Avogadro's number (6.022 × 10^23) is used as a conversion factor in chemistry because it allows us to relate the macroscopic world (grams) to the microscopic world (atoms or molecules). It provides a bridge between the two scales.
Avogadro's number is defined as the number of atoms, molecules, or formula units present in one mole of a substance. It allows us to establish a direct relationship between the mass of a substance (in grams) and the number of atoms or molecules it contains. By using Avogadro's number as a conversion factor, we can convert between the mass of a substance (in grams) and the number of particles (atoms or molecules) it contains.
On the other hand, the molar mass of a substance (in grams) represents the mass of one mole of that substance. It is derived from the atomic masses of the elements found in the substance, as listed in the periodic table. The molar mass is useful for calculating the mass of a given number of moles of a substance or determining the number of moles from a given mass.
While the molar mass is essential for many calculations, Avogadro's number is used as a conversion factor because it allows for direct conversions between mass (in grams) and the number of particles (atoms or molecules). It enables us to establish relationships between the macroscopic and microscopic properties of substances, making it a fundamental constant in chemistry.