Answer Happy

14-3
The following substances are some of the most common constituents of air. (i) Nitrogen (N₂, mass per mole = 28.0 g, 78.1% of atmosphere) (ii) Oxygen (O₂, mass per mole = 32.0 g, 20.9% of atmosphere) (iii) Argon (Ar, mass per mole = 39.9 g, 0.9% of atmosphere) (iv) Carbon dioxide (CO2, mass per mole = 44.0 g, 0.04% of atmosphere) (v) Neon (Ne, mass per mole = 20.1 g, 0.0.002% of atmosphere) (vi) Helium (He, mass per mole = 4.0 g, 0.0005% of atmosphere) (a) Rank the above molecules in order of their root-mean-square speed in air at 20°C, from fastest to slowest. Explain how you made your ranking. (b) Rank the above molecules in order of the temperature at which their root-mean-square speed would be 500 m/s, from highest temperature to lowest temperature. Explain how you made your ranking.