Question

Which of the following is not an assumption of the kinetic molecular theory for a gas?
A. Gases are made up of tiny particles in constant chaotic motion.
B. Gas particles are very small compared to the average distance between the particles.
C. Gas particles collide with the walls of their container in elastic collisions.
D. The average velocity of the gas particles is directly proportional to the mass of the gas particles at constant temperature.
E. All of the above are assumptions of the kinetic molecular theory.

Answer 1

Answer:

D. The average velocity of the gas particles is directly proportional to the mass of the gas particles at constant temperature.

Explanation:

The kinetic molecular theory of gasses states that the average kinetic energy of a collection of gas particles depends only on the temperature of the gas.

The relation is given as:

$v_a=2\sqrt{\frac{2R.T}{\pi.M} }$

where:

$v_a$ = average velocity of the gas particles

R = the ideal gas constant (in $8.314\ kg.m^2.s^{-2}.mol^{-1}.K^{-1}$)

T = absolute temperature of the gas (in K)

M = molar mass (in $kg.mol^{-1}$)