If I decrease the volume of a certain container containing a gas; the KE of the particles will increase and therefore the temperature should increase. But according to Charles's law both of these are directly proportional. I do understand the situation in which the temperature is increased and the result is an increase in volume. Also the case in which temperature is decreased which results in lowering of the KE and also results in attraction thus decreasing the volume. But I cant work my way from volume change to temperature effects. Thanks.
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A key assumption to Charles' law is that there is some way to keep the pressure constant in the system under consideration. You can also read the law the other way around (which is less confusing): when one decreases the volume of a container of gas, the pressure increases, and in order to prevent that increase, one has to decrease the temperature as well.
As long as one does not play around with the temperature, the most intuitive thing that can happen upon decreasing the container volume is that the pressure of the gas increases. This situation is not described by Charles' law.
Note that the kinetic energy of the molecules does not normally increase upon decreasing the volume: else, this would raise the temperature as well, in a manner inconsistent with the ideal gas law $pV = nkT$.
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1$\begingroup$ Compressing a gas is a common way to raise temperature, with pressure also rising. $\endgroup$ Apr 11, 2022 at 0:27