What Variables are Zero in Different Thermodynamic Conditions?

AI Thread Summary
The discussion centers on the need for a comprehensive list of thermodynamic variables that equal zero under specific conditions, such as isothermal, adiabatic, and constant volume processes. The original poster seeks clarification on how different initial conditions affect variables like work (w), heat (q), internal energy change (ΔU), and enthalpy change (ΔH). There is confusion regarding the application of these concepts, particularly when calculating values for processes involving expansion into a vacuum. The conversation highlights the importance of understanding the relationships between these variables and the conditions that influence them. A detailed list or resource would greatly assist in resolving these queries.
tyrasia
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Hello Everyone,

Is there a list online somewhere of which variable values are 0 and why (conceptually), based on initial conditions? Like I know that for a system at constant volume, w=0. I am looking for a list for the other effects like isothermal, adiabatic, what does pressure= if there is expansion in a vacuum (0?), isobaric, and such things like that. Thanks in advance!

Tyrasia
 
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I don't understand the question, more detail is better. What are the initial conditions? Presumably you are trying to solve some differential equation?

The example doesn't help me understand because "w" could be anything.
 
I am trying to find a list of what happens to the equations under conditions like, constant volume means work, or technically dw is 0. I know the equations (sorta) but don't know which terms will go to 0 under conditions likeisothermal expansion, expansion into a vacume, heating at constant pressure, adiabatic compression etc. when trying to find the values of q(heat),w(work),deltaU and deltaH given Volume and Temperature expanding in a vacume, for example, I got all 0s which I know is wrong. So I am looking for a list that can show me how the equations are affected by these conditions, or processes. Then I can figure out those 4 variables for a process which involves severel different processes sequential to each other.

Tyr
 
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