Calculating Isothermal Expansion Work - 2 Moles Ideal Gas, 380K

AI Thread Summary
To calculate the work done by 2 moles of an ideal gas expanding isothermally at 380 K to three times its initial volume, the equation W = nRT ln(Vf/Vi) is used. The values are n = 2, R = 8.31, and T = 380 K, with Vf defined as 3Vi. The confusion arose from not clearly defining the initial and final volumes, but it was clarified that Vf is indeed 3Vi. The final work done can be simplified to W = nRT ln(3), resolving the initial misunderstanding.
BlackMamba
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Hello,

I have what should be an easy problem, but I, of course, am having some issues.

Here's the problem: The temperature of 2 moles if an ideal gas is 380 K. How much work does the gas do in expanding isothermally to 3 times its initial volume?

So I know I'm going to to need to use this equation to find the work done:
W = nRT ln (\frac{V_f}{V_i})

I know that:

n = 2
R = 8.31
T = 380
Vi = (3)Vi
Vf = ?

I'm hung up on the volume portion of this problem. I don't have an initial or final volume and that's what I can't seem to work around. Any help would be greatly appreciated.

Thanks in advance.
 
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Vi = Vi
Vf = 3 Vi
since it expands three times its initial volume
 
please correct vi=3.vi to be vf=3 vi, so now the problem is solved..
 
W = nRTln(3)

(Vf/Vi ) = 3Vi/Vi = 3
 
Oh Lord. Something so simple that I couldn't put together. Thank you everyone for your reply. It is greatly appreciated. :)
 
simple

:smile:
BlackMamba said:
Hello,

I have what should be an easy problem, but I, of course, am having some issues.

Here's the problem: The temperature of 2 moles if an ideal gas is 380 K. How much work does the gas do in expanding isothermally to 3 times its initial volume?

So I know I'm going to to need to use this equation to find the work done:
W = nRT ln (\frac{V_f}{V_i})

I know that:

n = 2
R = 8.31
T = 380
Vi = (3)Vi
Vf = ?

I'm hung up on the volume portion of this problem. I don't have an initial or final volume and that's what I can't seem to work around. Any help would be greatly appreciated.

Thanks in advance.
vfinal=3vinitial
 
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