogadro's number. It represents the quantity of particles, such as atoms or molecules, in one mole of a substance. This constant is fundamental in chemistry, allowing scientists to convert between the mass of a substance and the number of particles it contains. Avogadro's number is crucial for understanding chemical reactions and stoichiometry. For example, if you have one mole of water (H₂O), it contains approximately 6.022 × 10²³ water molecules. This helps chemists calculate how much of a reactant is needed to produce a desired amount of product in a reaction.