Air from the outside is:



a. warmed, dried and cleaned by the nose and mouth

b. cooled, dried and cleaned by the nose and mouth

c. cooled, moistened and cleaned by the nose and mouth

d. warmed, moistened and cleaned by the nose and mouth

use the formula: v^2=(3kt)/m

where:

v is the velocity of a molecule

k is the boltzmann constant (1.38064852e-23 j/k)

t is the temperature of the molecule in the air

m is the mass of the molecule

for an h2 molecule at 20.0°c (293 k):

v^2 = 3 × 1.38e-23 j/k × 293 k / (2.00 u × 1.66e-27 kg/u)

v^2 = 3.65e+6 m^2/s^2

v = 1.91e+3 m/s

for an o2 molecule at same temp.:

v^2 = 3 × 1.38e-23 j/k × 293 k / (32.00 u × 1.66e-27 kg/u)

v^2 = 2.28e+5 m^2/s^2

v = 478 m/s

therefore, the ratio of h2: o2 velocities is:

1.91e+3 / 478 = 4.00