Physics: Expansion at constant pressure

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Discussion Overview

The discussion revolves around a problem involving the expansion of an ideal monoatomic gas at constant pressure. Participants are attempting to determine the number of moles of gas, the final temperature, and the work done by the gas during the expansion process. The focus is on the application of the ideal gas law and the calculations involved.

Discussion Character

  • Homework-related
  • Mathematical reasoning

Main Points Raised

  • One participant expresses confusion about finding the number of moles of gas using the ideal gas law (PV=nRT) and mentions issues with their calculations.
  • Another participant questions the meaning of "ideal monoatomic gas expand reversibly," prompting a discussion about the implications of these terms.
  • A participant suggests that the method of using the equation of state for the initial state seems appropriate, despite the confusion expressed by the original poster.
  • One participant advises against converting cubic meters to liters in the calculations.

Areas of Agreement / Disagreement

Participants do not appear to reach a consensus on the correct approach to the problem, as there are differing opinions on the calculations and methods used. The discussion remains unresolved regarding the specific errors in the original poster's approach.

Contextual Notes

There are limitations in the discussion regarding the assumptions made in the calculations, the dependence on unit conversions, and the clarity of the steps taken to arrive at the results.

FutureE'neer
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An unknown number of moles of an ideal monoatomic gas expand reversibly from Vi = 2.30 m3 to Vf = 3.10 m3, at a constant pressure of 1.71 atm and an initial temperature of 300 K.
Find the number of moles of gas.
Find the final temperature of the gas K.
Calculate the work done by the gas.

I cannot find the number of moles and I don't know what I'm doing wrong.
I'm using PV=nRT
Converting the pressure in atm to N/m^2 and m^3 to L. I'm using the initial volume for V, 8.315 for R and the initial temp in K and solving for n. I keep getting the same answer and it is coming up wrong. Please help!
 
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Keywords are "ideal monoatomic gas expand reversibly "
What does that mean to you?
 
that's how much it fluctuate's?
 
FutureE'neer said:
I cannot find the number of moles and I don't know what I'm doing wrong.
I'm using PV=nRT
Converting the pressure in atm to N/m^2 and m^3 to L. I'm using the initial volume for V, 8.315 for R and the initial temp in K and solving for n. I keep getting the same answer and it is coming up wrong. Please help!
Can you show what you did (and how do you know is wrong)?
The method (using equation of state for initial state) seems OK.
 
Don't change m^3 to litres
 

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