Discussion Overview
The discussion centers on the entropy change in an irreversible adiabatic process involving an ideal gas in a cylinder with a piston. Participants explore the implications of the first law of thermodynamics, the ideal gas law, and the nature of reversible versus irreversible processes. The scope includes theoretical analysis, mathematical reasoning, and conceptual clarification regarding entropy changes in different processes.
Discussion Character
- Exploratory
- Technical explanation
- Debate/contested
- Mathematical reasoning
Main Points Raised
- Some participants question the definition of "adiabatic" in the context of an irreversible process, noting that entropy change cannot be zero.
- Others propose that the change in internal energy can be expressed using the first law of thermodynamics, leading to equations relating temperature and volume.
- Several participants derive relationships for the new temperature and volume after the irreversible expansion, with some expressing concerns about algebraic errors in earlier calculations.
- Multiple reversible processes are suggested to transition from the initial to final states, including isobaric and isothermal steps, with participants discussing the work done and heat added in each case.
- There is a discussion about the conditions under which a process can be considered reversible, with some participants expressing uncertainty about how to determine reversibility without invoking the second law of thermodynamics.
Areas of Agreement / Disagreement
Participants do not reach a consensus on the definitions and implications of adiabatic and irreversible processes, as well as the calculations related to temperature and volume changes. There are competing views on the nature of reversibility and the correctness of derived equations.
Contextual Notes
Participants express uncertainty regarding the assumptions made in their calculations, particularly concerning the relationship between initial and final states in adiabatic processes. Some equations are noted to depend on specific conditions that may not hold in all scenarios.
Who May Find This Useful
This discussion may be useful for students and professionals interested in thermodynamics, particularly those exploring the nuances of irreversible processes and entropy changes in ideal gases.