Which process does more work?


and

Moderators: Chem_Mod, Chem_Admin

Eliza_Beglari_2L
Posts: 20
Joined: Sat Jul 09, 2016 3:00 am
Been upvoted: 1 time

Which process does more work?

Postby Eliza_Beglari_2L » Fri Feb 10, 2017 9:44 pm

From Chapter 8 Number 11:
A piston confines 0.200 mol Ne(g) in 1.20 L at 25 degrees C. Two experiments are performed. (a) The gas is allowed to expand through an additional 1.20 L against a constant pressure of 1.00 atm (b) The gas is allowed to expand reversibly and isothermally to the same final volume. Which process does more work?

How do you know which equation to use to compare the two processes?

Jeffrey_Huang_2K
Posts: 11
Joined: Fri Jul 22, 2016 3:00 am

Re: Which process does more work?

Postby Jeffrey_Huang_2K » Fri Feb 10, 2017 10:23 pm

You'll want to calculate the work done by each pathway.
Path A is done at constant pressure so use W=-P*DeltaV (irreversible pathway)
Path B is reversible expansion so use W=-nrT*ln(V2/V1) (reversible pathway)

Timothy_Yu_Dis3A
Posts: 11
Joined: Wed Sep 21, 2016 2:58 pm
Been upvoted: 1 time

Re: Which process does more work?

Postby Timothy_Yu_Dis3A » Sat Feb 11, 2017 12:07 am

The work calculated for a reversible and isothermal pathway is the maximum work possible, therefore it is always a higher value as compared to the work calculated for an irreversible pathway. Real life processes are irreversible, as not all heat is converted to work.

edward_qiao_3I
Posts: 27
Joined: Tue Oct 04, 2016 3:02 am
Been upvoted: 1 time

Re: Which process does more work?

Postby edward_qiao_3I » Sat Feb 11, 2017 4:53 pm

So when a question is asking you to consider the difference between reversible or irreversible processes, how can you tell the difference?

AKatukota
Posts: 100
Joined: Thu Jul 25, 2019 12:18 am

Re: Which process does more work?

Postby AKatukota » Thu Jan 30, 2020 10:12 pm

So for the first one, why does the volume remain 1.20L?

Connie Chen 1E
Posts: 51
Joined: Mon Jun 17, 2019 7:24 am

Re: Which process does more work?

Postby Connie Chen 1E » Fri Jan 31, 2020 12:47 pm

AKatukota wrote:So for the first one, why does the volume remain 1.20L?

The volume doesn't remain 1.20L, it expands an additional 1.20L.


Return to “Calculating Work of Expansion”

Who is online

Users browsing this forum: No registered users and 4 guests