# Homework Help: Heat capacity at constant volume explanation

1. May 12, 2007

### imy786

1. The problem statement, all variables and given/known data

Explain what is meant by the heat capacity at constant volume, CV, and the heat capacity at constant pressure, CP.

How are these two properties related for an ideal gas?

Why is CP generally greater than CV

2. Relevant equations

3. The attempt at a solution

heat capacity at constant volume- CV- as the heat input, Q, needed to warm a body, divided by the corresponding temperature rise , where the temperaute rise is small, and the heating is carried out at constant volume

heat capacity at constant pressure, CP. As the heat input, Q, needed to warm a body, divided by the corresponding temperature rise, where the temperaute rise is small, and the heating is carried out at constant pressure,

CV- theortical importance
cp- practical importance

2. May 12, 2007

### tronter

What are $$C_p$$ and $$C_v$$ for monatomic and diatomic gases? You can pretty much find your answers to your questions in any standard physics textbook.

3. May 12, 2007

### lalbatros

Both cv and vp are used in practice.
Cp is used maybe a little bit more often because many processes happen at a constant pressure.
The pressure can be the atmospheric pressure.
Or the pressure can be higher but it is often controlled to be constant, for various reasons including safety.

4. May 16, 2007

### imy786

Why is CP generally greater than CV?

coz Cp is used more often because more processes at constant pressure.

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How are these two properties related for an ideal gas?

Cp molar heat capacity of a monatomic gas is 5R/2
and for diatomic gas is 7R/2