Question

The ratio of masses of oxygen and nitrogen in a particular gaseous mixture is 1 : 4. The ratio of number of their molecule is _______.
(A) 1 : 4
(B) 7 : 32
(C) 1 : 8
(D) 3 : 16

Answer 1

answer : option (B) 7 : 32

explanation : It is given that ratio of masses of oxygen and nitrogen in a particular gaseous mixture is 1 : 4.

let mass of oxygen = m

then mass of nitrogen = 4m

as we know,

molecular mass of oxygen = 32g/mol

molecular mass of nitrogen = 28 g/mol

so, no of moles of oxygen = m/32

and then, no of oxygen molecules = m/32 × N .......(1)

where N is Avogadro's number.

similarly, no of moles of nitrogen = 4m/28

then, no of nitrogen molecules = 4m/28 × N ........(2)

from equations (1) and (2),

ratio of their no of molecules = {m/32 × N}/{4m/28 × N}

= 28/(4 × 32)

= 7/32

hence, answer is 7 : 32

Answer 2

Answer:

option (B) 7 : 32

Hope it will help you