A rigid container is maintained at and contains equal amounts (in moles) of four…
PHYSICS · Multi-part · A Level · Physics · Further mechanics and thermal physics · Further mechanics and thermal physics
Problem
A 2.0L rigid container is maintained at 400K and contains equal amounts (in moles) of four different ideal gases: hydrogen (H2), helium (He), oxygen (O2), and argon (Ar).
Treat each gas as monatomic or diatomic as indicated.
(a) Calculate the numerical value of the root‐mean‐square speed for the molecules or atoms of each gas in the container at the stated temperature. (Use molar masses in gmol−1: H2=2.02, He=4.00, O2=32.0, Ar=39.9.)
(b) Rank the four gases from fastest to slowest on the basis of their root‐mean‐square speeds, supporting your ordering with quantitative evidence.
(c) Even though your answer to part (b) shows large differences in molecular speed, each gas contributes equally to the measured temperature of the mixture. Explain how this observation is consistent with kinetic theory.