Final Pressure in Sealed System with Two Bulbs at Different Temperatures?

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    Thermodynamics
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Discussion Overview

The discussion revolves around a problem involving two bulbs of different volumes connected by a tube, where the bulbs are at different temperatures. Participants are exploring how to determine the final pressure in the system after the bulbs reach thermal equilibrium, while neglecting thermal expansion of the bulbs.

Discussion Character

  • Homework-related
  • Mathematical reasoning
  • Technical explanation

Main Points Raised

  • One participant initially assumes the system is isobaric, but another participant clarifies that the pressure changes in both containers to the same new value.
  • Participants discuss the application of the ideal gas law to find the number of moles of gas in each bulb, with one participant introducing the concept of a change in the number of moles in the smaller container.
  • There is a suggestion to calculate the number of moles using the provided values of pressure, volume, and temperature, leading to a realization that the ideal gas law (PV=nRT) can be applied.

Areas of Agreement / Disagreement

Participants do not agree on the initial assumption of isobaric conditions, with at least one participant asserting that the pressure is not constant across the system. The discussion remains unresolved regarding the final pressure calculation.

Contextual Notes

Participants note the lack of initial values for the number of moles, which may affect the calculations. The discussion also highlights the dependence on the ideal gas law and the assumptions made regarding the system's behavior.

Hozhoz
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Homework Statement


two bulbs of volumes 200cm^3 and 100cm^3 are connected by a short tube containing an insulating porous plug that permits equalization of pressure but not of temperature between bulbs. the system is sealed at 27°c when it contains oxygen under a pressure of 1 bar. the small bulb is immersed in an ice bath at 0°c and the large bulb is placed in a steam bath at 100°c. what is the final pressure inside the system ? neglect thermal expansion of the bulbs.
thank you.


Homework Equations





The Attempt at a Solution


i assume that the condition here is isobaric
 
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Hozhoz said:

Homework Statement


two bulbs of volumes 200cm^3 and 100cm^3 are connected by a short tube containing an insulating porous plug that permits equalization of pressure but not of temperature between bulbs. the system is sealed at 27°c when it contains oxygen under a pressure of 1 bar. the small bulb is immersed in an ice bath at 0°c and the large bulb is placed in a steam bath at 100°c. what is the final pressure inside the system ? neglect thermal expansion of the bulbs.
thank you.


Homework Equations





The Attempt at a Solution


i assume that the condition here is isobaric
It's not isobaric. The pressure changes in both containers to the same new value.

From the ideal gas law, how many moles of gas are present in each bulb to start with? Let Δn be the change in the number of moles in the small container. What is the change in the number of moles in the larger container, and, in terms of Δn, what are the final number of moles of gas in each of the two containers?

Chet
 
Chestermiller said:
It's not isobaric. The pressure changes in both containers to the same new value.

From the ideal gas law, how many moles of gas are present in each bulb to start with? Let Δn be the change in the number of moles in the small container. What is the change in the number of moles in the larger container, and, in terms of Δn, what are the final number of moles of gas in each of the two containers?

Chet
it didnt give me the value of n
 
It gave you ##P##, ##V##, and ##T##. Can't you figure out ##n##?
 
DrClaude said:
It gave you ##P##, ##V##, and ##T##. Can't you figure out ##n##?
oh yeah pv=nRT
 

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