## q rev

$\Delta S = \frac{q_{rev}}{T}$

connie 2C
Posts: 106
Joined: Thu Jul 11, 2019 12:17 am

### q rev

how do you know when the system is reversible?

sbeall_1C
Posts: 109
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### Re: q rev

A system undergoes reversible expansion when the change is made with infinitesimal changes to pressure. In a irreversible expansion, the change cannot be undone, and the reaction proceeds with a constant external pressure.

Juliet Stephenson 4E
Posts: 100
Joined: Wed Sep 18, 2019 12:21 am

### Re: q rev

A process is reversible if the system maintains thermodynamic equilibrium with its surroundings throughout the whole process. Reversible processes are less common than irreversible processes, and a perfectly reversible process is not possible.

Amy Xiao 1I
Posts: 101
Joined: Sat Jul 20, 2019 12:15 am

### Re: q rev

In terms of homework or test problems, they will most likely tell you explicitly that the system is being changed reversibly.

Eugene Chung 3F
Posts: 142
Joined: Wed Nov 15, 2017 3:03 am

### Re: q rev

In reality, all natural (real) processes are irreversible because biochemical systems often use highly irreversible rxns to speed up processes. Also, all spontaneous processes are irreversible. (like hot going to cold) Reversible reactions are the "ideal" and "perfect" system. (ex in class: perfect heat engine) and all heat can be converted to work. To answer your question then, the question should explicitly say that the reaction is reversible. This normally is worded with isothermal, meaning constant T, because T is constant along the pathway for reversible reactions.