Discussion Overview
The discussion revolves around a homework problem related to chemical equilibrium, specifically focusing on the calculation of total pressure in a closed vessel containing PCl5, PCl3, and Cl2 at equilibrium. Participants are attempting to apply the equilibrium constant expressions and the ideal gas law to arrive at the correct total pressure value.
Discussion Character
- Homework-related
- Mathematical reasoning
- Technical explanation
Main Points Raised
- The initial conditions and equilibrium constant (Kc) for the reaction PCl5(g) ↔ PCl3(g) + Cl2(g) are provided, with a focus on calculating total pressure at equilibrium.
- One participant mentions using the equation Kp=Kc(RT)^change in n to convert Kc to Kp, leading to a calculated Kp value of 2.1425.
- Another participant describes their approach using the ideal gas law (PV=nRT) to find the pressure of PCl5, resulting in a pressure of 2.5814 atm.
- There is a reference to using the small x approximation, where one participant eliminates x from the denominator in their equilibrium expression.
- The calculated value of x is 2.3517, which raises a question about whether this value justifies the small x approximation.
Areas of Agreement / Disagreement
Participants do not appear to agree on the correctness of the calculations, particularly regarding the application of the small x approximation and the resulting total pressure. The discussion remains unresolved as participants seek clarification and validation of their approaches.
Contextual Notes
There are potential limitations in the assumptions made regarding the small x approximation, as well as the dependence on the accuracy of the equilibrium constant and the ideal gas law application. The discussion does not resolve these issues.