Question

Estradiol is a female sexual hormone that causes maturation and maintenance of the female reproductive system. Elemental analysis of estradiol gave the mass percent composition: C, 79.37%; H, 8.88%; O, 11.75%. The molar mass of estradiol is 272.37 g/mol. Find the molecular formula of estradiol.

Answer 1

Answer:

The answer to your question is: Molecular formula =  C₁₈H₂₄O₂

Explanation:

Estradiol

C = 79.37 %

H = 8.88 %

O = 11.75 %

Molar mass = 272.37

Process    

Carbon   =    79.37 g

Hydrogen  =   8.88 g

Oxygen  =      11.75 g

                       12 g of Carbon   -----------------  1 mol

                       79.37 g               ----------------    x

                        x = (79.37 x 1) / 12

                       x = 6.61 mol

                      1 g of Hydrogen ----------------  1 mol

                     8.88 g                  ----------------   x

                      x = (8.88 x 1 ) / 1

                      x = 8.88 mol

                     16 g of Oxygen ------------------  1 mol

                     11.75 g                -----------------   x

                     x = (11.75 x 1) / 16

                     x = 0.73

Divide by the lowest number of moles

Carbon    = 6.61 / 0.72 = 9.2

Hydrogen =  8.88 / 0.73 = 12.2

Oxygen = 0.73/0.73 = 1

Empirical formula

                                         C₉H₁₂O₁

MW of the empirical formula = (12 x 9) + (12 x 1) + (16 x 1)

                                                = 136 g

Divide molar mass of estradiol by the molar mass of the empirical formula.

                    = 272 / 136

                   = 2

Then the molecular formula is:

                             2(C₉H₁₂O)  =  C₁₈H₂₄O₂