Kinetic Molecular Theory Video Lessons

Concept:

Problem: Which of the following statements are true?Check all that apply.__ The average kinetic energy of gas molecules increases with increasing temperature.__ There are gas molecules that move faster than the average.__ The average speed of gas molecules increases with increasing temperature.__ There are gas molecules that move slower than the average.__ All the gas molecules in a sample have the same kinetic energy.The kinetic molecular theory of gases explains how gas molecules behave in terms of motion, speed, and energy.One important aspect of this theory deals with the relationship between temperature and the average speed of the gas molecules. Increasing the temperature of a gas sample increases the average kinetic energy of the molecules. The kinetic energy of a molecule determines its speed. It is important to realize that not all molecules in a sample will have the same kinetic energy, which is why we refer to the average kinetic energy and the average speed. The speed of a particle with average kinetic energy is called the root mean square (rms) speed, vrms.The rms speed may be expressed by the following equation:vrms=3RTMwhere R is the ideal gas constant, T is the absolute temperature, and M is the molar mass of the substance in kilograms per mole.The constant motion of gas molecules causes diffusion and effusion. Diffusion is the gradual mixing of two substances resulting from the movement of their particles. Effusion is the gradual escape of gas molecules through microscopic holes in their container.

FREE Expert Solution
100% (223 ratings)
Problem Details

Which of the following statements are true?

Check all that apply.

__ The average kinetic energy of gas molecules increases with increasing temperature.
__ There are gas molecules that move faster than the average.
__ The average speed of gas molecules increases with increasing temperature.
__ There are gas molecules that move slower than the average.
__ All the gas molecules in a sample have the same kinetic energy.

The kinetic molecular theory of gases explains how gas molecules behave in terms of motion, speed, and energy.

One important aspect of this theory deals with the relationship between temperature and the average speed of the gas molecules. Increasing the temperature of a gas sample increases the average kinetic energy of the molecules. The kinetic energy of a molecule determines its speed. It is important to realize that not all molecules in a sample will have the same kinetic energy, which is why we refer to the average kinetic energy and the average speed. The speed of a particle with average kinetic energy is called the root mean square (rms) speed, vrms.

The rms speed may be expressed by the following equation:

${\mathbf{v}}_{\mathbf{rms}}\mathbf{=}\sqrt{\frac{\mathbf{3}\mathbf{RT}}{\mathbf{M}}}$

where R is the ideal gas constant, T is the absolute temperature, and M is the molar mass of the substance in kilograms per mole.

The constant motion of gas molecules causes diffusion and effusion. Diffusion is the gradual mixing of two substances resulting from the movement of their particles. Effusion is the gradual escape of gas molecules through microscopic holes in their container.