Molecular Weight
What is Molecular Weight?
Molecular weight (molecular mass) is the sum of the atomic masses of all atoms in a molecule, expressed in atomic mass units (amu or u), which are numerically equal to daltons (Da). It equals the molar mass in g/mol when expressed on a per-mole basis. For example, water (H₂O) has a molecular weight of 18.015 u. Molecular weight is used in stoichiometric calculations and in characterising polymers and biomolecules.
Key Facts
Frequently Asked Questions
Molecular weight (molecular mass) is the sum of the atomic masses of all atoms in a molecule, expressed in atomic mass units (amu or u), which are numerically equal to daltons (Da). It equals the molar mass in g/mol when expressed on a per-mole basis. For example, water (H₂O) has a molecular weight of 18.015 u. Molecular weight is used in stoichiometric calculations and in characterising polymers and biomolecules.