Question

I would like to know if the thermal motion of molecules stays constant if the pressure is increased at constant temperature or not. The viscosity increases with pressure, thus the friction between the molecules also. If the thermal energy is constant, will the motion of the molecules decrease due to higher friction?

Options:
A) Yes, the thermal motion remains constant regardless of pressure changes.
B) No, the thermal motion decreases as pressure increases due to increased friction.
C) The thermal motion increases with pressure to counteract higher friction.
D) Thermal motion varies, but it's not directly influenced by pressure changes.

Answer 1

The thermal motion of molecules remains constant when the pressure is increased at a constant temperature, according to the principles of the Kinetic Molecular Theory.

Step-by-step explanation:

Regarding whether the thermal motion of molecules stays constant with increased pressure at a constant temperature, the correct response is: A) Yes, the thermal motion remains constant regardless of pressure changes. According to the Kinetic Molecular Theory, at a given temperature, the average kinetic energy—and hence the thermal motion—of the gas molecules remains constant. This idea is supported by Amontons's law (also known as Gay-Lussac's law), which implies that the pressure of a gas increases due to more frequent and forceful collisions when the temperature increases, but not due to an increase in the thermal motion of the molecules at a constant temperature. Viscosity may increase with pressure but this does not imply a change in the average speed of the molecules.