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The most of the ideal gas law equation is based on the fact that the gaseous molecules are moving around and cause collisions and thus have some pressure. If these molecules were to not have any kinetic energy, and thus consequently would not suffer any collisions would the surface of let's say a balloon, a filled balloon, which is firm only due to the pressure offered by the gas inside, still be firm? would the volume of the gad contribute to its firmness and give it shape? won't the volume be affected too

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  • $\begingroup$ What about the gas around the balloon? What do you think it does? $\endgroup$ – Buck Thorn May 1 '20 at 12:10
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If ideal gas molecules had had no kinetic energy, there would have been no gas pressure. Inside nor outside the balloon. The outer gas would have been laying on the ground, the inner gas on the bottom of the balloon.

In such a case, the only remaining force, aside of gravity, would have been the elastic forces of the balloon, pulling the balloon rubber together to its original shape and volume.

For real gases compressed to volume about equal to tight arrangement of molecules, a sudden repulsive force and therefore pressure would have progressively appeared, due repulsion of electrons.

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  • $\begingroup$ Thanks a lot for answering! I still had a question though, given that the gas molecules aren't showing any kinetic energy, they'd probably have a fixed position over time, giving them a fixed shape, and as you said they'd be lying at the bottom. So what would cause to bring about an elastic force in the rubber balloon? Just this matter at the bottom? $\endgroup$ – mae May 1 '20 at 14:03
  • $\begingroup$ Elastic rubber force is gas independent. If you stretch a piece of rubber then after stretching is released, it contracts black again, regardless of if there is a gas around, or not. $\endgroup$ – Poutnik May 1 '20 at 14:06
  • $\begingroup$ You would not be able to blow up the balloon in the first place, at least now in the way how you are used to. You would be able to fill it by a densely packed gas, but the balloon would be heavy and hard. $\endgroup$ – Poutnik May 2 '20 at 5:13
  • $\begingroup$ That's right. So, the balloon obviously wouldn't hold structure as it would before when filled with a gas, and would instead behave like a deflated rubber balloon filled with a less fluid substance, almost like a solid in its physical properties due to the negligible kinetic energy of the gas molecules $\endgroup$ – mae May 2 '20 at 5:21
  • $\begingroup$ Yes, like solid. And everything around such a gas would freeze solid as well. Rubber would break when you would touch it. Note that even at absolute zero 0 K, matter does have residual kinetic energy, related to zero point oscillations. $\endgroup$ – Poutnik May 2 '20 at 5:26

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