Internal energy equals to average kinectic energy ?


by Outrageous
Tags: average, energy, equals, internal, kinectic
Outrageous
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#1
Dec27-12, 11:09 PM
P: 375
For ideal gas , can I assume Cv dT = nkT (3/2)
, thank you
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Andrew Mason
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Dec28-12, 12:47 PM
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Quote Quote by Outrageous View Post
For ideal gas , can I assume Cv dT = nkT (3/2)
, thank you
No. Molar heat capacity, Cv = 3R/2 only for ideal monatomic gases. You are also mixing temperature change with temperature here.

Using molar heat capacity 3R/2 for a monatomic ideal gas:

[itex]\int_{Ti}^{Tf} nC_vdT = \frac{3}{2}nR(T_f - T_i) = \frac{3}{2}nR\Delta T = \frac{3}{2}Nk\Delta T[/itex]



AM
Outrageous
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#3
Dec29-12, 03:41 AM
P: 375
Quote Quote by Andrew Mason View Post
No. Molar heat capacity, Cv = 3R/2 only for ideal monatomic gases. You are also mixing temperature change with temperature here.

Using molar heat capacity 3R/2 for a monatomic ideal gas:

[itex]\int_{Ti}^{Tf} nC_vdT = \frac{3}{2}nR(T_f - T_i) = \frac{3}{2}nR\Delta T = \frac{3}{2}Nk\Delta T[/itex]



AM
Thanks for compact explanation.


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