If I have an adiabatic and rigid container with air , and if I fill it more with air, according to Ideal Gas law, the number of moles, temperature, and pressure would increase. Why would temperature increase?
Per example, if I have a piston and adiabatic cylinder, and if I push the piston, due to my work, particles will gain velocity and Kinetic Energy will increase, which means more Temperature.
In the case of my rigid container, I would like to know why it would increase the temperature. I know there are more particles, they are tighter and they collide more, but I'm not providing any bonus energy, as heat or work, so their kinetic energy would mantain constant, and since an ideal gas only have elastic collisions, the temperature of whole system would be the same.
Would the explanation for this be the fact that there are entering new particles with energy too, that can share with other particles?
Best Answer
If you add gas particles to an insulated container of fixed volume, what happens to the temperature depends entirely on what energy you give those particles when you add them. If you give them the same average kinetic energy as the ideal gas particles already in the container, the temperature will not change.
Perhaps what is confusing you is that you are trying to use the ideal gas law to infer the temperature. That law is just a constraint on pressure, temperature, and density, but it isn't necessarily telling you the temperature, that depends on additional details. For example, in the Earth's atmosphere, the ideal gas law sets the density of the air, because the temperature and pressure are set by other considerations.