Question

Estimate the mean free path for a water molecule in water vapour at 373 k. Use information from exercises 13.1 and eq. (13.41) above.

Answer 1

The number density n is inversely proportional to absolute temperature.

Hence n373/n273=273/373 n373

=2.7*10^25*273/373

=2*10^25m^-3

Given d = 2.7*10^-10m ;

Therefore ,The mean free path lambda = 1/√2πd²n

=2.81*10^-7