At thermodynamics process of uncontrolled change satisfying the equation $Q=W=0$, is $[Q=$ heat supplied,…
At thermodynamics process of uncontrolled change satisfying the equation $Q=W=0$, is $[Q=$ heat supplied, $W=$ work done $]$
Free expansion
Cyclic
Isochoric
Isothermal
Solution
i. Free expansions are adiabatic expansions thus there is no exchange of heat between a system and its environment.
ii. Also, there is no work done on the system or by the system. $Q=W=0$, and according to the first law of thermodynamics,
$\Delta U=0$
iii. For example, when a balloon is ruptured suddenly, or a tire is suddenly punctured, the air inside rushes out rapidly but there is no displacement of a piston or any other surface.
iv. A free expansion is different than other thermodynamic processes because it is an uncontrolled change. It is an instantaneous change and the system is not in thermodynamic equilibrium.
v. A free expansion cannot be plotted on a $\mathrm{p}-\mathrm{V}$ diagram. Only its initial and the final state can be plotted.
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