Question

The empirical formula of a compound is CH20. Its molecular weight is 90. Calculate the molecular formula of the compound.

help me fast


​

Answer 1

ANSWER

Molecular formula=n × Empirical formula $\longrightarrow (1)$

(where n is the number of integer mutiple of the given Empirical formula )

Weight of  Empirical formula (CH₂O)  

Weight of CH₂O = Atomic mass of ( 1×Carbon + 2×Hydrogen + 1×Oxygen )

Atomic Mass of

Carbon = 12 amu

Hydrogen = 1 amu

Oxygen = 16 amu

$\implies$ Weight of CH₂O = 12+2+16 = 30

From (1) ,

$\sf n = \dfrac{Weight\; of\; Molecular \;Formula}{Weight \;of \;Empirical \;Formula}$

Given that weight of molecular formula = 90 .

We also know the value of weight of Empirical Formula = 30 .

$\sf \implies n=\dfrac{90}{30} = 3$

∵ n = 3 , Molecular Formula = 3 × Empirical Formula

$\implies$ Molecular formula = 3 × CH₂​O = C₃H₆O₃

$\red\bigstar$ Molecular Formula of The Compound is C₃H₆O₃