Internal Energy

isochoric/isometric:
isothermal:
isobaric:

Moderators: Chem_Mod, Chem_Admin

Kyra Dingle 1B
Posts: 55
Joined: Fri Sep 29, 2017 7:04 am

Internal Energy

Postby Kyra Dingle 1B » Thu Jan 18, 2018 1:48 pm

What is the difference between internal energy and enthalpy?

Sabrina Dunbar 1I
Posts: 57
Joined: Fri Sep 29, 2017 7:07 am
Been upvoted: 1 time

Re: Internal Energy

Postby Sabrina Dunbar 1I » Thu Jan 18, 2018 2:19 pm

Enthalpy is the amount of heat released or absorbed at constant pressure and it is written as H. When this H is changed between the products and the reactants in a chemical equation it becomes ∆H, meaning it is the change in enthalpy. This differs from the internal energy of the system greatly. The internal energy of a system is the sum of the work done on the system as well as the heat present in the system. The amount of heat gained or released by a substance at constant pressure (qp) is the same as ∆H, again meaning the change in enthalpy. This is how these two values, enthalpy and internal energy relate. ∆U=qp+w

Hammad Khan 2B
Posts: 51
Joined: Fri Sep 29, 2017 7:07 am
Been upvoted: 1 time

Re: Internal Energy

Postby Hammad Khan 2B » Fri Jan 19, 2018 6:15 am

Internal energy is the energy of the whole system work + enthalpy. While enthaply is just heat released or absorbed, a part of internal energy.

Katie Lam 1B
Posts: 52
Joined: Fri Sep 29, 2017 7:06 am

Re: Internal Energy

Postby Katie Lam 1B » Fri Jan 19, 2018 1:37 pm

However, when no expansion work is done, the change in internal energy is equal to the change in enthalpy.

Yutian Zhao -1J
Posts: 30
Joined: Fri Sep 29, 2017 7:05 am

Re: Internal Energy

Postby Yutian Zhao -1J » Sat Jan 20, 2018 1:12 pm

According to U=q+w, under constant pressure (deltaH=q),U=delta H+w. With that being said, the internal energy equals sum of enthalpy change and the work done by/on the system.


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

Who is online

Users browsing this forum: No registered users and 1 guest