Question

$N_2$ molecule is spherical of radius 100 pm.
(a) What is the volume of molecules of one mole gas?
(b) What is the value of van der waal's constant $b$?

Answer 1

Volume of one atom= $\frac{4}{3}\pi r^3$

$=\frac{4}{3}\times \frac{22}{7}\times ({10}^{-10}{)}^3$

$=4.19\times {10}^{-30}{m}^3$

Now for one mole,

Volume= $6.023\times {10}^{23}\times 4.19\times {10}^{-30}$

$=25.23\times {10}^{-7}{m}^3$

Now, Van der Waals constant $b=4\times \text{Volume occupied by 1 mole of gas}$

$=4\times 25.23\times {10}^{-7}$

$=11.009\times {10}^{-5}{m}^3/mol$ .