Expansion work


Moderators: Chem_Mod, Chem_Admin

Posts: 24
Joined: Fri Sep 25, 2015 3:00 am

Expansion work

Postby JukaKim_1D » Fri Jan 22, 2016 2:51 pm

What does it mean when problems state no expansion work? does that mean that the volume doesn't change? how else would it do work if the volume does not change?

Posts: 37
Joined: Fri Sep 25, 2015 3:00 am

Re: Expansion work

Postby Johnchou1A » Fri Jan 22, 2016 3:12 pm

When it states "no expansion work," deltaV is 0. When deltaV is 0, it means that there is no work done, and that the only change in internal energy will be due to heat. Thus, deltaU = q

Darlene Fung 1J
Posts: 20
Joined: Fri Sep 25, 2015 3:00 am

Re: Expansion work

Postby Darlene Fung 1J » Fri Jan 22, 2016 4:36 pm

Yes it means that the volume doesn't change. Instead, work is done by heat.

Posts: 26
Joined: Fri Sep 25, 2015 3:00 am

Re: Expansion work

Postby amyjunus1A » Tue Jan 26, 2016 9:01 am

To make it even easier to understand, keep in mind that work can be converted to heat, and (although not all may be transferred) thus heat can be converted to work! Thus no change in volume (even though its the most common way to make work) is necessary for work. Hopefully this helps a little.

Posts: 19497
Joined: Thu Aug 04, 2011 1:53 pm
Has upvoted: 878 times

Re: Expansion work

Postby Chem_Mod » Tue Jan 26, 2016 1:12 pm

Besides mechanical work (by expansion), there are also chemical and electrical work. Heat is a kind of energy, it is not work. It can be converted to work by expanding the system. In this case it simply means there is no mechanical work which means no volume change.

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

Who is online

Users browsing this forum: No registered users and 1 guest