Molecular speeds: average, RMS, most probable
Gaseous State · Chemistry
Study notes
For N₂ at 300 K (M = 0.028 kg/mol), find all three speeds. v_mp = √(2RT/M) = √(2 × 8.314 × 300/0.028) = 422 m/s. v_avg = √(8RT/πM) = 1.128 × 422 = 476 m/s. v_rms = √(3RT/M) = 1.225 × 422 = 517 m/s. Check ratio 1 : 1.128 : 1.225 ✓. RMS is highest because squaring weights the fast tail.