Final answer:
Avogadro's number represents the experimentally determined number of atoms, molecules, or formula units contained in a sample of a pure substance with a mass in grams numerically equal to the molar/molecular mass of the substance. It is approximately 6.02 × 10^23 and provides a convenient way to relate the mass of a substance to the number of particles it contains.
Step-by-step explanation:
Avogadro's number represents the experimentally determined number of atoms, molecules, or formula units contained in a sample of a pure substance with a mass in grams numerically equal to the molar mass or molecular mass of the pure substance. Avogadro's number is defined as the number of atoms or molecules in one mole, which is approximately 6.02 × 10^23. It is a convenient amount unit for expressing very large numbers of atoms or molecules and helps to relate the mass of a substance to the number of particles it contains.