Atomic Mass: Atomic mass refers to the mass of a single atom of an element. It is typically expressed in atomic mass units (u) or unified atomic mass units (u), where 1 atomic mass unit is defined as 1/12th the mass of a carbon-12 atom. Atomic mass is specific to each individual atom and represents the sum of the masses of protons, neutrons, and electrons in the atom.
Molar Mass: Molar mass, also known as molecular weight, is the mass of one mole of a substance. It is expressed in grams per mole (g/mol). Molar mass is calculated by summing up the atomic masses of all the atoms in a molecule. It is used to convert between the mass of a substance and the number of moles present, as defined by Avogadro's constant (6.022 × 10^23 particles per mole).
Formula Weight: Formula weight is the sum of the atomic masses of all the atoms in a chemical formula. It is used to calculate the mass of a compound or molecule. Formula weight can be calculated for both molecular compounds (covalently bonded) and ionic compounds (composed of ions). In the case of ionic compounds, the formula weight represents the sum of the masses of the ions present in the formula unit.
While molar mass and formula weight are related concepts, they differ in their application. Molar mass specifically refers to the mass of one mole of a substance, whereas formula weight is a term used to describe the mass of a compound or molecule, regardless of the amount present. Molar mass is used in stoichiometric calculations, such as determining the number of moles or mass of a substance in a reaction, while formula weight helps in determining the mass or quantity of a compound in a given context.