Question

Find the molecular formula based on the following percent compositions and molar mass

C: 80.19% H: 9.63 % O : 10.17% ; 314.51 g/mol

Answer 1

Answer: First find out the mass of carbon, hydrogen and oxygen using following formula;

Mass of Carbon

In 100% → 80.19% Carbon

So, 314.51 → (314.51 x 80.19)/ 100 = 252.20 gm/mol Carbon Present

Similarly for 30.28 gm/mol Hygrogen and 31.98 = 32 gm/mol Oxygen is present

No of atoms is calculated by dividing gms of carbon with its atomic mass, gms of hydrogen with its atomic mass and gms of oxygen with its atomic mass.

So no of carbon atoms = 252.20/12 = 21

No of hydrogens atoms= 30.28/1 = 30

And no of oxygen atoms = 32/16 = 2

So the molecular formula is = C₂₁H₃₀O₂