Question

According to kinetic theory of gases, for a diatomic molecule:
A.The pressure exerted by the gas is proportional to the mean velocity of the molecules
B.The pressure exerted by the gas is proportional to the root mean square velocity of the molecules
C.The root mean square velocity is inversely proportional to the temperature
D.The mean translational kinetic energy of the molecules is proportional to the absolute temperature.

Answer 1

The kinetic theory of gases assumes that the molecules are very small relative to the distance between the molecules. The molecules are in constant, random motion and frequently collide with each other and with the walls of any container and the higher the temperature, the greater is the motion.

Complete step by step answer:
As we know, the average or the total kinetic energy is given by:
$K.E = \dfrac{3}{2}RT$
which in turn gives that, $K.E. \propto T$ .
This means that the mean translational kinetic energy of the molecules is proportional to the absolute temperature.
Example-For example, a ball that is dropped only has translational kinetic energy. However, a ball that rolls down a ramp rotates as it travels downward. The ball has rotational kinetic energy from the rotation about its axis and translational kinetic energy from its translational motion.

Therefore, the correct option is option D.

Note:
Thermodynamic temperature is defined as the absolute measure of temperature and is one of the principal parameters in the science of thermodynamics. Thermodynamic temperature is defined by the third law of thermodynamics in which states that the absolute temperature scale is a scale that possesses theoretically lowest temperature the null or zero point. The postulates of the kinetic-molecular theory of gases are as follows:
-The ideal gas molecules are constantly moving
-They have negligible volume
-They possess negligible intermolecular forces
-They undergo perfectly elastic collisions
-They have an average kinetic energy proportional to the ideal gas's absolute temperature.