Constant Pressure and Volume

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Sophia Dinh 1D
Posts: 100
Joined: Thu Jul 25, 2019 12:15 am

Constant Pressure and Volume

Postby Sophia Dinh 1D » Fri Feb 14, 2020 1:35 pm

what is the difference in calculation of a constant pressure system vs a constant volume system?

AronCainBayot2K
Posts: 101
Joined: Fri Aug 30, 2019 12:17 am

Re: Constant Pressure and Volume

Postby AronCainBayot2K » Fri Feb 14, 2020 2:21 pm

Cp=DeltaH/Delta T and Cv=DeltaU/Delta T. Calculations can also vary depending on if the atom is monoatomic, linear, etc this is when dealing with Cv,m and Cp,m.

Abhi Vempati 2H
Posts: 104
Joined: Fri Aug 09, 2019 12:17 am

Re: Constant Pressure and Volume

Postby Abhi Vempati 2H » Sat Feb 15, 2020 12:08 am

Adding on to what was said above, in constant pressure systems, we typically have to account for expansion work, but in constant volume systems, we don't (the gas can't expand if there's no volume change). Hope this helps!

Betania Hernandez 2E
Posts: 107
Joined: Fri Aug 02, 2019 12:15 am

Re: Constant Pressure and Volume

Postby Betania Hernandez 2E » Sun Feb 16, 2020 2:50 pm

Calculations vary for monoatomic gases since Cv is 3R/2 under constant volume and Cp is 5R/2 under constant pressure.

Alondra
Posts: 36
Joined: Tue Feb 26, 2019 12:15 am

Re: Constant Pressure and Volume

Postby Alondra » Sun Feb 16, 2020 7:46 pm

Constant pressure: for monatomic it’s 5R/2; for diatomic it’s 7R/2


Constant volume: for monatomic it’s 3R/2; for diatomic it’s 5R/2

Areli C 1L
Posts: 95
Joined: Wed Nov 14, 2018 12:19 am

Re: Constant Pressure and Volume

Postby Areli C 1L » Sun Feb 16, 2020 7:51 pm

Alondra wrote:Constant pressure: for monatomic it’s 5R/2; for diatomic it’s 7R/2


Constant volume: for monatomic it’s 3R/2; for diatomic it’s 5R/2


I addition to this, Organic Chemistry tutor has an entire video dedicated to this topic.

Nathan Rothschild_2D
Posts: 131
Joined: Fri Aug 02, 2019 12:15 am

Re: Constant Pressure and Volume

Postby Nathan Rothschild_2D » Sun Feb 16, 2020 9:53 pm

Why is the calculation for monatomic atoms lower than that of diatomic atoms.


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