Question

The empirical formula of styrene is ch; its molar mass is 104.1 g/mol. what is the molecular formula of styrene? select one:

a. c2h4

b. c8h8

c. c10h12

d. c6h6

e. none of these

Answer 1

The empirical formula is a formula of a compound showing the proportion of each element involved in the compounds but it does not represent the total number of atoms in the compound. It is the lowest number of ratio between the elements in the compound. In order, to determine the actual number of the atoms or the molecular formula of the compounds, we make use of the molar mass of the compound. 

To determine the molecular formula, we multiply a value to the empirical formula. Then, calculate the molar mass and see whether it is equal to the one given (104.1 g/ mol). From the choices, the only valid options are b, d and e.
                  molar mass
1     CH          13.02
8   C8H8      104.16
6   C6H6      78.12

Therefore the correct answer is option B.

Answer 2

Answer:

b. C₈H₈

Explanation:

The empirical formula of styrene is CH. To calculate the molecular formula, we have to calculate "n", where n:

$n=\frac{molar\ mass\ molecular\ formula }{molar\ mass\ empirical\ formula}$

The molar mass of the empirical formula is C + H = 12.01 + 1.00 = 13.01 g/mol

The molar mass of the molecular formula is 104.1 g/mol

n = (104.1 g/mol) / (13.01 g/mol) ≈ 8

The molecular formula is:

Molecular formula = n × Empirical formula = 8 × CH = C₈H₈