are there easy ways to calculate the empirical formula and molecular formula of a compound? if asked in NEET to finish in less than a minute?

Asked by pereirajaison43 | 28th Jul, 2020, 09:03: PM

Expert Answer:

There is only one method to solve these type of question. Which has several steps.
Let's unserstand these steps to calculate empirical formula by an example.
 
Question-A compound contains 38.8% of C,16.0% of H and 45.2% of N.What is the formula of the compound?
 
Solution-  

Given:
 
C =38.8% 
 
H =16.0% 
 
N =45.2%
 
 

 

Element

% Composition

Atomic Mass

Atomic Ratio

Simplest Ratio

C

38.8

12

3.23≈3

1

N

45.2

14

3.21≈3

1

H

16

1

16

5

 

The empirical formula of the compound is CH3-NH2

 

If you want to calculate Molecular formula then-

Molecular Formula= n(Empirical Formula)

n=Molecular Mass/Empirical formula Mass

Answered by Ravi | 29th Jul, 2020, 03:18: PM