Question

The cutoff text in the table is CO2 with r(nm)=0.230

Molecular collisions consider the atmosphere as made up from 80% N2 and 20% O2 gases. At a pressure P, the N2 and O2 gases will have partial pressure of PN and Po respectively so that P PN + Po. If nN and no are the concentration of N2 and O2 molecules respectively then PN nNkT, and Po nokT, Consider a vacuum chamber in which the total pressure is 10-5 torm Assume 27 °C a. Calculate the concentrations of N2 and 02 gases in the chamber. b. Suppose that we simply consider the collisions of N2 with N and O with O and neglect N and O2 collisions. Calculate the mean free path for N2 and O2 molecules. See Table 1.11 C. What are the mean free paths for each gas if the gas were in the container alone at 10 torr? d. Obviously the calculation in b is not correct because we neglected collisions between N2 and 02 Suppose that we try to improve our calculations by using some average value for the collisional radius r by averaging that involves the relative concentrations of molecular species in the tank, that is rin2n2 ni + n2 where the subscript 1 refers to molecular species 1 (N2) and 2 to species 2 (02) and we take n = n1 + n2 in the mean free path equation since all molecules are involved in the collisions Calculate the mean free path using these parameters. What is your conclusion? (See also Question 1.11) Table 1.11 Radii for molecular or atomic collisions in gases Molecule or Atom Ne Ar 02 0.143 0.148 0.100 0.158 0 nm

Answer 1

20 % or 0.2 0.

K303 JK 1.38 x 30、시5-3- Molec

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