Question

Which of the following contain least no. of molecules
a) 22gm CO2
b) 1.2 lit of CH4
c) 0.1 mole of H2O
d) 2.3gm of N2​

Answer 1

Answer:

Let N be the Avogadro's number.

Mass is divided with molar mass to obtain the number of moles.

The number of moles are multiplied with Avogadro's number to obtain number of molecules.

(A) 52 g of N

2

O

5

=

(28+80)g/mol

52g

×N=0.48N

(B) 36 g of H

2

O=

18g/mol

36g

×N=2N

(C) 28 g of CO =

28g/mol

28g

×N=N

(D) 51 g NH

3

=

17g/mol

51g

×N=3N

Hence, 52 g of N

2

O

5

contains least number of molecules.