Question

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.
Which of the following statements are true?

Check all that apply.

The temperature of a gas sample is independent of the average kinetic energy.
All the gas molecules in a sample cannot have the same kinetic energy.
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 decreases with decreasing temperature.

Answer 1

Answer:

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 decreases with decreasing temperature.

Explanation:

The kinetic energy of the molecules is the energy associated with the movement of them, and the average value of it can be calculated by the equation:

Ek = (1/2)m*v²

Where m is the mass and v is the average velocity of the molecules.

The temperature is a way to measure the energy of the molecules, thus, it's not independent of the average kinetic energy. Actually, for an ideal gas, the energy can be calculated by the temperature as:

Ek = (3/2)*(R/Na)*T

Where is the gas constant, Na the Avogadro's number, and T the is the temperature.

Thus, the average kinetic energy of gas molecules increases with increasing temperature, because they're directly proportional. When the average kinetic energy decreases, the temperature also decreases, and by the first equation, the velocity decreases too, thus the average speed of gas molecules decreases with decreasing temperature.

The value found in the equation is the average, thus, some molecules may have higher or lower energy, and because of that can move faster os slower than the average. For an ideal gas, all the molecules have the same kinetic energy, so it's possible to all the gas molecules in a sample have the same kinetic energy.