Percentage of Mass

Percentage of Composition of a Compound

  1. To find the percentage of composition of a substance means to find the percentage of mass of each element in the molecule of the substance to the mass of the molecule.
  2. The percentage of mass of an element can be determined by the following equation:

    RAM = Relative atomic mass
    RMM = Relative molecular mass


Calculate the percentage of composition of DDT (C14H9Cl5). [Relative atomic mass: Carbon = 14; Hydrogen = 1; Chlorine = 35.5]


Relative molecular mass of DDT