Reversible and Irreversible Expansion/Compression Processes: Screencasts
Shows graphically the areas on a pressure-volume diagram that are proportional to work for reversible and irreversible expansions and compressions of a gas in a piston/cylinder.
Important Equations:
For an ideal gas:
\(\Delta U = C_V \Delta T\) \[\Delta H = C_P \Delta T \]
For reversible or irreversible processes:
\[W = – \int P_{ext} dV \]
where \(P_{ext} \) is the external pressure
For reversible processes:
\[W = – \int PdV, \]
where \(P\) is the gas pressure
For irreversible processes with a constant external pressure \((P_{ext})\):
\[W = – P_{ext} \Delta V, \]
where \(P_{ext}\) is the final external pressure
For an ideal gas in a reversible, adiabatic process:
\[\Delta S = 0\]
Adiabatic reversible expansion or compression (open or closed system) for an ideal gas:
\[ \frac {T_2}{T_1} = \left( \frac {P_2}{P_1}\right)^{\frac{R}{C_P}} \]