Example 8.5


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Tiffany Cao 1D
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Example 8.5

Postby Tiffany Cao 1D » Thu Mar 15, 2018 10:50 pm

For practice example 8.5 on page 274, why did we assume that delta U was 0 in the second step of part B?

Cam Bear 2F
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Re: Example 8.5

Postby Cam Bear 2F » Thu Mar 15, 2018 11:28 pm

Delta U=0 for the isothermal expansion of an ideal gas.

Cam Bear 2F
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Joined: Thu Jul 27, 2017 3:01 am

Re: Example 8.5

Postby Cam Bear 2F » Thu Mar 15, 2018 11:30 pm

Path A is a reversible expansion and Part B is an irreversible expansion but both still take place isothermally.

Pooja Nair 1C
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Re: Example 8.5

Postby Pooja Nair 1C » Fri Mar 16, 2018 12:02 am

Even as an ideal gas expands isothermally, its molecules continue to move at the same speed, so the kinetic energy doesn't change. Also the total potential energy of these molecules is the same because there aren't any intramolecular forces. Since neither the total kinetic energy nor the total potential energy changes, the internal energy of the gas doesn't change, making delta U = 0 for isothermal expansions of ideal gas.


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