9.1: Kinetic Theory of Temperature and Pressure

Describe the pressure a gas exerts on its container in terms of molecular motion within that gas.

Molecules within a gas collide with and exert forces on other molecules within the gas and with the container in which the gas is contained.

• Collisions involving pairs of molecules or a molecule and a fixed object can be described and analyzed using conservation of momentum principles.

• The pressure exerted by a fluid on a surface is the ratio of the sum of the magnitudes of the perpendicular components of the forces exerted by the fluid’s molecules on the surface to the area of the surface. 

• Pressure exists within the gas itself, not just at the boundary between the gas and the container.

Describe the temperature of a system in terms of the molecular motion within that system.

The temperature of a system is characterized by the average kinetic energy of the molecules within that system.

• The Maxwell-Boltzmann distribution provides a graphical representation of the energies and speeds of molecules at a given temperature.

• The root-mean-square speed corresponding to the average kinetic energy for an ideal gas at a given temperature can be obtained from the Maxwell-Boltzmann distribution.