Three 1.00-L flasks at 25°C and 725 torr contain the gases CH 4 (flask A),CO 2 (flask B),and C 2 H 6 (flask C).
-In which single flask do the molecules have the greatest mass,the greatest average velocity,and the highest kinetic energy?
A)Flask A
B)Flask B
C)Flask C
D)All are the same.
E)No one flask has all these.

Question

Quizplus · Accepted Answer

The greatest mass is determined by the molar mass of the molecules. CH4 (flask A) has the lowest molar mass, CO2 (flask B) has a higher molar mass, and C2H6 (flask C) has the highest molar mass. The greatest average velocity is inversely related to the square root of the molar mass, meaning CH4 (flask A) molecules move the fastest. The highest kinetic energy depends on both mass and velocity, but at the same temperature and pressure, all gases have the same average kinetic energy per molecule due to the kinetic molecular theory. Therefore, no single flask has the greatest mass, greatest average velocity, and highest kinetic energy simultaneously.

Three 100-L Flasks at 25°C and 725 Torr Contain the Gases