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### Equation for a non-state property?

Posted: Wed Jan 10, 2018 10:12 pm
So I know that a state property is not dependent on path taken, but rather just final - initial. However, for a non-state property like work and heat, what would be the equation to solve for it?

### Re: Equation for a non-state property?

Posted: Wed Jan 10, 2018 10:14 pm
In a sense it is like finding the total distance traveled by a particle. You add up all the distances (changes) it undergoes and add them together, disregarding negatives.

### Re: Equation for a non-state property?

Posted: Wed Jan 10, 2018 11:03 pm
The sum of the two non-state properties, work and heat, creates an equation that is a state property. Each of the two is dependent on the process of achieving the final from the initial, making the result not constant.

### Re: Equation for a non-state property?

Posted: Thu Jan 11, 2018 12:29 am
I think Wilson Yeh wants to know of there is a standard equation that can be applied to situations involving heat or other not state properties that we will have to know? or is the value subjective depending on the situation?

### Re: Equation for a non-state property?

Posted: Thu Jan 11, 2018 2:16 am
For expansion work under constant external pressure, you can use the eq. w = -Pexternal * deltaV to calculate the work done by the system. There's also a table somewhere in the beginning of Chapter 8, which if I remember correctly, lists various types of work.

As for heat, when pressure is constant, q = delta H