Physics · Heat and Thermodynamics

The correct answer is that molecules do not exert any force on each other, except during elastic collisions. This is a key postulate of the kinetic theory of gases, which helps explain why gases expand to fill their containers and are compressible. Option B is incorrect because the postulate is that molecular size is much smaller than the distance between them. Option C is incorrect because a gas contains a large number of molecules, allowing for measurable macroscopic properties like pressure. Option D is incorrect because gas molecules are in constant random motion, contributing to the pressure exerted by gases.

This is correct because one of the fundamental postulates of the kinetic theory of gases is that molecules do not exert forces on each other except during collisions.

This is incorrect; the postulate states that the size of molecules is much smaller than the distance between them, allowing gases to be compressible.

This is incorrect because a finite volume of gas actually contains a very large number of molecules, which is why gases exhibit properties like pressure and temperature.

This is incorrect; gas molecules are in constant random motion, which is a key postulate of kinetic molecular theory.