Cv vs. Cp

Volume: $\Delta S = nR\ln \frac{V_{2}}{V_{1}}$
Temperature: $\Delta S = nC\ln \frac{T_{2}}{T_{1}}$

TanveerDhaliwal3G
Posts: 105
Joined: Fri Aug 30, 2019 12:17 am

Cv vs. Cp

When should we use Cv and when should we use Cp?

William Francis 2E
Posts: 101
Joined: Wed Sep 18, 2019 12:20 am

Re: Cv vs. Cp

Cv is used for systems with constant volume. Cp is used for systems with constant pressure.

Alondra
Posts: 36
Joined: Tue Feb 26, 2019 12:15 am

Re: Cv vs. Cp

Cv is used for systems with constant volume; Cv= (3/2)R, if diatomic then Cv= (5/2)R

Cp is used for systems with constant pressure; Cp = (5/2)R, if diatomic then Cv= (7/2)R

Rida Ismail 2E
Posts: 139
Joined: Sat Sep 07, 2019 12:16 am

Re: Cv vs. Cp

Cv is strictly for constant volume and Cp is for constant pressure.

SVajragiri_1C
Posts: 115
Joined: Thu Jul 11, 2019 12:16 am

Re: Cv vs. Cp

Cv refers to the molar heat capacity of a gas at constant volume. Cp refers to the molar heat capacity of a gas at constant pressure. The two are different because in order to maintain the same pressure throughout a reaction the volume would have to be changing, and maintaining volume would require work to keep the piston from moving. Constant v calorimetry uses a bomb calorimeter.

Jacob Villar 2C
Posts: 105
Joined: Sat Aug 17, 2019 12:18 am

Re: Cv vs. Cp

It depends on the conditions of the system, for example, a system with constant volume would have Cv (notice the subscript v) and a system with a constant pressure would be written as Cp for the molar heat constant.