## Cv vs Cp

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

Karina Kong 2H
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### Cv vs Cp

When do we use Cv vs Cp?

LNgo 1G
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### Re: Cv vs Cp

Use Cv when volume is constant and Cp when pressure is constant.

Dina 2k
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### Re: Cv vs Cp

the values are usually given to us, unless it's for an ideal gas, in which the equation sheet gives the formula.

Kyle Rex 1K
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### Re: Cv vs Cp

Cv is when there is no change in volume and Cp when there is no change in pressure

Sanjana Munagala_1j
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Been upvoted: 1 time

### Re: Cv vs Cp

I want to also point out that you use Cv also when solving for an entropy change in a system that has both a volume change and a temperature change. This is because you have to treat the two changes independently. Therefore when calculating the entropy change due to a temperature change, you have to assume that the volume is constant.

Hope that helps!

Astrid Lunde 1I
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### Re: Cv vs Cp

Cv is constant volume and Cp is constant pressure.

ThomasNguyen_Dis1H
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### Re: Cv vs Cp

Cv is at constant volume and Cp is at constant pressure. For most problems, we use Cv so when in doubt use Cv.

Luc Zelissen 1K
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### Re: Cv vs Cp

Also remember that for Ideal gasses you can use the equation, Cpm = Cvm + R

Jarrett Peyrefitte 2K
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### Re: Cv vs Cp

Cv = Constant volume
Cp = Constant pressure

Rhea Shah 2F
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### Re: Cv vs Cp

Cv is used when volume is held constant, and is equal to 3/2R. Cp is used when pressure is held constant and is equal to 5/2R

Natalie Benitez 1E
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### Re: Cv vs Cp

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

pmokh14B
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### Re: Cv vs Cp

we use Cv when the volume is constant(isochoric) and Cp when pressure is constant (isobaric)

JesseAuLec1Dis1G
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### Re: Cv vs Cp

Cv is used when there's constant volume and Cp is used when there's constant pressure.

Kishan Shah 2G
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### Re: Cv vs Cp

Basically, Cv represents the heat capacity at constant volume, so a bomb calorimeter per say. Cp represents heat capacity at constant pressure, so an irreversible expansion. Cv is 3/2R and Cp is 5/2R

Emil Velasco 1H
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### Re: Cv vs Cp

Cv is constant volume and Cp is constant pressure

kausalya_1k
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### Re: Cv vs Cp

we use Cv for when volume is constant (isochoric) and Cp when pressure is constant (isobaric)

Deja Nora
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### Re: Cv vs Cp

Cv represents constant volume while Cp represents constant pressure

Anish Natarajan 4G
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### Re: Cv vs Cp

Generally it will be stated within the parameters of the problem whether or not pressure/volume is constant.