Chemistry-TGhermodynamics Piston Cylinder Device question

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Discussion Overview

The discussion revolves around a homework problem involving a piston cylinder device containing R-134A. Participants are exploring the quality of the refrigerant, work done during the process, and heat transfer, with a focus on the changing volume throughout the process.

Discussion Character

  • Homework-related

Main Points Raised

  • One participant expresses uncertainty about calculating the quality of R-134A due to the changing volume during the process.
  • Another participant questions whether "quality" might be a misinterpretation and suggests it could be "quantity."
  • A third participant asserts that the term "quality" is indeed correct in this context.
  • A fourth participant expresses relief at not having to solve the problem themselves, indicating the complexity of the issue.

Areas of Agreement / Disagreement

There is disagreement regarding the interpretation of the term "quality" in the context of the problem, with some participants questioning its application while others defend its use. The discussion remains unresolved.

Contextual Notes

Participants have not reached a consensus on how to approach the quality calculation, and there are uncertainties regarding the implications of the changing volume on the problem.

meeklobraca
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Homework Statement



A piston cylinder device with a spring attached initially contains 0.02m^3 of R-134A at 50C. A valve connected to the cylinder is opened and 20kg of R-134A enters the device from a supply line at 800kPa and 80C. The spring is compressed and the piston moves up. The process stops when the pressure inside the cylinder reaches 1MPa, at a temperature of 100C and a volume of 0.6m^3.

a) The quality (x) of the R-134A in state 1?
b) Work done in this process (kJ)?
c) Amount of heat transferred to/from device (kJ)?


Homework Equations





The Attempt at a Solution



Im stuck at the quality aspect of the question. In most piston cylinder devices the volume is constant at least for a little but I think the volume is constantly changing throughout the problem. So I don't know how to get the quality with the information given.

Any help would be appreciated!
 
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I'm still thinking about "state 1"...

Quality? Perhaps that should be quantity?
 
No, it shouldnt.
 
glad it's your problem and not mine!
 

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