The Kinetic Molecular Theory of Gases Learning Goal To understand some aspects o

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The Kinetic Molecular Theory of Gases Learning Goal To understand some aspects of molecular motion in the gas phase 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: 3RT ns where Ris 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. Part A Which of the following state ments 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 temperature of a gas sample is independent of the average kinetic energy The average speed of gas molecules decreases with decreasing temperature All the gas molecules in a sample cannot have the same kinetic energy Submit My Answers Give Up

Explanation / Answer

Assumption of kinetic theory :

That means temperature increases the kinetic energy of the gas also increases. When the temperature decreases the kinetic energy also decreases.

Speed of the molecule is inversely proportional to mass of the molecule since the speed of the gas molecule is depend upon the mass

Some are moving fast, others relatively slowly

The answer is

         The average kinetic energy is increase with increase temperature.

        The average speed of gas molecule decreases with decreasing temperature

All the gas molecule in the sample will not have same kinetic energy

Part B

Diffusion:

Mixing molecules of one gas with molecules of another gas is called diffusion

effusion:

motion of the gases from one container to another by passing through small hole is called effusion

Answer is

Diffusion

When   a cowoker microwavas popcorn you can smell the vapours in your office 5 mins later

Hair spray applied in the bedroom can be smelled in hallway a short time later.

Effussion

When a small hole is made in top of a coke bottle the CO2 gas moves out of the bottle over time

When the is a leak in the gas cylinder the volume of the gas decrease slowly over time.

Part C

The mass of the gas are inversely proportional to RMS speed of the gas

Since the answer is

More massive gas molecule have lower rms speed then less massive molecule

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