# Constant Volume Specific Heat

#### melanie

Just trying to locate specific heat constants with constant volume (not pressure), any ideas where to find this?

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#### abercrombiems02

If you have a thermodynamic set of property tables it would be in the column with Cv (v should be a subscript) if you are looking at Cp that is the specific heat at constant pressure. They should be fairly close in most non-extreme conditions so becareful what your looking at

#### Dr.Brain

$C_p$ : Specific Heat at constant pressure
$C_v$ : Specific Heat at constant volume

Also $C_p - C_v = R$

$\frac {C_p}{C_v} = lamda$

where lamda = $1 + \frac {2}{f}$

Where f=degrees of freedon

for monoatomic gas , f=3
for diatomic gas , f=3

You can solve for two expressions at the top to get Cp

BJ

#### quark

One correction to Dr.Brain's post. f for diatomic gases is 5

#### siddharth

Homework Helper
Gold Member
quark said:
One correction to Dr.Brain's post. f for diatomic gases is 5
And that's only at around room temperature's where the vibrational degree of freedom is absent. At high temperatures, f will be 7 for diatomic gases.

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