Complex sentence: It is calculated as the sum of the atomic weights of each constituent element multiplied by the number of atoms of that element in the molecular formula.small to medium size molecules, measured by mass spectrometry, determines stoichiometry.
Split into simpler sentences: It is calculated as the sum of the atomic weights of each constituent element multiplied by the number of atoms of that element in the molecular formula. The molecular mass of small to medium size molecules, measured by mass spectrometry, determines stoichiometry.