Due to the use of the same reference substance in defining the atomic mass unit and the mole, the formula mass (amu) and molar mass (g/mol) for any substance are numerically equivalent (for example, one H 2 O molecule… The formula mass of a substance is the sum of the average atomic masses of each atom represented in the chemical formula and is expressed in atomic mass units.

The formula mass of a covalent compound is also called the molecular mass. The mass in grams of 1 mole of substance is its molar mass.

formula mass — sum of the average masses for all atoms represented in a chemical formula; for covalent compounds, this is also the molecular mass. formula mass of a substance — the sum of the average atomic masses of each atom represented in the chemical formula and is expressed in atomic mass units. mole — amount of substance containing the same number of atoms, molecules, ions, or other entities as the number of atoms in exactly 12 grams of 12 C. chemical identity of a substance — defined by the types and relative numbers of atoms composing its fundamental entities (molecules in the case of covalent compounds, ions in the case of ionic compounds).