Work and Ideal Gases: Calculate Initial Volume

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Homework Help Overview

The problem involves calculating the initial volume of one mole of an ideal gas that does 1975 J of work during an isothermal expansion to a final pressure of 1.2 atm and a volume of 24 L. The universal gas constant is provided.

Discussion Character

  • Exploratory, Assumption checking, Mathematical reasoning

Approaches and Questions Raised

  • Participants discuss the need for temperature in the work equations and question how to derive it without direct information. There is also inquiry about solving for a variable within a logarithmic equation.

Discussion Status

Some participants have suggested relevant equations and are encouraging a step-by-step setup of the problem. There is an ongoing exploration of how to approach the calculations without complete information.

Contextual Notes

Participants note the absence of temperature in the problem statement and express uncertainty about how to proceed with the calculations involving logarithms.

Jake4
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Homework Statement



One mole of an ideal gas does 1975 J of work on the surroundings as it expands isothermally to a final pressure of 1.2 atm and a volume of 24 L.

find the initial volume. The universal gas constant is 8.31451 J/K mol




The Attempt at a Solution



Something he touched on in class, but I don't have relevant equations in my notes.

thanks guys!
 
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It seems as if for the work equations, I would also need the Temperature. Is there a way around that? or possibly an equation that allows me to get it?

Also, this is one of those things, that I just simply haven't done before... but how would I solve for a variable within the ln?

you end up with W=nRT*lnVf/Vi So how would I be solving for that Vi?
 
Jake4 said:
It seems as if for the work equations, I would also need the Temperature. Is there a way around that? or possibly an equation that allows me to get it?

Also, this is one of those things, that I just simply haven't done before... but how would I solve for a variable within the ln?

you end up with W=nRT*lnVf/Vi So how would I be solving for that Vi?


Let's take this one step at a time.
That is, let's first set up the equations.
After that we'll see how we can solve them. :smile:


You ask how you can get the temperature T.
Well, perhaps you have overlooked the relevant equation on the wiki page.

It's:

p V = n R T​



Can you set up the equations? :confused:
 
Jake4 said:
It seems as if for the work equations, I would also need the Temperature. Is there a way around that? or possibly an equation that allows me to get it?
T = PV/nR

Also, this is one of those things, that I just simply haven't done before... but how would I solve for a variable within the ln?

you end up with W=nRT*lnVf/Vi So how would I be solving for that Vi?
Use:

e^{\ln x} = xAM
 

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