Kinetic molecular theory of gases. HELPS!!!

[ucla2134]

The kinetic molecular theory predicts that at a given temperature:
a/ all gas molecules have the same kinetic energy
b/ all gas molecules have the same average velocities
c/ only real gas molecules collides with each other
d/ on the average, heavier molecules move more slowly
e/ elastic collisions result in the loss of energy



My answer is BOTH A and D since KE=cT=(1/2)mv^2
But the answer is D. That means that answer A is wrong
Can you guys tell me why i'm wrong
Thanks a BUNCH.

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[z123]

The kinetic molecular theory predicts that at a given temperature:
a/ all gas molecules have the same kinetic energy
b/ all gas molecules have the same average velocities
c/ only real gas molecules collides with each other
d/ on the average, heavier molecules move more slowly
e/ elastic collisions result in the loss of energy



My answer is BOTH A and D since KE=cT=(1/2)mv^2
But the answer is D. That means that answer A is wrong
Can you guys tell me why i'm wrong
Thanks a BUNCH.

Answer A is wrong because...it states simply that gas molecules @ the same temperature have the same kinetic energy. It should have stated that gas molecules @ the same temperature have the same AVERAGE kinetic energy.

Reason being that when we increase the temperature, not all of the gas moelcules will be moving @ the same speed. Some will collide against the walls of the container harder than others (meaning that they have more speed, in other words more energy), therefore, when we talk about the relationship btw absolute temperature & kinetic energy, we are only talking about the averages. (Another way of seeing this is by looking @ the Maxwell Distribution Curves.)

Hope that helps a bit.

 

[ucla2134]

Answer A is wrong because...it states simply that gas molecules @ the same temperature have the same kinetic energy. It should have stated that gas molecules @ the same temperature have the same AVERAGE kinetic energy.

Reason being that when we increase the temperature, not all of the gas moelcules will be moving @ the same speed. Some will collide against the walls of the container harder than others (meaning that they have more speed, in other words more energy), therefore, when we talk about the relationship btw absolute temperature & kinetic energy, we are only talking about the averages. (Another way of seeing this is by looking @ the Maxwell Distribution Curves.)

Hope that helps a bit.

THANKS A BUNCH