Question

At absolute zero the molecular motion of gases ceases to zero.
A.True
B.False

Answer 1

Hint:
-The kinetic theory of gases is the law that holds for all gases irrespective of the nature of the gas and is based on experimental observations. This theory takes into account the molecular concept as well as the motion of the particles. The various postulates of the kinetic theory of gases are:
-Molecules comprising a gas are always in a ceaseless motion and move in all directions.
-The molecules of the gas have a very small size such that the total volume occupied by all the gas molecules is a negligible fraction as compared to the total volume occupied by the gas.
-The molecules of the gas collide with one another and also with the walls of the containing vessel. As a result of collisions, the speed and direction of the molecules go on changing constantly.
-The collisions between the molecules are perfectly elastic such that the total kinetic energy of the gas remains unchanged.
-The pressure exerted by the gas is due to the bombardment of the moving molecules on the vessel containing the gas.
-The molecules of the gas do not exert any force of attraction on each other.
-The average kinetic energy of the molecules increases or decreases with the rise or fall in temperature. -Therefore, the average kinetic energy of the gas molecule is the function of temperature only.
-The motion of the molecules, forces between the molecules, and arrangement of atoms within the molecules are responsible for the physical properties of the gas.

Complete step by step answer:
The seventh postulate of the kinetic theory of gases says that the average kinetic energy of a gas molecule is directly proportional to absolute temperature.
The kinetic energy for the gas molecule is given by
$K.E = \dfrac{3}{2}kT$
where k is the Boltzmann constant.
At absolute zero, i.e. $T = 0$
$K.E = O$
So we can see that at absolute zero temperature the kinetic energy of the molecular motion of gases ceases to zero.
After discussing we can conclude that the given statement is true.

Thus, the correct option is (A).

Note: A real gas is a gas which does not obey the general gas equation and all other gas laws strictly but tends toward ideality at low pressure and high temperature.
-All gases are real gases.
-The volume occupied by the molecules of real gases is not negligible.
-The attractive forces between gas molecules are appreciable due to which the pressure is less than that calculated from gas laws.