Question 1189566:  Draw the P-V diagram for an irreversible expansion of gas from 0.500 L to 2.00 L. The initial pressure is 1.25 ×10⁴ atm, and the temperature remains at a constant 273 K. 
 Answer by CPhill(1987)      (Show Source): 
You can  put this solution on YOUR website! **Understanding Irreversible Expansion**
 
* **Reversible Expansion:** In a reversible expansion, the system is always infinitesimally close to equilibrium. This means the process can be reversed by an infinitesimal change in conditions. On a P-V diagram, a reversible expansion is represented by a smooth curve. 
* **Irreversible Expansion:** In an irreversible expansion, the system is not at equilibrium during the process. This is often due to a sudden change in conditions or the presence of friction. The work done by the system is less than in a reversible process between the same initial and final states.
 
**Drawing the P-V Diagram**
 
1. **Axes:** Draw a set of axes with Pressure (P) on the vertical axis and Volume (V) on the horizontal axis.
 
2. **Initial State:** Mark the initial state of the gas: 
   * V1 = 0.500 L 
   * P1 = 1.25 × 10⁴ atm
 
3. **Final State:** Mark the final state of the gas: 
   * V2 = 2.00 L
 
4. **Irreversible Path:** Since the expansion is irreversible, we cannot draw a smooth curve. Instead, we represent it with a dashed line or a series of small steps. The path will be lower than the curve for a reversible isothermal expansion.
 
5. **Isothermal Curve (Optional):** For comparison, you can draw a dashed curve representing a reversible isothermal expansion between the same initial and final states. This curve will be higher than the irreversible path.
 
**Key Features of the Diagram**
 
* The irreversible path will start at the initial state (P1, V1) and end at the final state (P2, V2). 
* The path will be below the reversible isothermal curve (if drawn). 
* The area under the irreversible path represents the work done by the gas, which will be less than the work done in a reversible expansion.
 
**Note:** The exact shape of the irreversible path is not crucial, as long as it indicates that the process is irreversible and the work done is less than in a reversible process. 
 
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