Constant Pressure/Volume

[Layal Suboh 1I]

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]

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]

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]

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]

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

[Cameron_Greenberg_3C]

"Open beaker" implies constant pressure of 1 atm.

[Fionna Shue 4L]

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