Degrees of Freedom and Molar Specific Heats

AI Thread Summary
In a discussion about a diatomic gas expanding at constant pressure, a participant calculated the increase in internal energy after adding 70J of heat. They used the relationship between heat added and specific heats, concluding that the internal energy increase is 50J based on the Cp/Cv ratio for diatomic gases. Another participant confirmed the calculation as correct. The process is identified as isobaric, where the gas molecules rotate but do not oscillate. The exchange highlights the importance of understanding specific heat ratios in thermodynamic processes.
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Homework Statement



We give 70J as heat to a diatomic gas, which then expands at constant pressure. The gas molecules rotate but do not oscillate. By how much does the internal energy of the gas increase.

Homework Equations





The Attempt at a Solution



I did it this way:
Heat added = nCp dT = 70J.
Let Internal energy = nCv dT = x (say).
Dividing both equations, we obtain:
Cp/Cv = 70/x.
But, Cp/Cv is nothing but the ration of speicifc heat which for a diatomic gas is known to be 7/5. So, x = 50J.

Am I correct? the solution is not given in the book!

Thanks a ton in advance!
 
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It is an isobaric process.

Your answer is 100% correct.
 
Thanks a ton!

Thank-you so very much. I really appreciate it.
 

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