Constant Pressure/Volume

Moderators: Chem_Mod, Chem_Admin

Layal Suboh 1I
Posts: 61
Joined: Fri Sep 28, 2018 12:23 am

Constant Pressure/Volume

Postby Layal Suboh 1I » Wed Feb 06, 2019 4:56 pm

Hello,

Dr. Lavelle went over a question in class last week that said "an exothermic reaction occurs an open beaker producing a net 8 moles of gas at 25 C. What is the change in internal energy?"

How do we know that this reaction is occurring under conditions of constant pressure?

Thanks!

ariana_apopei1K
Posts: 89
Joined: Fri Sep 28, 2018 12:27 am
Been upvoted: 1 time

Re: Constant Pressure/Volume

Postby ariana_apopei1K » Wed Feb 06, 2019 8:12 pm

Hi, I just checked my notes and i wrote "assume P=1 atm, use PV=nRT), meaning the pressure is constant at 1 atm. Maybe he only said this verbally or something and it wasn't on the slides and you might have missed it? I hope this helps!

Kelsey Warren 1I
Posts: 60
Joined: Fri Sep 28, 2018 12:15 am

Re: Constant Pressure/Volume

Postby Kelsey Warren 1I » Wed Feb 06, 2019 8:14 pm

Also, the pressure has to be constant in an open beaker because the pressure in the beaker would equal the atmospheric pressure, which is constant.

Henry Dudley 1G
Posts: 61
Joined: Fri Sep 28, 2018 12:16 am

Re: Constant Pressure/Volume

Postby Henry Dudley 1G » Sat Feb 09, 2019 2:51 pm

If the pressure is not stated, it is assumed to be 1 atm. So in this case, it is assumed that the pressure is constant at 1 atm.

Abby-Hile-1F
Posts: 46
Joined: Fri Sep 28, 2018 12:16 am

Re: Constant Pressure/Volume

Postby Abby-Hile-1F » Sun Feb 10, 2019 4:13 pm

So if pressure is not given, can we assume that it will remain constant at 1 atm?

Cameron_Greenberg_3C
Posts: 60
Joined: Fri Sep 28, 2018 12:26 am

Re: Constant Pressure/Volume

Postby Cameron_Greenberg_3C » Sat Feb 16, 2019 4:40 pm

"Open beaker" implies constant pressure of 1 atm.

Fionna Shue 4L
Posts: 59
Joined: Fri Sep 28, 2018 12:18 am

Re: Constant Pressure/Volume

Postby Fionna Shue 4L » Wed Feb 20, 2019 6:03 pm

If the reaction is taking place in an open beaker, pressure will be constant


Return to “Thermodynamic Systems (Open, Closed, Isolated)”

Who is online

Users browsing this forum: No registered users and 0 guests