Question

The average molecular speed in a sample of O3 gas at a certain temperature is 353 m/s. The average molecular speed in a sample of Kr gas is ? m/s at the same temperature.

Answer 1

From kinetic theory of gases we know that, average speed of an gas with Molar mass M, at Temperature T(in kelvin) is Given by:

V_{​​​​​avg} =

R is universal gas constant= 0.0821 atm.L/ mol.K

Molar mass of O3 = 48g/mol

Molar mass of Kr = 83.7g/mol

So, using the above equation

V(Kr)/ V(O3) =  

=

=0.74

So,

V(Kr) = V(O3) * 0.74

= 353m/s * 0.74

= 261.2 m/s (Answer)