isothermal = no internal energy change

isochoric/isometric:
isothermal:
isobaric:

Moderators: Chem_Mod, Chem_Admin

Kyung_Jin_Kim_1H
Posts: 53
Joined: Thu Jul 27, 2017 3:00 am

isothermal = no internal energy change

Postby Kyung_Jin_Kim_1H » Sat Mar 17, 2018 4:22 pm

If there is no change in temperature/system is isothermal, does it imply no change in internal energy? Since deltaU=q+w and q=mCdeltaT, I get that q=0 if change in temperature is 0. I don't understand how w=0 as well though.

Rachel Brown 3A
Posts: 52
Joined: Fri Sep 29, 2017 7:06 am

Re: isothermal = no internal energy change

Postby Rachel Brown 3A » Sat Mar 17, 2018 4:43 pm

for isothermal reactions, delta U = 0 which means that q=-w. however, it does not necessarily mean that q=0. Even though temperature is the same, heat can and will still be transferred to counter the work being done so that the internal energy remains at 0. q is only 0 is the system is "adiabatic." Hope this helps!

Helen Shi 1J
Posts: 78
Joined: Sat Jul 22, 2017 3:00 am

Re: isothermal = no internal energy change

Postby Helen Shi 1J » Sun Mar 18, 2018 9:37 am

Is delta U zero for all reversible reactions or just isothermal?

Kevin Ru 1D
Posts: 50
Joined: Thu Jul 13, 2017 3:00 am

Re: isothermal = no internal energy change

Postby Kevin Ru 1D » Sun Mar 18, 2018 2:29 pm

I believe it applies to just isothermal reactions.

Justin Lai 1C
Posts: 50
Joined: Fri Sep 29, 2017 7:04 am

Re: isothermal = no internal energy change

Postby Justin Lai 1C » Sun Mar 18, 2018 2:38 pm

Only isothermal reactions have u = 0 so q = -w. T being 0 does not always mean that q = 0. Isothermal reaction is when T = 0. This is because as work may be done by or done on the system, there is a supply or removal of heat from the system so that T = 0 and that the internal energy of the system remains constant.

Adiabatic is when q = 0. Here T does not equal 0. This means that there is a change in internal energy.


Return to “Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)”

Who is online

Users browsing this forum: No registered users and 1 guest