Explanation:
In order to find the molecular formula, we have to find the empirical formula first of all.
It is known that is a styrofoam, elements present are carbon and hydrogen atoms.
Element   %     Atomic mass    Molar ratio      Simple ratio
  C     92.25      12.01        [tex]\frac{92.25}{12.01}[/tex] = 7.68          [tex]\frac{7.68}{7.68}[/tex] = 1
   H     7.75       1.008       [tex]\frac{7.75}{1.008}[/tex] = 7.68          [tex]\frac{7.68}{7.68}[/tex] = 1
As empirical formula of styrofoam is C_{x}H_{x}.
Hence, empirical mass = (12.01 + 1.008) g/mol = 13.018 g/mol = 13.0 g/mol (approx)
Molar mass given is 104 g/mol.
So, Â Â [tex]\frac{\text{molar mass}}{\text{empirical formula mass}}[/tex] = [tex]\frac{104}{13.0}[/tex] = 8
Thus, we can conclude that molecular formula of the given styrene is [tex]C_{8}H_{8}[/tex].
