Due to this all the gases escape from the surface of the Moon. . No hydrogen in Earth’s atmosphere . As the root mean square speed of hydrogen is much greater than that of nitrogen, it easily escapes from the earth’s atmosphere.
In fact, the presence of nonreactive nitrogen instead of highly combustible hydrogen deters many disastrous consequences. - - - - Unit Kinetic theory of gases . . .
Most probable speed ( V mp ) It is defined as the speed acquired by most of the molecules of the gas. RT M kT mp = ( . ) kT mp = ( . ) The derivation of equations ( .
), ( . ) is beyond the scope of the book Comparison of v rms , v and v mp Among the speeds v rms is the largest and v mp is the least v rms > v > v mp Ratio-wise, v rms : v : v mp = : : : . : . π EXAMPLE .
Ten particles are moving at the speed of , , , , , , , , and m s - . Calculate rms speed, average speed and most probable speed. Solution The average speed m s + + To find the rms speed, first calculate the mean square speed v v m s The rms speed m s rms = The most probable speed is m s - because three of the particles have that speed. (b) The average kinetic energy per molecule is kT .
It depends only on absolute temperature of the gas and is independent of the nature of molecules. Since both the gas molecules are at the same temperature, they have the same average kinetic energy per molecule. k is Boltzmaan constant. kT J (c) Average kinetic energy of total oxygen molecules = O N kT where N