Cv and Cp

[Parker Smith]

Dr. Lavelle said that Cp is equivalent to enthalpy change, but why is Cv not included in this?

[Kevin Xu 4F]

I think both Cv and Cp can be used to calculator enthalpy change in the formula q= nCT. Just know that Cv means the molar heat capacity of a gas at a constant volume whereas Cp means the molar heat capacity of a gas at a constant pressure.

[WesleyWu_1C]

Since enthalpy change is usually under constant pressure, maybe that's why only Cp equals enthalpy change.

[Leila_4G]

Do solids and liquids only use C? Or do they use Cv? I'm pretty sure they don't use Cp.

[Luc Zelissen 1K]

Do solids and liquids only use C? Or do they use Cv? I'm pretty sure they don't use Cp.

They are the same for solids and liquids. For gasses, they are easily compressible, meaning their specific volume can easily change, while solids and liquids cannot change volume that easily so we just say that Cv=Cp.

[Emily Chirila 2E]

The values are the same in solids and liquids. In gases, Cv is constant volume and Cp is constant pressure so the values will be different. I think Cp may be used because Cp calorimetry gives enthalpy values, whereas Cv calorimetry gives heat capacity of the whole container/all parts

[ValerieChavarin 4F]

They are equal in the case of solids and liquids but change for gases due to compression and expansion.

[705367472]

So solids and liquids only use C? Also for gases it depends on certain factors?

[Shutong Hou_1F]

The change in enthalpy is equal to heat released or absorbed only when the reaction happens at a constant pressure. So the value of q(heat) calculated by Cp is equal to change in enthalpy, but not by Cv.

[AniP_2D]

If I'm not mistaken, Cv is used under constant volume while Cp is used under constant pressure.