Question

The constant pressure molar heat capacity of argon, C_{p,m}C

p,m

​

, is


20.79\text{ J K}^{-1}\text{ mol}^{-1}20.79 J K

−1

mol

−1

at 298\text{ K}298 K. What


will be the value of the constant volume molar heat capacity of argon,


C_{V,m}C

V,m

​

, at this temperature?

Answer 1

Constant-volume molar heat capacity of argon is 12.47 J K ⁻¹mol⁻¹

Step-by-step explanation:

Argon is a monoatomic gas that behaves as an ideal gas at 298K.

Using the first law of thermodinamics you can obtain:

Work, Q, for constant pressure molar heat capacity,CP:

CP = (5/2)R

For constant-volume molar heat capacity,CV:

CV = (3/2)R

That means:

2CP/5 = 2CV/3

3/5 = CV / CP

As CP of Argon is 20.79 J K ⁻¹mol⁻¹, CV will be:

3/5 = CV / CP

3/5 = CV / 20.79 J K ⁻¹mol⁻¹

12.47 J K ⁻¹mol⁻¹ = CV

Constant-volume molar heat capacity of argon is 12.47 J K ⁻¹mol⁻¹