Chemistry – Stoichiometry - Relative masses of atoms and molecules | e-Consult
Stoichiometry - Relative masses of atoms and molecules (1 questions)
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Relative molecular mass (Mr) is the mass of a molecule compared to the mass of a hydrogen atom, using a scale where the mass of hydrogen is defined as 1. It is calculated by adding the relative atomic masses (Ar) of all the atoms in the molecule.
Example: Water (H2O)
Ar(H) = 1 ; Ar(O) = 16
Mr(H2O) = (2 x Ar(H)) + Ar(O) = (2 x 1) + 16 = 18 g/mol