Molecular Formula 1

Molecular Formula: The actual formula for a molecule.


A compound has an empirical formula of ClCH2 and a molecular weight of 98.96 g/mol. What is its molecular formula?


  1. Find the mass of the empirical unit.

    Mass of empirical unit = mass Cl + mass C + 2(mass H)

    Mass of empirical unit = 35.45 + 12.00 + 2(1.008) = 49.47 g/mol

  2. Figure out how many empirical units are in a molecular unit.

    # of empirical units = (mass of molecular unit/ mass of empirical unit)

    (98.96 g/mol) / (49.47 g/mol) = 2.000 empirical units per molecular unit

  3. Write the molecular formula.

    It takes two empirical units to make a molecular unit, so, the molucular formula is:



More difficult example

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