Question -
Answer -
Temperature of the nitrogen molecule, T =300 K
Atomic mass of nitrogen =14.0076 u
Hence, mass of the nitrogen molecule, m =2 × 14.0076 = 28.0152 u
But 1 u = 1.66 × 10−27 kg
∴m = 28.0152 ×1.66 × 10−27 kg
Planck’s constant, h = 6.63× 10−34 Js
Boltzmann constant, k =1.38 × 10−23 J K−1
Wehave the expression that relates mean kinetic energy 
of the nitrogen molecule with the rootmean square speed 
as:
Hence, the de Brogliewavelength of the nitrogen molecule is given as:
Therefore,the de Broglie wavelength of the nitrogen molecule is 0.028 nm.