Nitrogen molecule average speed

At room temperature, the average speed of a nitrogen molecule is found to be about one-quarter mile per second. In one second, however, the nitrogen molecule has collided with many other molecules, so its motion follows a zig-zag path. Although the average distance between molecules is small, the molecule passes by many other molecules without hitting them, so the distance it travels between collisions is about fifteen times the average distance between the molecules (at room pressure and temperature). 

B) The average speed of the nitrogen molecules is the same as the average speed of the argon molecules. 

How does the average speed of a nitrogen molecule in air compare to that of an oxygen molecule in air (Air is approximately 20% oxygen and 80% nitrogen by moles.)... 

FIG U R E 9.14 The Maxwell-Boltzmann distribution of molecular speeds in nitrogen at three temperatures. The peak in each curve gives the most probable speed, u p, which is slightly smaller than the root-mean-square speed, Urms The average speed Uav (obtained simply by adding the speeds and dividing by the number of molecules in the sample) lies in between. All three measures give comparable estimates of typical molecular speeds and show how these speeds increase with temperature. 

Calculate the average speed of a nitrogen molecule in air at room temperature (25 °C). Hint use SI units for R and for molar mass, and u will come out in m/s. 

EXERCISE 5.13 At what temperature do hydrogen molecules, H2, have the same rms speed as nitrogen molecules, N2, at 455°C At what temperature do hydrogen molecules have the same average kinetic energy ... 

For nitrogen at 298 K, substituting k = 1.38 x 10 23 J-K 1, andM= 28 g-mol 1. Then, the average velocity is 475 ru-s, which is much faster than that of the speed of sound. This imphes that the thermal movement of gaseous molecules is very intense. 

You learned that in a mixture each gas exerted a partial pressure in proportion to its mole fraction. Yet in a box of air, the average N2 molecule, because of its greater speed hits the walls more frequently than the average O2 molecule, suggesting that nitrogen might contribute more than 80% of the pressure. Explain the apparent discrepancy. 

The response speed, associated with the adsorption of vapor molecules on free sites in the PPy films, was typically found to be faster than the recovery speed, consisting of the desorption and evaporation of the analyte molecules from the occupied sensing sites, see Fig. 7.10a. This became especially evident in nontemplated films. On average the response time of nontemplated and DG-structured films on exposure to solvent vapors was similar, but on purging with nitrogen the structured films outperformed the nontemplated deposits, see Fig. 7.10a. Curiously, the response times varied very little with different vapor concentrations. 

A Figure 10.13 Distribution of molecular speeds for nitrogen gas. (a) The effect of temperature on molecular speed. The relative area under the curve for a range of speeds gives the relative fraction of molecules that have those speeds, (b) Position of most probable (Ump), average (Uav), and root-mean-square (u,rns) speeds of gas molecules. The data shown here are for nitrogen gas at 0°C. 

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