Question

The relative density of a mixture of nitrogen
and oxygen is 14.4 (H = 1) and the relative densities of nitrogen and oxygen are 14.0 and 16.0 (H = 1) respectively. Calculate the composition of the mixture (i) by volume and (ii) by mass.​

Answer 1

Explanation:

(i) Let 1 mL of the mixture contain x mL of N

2

and (1 - x) mL of O

2

.

Mass of x mL of N

2

=140×x=14xg (Mass =d×V)

Mass of (1 - x) mL of O

2

=16.0×(1−x)=(16.0−16x)g

Total mass of mixture =14x+16.0−16x

So, 14x+16.0−16x=14.4×1=14.4

or x = 0.8 , i.e., 80% by volume

Oxygen =1−x=(1−0.8)=0.2, i.e., 20% by volume.

(ii) Let 1 g of the mixture contain x g of N

2

and (1- x) g of oxygen.

Volume of x g of N

2

=

14.0

x

(V=

density

mass

)

Volume of (1-x) g of O

2

=

16.0

(1−x)

Total volume of the mixture =

14.0

1

+

16.0

(1−x)

So, =

14.0

1

+

16.0

(1−x)

=

14.4

1

or x=0.7778, i.e., 77.78% by mass

Oxygen =(1−x)=(1−0.7778)=0.2222

i.e., 22.22% by mass.