Finding the heat transferred in an ininitesimal quasistatic process

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The discussion focuses on deriving the expression for heat transferred in an infinitesimal quasistatic process for an ideal gas, represented by the equation dQ = (C_V/nR)VdP + (C_P/nR)PdV. Participants express uncertainty about how to start the derivation, with one suggesting the use of the first law of thermodynamics, dQ = dU + PdV. Another participant recommends beginning with the equation dQ = mCdT, emphasizing that the heat capacity varies depending on the gas's work during heat transfer. The key to progressing is to relate changes in temperature (dT) to the ideal gas law, PV = nRT. This approach aims to clarify the relationship between heat transfer and changes in pressure and volume for an ideal gas.
Narcol2000
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For an ideal gas PV=nRT where n is the number of moles show that the heat transferred can be written as:

<br /> dQ = \frac{C_V}{nR}VdP + \frac{C_P}{nR}PdV<br />

Really not sure where to start with this...

I have used

<br /> dQ = dU + PdV<br />

But it hasn't really lead anywhere.
 
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Narcol2000 said:
For an ideal gas PV=nRT where n is the number of moles show that the heat transferred can be written as:

<br /> dQ = \frac{C_V}{nR}VdP + \frac{C_P}{nR}PdV<br />

Really not sure where to start with this...

I have used

<br /> dQ = dU + PdV<br />

But it hasn't really lead anywhere.
Start with:

dQ = mCdT where C is the heat capacity of the gas. (The heat capacity, of course, depends on whether the gas does work as the heat flows into the gas, so it does not have a fixed value).

Using PV = nRT, what is dT? That should get you going in the right direction.

AM
 
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