Understanding Isothermal Processes

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The discussion focuses on the isothermal process, where the first law of thermodynamics states that ΔU = 0, leading to Q = -W. Heat entering the system results in work done by the gas on its surroundings without changing internal energy. The question arises about how gas molecules exert more pressure on the walls while maintaining constant kinetic energy. It is clarified that heating the gas increases molecular kinetic energy, which is then transferred to work as the gas pushes the piston. This highlights the balance between energy input and work output in isothermal conditions.
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I've gone through a some of our textbooks but none of them effectively explains this process clearly. For the isothermal process, according to the first law of thermodynamics, ΔU = 0, indicating that Q = -W. So if heat flows into the system, all the energy put in is converted to work which the gas does on the surroundings. However, microscopically, how do the molecules exert more force on the wall (i.e. more pressure) without a change in their kinetic energy (i.e. their internal energy)? Taking a container with a movable piston, if the gas moves the piston by work - doesn't that mean that the molecules have gained more kinetic energy to move it?

Thanks in advance!
 
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Yes, when you heat the gas the molecules gain kinetic energy, and they lose it pushing the piston.
 

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