Percentage of Mass

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13 years ago

Percentage of Composition of a Compound

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.
The percentage of mass of an element can be determined by the following equation:

RAM = Relative atomic mass
RMM = Relative molecular mass

Example

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

Answer:

Relative molecular mass of DDT
=14(12)+9(1)+5(35.5)
=354.5