Internal energy equals to average kinectic energy ?

AI Thread Summary
For ideal gases, the molar heat capacity Cv is equal to 3R/2 only for ideal monatomic gases. The equation Cv dT = nkT (3/2) is incorrect as it conflates temperature change with temperature itself. The correct integration for heat transfer involves the relationship between Cv and temperature change, expressed as ∫ nCv dT = (3/2)nRΔT. This results in the equation (3/2)NkΔT for monatomic ideal gases. Understanding these distinctions is crucial for accurate thermodynamic calculations.
Outrageous
Messages
373
Reaction score
0
For ideal gas , can I assume Cv dT = nkT (3/2)
, thank you
 
Physics news on Phys.org
Outrageous said:
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:

\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
AM
 
Andrew Mason said:
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:

\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



AM

Thanks for compact explanation.
 
Thread 'Question about pressure of a liquid'
I am looking at pressure in liquids and I am testing my idea. The vertical tube is 100m, the contraption is filled with water. The vertical tube is very thin(maybe 1mm^2 cross section). The area of the base is ~100m^2. Will he top half be launched in the air if suddenly it cracked?- assuming its light enough. I want to test my idea that if I had a thin long ruber tube that I lifted up, then the pressure at "red lines" will be high and that the $force = pressure * area$ would be massive...
I feel it should be solvable we just need to find a perfect pattern, and there will be a general pattern since the forces acting are based on a single function, so..... you can't actually say it is unsolvable right? Cause imaging 3 bodies actually existed somwhere in this universe then nature isn't gonna wait till we predict it! And yea I have checked in many places that tiny changes cause large changes so it becomes chaos........ but still I just can't accept that it is impossible to solve...
Back
Top