Calculate the mean free path of air molecules at 3.50 * 10-13 atm and 300 k. (this pressure is readily attainable in the laboratory; see exercise 18.23.) as in example 1

The mean free path can be defined as the average distance between collisions for gas molecules. It can be calculated using the formula:

∧ = ---------(1)

Given :

T = 300 K

P = 3.50 * 10-13 atm = 3.55 * 10^-8 pascals

d = diameter of air molecules = 2* radius of air molecules

                                                 = 2* 2*10^-10 m = 4*10^-10 m

k = Boltzmann constant = 1.38 * 10^-23 J/K

Na = avogadro's number = 6.023 * 10^23

Substituting in equation(1) we get:

∧ = 1.38 *10^-23* 300/√2*π*(4*10^-10)²*3.55*10^-8

  = 1.641*10^5 m

the awnser is group 12

the answer is b because, investigating whether another species of moth also drinks tears might be interesting, but it would not directly explain why this species of moth does.

to explain why this species of moth drinks tears, the scientist could ask: "what nutrients that moths need are in elephant tears? "

the scientist could experiment with moth repellent or oter ways to keep the moths away, but that would not answer his original question.