Question

Arrange the following in the increasing order of number of molecules.

• A. 50 cc of ${\text{SO}}_2$ at S.T.P
• B. 100 cc of ${\text{N}}_2$ at S.T.P
• C. 150 cc of ${\text{O}}_2$ at S.T.P
• D. 200 cc of ${\text{NH}}_3$ at S.T.P

Answer 1

1 litre = 1000 $c{m}^3$ = 1000 cc
We know that, volume of 1 mole of gas at S.T.P = 22.4 L = 22400 $c{m}^3$ = 22400 cc.
200 cc of ${\text{NH}}_3$ at S.T.P contains $\frac{(6.022\times {10}^{23}\times 200)}{22400}=0.0537\times {10}^{23}$ molecules
150 cc of ${\text{O}}_2$ at S.T.P $\frac{(6.022\times {10}^{23}\times 150)}{22400}=0.0403\times {10}^{23}$ molecules
100 cc of ${\text{N}}_2$ at S.T.P
$\frac{(6.022\times {10}^{23}\times 100)}{22400}=0.0268\times {10}^{23}$ molecules
50 cc of ${\text{SO}}_2$ at S.T.P $\frac{(6.022\times {10}^{23}\times 50)}{22400}=0.013\times {10}^{23}$ molecules.