Question

The insulating and packing material Styrofoam is a dating and packing material Styrofoam is a polymer of styrene. Find the molecular formula of sy ene given its percent composition: 922 775 H The approximate molar mass of styrene is 104 g/mol. A) CHE BỊ CH C)C12H D) CH12 E) C8Hg

Answer 1

Step-by-step 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
`(92.25)/(12.01)` = 7.68
`(7.68)/(7.68)` = 1

H 7.75 1.008
`(7.75)/(1.008)` = 7.68
`(7.68)/(7.68)` = 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,
`\frac{\text{molar mass}}{\text{empirical formula mass}}` =
`(104)/(13.0)` = 8

Thus, we can conclude that molecular formula of the given styrene is
`C_(8)H_(8)`.