Question

Kinetic energy of a gas depends upon its:
A) Molecular mass
B) Atomic mass
C) Equivalent mass
D) None of these

Answer 1

Hint:Molecules of gases possess kinetic energy that is why gases are highly volatile and have the tendency to fill the container in which they are filled. The average kinetic energy of gas particles is proportional to the absolute temperature of the gas, and all gases at the same temperature have the same average kinetic energy.


Complete answer:
Kinetic energy of a gas depends only upon absolute temperature. As the temperature is the same therefore the K.E. is the same.
Kinetic energy of gases can be calculated by the formula:
$Kinetic Energy = \frac{3}/{2}RT$
You can see from the above formula that average kinetic energy of the particles in a gas is proportional to the temperature of the gas. Because the mass of these particles is constant, the particles must move faster as the gas becomes warmer.
The molecular mass, atomic mass and the equivalence mass of gases does not change and hence the kinetic energy is independent of these qualities.
This relation of the temperature and the kinetic energy of gases is drawn from the kinetic molecular theory of gases which is stated as :
1) The experimental observations about the behavior of gases can be explained with a simple theoretical model known as the kinetic molecular theory. This theory is based on the following postulates, or assumptions.
2) Gases are made of a large number of particles that are hard, spherical objects in a state of constant, random motion.
3) The gas particles move in a straight line until they collide with another particle or the walls of the container.
4) The gas particles are much smaller than the distance between particles. Most of the volume of a gas is therefore empty space.
5) Force of attraction between gas particles or between the particles and the walls of the container is absent.
6) Collisions between gas particles or collisions with the walls of the container are perfectly elastic. None of the energy of a gas particle is lost when it collides with another particle or with the walls of the container.
7) The average kinetic energy of a collection of gas particles depends on the temperature of the gas and nothing else.

Hence the correct option is (D).


Note: To figure the total kinetic energy, We multiply the average kinetic energy by the number of molecules you have, where n is the number of moles.kinetic theory of gases has limitations but it provided the base to derive certain laws like ideal gas law and vander waals equation.