Answer:
C18H24O3
Explanation:
Step 1:
Data obtained from the question. This include the following:
Mass of estriol = 13.42g
Mass of CO2 = 36.86g
Mass of H2O = 10.06g
Molar mass of estriol = 288.38g/mol
Step 2:
Determination of the mass of Carbon (C), Hydrogen (H) and Oxygen (O) present in the compound. This is illustrated below:
For Carbon, C:
Molar mass of CO2 = 12 + (2x16) = 44g/mol
Mass of C in CO2 = 12/44 x 36.86 = 10.05g
For Hydrogen, H:
Molar Mass of H2O = (2x1) + 16 = 18g/mol
Mass of H in H2O = 2/18 x 10.06 = 1.12g
For Oxygen, O:
Mass of O = 13.42 – (10.05 + 1.12) = 2.25g
Step 3:
Determination of the empirical formula for estriol. This is illustrated below:
C = 10.05g
H = 1.12g
O = 2.25g
Divide by their molar mass
C = 10.05/12 = 0.8375
H = 1.12/1 = 1.12
O = 2.25/16 = 0.1406
Divide by the smallest i.e 0.1406
C = 0.8375/0.1406 = 6
H = 1.12/0.1406 = 8
O = 0.1406/0.1406 = 1
Therefore, the empirical formula for estriol is C6H8O
Step 4:
Determination of the molecular formula for estriol. This is illustrated below:
Molecular formula is simply a multiple of the empirical formula i.e
Molecular formula => [C6H8O]n
[C6H8O]n = 288.38g/mol
[(12x6) + (8x1) + 16]n = 288.38
[72 + 8 + 16]n = 288.38
96n = 288.38
Divide both side by 96
n = 288.38/96 = 3
Molecular formula => [C6H8O]n
=> [C6H8O]n
=> [C6H8O]3
=> C18H24O3
Therefore, the molecular formula for estriol is C18H24O3
