Why is the Cp value of any gas always greater than the Cv value?I don't want the mathematical proof from the formula Cp-Cv=R... I want the physical interpretation

Hi! Think about what work the gas has to do when it is heated at constant pressure rather than constant volume, is it more? Less? Why?

Let me know if you need any more pointers :)

Cp is based on the enthalpy and Cv is based on the internal energy. And the enthalpy = internal energy + PV work. At constant volume, there is no work. But at constant pressure, volume changes and there is work done. Did you get it? If not clear clarify the part you are not sure about.

Hi Frank, we try not to answer people's homework here, just give them pointers, could you try to stick to that please? :)

Capuchin,
I did not know such a rule! My life is short and I want to have a direct and clear communication, unless there is some other reason. If I ask a question, I would want someone who knows give me the specific and detailed answer so that I can learn and do right.

Why just pointers? Maybe I am not familiar with the purpose of this charter/organization. Are you a director or founder of this website?

Sincerely,
Frank

I have only just come to provide answers on this site the past month or so, and I completely agree that in most cases direct and clear answers are the best.

However, this site is used by a lot of students who are looking for help with homework, and by help I mean ANSWERS.

Often they are not concerned with how the answer is achieved and they are more concerned with the answer itself, I certainly know that was the case with me at one point in my life.

I think that the best policy, when the question looks like a standard homework question is to give pointers to make the asker think about what the answer is, rather than giving them a string of words to copy down. That doesn't help their progression in the slightest.

I hope you can understand what I'm trying to say, a lot of student underestimate the value of learning.

Thanks for the explanation.