## reversible vs irreversible work

Moderators: Chem_Mod, Chem_Admin

Deja Nora
Posts: 11
Joined: Fri Sep 28, 2018 12:22 am

### reversible vs irreversible work

I am a little confused on how you can tell whether a system is reversible or not?

Rachel Yu 1G
Posts: 113
Joined: Fri Aug 09, 2019 12:15 am

### Re: reversible vs irreversible work

A system is reversible if the reactants can form the products AND the products can form the reactants. I think usually it will be given whether in the prompt if a reaction is reversible or not. However, there are some cases where you know if the reaction was reversible. An example of a reversible reaction would be a piston a compressed gas can expand to its original state if the piston is free to move. If the piston is not free to move (something blocks the piston) then it would be an irreversible reaction. My TA also said that another example of irreversible reactions are combustion reactions.

ELu 1J
Posts: 51
Joined: Thu Jul 25, 2019 12:16 am

### Re: reversible vs irreversible work

A reversible system is usually one where the reactants and products fluctuate slowly to reach equilibrium.

Caroline Beecher 2H
Posts: 51
Joined: Wed Nov 14, 2018 12:21 am

### Re: reversible vs irreversible work

Also, reversible systems use infinitesimal steps to calculate change of variables. These small steps make it possible for it to be reversible, as it will always be close to equilibrium.

205291012
Posts: 50
Joined: Mon Nov 11, 2019 12:17 am

### Re: reversible vs irreversible work

in thermodynamics, the external pressure is not constant for a reversible process. Here, internal pressure is equal to the external pressure. If you increase the external pressure by a very small amount, the piston will compress. Reversible process always does more work and the change is gradual and slow.

for an irreversible process, the external pressure is constant. Small changes in external pressure will not cause the system to do work. The work done in an irreversible process is always less than the work done in a reversible process. And the change is sudden not gradual.

Return to “Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)”

### Who is online

Users browsing this forum: No registered users and 2 guests