Ideal Gas Problem

[TommyTman]

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This is a lecture problem from EK. It is incredibly simple but I don't know how they are arriving at the answer.

The question goes; "A force is applied to a container of gas reducing its volume by half. The temperature of the gas:

A. Decreases
B. Increases
C. Remains Constant
D. The temp change depends upon the amount of force used

The answer is B. I was thinking PV/T=constant and that if V decreases, P would increase and T would be unaffected.

 

[icedragon]

There is work being done on the container, so imagine that work transferring to the gas increasing the internal energy of the gas particles. The kinetic energy = 3/2 RT, thus increasing KE means directly increasing temperature as well.

 

[chill3]

There is work being done on the container, so imagine that work transferring to the gas increasing the internal energy of the gas particles. The kinetic energy = 3/2 RT, thus increasing KE means directly increasing temperature as well.

Another good way to think of it is that you have an initial volume of gas that is not actually changed in the problem. The problem essentially states that the container volume is decreased. You still have the same amount of gas, just squished into a smaller area. Since we know this will increase P, we know that T will increase.

 

[TommyTman]

Awesome thanks alot guys I appreciate it.