Temperature Changes Along Irreversible Pathway

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Tiffany Chao 2H
Posts: 117
Joined: Fri Aug 09, 2019 12:17 am

Temperature Changes Along Irreversible Pathway

Postby Tiffany Chao 2H » Mon Feb 10, 2020 2:39 am

Why does temperature change along an irreversible pathway? Why does it decrease then increase?

Thanks

Elizabeth Bowen 1J
Posts: 53
Joined: Wed Nov 14, 2018 12:20 am

Re: Temperature Changes Along Irreversible Pathway

Postby Elizabeth Bowen 1J » Mon Feb 10, 2020 2:48 am

Because, if you reference the graphs that lavelle gave us for reversible vs non reversible pathways, you can see that in irreversible pathways, the reaction follows two straight steps, rather than a curve. Since the two steps are straight, one is at constant volume, and the other is at constant pressure, meaning that temperature must decrease and then increase, since the reaction isn't at equilibrium at all times like in the reversible pathway. This makes sense given the ideal gas law PV=nRT--> you can see that the temperature must decrease then increase if a reaction follows an irreversible pathway but the initial and final temperatures are the same. Since T=PV/nR,you can see how the temperature would change along an irreversible pathway by looking at the graph and seeing how when pressure is constant, volume changes, and vice versa.

Tiffany Chao 2H
Posts: 117
Joined: Fri Aug 09, 2019 12:17 am

Re: Temperature Changes Along Irreversible Pathway

Postby Tiffany Chao 2H » Wed Feb 12, 2020 12:00 pm

Makes sense! Thank you!

Robert Tran 1B
Posts: 118
Joined: Thu Jul 11, 2019 12:15 am

Re: Temperature Changes Along Irreversible Pathway

Postby Robert Tran 1B » Wed Feb 12, 2020 1:03 pm

During a reversible expansion, the change in volume is slow enough that the temperature can stay constant. However, in an irreversible change, the process occurs too quickly to keep the temperature constant.


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