The highest building in Montreal is the ‘1 square building’, with a height of 203m. The atmospheric pressure in the streets of Montreal is P1 = 9.9 x 104 Pa. Suppose air density is constant : ρair = 1,2 kg/m3 and g = 9.8 m/s2. Suppose the rooftop temperature to be T = 298K, and the air composition is 100% N2 molecules. d. How would you find the probability for a molecule picked randomly to have a speed in the range vrms and vrms+5.0 m/s. (No calculations needed) e. Find the ratio between the most probable speed (vmp) and the mean speed (vmean). The collision cross-section of N2 molecules is 0.43 nm2. f. Find the collision frequency. Is it in the order of magnitude that you were expecting?
The highest building in Montreal is the ‘1 square building’, with a height of 203m.
The atmospheric pressure in the streets of Montreal is P1 = 9.9 x 104 Pa.
Suppose air density is constant : ρair = 1,2 kg/m3 and g = 9.8 m/s2.
Suppose the rooftop temperature to be T = 298K, and the air composition is 100% N2 molecules.
d. How would you find the probability for a molecule picked randomly to have a speed in the range vrms and vrms+5.0 m/s. (No calculations needed)
e. Find the ratio between the most probable speed (vmp) and the mean speed (vmean).
The collision cross-section of N2 molecules is 0.43 nm2.
f. Find the collision frequency. Is it in the order of magnitude that you were expecting?
Now, consider Earth's atmosphere as 80% N2 and 20% O2. (No calculations needed)
g. Explain if larger, smaller, or equal to the previous situation:
- Ratio vmp/vmean
- The rms speed vrms
- Probability to find a molecule at a speed between vrms and vrms+5.0 m/s.
- Collision frequency.
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