Reversible an Irreversible [ENDORSED]

isochoric/isometric: $\Delta V = 0$
isothermal: $\Delta T = 0$
isobaric: $\Delta P = 0$

Megan Purl 1E
Posts: 49
Joined: Fri Sep 29, 2017 7:07 am

Reversible an Irreversible

What is the difference between a reversible and irreversible pathway? What makes a pathway reversible or irreversible, and can someone explain the meaning of the graphs of the two different pathways?

Priyanka Bhakta 1L
Posts: 50
Joined: Fri Sep 29, 2017 7:04 am

Re: Reversible an Irreversible

A reversible pathway tends to take longer because the differences in temperature or pressure between the system and its surroundings are so small that the change only occurs in small, slow increments (which is why we derived the equations used for reversible functions from an integral). Since the change is so small, the process is able to go forwards and backwards (reverse) because the change occurs in small increments and could switch directions.

An irreversible pathway is a faster, more permanent process that comes out of the differences (typically pressure) between the system and its immediate surroundings being quite large or sizable so that once the system does work and corrects itself, the process is at a point at which no more changes can be done on its own.

hope that makes sense!

Morgan Baxter 1E
Posts: 50
Joined: Thu Jul 27, 2017 3:00 am

Re: Reversible an Irreversible  [ENDORSED]

Also, more work is done in a reversible reaction. Looking at the graph of volume vs pressure for brother reversible and irreversible reactions, the area under the curve (aka the integral) is work. It makes sense that more work is done in a reversible reaction because the area under the curve is visibly larger.

Timothy Kim 1B
Posts: 62
Joined: Fri Sep 29, 2017 7:04 am

Re: Reversible an Irreversible

In edition to a reversible reaction being more efficient (more useful work done), a reversible has a constant Temperature and Volume and Pressure are inversely related.

An irreversible pathway has a changing temperature and work is done against a constant external pressure.

Magdalena Palavecino 1A
Posts: 54
Joined: Fri Sep 29, 2017 7:04 am

Re: Reversible an Irreversible

Is it correct to think that in a reversible expansion, the deltaStotal would be zero, and that in an irreversible expansion the deltaSsurrounding would be zero?