Deriving the equation for lines of constant enthelpy

In summary, the equation for (dP/dV)H can be derived by combining the equation of state with the equation for dH, and taking the partial derivative of P with respect to V while holding H constant. Various methods such as the triple product rule and Maxwell relationships may be used to solve this equation.
  • #1
djkuehlos14
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How would one derive the equation for (dP/dV)H? That is the partial of P over the partial of V, holding H constant. I've tried many different things, triple product rule, maxwell relationships, and nothing seems to work. I appreciate any advice.
 
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  • #2
djkuehlos14 said:
How would one derive the equation for (dP/dV)H? That is the partial of P over the partial of V, holding H constant. I've tried many different things, triple product rule, maxwell relationships, and nothing seems to work. I appreciate any advice.

You need to start with the equation of state, and write
[tex]dT=(\frac{\partial T}{\partial P})_VdP+(\frac{\partial T}{\partial V})_PdV[/tex]

You need to combine this with the equation:

[tex]dH=C_PdT+(V-T(\frac{\partial V}{\partial T})_P)dP[/tex]
 

What is the equation for lines of constant enthalpy?

The equation for lines of constant enthalpy is H = U + PV, where H is enthalpy, U is internal energy, P is pressure, and V is volume.

What is the purpose of deriving the equation for lines of constant enthalpy?

The purpose of deriving the equation for lines of constant enthalpy is to understand the relationship between enthalpy, internal energy, pressure, and volume in a thermodynamic system. This equation is essential in studying and analyzing thermodynamic processes.

How do you derive the equation for lines of constant enthalpy?

The equation for lines of constant enthalpy can be derived using the first law of thermodynamics, which states that the change in internal energy of a system is equal to the heat added to the system minus the work done by the system.

What does a line of constant enthalpy represent?

A line of constant enthalpy represents a set of thermodynamic states where the enthalpy remains constant. This means that the enthalpy does not change even if there are changes in internal energy, pressure, or volume.

Why is the enthalpy a useful thermodynamic property?

Enthalpy is a useful thermodynamic property because it provides a convenient way to measure and calculate the heat transfer in a system at constant pressure. It also allows for the comparison of different thermodynamic processes and the determination of the direction of a spontaneous process.

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